fix: patch flaws and refactor routes

Signed-off-by: skidoodle <contact@albert.lol>

.gitignore

@@ -1,3 +1,2 @@
 storage/*
-# Added by goreleaser init:
 dist/

.goreleaser.yaml

@@ -4,6 +4,9 @@ before:
   hooks:
     - go mod tidy
 
+snapshot:
+  version_template: "{{ .Version }}"
+
 builds:
   - env:
       - CGO_ENABLED=0
@@ -13,7 +16,8 @@ builds:
       - amd64
       - arm64
     ldflags:
-      - -s -w -X main.version={{.Version}} -X main.commit={{.Commit}} -X main.date={{.Date}}
+      - -s -w
+      - -X github.com/skidoodle/safebin/internal/app.Version={{.Version}}
     flags:
       - -trimpath
 
@@ -26,7 +30,6 @@ archives:
       {{- else }}{{ .Arch }}{{ end }}
     formats: ["tar.gz"]
     files:
-      - web/**/*
       - README.md
 
 dockers:
@@ -37,8 +40,6 @@ dockers:
     goos: linux
     goarch: amd64
     dockerfile: Dockerfile.release
-    extra_files:
-      - web
     build_flag_templates:
       - "--platform=linux/amd64"
       - "--label=org.opencontainers.image.title={{ .ProjectName }}"
@@ -51,8 +52,6 @@ dockers:
     goos: linux
     goarch: arm64
     dockerfile: Dockerfile.release
-    extra_files:
-      - web
     build_flag_templates:
       - "--platform=linux/arm64"
       - "--label=org.opencontainers.image.title={{ .ProjectName }}"

Dockerfile

@@ -1,39 +1,42 @@
-FROM --platform=$BUILDPLATFORM golang:1.25.5 AS builder
+FROM --platform=$BUILDPLATFORM golang:1.25.6-alpine AS builder
+WORKDIR /src
 
-WORKDIR /app
+COPY go.mod go.sum ./
+RUN go mod download
 
 COPY . .
 
 ARG TARGETOS
 ARG TARGETARCH
+ARG VERSION=dev
 
 RUN --mount=type=cache,target=/root/.cache/go-build \
     CGO_ENABLED=0 GOOS=$TARGETOS GOARCH=$TARGETARCH go build \
-    -ldflags="-s -w" \
+    -ldflags="-s -w -X github.com/skidoodle/safebin/internal/app.Version=$VERSION" \
     -trimpath \
-    -o /app/safebin .
+    -o /bin/safebin .
 
-FROM debian:trixie-slim
+FROM alpine:latest AS sys-context
+RUN apk add --no-cache ca-certificates mailcap
+RUN echo "appuser:x:10001:10001:appuser:/:/sbin/nologin" > /etc/passwd_app \
+    && echo "appuser:x:10001:appuser" > /etc/group_app
+RUN mkdir -p /app/storage
 
-LABEL org.opencontainers.image.source="https://github.com/skidoodle/safebin"
-LABEL org.opencontainers.image.description="Minimalist, self-hosted file storage with Zero-Knowledge at Rest encryption."
-LABEL org.opencontainers.image.licenses="GPL-2.0-only"
+FROM scratch
+COPY --from=sys-context /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+COPY --from=sys-context /etc/mime.types /etc/mime.types
+COPY --from=sys-context /etc/passwd_app /etc/passwd
+COPY --from=sys-context /etc/group_app /etc/group
+COPY --from=builder /bin/safebin /app/safebin
+COPY --from=sys-context --chown=10001:10001 /app/storage /app/storage
 
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    ca-certificates \
-    media-types \
-    && rm -rf /var/lib/apt/lists/*
-
-RUN useradd -m -u 10001 -s /bin/bash appuser
 WORKDIR /app
-
-COPY --from=builder /app/safebin .
-COPY --from=builder /app/web ./web
-
-RUN mkdir -p /app/storage && chown 10001:10001 /app/storage
-VOLUME ["/app/storage"]
-
 USER 10001
+VOLUME ["/app/storage"]
 EXPOSE 8080
 
+ENV SAFEBIN_HOST=0.0.0.0 \
+    SAFEBIN_PORT=8080 \
+    SAFEBIN_STORAGE=/app/storage
+
 ENTRYPOINT ["/app/safebin"]

Dockerfile.release

@@ -1,20 +1,25 @@
-FROM debian:trixie-slim
+FROM alpine:latest AS sys-context
+RUN apk add --no-cache ca-certificates mailcap
+RUN echo "appuser:x:10001:10001:appuser:/:/sbin/nologin" > /etc/passwd_app \
+    && echo "appuser:x:10001:appuser" > /etc/group_app
+RUN mkdir -p /app/storage
 
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    ca-certificates \
-    media-types \
-    && rm -rf /var/lib/apt/lists/*
+FROM scratch
+COPY --from=sys-context /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+COPY --from=sys-context /etc/mime.types /etc/mime.types
+COPY --from=sys-context /etc/passwd_app /etc/passwd
+COPY --from=sys-context /etc/group_app /etc/group
+
+COPY safebin /app/safebin
+COPY --from=sys-context --chown=10001:10001 /app/storage /app/storage
 
-RUN useradd -m -u 10001 -s /bin/bash appuser
 WORKDIR /app
-
-COPY safebin .
-COPY web ./web
-
-RUN mkdir -p /app/storage && chown 10001:10001 /app/storage
-VOLUME ["/app/storage"]
-
 USER 10001
+VOLUME ["/app/storage"]
 EXPOSE 8080
 
+ENV SAFEBIN_HOST=0.0.0.0 \
+    SAFEBIN_PORT=8080 \
+    SAFEBIN_STORAGE=/app/storage
+
 ENTRYPOINT ["/app/safebin"]

README.md

@@ -1,45 +1,36 @@
 # safebin
 
-`safebin` is a minimalist, self-hosted file storage service with **Zero-Knowledge at Rest** encryption.
+[![Go Version](https://img.shields.io/badge/Go-1.25+-00ADD8?style=flat-square&logo=go)](https://go.dev/)
+[![License](https://img.shields.io/badge/License-GPLv2-blue.svg?style=flat-square)](LICENSE)
+[![Docker Image](https://img.shields.io/badge/Docker-ghcr.io%2Fskidoodle%2Fsafebin-blue?style=flat-square&logo=docker)](https://github.com/skidoodle/safebin/pkgs/container/safebin)
 
-## Features
+**safebin** is a minimalist, self-hosted file storage service designed for efficiency and privacy. It utilizes **Convergent Encryption** to provide secure storage at rest while automatically deduplicating identical files to save disk space.
 
-- **End-to-End Encryption**: Files are encrypted using AES-128-GCM before being written to disk.
-- **Key-Derived URLs**: The decryption key is part of the URL. The server uses this key to locate and decrypt the file on the fly.
-- **Integrity**: Uses GCM (Galois/Counter Mode) to ensure files cannot be tampered with while stored.
-- **Storage Deduplication**: Identical files result in the same ID, saving disk space.
-- **Chunked Uploads**: Supports large file uploads via the web interface using 8MB chunks.
+## 📖 Architecture & Security Model
 
-## Usage
+Safebin is designed to be **Host-Proof at Rest**. While it is not a client-side E2EE solution, it ensures that the server cannot access stored data without the specific link generated at upload time.
 
-### Web Interface
-Simply drag and drop files into the browser. The interface handles chunking and provides a shareable link once the upload is finalized.
+### How it Works
+1.  **Upload**: The server receives the file stream and calculates a SHA-256 hash of the content.
+2.  **Key Generation**: This hash becomes the encryption key (Convergent Encryption).
+3.  **Encryption**: The file is encrypted using **AES-128-GCM** and written to disk.
+4.  **Deduplication**: Because the key is derived from the content, identical files generate the same ID. The server detects this and stores only one physical copy, regardless of how many times it is uploaded.
+5.  **Zero-Knowledge Storage**: The server saves the file metadata (ID, size, expiry) but **discards the encryption key**.
+6.  **Link Generation**: The key is encoded into the URL fragment returned to the user.
 
-### Command Line (CLI)
-You can upload files directly using `curl`:
+> **Security Note**: If the server's database or physical storage is seized, the files are mathematically inaccessible. However, because encryption occurs on the server, the process does have access to the plaintext in memory during the brief window of upload and download.
 
-```bash
-curl -F 'file=@photo.jpg' https://bin.example.com
-```
+## ✨ Features
 
-The server will return a direct link:
-`https://bin.example.com/0iEZGtW-ikVdu...jpg`
+-   **Convergent Encryption & Deduplication**: Files are addressed by their content. Uploading the same file twice results in a single storage entry, significantly reducing disk usage.
+-   **Tamper-Proof Storage**: Uses Galois/Counter Mode (GCM) to ensure data integrity. Modified files will fail decryption.
+-   **Volatile Keys**: Decryption keys reside only in the generated URLs, not in the database.
+-   **Smart Retention**: A cubic scaling algorithm prioritizes keeping small files (snippets, logs) for a long time, while large binaries expire quickly.
+-   **Chunked Uploads**: Robust handling of large files via the web interface using 8MB chunks.
 
-## Configuration
+## 🚀 Deployment
 
-`safebin` can be configured via environment variables or command-line flags:
-
-| Flag | Environment Variable | Description | Default |
-| :--- | :--- | :--- | :--- |
-| `-h` | `SAFEBIN_HOST` | Bind address for the server. | `0.0.0.0` |
-| `-p` | `SAFEBIN_PORT` | Port to listen on. | `8080` |
-| `-s` | `SAFEBIN_STORAGE` | Directory for encrypted storage. | `./storage` |
-| `-m` | `SAFEBIN_MAX_MB` | Maximum file size in MB. | `512` |
-
-## Deployment
-
-### Docker Compose
-The easiest way to deploy is using the provided `compose.yaml`:
+### Docker Compose (Recommended)
 
 ```yaml
 services:
@@ -48,35 +39,64 @@ services:
     container_name: safebin
     restart: unless-stopped
     ports:
-      - 8080:8080
+      - "8080:8080"
     environment:
-      - SAFEBIN_HOST=0.0.0.0
-      - SAFEBIN_PORT=8080
-      - SAFEBIN_STORAGE=/app/storage
       - SAFEBIN_MAX_MB=512
     volumes:
-      - data:/app/storage
+      - safebin_data:/app/storage
 
 volumes:
-  data:
+  safebin_data:
 ```
 
-### Manual Build
+### Manual Installation
+
 Requires Go 1.25 or higher.
 
 ```bash
+# Build the binary
 go build -o safebin .
-./safebin -p 8080 -s ./data
+
+# Run the server
+./safebin -p 8080 -s ./data -m 1024
 ```
 
-## Retention Policy
+## ⚙️ Configuration
 
-The server runs a background cleanup task every hour. Retention is calculated using a cubic scaling formula to prioritize small files:
+Configuration is handled via environment variables or command-line flags. Flags take precedence over environment variables.
 
-- **Small files (e.g., < 1MB)**: Kept for up to **365 days**.
-- **Large files (at Max MB)**: Kept for **24 hours**.
-- **Temporary Uploads**: Unfinished chunked uploads are purged after **4 hours**.
+| Flag | Environment Variable | Description | Default |
+| :--- | :--- | :--- | :--- |
+| `-h` | `SAFEBIN_HOST` | Interface/Bind address. | `0.0.0.0` |
+| `-p` | `SAFEBIN_PORT` | Port to listen on. | `8080` |
+| `-s` | `SAFEBIN_STORAGE` | Directory for database and files. | `./storage` |
+| `-m` | `SAFEBIN_MAX_MB` | Maximum allowed file size in MB. | `512` |
 
-## License
+## 💻 Usage
 
-This project is licensed under the **GNU General Public License v2.0**.
+### Web Interface
+Navigate to `http://localhost:8080`. Drag and drop files to upload. The browser handles chunking automatically.
+
+### CLI (curl)
+Safebin is optimized for terminal usage. You can upload files directly via `curl`:
+
+```bash
+# Upload a file
+curl -F 'file=@screenshot.png' https://bin.example.com
+
+# Response
+https://bin.example.com/0iEZGtW-ikVdu...png
+```
+
+## ⏳ Retention Policy
+
+To keep storage manageable, Safebin runs a cleanup task every hour. File lifetime is determined by size using a cubic curve:
+
+*   **Small Files (< 1MB)**: Retained for **365 days**.
+*   **Medium Files (~50% Max Size)**: Retained for ~30 days.
+*   **Large Files (Max Size)**: Retained for **24 hours**.
+*   **Incomplete Uploads**: Purged after **4 hours**.
+
+## 📄 License
+
+This project is licensed under the [GNU General Public License v2.0](LICENSE).

go.mod

@@ -1,3 +1,7 @@
 module github.com/skidoodle/safebin
 
-go 1.25.5
+go 1.25.6
+
+require go.etcd.io/bbolt v1.4.3
+
+require golang.org/x/sys v0.40.0 // indirect

go.sum

@@ -0,0 +1,14 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+go.etcd.io/bbolt v1.4.3 h1:dEadXpI6G79deX5prL3QRNP6JB8UxVkqo4UPnHaNXJo=
+go.etcd.io/bbolt v1.4.3/go.mod h1:tKQlpPaYCVFctUIgFKFnAlvbmB3tpy1vkTnDWohtc0E=
+golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
+golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=
+golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/app/config.go

@@ -4,9 +4,47 @@ import (
 	"flag"
 	"fmt"
 	"html/template"
+	"io/fs"
 	"log/slog"
 	"os"
 	"strconv"
+	"time"
+
+	"go.etcd.io/bbolt"
+)
+
+var (
+	Version = "dev"
+)
+
+const (
+	DefaultHost     = "0.0.0.0"
+	DefaultPort     = 8080
+	DefaultStorage  = "./storage"
+	DefaultMaxMB    = 512
+	ServerTimeout   = 10 * time.Minute
+	ShutdownTimeout = 10 * time.Second
+
+	UploadChunkSize    = 8 << 20
+	MinChunkSize       = 1 << 20
+	MaxRequestOverhead = 10 << 20
+	PermUserRWX        = 0o700
+	MegaByte           = 1 << 20
+	ChunkSafetyMargin  = 2
+
+	SlugLength = 22
+	KeyLength  = 16
+
+	CleanupInterval = 1 * time.Hour
+	TempExpiry      = 4 * time.Hour
+	MinRetention    = 24 * time.Hour
+	MaxRetention    = 365 * 24 * time.Hour
+
+	DBDirName         = "db"
+	DBFileName        = "safebin.db"
+	DBBucketName      = "files"
+	DBBucketIndexName = "expiry_index"
+	TempDirName       = "tmp"
 )
 
 type Config struct {
@@ -19,40 +57,51 @@ type App struct {
 	Conf   Config
 	Tmpl   *template.Template
 	Logger *slog.Logger
+	DB     *bbolt.DB
+	Assets fs.FS
 }
 
 func LoadConfig() Config {
-	h := getEnv("SAFEBIN_HOST", "0.0.0.0")
-	p := getEnvInt("SAFEBIN_PORT", 8080)
-	s := getEnv("SAFEBIN_STORAGE", "./storage")
-	mDefault := int64(getEnvInt("SAFEBIN_MAX_MB", 512))
+	hostEnv := getEnv("SAFEBIN_HOST", DefaultHost)
+	portEnv := getEnvInt("SAFEBIN_PORT", DefaultPort)
+	storageEnv := getEnv("SAFEBIN_STORAGE", DefaultStorage)
+	maxMBEnv := int64(getEnvInt("SAFEBIN_MAX_MB", DefaultMaxMB))
 
-	var m int64
-	flag.StringVar(&h, "h", h, "Bind address")
-	flag.IntVar(&p, "p", p, "Port")
-	flag.StringVar(&s, "s", s, "Storage directory")
-	flag.Int64Var(&m, "m", mDefault, "Max file size in MB")
+	var host string
+	var port int
+	var storage string
+	var maxMB int64
+
+	flag.StringVar(&host, "h", hostEnv, "Bind address")
+	flag.IntVar(&port, "p", portEnv, "Port")
+	flag.StringVar(&storage, "s", storageEnv, "Storage directory")
+	flag.Int64Var(&maxMB, "m", maxMBEnv, "Max file size in MB")
 	flag.Parse()
 
-	return Config{Addr: fmt.Sprintf("%s:%d", h, p), StorageDir: s, MaxMB: m}
+	return Config{
+		Addr:       fmt.Sprintf("%s:%d", host, port),
+		StorageDir: storage,
+		MaxMB:      maxMB,
+	}
 }
 
-func getEnv(k, f string) string {
-	if v, ok := os.LookupEnv(k); ok {
-		return v
+func getEnv(key, fallback string) string {
+	if value, ok := os.LookupEnv(key); ok {
+		return value
 	}
-	return f
+	return fallback
 }
 
-func getEnvInt(k string, f int) int {
-	if v, ok := os.LookupEnv(k); ok {
-		if i, err := strconv.Atoi(v); err == nil {
+func getEnvInt(key string, fallback int) int {
+	if value, ok := os.LookupEnv(key); ok {
+		i, err := strconv.Atoi(value)
+		if err == nil {
 			return i
 		}
 	}
-	return f
+	return fallback
 }
 
-func ParseTemplates() *template.Template {
-	return template.Must(template.ParseGlob("./web/templates/*.html"))
+func ParseTemplates(fsys fs.FS) *template.Template {
+	return template.Must(template.ParseFS(fsys, "*.html"))
 }

internal/app/config_test.go

@@ -0,0 +1,37 @@
+package app
+
+import (
+	"testing"
+)
+
+func TestGetEnv(t *testing.T) {
+	key := "SAFEBIN_TEST_KEY"
+	val := "somevalue"
+
+	if got := getEnv(key, "default"); got != "default" {
+		t.Errorf("Expected default, got %s", got)
+	}
+
+	t.Setenv(key, val)
+	if got := getEnv(key, "default"); got != val {
+		t.Errorf("Expected %s, got %s", val, got)
+	}
+}
+
+func TestGetEnvInt(t *testing.T) {
+	key := "SAFEBIN_TEST_INT"
+
+	if got := getEnvInt(key, 8080); got != 8080 {
+		t.Errorf("Expected default 8080, got %d", got)
+	}
+
+	t.Setenv(key, "9090")
+	if got := getEnvInt(key, 8080); got != 9090 {
+		t.Errorf("Expected 9090, got %d", got)
+	}
+
+	t.Setenv(key, "notanumber")
+	if got := getEnvInt(key, 8080); got != 8080 {
+		t.Errorf("Expected fallback on invalid input, got %d", got)
+	}
+}

internal/app/db.go

@@ -0,0 +1,46 @@
+package app
+
+import (
+	"os"
+	"path/filepath"
+	"time"
+
+	"go.etcd.io/bbolt"
+)
+
+type FileMeta struct {
+	ID        string    `json:"id"`
+	Size      int64     `json:"size"`
+	CreatedAt time.Time `json:"created_at"`
+	ExpiresAt time.Time `json:"expires_at"`
+}
+
+func InitDB(storageDir string) (*bbolt.DB, error) {
+	dbDir := filepath.Join(storageDir, DBDirName)
+	if err := os.MkdirAll(dbDir, PermUserRWX); err != nil {
+		return nil, err
+	}
+
+	path := filepath.Join(dbDir, DBFileName)
+	db, err := bbolt.Open(path, 0600, &bbolt.Options{Timeout: 1 * time.Second})
+	if err != nil {
+		return nil, err
+	}
+
+	err = db.Update(func(tx *bbolt.Tx) error {
+		if _, err := tx.CreateBucketIfNotExists([]byte(DBBucketName)); err != nil {
+			return err
+		}
+		if _, err := tx.CreateBucketIfNotExists([]byte(DBBucketIndexName)); err != nil {
+			return err
+		}
+		return nil
+	})
+
+	if err != nil {
+		_ = db.Close()
+		return nil, err
+	}
+
+	return db, nil
+}

internal/app/db_test.go

@@ -0,0 +1,104 @@
+package app
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"go.etcd.io/bbolt"
+)
+
+func TestInitDB(t *testing.T) {
+	tmpDir := t.TempDir()
+
+	db, err := InitDB(tmpDir)
+	if err != nil {
+		t.Fatalf("InitDB failed: %v", err)
+	}
+	defer func() {
+		if err := db.Close(); err != nil {
+			t.Errorf("Failed to close DB: %v", err)
+		}
+	}()
+
+	dbPath := filepath.Join(tmpDir, DBDirName, DBFileName)
+	if _, err := os.Stat(dbPath); os.IsNotExist(err) {
+		t.Error("Database file was not created")
+	}
+
+	err = db.View(func(tx *bbolt.Tx) error {
+		if b := tx.Bucket([]byte(DBBucketName)); b == nil {
+			t.Errorf("Bucket '%s' was not created", DBBucketName)
+		}
+		if b := tx.Bucket([]byte(DBBucketIndexName)); b == nil {
+			t.Errorf("Bucket '%s' was not created", DBBucketIndexName)
+		}
+		return nil
+	})
+	if err != nil {
+		t.Errorf("View failed: %v", err)
+	}
+}
+
+func TestDB_MetadataLifecycle(t *testing.T) {
+	tmpDir := t.TempDir()
+	db, err := InitDB(tmpDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		if err := db.Close(); err != nil {
+			t.Errorf("Failed to close DB: %v", err)
+		}
+	}()
+
+	app := &App{
+		Conf: Config{StorageDir: tmpDir, MaxMB: 100},
+		DB:   db,
+	}
+
+	fileID := "test-file-id"
+	fileSize := int64(1024)
+
+	if err := app.RegisterFile(fileID, fileSize); err != nil {
+		t.Fatalf("RegisterFile failed: %v", err)
+	}
+
+	err = db.View(func(tx *bbolt.Tx) error {
+		b := tx.Bucket([]byte(DBBucketName))
+		data := b.Get([]byte(fileID))
+		if data == nil {
+			t.Fatal("Metadata not found in DB")
+		}
+
+		var meta FileMeta
+		if err := json.Unmarshal(data, &meta); err != nil {
+			t.Fatalf("Failed to unmarshal meta: %v", err)
+		}
+
+		if meta.ID != fileID {
+			t.Errorf("Want ID %s, got %s", fileID, meta.ID)
+		}
+		if meta.Size != fileSize {
+			t.Errorf("Want Size %d, got %d", fileSize, meta.Size)
+		}
+		if meta.ExpiresAt.Before(time.Now()) {
+			t.Error("Expiration time is in the past")
+		}
+
+		bIndex := tx.Bucket([]byte(DBBucketIndexName))
+		indexKey := []byte(meta.ExpiresAt.Format(time.RFC3339) + "_" + fileID)
+		if val := bIndex.Get(indexKey); val == nil {
+			t.Error("Index entry not found")
+		} else if string(val) != fileID {
+			t.Errorf("Index value mismatch: want %s, got %s", fileID, string(val))
+		}
+
+		return nil
+	})
+	if err != nil {
+		t.Error(err)
+	}
+}

internal/app/download.go

@@ -0,0 +1,107 @@
+package app
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"mime"
+	"net/http"
+	"os"
+	"path/filepath"
+
+	"github.com/skidoodle/safebin/internal/crypto"
+	"go.etcd.io/bbolt"
+)
+
+func (app *App) HandleGetFile(writer http.ResponseWriter, request *http.Request) {
+	slug := request.PathValue("slug")
+	if len(slug) < SlugLength {
+		app.SendError(writer, request, http.StatusBadRequest)
+		return
+	}
+
+	keyBase64 := slug[:SlugLength]
+	ext := slug[SlugLength:]
+
+	key, err := base64.RawURLEncoding.DecodeString(keyBase64)
+	if err != nil || len(key) != KeyLength {
+		app.SendError(writer, request, http.StatusUnauthorized)
+		return
+	}
+
+	id := crypto.GetID(key, ext)
+
+	var meta FileMeta
+	err = app.DB.View(func(tx *bbolt.Tx) error {
+		b := tx.Bucket([]byte(DBBucketName))
+		if b == nil {
+			return fmt.Errorf("bucket not found")
+		}
+		data := b.Get([]byte(id))
+		if data == nil {
+			return fmt.Errorf("file not found")
+		}
+		return json.Unmarshal(data, &meta)
+	})
+
+	if err != nil {
+		app.SendError(writer, request, http.StatusNotFound)
+		return
+	}
+
+	path := filepath.Join(app.Conf.StorageDir, id)
+	info, err := os.Stat(path)
+	if err != nil {
+		app.SendError(writer, request, http.StatusNotFound)
+		return
+	}
+
+	if info.Size() != meta.Size {
+		app.Logger.Error("Integrity check failed: disk size mismatch",
+			"id", id,
+			"disk_bytes", info.Size(),
+			"expected_bytes", meta.Size,
+		)
+		app.SendError(writer, request, http.StatusInternalServerError)
+		return
+	}
+
+	file, err := os.Open(path)
+
+	if err != nil {
+		app.Logger.Error("Failed to open file", "path", path, "err", err)
+		app.SendError(writer, request, http.StatusInternalServerError)
+		return
+	}
+
+	defer func() {
+		if closeErr := file.Close(); closeErr != nil {
+			app.Logger.Error("Failed to close file", "err", closeErr)
+		}
+	}()
+
+	streamer, err := crypto.NewGCMStreamer(key)
+
+	if err != nil {
+		app.Logger.Error("Failed to create crypto streamer", "err", err)
+		app.SendError(writer, request, http.StatusInternalServerError)
+		return
+	}
+
+	decryptor := crypto.NewDecryptor(file, streamer.AEAD, info.Size())
+
+	contentType := mime.TypeByExtension(ext)
+	if contentType == "" {
+		contentType = "application/octet-stream"
+	}
+
+	csp := "default-src 'none'; img-src 'self' data:; media-src 'self' data:; " +
+		"style-src 'unsafe-inline'; sandbox allow-forms allow-scripts allow-downloads allow-same-origin"
+
+	writer.Header().Set("Content-Type", contentType)
+	writer.Header().Set("Content-Security-Policy", csp)
+	writer.Header().Set("X-Content-Type-Options", "nosniff")
+	writer.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename=%q", slug))
+
+	http.ServeContent(writer, request, slug, info.ModTime(), decryptor)
+}

internal/app/handlers.go

@@ -1,307 +0,0 @@
-package app
-
-import (
-	"encoding/base64"
-	"fmt"
-	"io"
-	"mime"
-	"net/http"
-	"os"
-	"path/filepath"
-	"regexp"
-	"strconv"
-
-	"github.com/skidoodle/safebin/internal/crypto"
-)
-
-var reUploadID = regexp.MustCompile(`^[a-zA-Z0-9]{10,50}$`)
-
-func (app *App) HandleHome(w http.ResponseWriter, r *http.Request) {
-	err := app.Tmpl.ExecuteTemplate(w, "base", map[string]any{
-		"MaxMB": app.Conf.MaxMB,
-		"Host":  r.Host,
-	})
-	if err != nil {
-		app.Logger.Error("Template error", "err", err)
-	}
-}
-
-func (app *App) HandleUpload(w http.ResponseWriter, r *http.Request) {
-	limit := (app.Conf.MaxMB << 20) + (1 << 20)
-	r.Body = http.MaxBytesReader(w, r.Body, limit)
-
-	file, header, err := r.FormFile("file")
-	if err != nil {
-		if err.Error() == "http: request body too large" {
-			app.SendError(w, r, http.StatusRequestEntityTooLarge)
-			return
-		}
-		app.SendError(w, r, http.StatusBadRequest)
-		return
-	}
-	defer file.Close()
-
-	tmpPath := filepath.Join(app.Conf.StorageDir, "tmp", fmt.Sprintf("up_%d", os.Getpid()))
-	tmp, err := os.Create(tmpPath)
-	if err != nil {
-		app.Logger.Error("Failed to create temp file", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-	defer os.Remove(tmpPath)
-	defer tmp.Close()
-
-	if _, err := io.Copy(tmp, file); err != nil {
-		app.Logger.Error("Failed to write temp file", "err", err)
-		app.SendError(w, r, http.StatusRequestEntityTooLarge)
-		return
-	}
-
-	app.FinalizeFile(w, r, tmp, header.Filename)
-}
-
-func (app *App) HandleChunk(w http.ResponseWriter, r *http.Request) {
-	r.Body = http.MaxBytesReader(w, r.Body, 10<<20)
-
-	uid := r.FormValue("upload_id")
-	idx, err := strconv.Atoi(r.FormValue("index"))
-	if err != nil {
-		app.SendError(w, r, http.StatusBadRequest)
-		return
-	}
-
-	const chunkSize = 8 << 20
-	maxChunks := int((app.Conf.MaxMB<<20)/chunkSize) + 2
-
-	if !reUploadID.MatchString(uid) || idx > maxChunks || idx < 0 {
-		app.SendError(w, r, http.StatusBadRequest)
-		return
-	}
-
-	file, _, err := r.FormFile("chunk")
-	if err != nil {
-		if err.Error() == "http: request body too large" {
-			app.SendError(w, r, http.StatusRequestEntityTooLarge)
-			return
-		}
-		app.SendError(w, r, http.StatusBadRequest)
-		return
-	}
-	defer file.Close()
-
-	dir := filepath.Join(app.Conf.StorageDir, "tmp", uid)
-	if err := os.MkdirAll(dir, 0700); err != nil {
-		app.Logger.Error("Failed to create chunk dir", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	dest, err := os.Create(filepath.Join(dir, strconv.Itoa(idx)))
-	if err != nil {
-		app.Logger.Error("Failed to create chunk file", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-	defer dest.Close()
-
-	if _, err := io.Copy(dest, file); err != nil {
-		app.Logger.Error("Failed to save chunk", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-}
-
-func (app *App) HandleFinish(w http.ResponseWriter, r *http.Request) {
-	uid := r.FormValue("upload_id")
-	total, err := strconv.Atoi(r.FormValue("total"))
-	if err != nil {
-		app.SendError(w, r, http.StatusBadRequest)
-		return
-	}
-
-	const chunkSize = 8 << 20
-	maxChunks := int((app.Conf.MaxMB<<20)/chunkSize) + 2
-
-	if !reUploadID.MatchString(uid) || total > maxChunks || total <= 0 {
-		app.SendError(w, r, http.StatusBadRequest)
-		return
-	}
-
-	tmpPath := filepath.Join(app.Conf.StorageDir, "tmp", "m_"+uid)
-	merged, err := os.Create(tmpPath)
-	if err != nil {
-		app.Logger.Error("Failed to create merge file", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-	defer os.Remove(tmpPath)
-	defer merged.Close()
-
-	limit := app.Conf.MaxMB << 20
-	var written int64
-
-	for i := range total {
-		partPath := filepath.Join(app.Conf.StorageDir, "tmp", uid, strconv.Itoa(i))
-		part, err := os.Open(partPath)
-		if err != nil {
-			app.Logger.Error("Missing chunk during merge", "uid", uid, "index", i, "err", err)
-			app.SendError(w, r, http.StatusBadRequest)
-			return
-		}
-
-		n, err := io.Copy(merged, part)
-		part.Close()
-		if err != nil {
-			app.Logger.Error("Failed to append chunk", "err", err)
-			app.SendError(w, r, http.StatusInternalServerError)
-			return
-		}
-
-		written += n
-		if written > limit {
-			app.SendError(w, r, http.StatusRequestEntityTooLarge)
-			return
-		}
-	}
-
-	if err := merged.Close(); err != nil {
-		app.Logger.Error("Failed to close merged file", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	mergedRead, err := os.Open(tmpPath)
-	if err != nil {
-		app.Logger.Error("Failed to open merged file", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-	defer mergedRead.Close()
-
-	app.FinalizeFile(w, r, mergedRead, r.FormValue("filename"))
-	os.RemoveAll(filepath.Join(app.Conf.StorageDir, "tmp", uid))
-}
-
-func (app *App) HandleGetFile(w http.ResponseWriter, r *http.Request) {
-	slug := r.PathValue("slug")
-	if len(slug) < 22 {
-		app.SendError(w, r, http.StatusBadRequest)
-		return
-	}
-
-	keyBase64 := slug[:22]
-	ext := slug[22:]
-
-	key, err := base64.RawURLEncoding.DecodeString(keyBase64)
-	if err != nil || len(key) != 16 {
-		app.SendError(w, r, http.StatusUnauthorized)
-		return
-	}
-
-	id := crypto.GetID(key, ext)
-	path := filepath.Join(app.Conf.StorageDir, id)
-
-	info, err := os.Stat(path)
-	if err != nil {
-		app.SendError(w, r, http.StatusNotFound)
-		return
-	}
-
-	f, err := os.Open(path)
-	if err != nil {
-		app.Logger.Error("Failed to open file", "path", path, "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-	defer f.Close()
-
-	streamer, err := crypto.NewGCMStreamer(key)
-	if err != nil {
-		app.Logger.Error("Failed to create crypto streamer", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	decryptor := crypto.NewDecryptor(f, streamer.AEAD, info.Size())
-
-	contentType := mime.TypeByExtension(ext)
-	if contentType == "" {
-		contentType = "application/octet-stream"
-	}
-
-	w.Header().Set("Content-Type", contentType)
-	w.Header().Set("Content-Security-Policy", "default-src 'none'; img-src 'self' data:; media-src 'self' data:; style-src 'unsafe-inline'; sandbox allow-forms allow-scripts allow-downloads allow-same-origin")
-	w.Header().Set("X-Content-Type-Options", "nosniff")
-	w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename=%q", slug))
-
-	http.ServeContent(w, r, slug, info.ModTime(), decryptor)
-}
-
-func (app *App) FinalizeFile(w http.ResponseWriter, r *http.Request, src *os.File, filename string) {
-	if _, err := src.Seek(0, 0); err != nil {
-		app.Logger.Error("Seek failed", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	key, err := crypto.DeriveKey(src)
-	if err != nil {
-		app.Logger.Error("Key derivation failed", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	ext := filepath.Ext(filename)
-	id := crypto.GetID(key, ext)
-
-	if _, err := src.Seek(0, 0); err != nil {
-		app.Logger.Error("Seek failed", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	finalPath := filepath.Join(app.Conf.StorageDir, id)
-
-	if _, err := os.Stat(finalPath); err == nil {
-		app.RespondWithLink(w, r, key, filename)
-		return
-	}
-
-	out, err := os.Create(finalPath + ".tmp")
-	if err != nil {
-		app.Logger.Error("Failed to create final file", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-	defer func() {
-		out.Close()
-		os.Remove(finalPath + ".tmp")
-	}()
-
-	streamer, err := crypto.NewGCMStreamer(key)
-	if err != nil {
-		app.Logger.Error("Failed to create streamer", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	if err := streamer.EncryptStream(out, src); err != nil {
-		app.Logger.Error("Encryption failed", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	if err := out.Close(); err != nil {
-		app.Logger.Error("Failed to close final file", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	if err := os.Rename(finalPath+".tmp", finalPath); err != nil {
-		app.Logger.Error("Failed to rename final file", "err", err)
-		app.SendError(w, r, http.StatusInternalServerError)
-		return
-	}
-
-	app.RespondWithLink(w, r, key, filename)
-}

internal/app/retention_test.go

@@ -0,0 +1,52 @@
+package app
+
+import (
+	"testing"
+	"time"
+)
+
+func TestCalculateRetention(t *testing.T) {
+	maxMB := int64(100)
+
+	tests := []struct {
+		name     string
+		fileSize int64
+		wantMin  time.Duration
+		wantMax  time.Duration
+	}{
+		{
+			name:     "Tiny file (Max retention)",
+			fileSize: 1024,
+			wantMin:  MaxRetention - time.Hour,
+			wantMax:  MaxRetention,
+		},
+		{
+			name:     "Max size file (Min retention)",
+			fileSize: 100 * MegaByte,
+			wantMin:  MinRetention,
+			wantMax:  MinRetention + time.Minute,
+		},
+		{
+			name:     "Half size file (Somewhere in between)",
+			fileSize: 50 * MegaByte,
+			wantMin:  24 * time.Hour,
+			wantMax:  MaxRetention,
+		},
+		{
+			name:     "Oversized file (Min retention)",
+			fileSize: 200 * MegaByte,
+			wantMin:  MinRetention,
+			wantMax:  MinRetention + time.Minute,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := CalculateRetention(tc.fileSize, maxMB)
+			if got < tc.wantMin || got > tc.wantMax {
+				t.Errorf("Retention for size %d: got %v, want between %v and %v",
+					tc.fileSize, got, tc.wantMin, tc.wantMax)
+			}
+		})
+	}
+}

internal/app/server.go

@@ -5,26 +5,62 @@ import (
 	"fmt"
 	"net/http"
 	"path/filepath"
+	"strings"
 )
 
 func (app *App) Routes() *http.ServeMux {
 	mux := http.NewServeMux()
-	fs := http.FileServer(http.Dir("./web/static"))
-	mux.Handle("GET /static/", http.StripPrefix("/static/", fs))
+
+	mux.Handle("GET /static/", http.StripPrefix("/static/", app.handleStatic()))
 	mux.HandleFunc("GET /{$}", app.HandleHome)
 	mux.HandleFunc("POST /{$}", app.HandleUpload)
 	mux.HandleFunc("POST /upload/chunk", app.HandleChunk)
 	mux.HandleFunc("POST /upload/finish", app.HandleFinish)
 	mux.HandleFunc("GET /{slug}", app.HandleGetFile)
+
 	return mux
 }
 
-func (app *App) RespondWithLink(w http.ResponseWriter, r *http.Request, key []byte, originalName string) {
+func (app *App) handleStatic() http.Handler {
+	fs := http.FileServer(http.FS(app.Assets))
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "" || strings.HasSuffix(r.URL.Path, "/") || strings.HasSuffix(r.URL.Path, ".html") {
+			http.NotFound(w, r)
+			return
+		}
+		fs.ServeHTTP(w, r)
+	})
+}
+
+func (app *App) HandleHome(writer http.ResponseWriter, request *http.Request) {
+	err := app.Tmpl.ExecuteTemplate(writer, "layout", map[string]any{
+		"MaxMB":   app.Conf.MaxMB,
+		"Host":    request.Host,
+		"Version": Version,
+	})
+
+	if err != nil {
+		app.Logger.Error("Template error", "err", err)
+	}
+}
+
+func (app *App) RespondWithLink(writer http.ResponseWriter, request *http.Request, key []byte, originalName string) {
 	keySlug := base64.RawURLEncoding.EncodeToString(key)
 	ext := filepath.Ext(originalName)
-	link := fmt.Sprintf("%s/%s%s", r.Host, keySlug, ext)
-	if r.Header.Get("X-Requested-With") == "XMLHttpRequest" {
-		fmt.Fprintf(w, `
+
+	const unsafeChars = "\"<> \\/:;?@[]^`{}|~"
+	safeExt := strings.Map(func(r rune) rune {
+		if strings.ContainsRune(unsafeChars, r) {
+			return -1
+		}
+		return r
+	}, ext)
+
+	link := fmt.Sprintf("%s/%s%s", request.Host, keySlug, safeExt)
+
+	if request.Header.Get("X-Requested-With") == "XMLHttpRequest" {
+		html := `
 			<div class="result-container">
 				<div class="dim result-label">Upload Complete:</div>
 				<div class="copy-box">
@@ -34,27 +70,44 @@ func (app *App) RespondWithLink(w http.ResponseWriter, r *http.Request, key []by
 				<div class="reset-wrapper">
 					<button class="reset-btn" onclick="resetUI()">Upload another</button>
 				</div>
-			</div>`, link)
+			</div>`
+
+		if _, err := fmt.Fprintf(writer, html, link); err != nil {
+			app.Logger.Error("Failed to write response", "err", err)
+		}
 		return
 	}
-	scheme := "https"
-	if r.TLS == nil {
+
+	scheme := request.Header.Get("X-Forwarded-Proto")
+	if scheme == "" {
+		scheme = "https"
+		if request.TLS == nil {
 			scheme = "http"
 		}
-	fmt.Fprintf(w, "%s://%s\n", scheme, link)
 	}
 
-func (app *App) SendError(w http.ResponseWriter, r *http.Request, code int) {
-	if r.Header.Get("X-Requested-With") == "XMLHttpRequest" {
-		w.WriteHeader(code)
-		fmt.Fprintf(w, `
+	if _, err := fmt.Fprintf(writer, "%s://%s\n", scheme, link); err != nil {
+		app.Logger.Error("Failed to write response", "err", err)
+	}
+}
+
+func (app *App) SendError(writer http.ResponseWriter, request *http.Request, code int) {
+	if request.Header.Get("X-Requested-With") == "XMLHttpRequest" {
+		writer.WriteHeader(code)
+
+		html := `
 			<div class="result-container">
 				<div class="error-text">Error %d</div>
 				<div class="reset-wrapper">
 					<button class="reset-btn" onclick="resetUI()">Try again</button>
 				</div>
-			</div>`, code)
+			</div>`
+
+		if _, err := fmt.Fprintf(writer, html, code); err != nil {
+			app.Logger.Error("Failed to write error response", "err", err)
+		}
 		return
 	}
-	http.Error(w, http.StatusText(code), code)
+
+	http.Error(writer, http.StatusText(code), code)
 }

internal/app/server_test.go

@@ -0,0 +1,339 @@
+package app
+
+import (
+	"bytes"
+	"encoding/base64"
+	"fmt"
+	"io"
+	"log/slog"
+	"mime/multipart"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/skidoodle/safebin/internal/crypto"
+)
+
+func setupTestApp(t *testing.T) (*App, string) {
+	storageDir := t.TempDir()
+	if err := os.MkdirAll(filepath.Join(storageDir, TempDirName), 0700); err != nil {
+		t.Fatalf("Failed to create temp dir: %v", err)
+	}
+
+	webDir := filepath.Join(storageDir, "web")
+	if err := os.MkdirAll(webDir, 0700); err != nil {
+		t.Fatalf("Failed to create web dir: %v", err)
+	}
+
+	if err := os.WriteFile(filepath.Join(webDir, "layout.html"), []byte(`{{define "layout"}}{{template "content" .}}{{end}}`), 0600); err != nil {
+		t.Fatalf("Failed to write layout.html: %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(webDir, "home.html"), []byte(`{{define "content"}}OK{{end}}`), 0600); err != nil {
+		t.Fatalf("Failed to write home.html: %v", err)
+	}
+
+	testFS := os.DirFS(webDir)
+	tmpl := ParseTemplates(testFS)
+
+	db, err := InitDB(storageDir)
+	if err != nil {
+		t.Fatalf("Failed to init db: %v", err)
+	}
+	t.Cleanup(func() {
+		if err := db.Close(); err != nil {
+			t.Errorf("Failed to close DB: %v", err)
+		}
+	})
+
+	app := &App{
+		Conf: Config{
+			StorageDir: storageDir,
+			MaxMB:      10,
+		},
+		Logger: discardLogger(),
+		Tmpl:   tmpl,
+		Assets: testFS,
+		DB:     db,
+	}
+
+	return app, storageDir
+}
+
+func discardLogger() *slog.Logger {
+	return slog.New(slog.NewTextHandler(io.Discard, nil))
+}
+
+func TestIntegration_StandardUploadAndDownload(t *testing.T) {
+	app, _ := setupTestApp(t)
+	server := httptest.NewServer(app.Routes())
+	defer server.Close()
+
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+	part, err := writer.CreateFormFile("file", "test.txt")
+	if err != nil {
+		t.Fatalf("CreateFormFile failed: %v", err)
+	}
+	content := []byte("Hello Safebin")
+	if _, err := part.Write(content); err != nil {
+		t.Fatalf("Write part failed: %v", err)
+	}
+	if err := writer.Close(); err != nil {
+		t.Fatalf("Writer close failed: %v", err)
+	}
+
+	req, _ := http.NewRequest("POST", server.URL+"/", body)
+	req.Header.Set("Content-Type", writer.FormDataContentType())
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatalf("Upload request failed: %v", err)
+	}
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			t.Errorf("Failed to close response body: %v", err)
+		}
+	}()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("Upload failed status: %d", resp.StatusCode)
+	}
+
+	respBytes, _ := io.ReadAll(resp.Body)
+	respStr := string(respBytes)
+	parts := strings.Split(strings.TrimSpace(respStr), "/")
+	slugWithExt := parts[len(parts)-1]
+
+	downloadURL := fmt.Sprintf("%s/%s", server.URL, slugWithExt)
+	resp, err = http.Get(downloadURL)
+	if err != nil {
+		t.Fatalf("Download request failed: %v", err)
+	}
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			t.Errorf("Failed to close download response body: %v", err)
+		}
+	}()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("Download failed status: %d", resp.StatusCode)
+	}
+
+	downloadedContent, _ := io.ReadAll(resp.Body)
+	if !bytes.Equal(content, downloadedContent) {
+		t.Errorf("Content mismatch. Want %s, got %s", content, downloadedContent)
+	}
+}
+
+func TestIntegration_ChunkedUpload(t *testing.T) {
+	app, _ := setupTestApp(t)
+	server := httptest.NewServer(app.Routes())
+	defer server.Close()
+
+	uploadID := "testchunkid123"
+	content := []byte("Chunk1Content-Chunk2Content")
+	chunk1 := content[:13]
+	chunk2 := content[13:]
+
+	uploadChunk(t, server.URL, uploadID, 0, chunk1)
+	uploadChunk(t, server.URL, uploadID, 1, chunk2)
+
+	finishURL := fmt.Sprintf("%s/upload/finish", server.URL)
+	form := map[string]string{
+		"upload_id": uploadID,
+		"total":     "2",
+		"filename":  "chunked.txt",
+	}
+
+	resp := postForm(t, finishURL, form)
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			t.Errorf("Failed to close finish response body: %v", err)
+		}
+	}()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("Finish failed: %d", resp.StatusCode)
+	}
+
+	respBytes, _ := io.ReadAll(resp.Body)
+	respStr := string(respBytes)
+	parts := strings.Split(strings.TrimSpace(respStr), "/")
+	slugWithExt := parts[len(parts)-1]
+
+	downloadURL := fmt.Sprintf("%s/%s", server.URL, slugWithExt)
+	dlResp, err := http.Get(downloadURL)
+	if err != nil {
+		t.Fatalf("Download request failed: %v", err)
+	}
+	dlBytes, _ := io.ReadAll(dlResp.Body)
+	if err := dlResp.Body.Close(); err != nil {
+		t.Errorf("Failed to close download response body: %v", err)
+	}
+
+	if !bytes.Equal(content, dlBytes) {
+		t.Errorf("Chunked reassembly failed. Want %s, got %s", content, dlBytes)
+	}
+}
+
+func TestIntegration_ChunkedUpload_VerifyEncryption(t *testing.T) {
+	app, storageDir := setupTestApp(t)
+	server := httptest.NewServer(app.Routes())
+	defer server.Close()
+
+	uploadID := "securechunk123"
+	plaintext := []byte("This is a secret message that should be encrypted")
+
+	uploadChunk(t, server.URL, uploadID, 0, plaintext)
+
+	chunkPath := filepath.Join(storageDir, TempDirName, uploadID, "0")
+	encryptedData, err := os.ReadFile(chunkPath)
+	if err != nil {
+		t.Fatalf("Failed to read chunk file: %v", err)
+	}
+
+	if bytes.Contains(encryptedData, plaintext) {
+		t.Fatal("Chunk file contains plaintext data!")
+	}
+
+	if len(encryptedData) <= crypto.KeySize {
+		t.Fatalf("Chunk file too small: %d bytes", len(encryptedData))
+	}
+
+	key := encryptedData[:crypto.KeySize]
+	ciphertext := encryptedData[crypto.KeySize:]
+
+	streamer, err := crypto.NewGCMStreamer(key)
+	if err != nil {
+		t.Fatalf("Failed to create streamer: %v", err)
+	}
+
+	r := bytes.NewReader(ciphertext)
+	d := crypto.NewDecryptor(r, streamer.AEAD, int64(len(ciphertext)))
+
+	decrypted, err := io.ReadAll(d)
+	if err != nil {
+		t.Fatalf("Failed to decrypt chunk: %v", err)
+	}
+
+	if !bytes.Equal(decrypted, plaintext) {
+		t.Errorf("Decrypted data mismatch.\nWant: %s\nGot:  %s", plaintext, decrypted)
+	}
+}
+
+func TestIntegration_Upload_VerifyEncryption(t *testing.T) {
+	app, storageDir := setupTestApp(t)
+	server := httptest.NewServer(app.Routes())
+	defer server.Close()
+
+	plaintext := []byte("Sensitive Data For Full Upload")
+
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+	part, err := writer.CreateFormFile("file", "secret.txt")
+	if err != nil {
+		t.Fatalf("CreateFormFile failed: %v", err)
+	}
+	if _, err := part.Write(plaintext); err != nil {
+		t.Fatalf("Write failed: %v", err)
+	}
+	if err := writer.Close(); err != nil {
+		t.Fatalf("Writer close failed: %v", err)
+	}
+
+	req, _ := http.NewRequest("POST", server.URL+"/", body)
+	req.Header.Set("Content-Type", writer.FormDataContentType())
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			t.Errorf("Failed to close response body: %v", err)
+		}
+	}()
+
+	respBytes, _ := io.ReadAll(resp.Body)
+	slug := filepath.Base(strings.TrimSpace(string(respBytes)))
+
+	if len(slug) < SlugLength {
+		t.Fatalf("Invalid slug: %s", slug)
+	}
+	keyBase64 := slug[:SlugLength]
+	key, _ := base64.RawURLEncoding.DecodeString(keyBase64)
+	ext := filepath.Ext("secret.txt")
+	id := crypto.GetID(key, ext)
+
+	finalPath := filepath.Join(storageDir, id)
+	finalData, err := os.ReadFile(finalPath)
+	if err != nil {
+		t.Fatalf("Failed to read final file: %v", err)
+	}
+
+	if bytes.Contains(finalData, plaintext) {
+		t.Fatal("Final file contains plaintext!")
+	}
+
+	streamer, _ := crypto.NewGCMStreamer(key)
+	d := crypto.NewDecryptor(bytes.NewReader(finalData), streamer.AEAD, int64(len(finalData)))
+	decrypted, _ := io.ReadAll(d)
+
+	if !bytes.Equal(decrypted, plaintext) {
+		t.Error("Final file decryption failed")
+	}
+}
+
+func uploadChunk(t *testing.T, baseURL, uid string, idx int, data []byte) {
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+	if err := writer.WriteField("upload_id", uid); err != nil {
+		t.Fatalf("WriteField upload_id failed: %v", err)
+	}
+	if err := writer.WriteField("index", fmt.Sprintf("%d", idx)); err != nil {
+		t.Fatalf("WriteField index failed: %v", err)
+	}
+	part, err := writer.CreateFormFile("chunk", "blob")
+	if err != nil {
+		t.Fatalf("CreateFormFile failed: %v", err)
+	}
+	if _, err := part.Write(data); err != nil {
+		t.Fatalf("Write part failed: %v", err)
+	}
+	if err := writer.Close(); err != nil {
+		t.Fatalf("Writer close failed: %v", err)
+	}
+
+	req, _ := http.NewRequest("POST", baseURL+"/upload/chunk", body)
+	req.Header.Set("Content-Type", writer.FormDataContentType())
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil || resp.StatusCode != http.StatusOK {
+		t.Fatalf("Chunk %d upload failed: %v", idx, err)
+	}
+	if err := resp.Body.Close(); err != nil {
+		t.Errorf("Failed to close chunk response body: %v", err)
+	}
+}
+
+func postForm(t *testing.T, url string, fields map[string]string) *http.Response {
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+	for k, v := range fields {
+		if err := writer.WriteField(k, v); err != nil {
+			t.Fatalf("WriteField %s failed: %v", k, err)
+		}
+	}
+	if err := writer.Close(); err != nil {
+		t.Fatalf("Writer close failed: %v", err)
+	}
+
+	req, _ := http.NewRequest("POST", url, body)
+	req.Header.Set("Content-Type", writer.FormDataContentType())
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatalf("Post form failed: %v", err)
+	}
+	return resp
+}

internal/app/storage.go

@@ -2,49 +2,320 @@ package app
 
 import (
 	"context"
+	"crypto/rand"
+	"encoding/json"
+	"fmt"
+	"io"
 	"math"
 	"os"
 	"path/filepath"
+	"strconv"
 	"time"
+
+	"github.com/skidoodle/safebin/internal/crypto"
+	"go.etcd.io/bbolt"
 )
 
 func (app *App) StartCleanupTask(ctx context.Context) {
-	ticker := time.NewTicker(1 * time.Hour)
+	ticker := time.NewTicker(CleanupInterval)
+
 	for {
 		select {
 		case <-ctx.Done():
+			ticker.Stop()
 			return
 		case <-ticker.C:
-			app.CleanDir(app.Conf.StorageDir, false)
-			app.CleanDir(filepath.Join(app.Conf.StorageDir, "tmp"), true)
+			app.CleanStorage()
+			app.CleanTemp(filepath.Join(app.Conf.StorageDir, TempDirName))
 		}
 	}
 }
 
-func (app *App) CleanDir(path string, isTmp bool) {
-	entries, _ := os.ReadDir(path)
+func (app *App) saveChunk(uid string, idx int, src io.Reader) error {
+	dir := filepath.Join(app.Conf.StorageDir, TempDirName, uid)
+
+	if err := os.MkdirAll(dir, PermUserRWX); err != nil {
+		return fmt.Errorf("create chunk dir: %w", err)
+	}
+
+	dest, err := os.Create(filepath.Join(dir, strconv.Itoa(idx)))
+	if err != nil {
+		return fmt.Errorf("create chunk file: %w", err)
+	}
+
+	defer func() {
+		if closeErr := dest.Close(); closeErr != nil {
+			app.Logger.Error("Failed to close chunk dest", "err", closeErr)
+		}
+	}()
+
+	key := make([]byte, crypto.KeySize)
+	if _, err := rand.Read(key); err != nil {
+		return fmt.Errorf("generate chunk key: %w", err)
+	}
+
+	if _, err := dest.Write(key); err != nil {
+		return fmt.Errorf("write chunk key: %w", err)
+	}
+
+	streamer, err := crypto.NewGCMStreamer(key)
+	if err != nil {
+		return fmt.Errorf("create streamer: %w", err)
+	}
+
+	if err := streamer.EncryptStream(dest, src); err != nil {
+		return fmt.Errorf("encrypt chunk: %w", err)
+	}
+
+	return nil
+}
+
+func (app *App) openChunkDecryptor(uid string, idx int) (io.ReadCloser, error) {
+	partPath := filepath.Join(app.Conf.StorageDir, TempDirName, uid, strconv.Itoa(idx))
+	f, err := os.Open(partPath)
+	if err != nil {
+		return nil, fmt.Errorf("open chunk %d: %w", idx, err)
+	}
+
+	key := make([]byte, crypto.KeySize)
+	if _, err := io.ReadFull(f, key); err != nil {
+		_ = f.Close()
+		return nil, fmt.Errorf("read chunk key %d: %w", idx, err)
+	}
+
+	info, err := f.Stat()
+	if err != nil {
+		_ = f.Close()
+		return nil, fmt.Errorf("stat chunk %d: %w", idx, err)
+	}
+
+	bodySize := info.Size() - int64(crypto.KeySize)
+	if bodySize < 0 {
+		_ = f.Close()
+		return nil, fmt.Errorf("invalid chunk size %d", idx)
+	}
+
+	bodyReader := io.NewSectionReader(f, int64(crypto.KeySize), bodySize)
+
+	streamer, err := crypto.NewGCMStreamer(key)
+	if err != nil {
+		_ = f.Close()
+		return nil, fmt.Errorf("create streamer %d: %w", idx, err)
+	}
+
+	decryptor := crypto.NewDecryptor(bodyReader, streamer.AEAD, bodySize)
+
+	return &chunkReadCloser{Decryptor: decryptor, f: f}, nil
+}
+
+type chunkReadCloser struct {
+	*crypto.Decryptor
+	f *os.File
+}
+
+func (c *chunkReadCloser) Close() error {
+	return c.f.Close()
+}
+
+type SequentialChunkReader struct {
+	app        *App
+	uid        string
+	total      int
+	currentIdx int
+	currentRC  io.ReadCloser
+}
+
+func (s *SequentialChunkReader) Read(p []byte) (n int, err error) {
+	if s.currentRC == nil {
+		if s.currentIdx >= s.total {
+			return 0, io.EOF
+		}
+		rc, err := s.app.openChunkDecryptor(s.uid, s.currentIdx)
+		if err != nil {
+			return 0, err
+		}
+		s.currentRC = rc
+	}
+
+	n, err = s.currentRC.Read(p)
+	if err == io.EOF {
+		_ = s.currentRC.Close()
+		s.currentRC = nil
+		s.currentIdx++
+
+		if n > 0 {
+			return n, nil
+		}
+		return s.Read(p)
+	}
+
+	return n, err
+}
+
+func (s *SequentialChunkReader) Close() error {
+	if s.currentRC != nil {
+		return s.currentRC.Close()
+	}
+	return nil
+}
+
+func (app *App) encryptAndSave(src io.Reader, key []byte, finalPath string) error {
+	out, err := os.Create(finalPath + ".tmp")
+	if err != nil {
+		return fmt.Errorf("create final file: %w", err)
+	}
+
+	var closed bool
+
+	defer func() {
+		if !closed {
+			if closeErr := out.Close(); closeErr != nil {
+				app.Logger.Error("Failed to close final file", "err", closeErr)
+			}
+		}
+
+		if removeErr := os.Remove(finalPath + ".tmp"); removeErr != nil && !os.IsNotExist(removeErr) {
+			app.Logger.Error("Failed to remove temp final file", "err", removeErr)
+		}
+	}()
+
+	streamer, err := crypto.NewGCMStreamer(key)
+	if err != nil {
+		return fmt.Errorf("create streamer: %w", err)
+	}
+
+	if err := streamer.EncryptStream(out, src); err != nil {
+		return fmt.Errorf("encrypt stream: %w", err)
+	}
+
+	if err := out.Close(); err != nil {
+		return fmt.Errorf("close final file: %w", err)
+	}
+
+	closed = true
+
+	if err := os.Rename(finalPath+".tmp", finalPath); err != nil {
+		return fmt.Errorf("rename final file: %w", err)
+	}
+
+	return nil
+}
+
+func (app *App) RegisterFile(id string, size int64) error {
+	retention := CalculateRetention(size, app.Conf.MaxMB)
+	meta := FileMeta{
+		ID:        id,
+		Size:      size,
+		CreatedAt: time.Now(),
+		ExpiresAt: time.Now().Add(retention),
+	}
+
+	return app.DB.Update(func(tx *bbolt.Tx) error {
+		bFiles := tx.Bucket([]byte(DBBucketName))
+		bIndex := tx.Bucket([]byte(DBBucketIndexName))
+
+		data, err := json.Marshal(meta)
+		if err != nil {
+			return err
+		}
+
+		if err := bFiles.Put([]byte(id), data); err != nil {
+			return err
+		}
+
+		indexKey := []byte(meta.ExpiresAt.Format(time.RFC3339) + "_" + id)
+		return bIndex.Put(indexKey, []byte(id))
+	})
+}
+
+func (app *App) CleanStorage() {
+	now := time.Now().Format(time.RFC3339)
+	var toDeleteIDs []string
+	var toDeleteKeys []string
+
+	err := app.DB.View(func(tx *bbolt.Tx) error {
+		bIndex := tx.Bucket([]byte(DBBucketIndexName))
+		if bIndex == nil {
+			return nil
+		}
+		c := bIndex.Cursor()
+
+		for k, v := c.First(); k != nil; k, v = c.Next() {
+			if string(k) > now {
+				break
+			}
+
+			toDeleteKeys = append(toDeleteKeys, string(k))
+			toDeleteIDs = append(toDeleteIDs, string(v))
+		}
+		return nil
+	})
+
+	if err != nil {
+		app.Logger.Error("Failed to view DB for cleanup", "err", err)
+		return
+	}
+
+	if len(toDeleteIDs) == 0 {
+		return
+	}
+
+	err = app.DB.Update(func(tx *bbolt.Tx) error {
+		bFiles := tx.Bucket([]byte(DBBucketName))
+		bIndex := tx.Bucket([]byte(DBBucketIndexName))
+
+		for i, id := range toDeleteIDs {
+			path := filepath.Join(app.Conf.StorageDir, id)
+			if err := os.RemoveAll(path); err != nil {
+				app.Logger.Error("Failed to remove expired file", "path", id, "err", err)
+			}
+
+			if err := bFiles.Delete([]byte(id)); err != nil {
+				app.Logger.Error("Failed to delete metadata", "id", id, "err", err)
+			}
+
+			if err := bIndex.Delete([]byte(toDeleteKeys[i])); err != nil {
+				app.Logger.Error("Failed to delete index", "key", toDeleteKeys[i], "err", err)
+			}
+		}
+		return nil
+	})
+
+	if err != nil {
+		app.Logger.Error("Failed to update DB during cleanup", "err", err)
+	}
+}
+
+func (app *App) CleanTemp(path string) {
+	entries, err := os.ReadDir(path)
+	if err != nil {
+		app.Logger.Error("Failed to read temp dir", "err", err)
+		return
+	}
+
 	for _, entry := range entries {
-		info, _ := entry.Info()
-		expiry := 4 * time.Hour
-		if !isTmp {
-			expiry = CalculateRetention(info.Size(), app.Conf.MaxMB)
+		info, err := entry.Info()
+		if err != nil {
+			continue
 		}
 
-		if time.Since(info.ModTime()) > expiry {
-			os.RemoveAll(filepath.Join(path, entry.Name()))
+		if time.Since(info.ModTime()) > TempExpiry {
+			if err := os.RemoveAll(filepath.Join(path, entry.Name())); err != nil {
+				app.Logger.Error("Failed to remove expired temp file", "path", entry.Name(), "err", err)
+			}
 		}
 	}
 }
 
-func CalculateRetention(fileSize int64, maxMB int64) time.Duration {
-	const (
-		minAge = 24 * time.Hour
-		maxAge = 365 * 24 * time.Hour
-	)
-	ratio := math.Max(0, math.Min(1, float64(fileSize)/float64(maxMB<<20)))
-	retention := float64(maxAge) * math.Pow(1.0-ratio, 3)
-	if retention < float64(minAge) {
-		return minAge
+func CalculateRetention(fileSize, maxMB int64) time.Duration {
+	ratio := math.Max(0, math.Min(1, float64(fileSize)/float64(maxMB*MegaByte)))
+
+	invRatio := 1.0 - ratio
+	retention := float64(MaxRetention) * (invRatio * invRatio * invRatio)
+
+	if retention < float64(MinRetention) {
+		return MinRetention
 	}
+
 	return time.Duration(retention)
 }

internal/app/storage_test.go

@@ -0,0 +1,213 @@
+package app
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/json"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/skidoodle/safebin/internal/crypto"
+	"go.etcd.io/bbolt"
+)
+
+func TestCleanup_AbandonedChunks(t *testing.T) {
+	tmpDir := t.TempDir()
+	tmpStorage := filepath.Join(tmpDir, TempDirName)
+	if err := os.MkdirAll(tmpStorage, 0700); err != nil {
+		t.Fatalf("MkdirAll failed: %v", err)
+	}
+
+	db, err := InitDB(tmpDir)
+	if err != nil {
+		t.Fatalf("InitDB failed: %v", err)
+	}
+	defer func() {
+		if err := db.Close(); err != nil {
+			t.Errorf("Failed to close DB: %v", err)
+		}
+	}()
+
+	app := &App{
+		Conf:   Config{StorageDir: tmpDir},
+		Logger: discardLogger(),
+		DB:     db,
+	}
+
+	chunkDir := filepath.Join(tmpStorage, "some_upload_id")
+	if err := os.MkdirAll(chunkDir, 0700); err != nil {
+		t.Fatalf("MkdirAll chunkDir failed: %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(chunkDir, "0"), []byte("chunk data"), 0600); err != nil {
+		t.Fatalf("WriteFile chunk failed: %v", err)
+	}
+
+	oldTime := time.Now().Add(-TempExpiry - time.Hour)
+	if err := os.Chtimes(chunkDir, oldTime, oldTime); err != nil {
+		t.Fatalf("Chtimes failed: %v", err)
+	}
+
+	app.CleanTemp(tmpStorage)
+
+	if _, err := os.Stat(chunkDir); !os.IsNotExist(err) {
+		t.Error("Cleanup failed to remove abandoned chunk directory")
+	}
+}
+
+func TestCleanup_ExpiredStorage(t *testing.T) {
+	storageDir := t.TempDir()
+	db, err := InitDB(storageDir)
+	if err != nil {
+		t.Fatalf("InitDB failed: %v", err)
+	}
+	defer func() {
+		if err := db.Close(); err != nil {
+			t.Errorf("Failed to close DB: %v", err)
+		}
+	}()
+
+	app := &App{
+		Conf: Config{
+			StorageDir: storageDir,
+			MaxMB:      100,
+		},
+		Logger: discardLogger(),
+		DB:     db,
+	}
+
+	filename := "large_file_id"
+	path := filepath.Join(storageDir, filename)
+	f, err := os.Create(path)
+	if err != nil {
+		t.Fatalf("Create file failed: %v", err)
+	}
+	if err := f.Truncate(100 * MegaByte); err != nil {
+		t.Fatalf("Truncate failed: %v", err)
+	}
+	if err := f.Close(); err != nil {
+		t.Fatalf("Close file failed: %v", err)
+	}
+
+	expiredMeta := FileMeta{
+		ID:        filename,
+		Size:      100 * MegaByte,
+		CreatedAt: time.Now().Add(-MinRetention - 2*time.Hour),
+		ExpiresAt: time.Now().Add(-time.Hour),
+	}
+
+	if err := app.DB.Update(func(tx *bbolt.Tx) error {
+		bFiles := tx.Bucket([]byte(DBBucketName))
+		bIndex := tx.Bucket([]byte(DBBucketIndexName))
+
+		data, _ := json.Marshal(expiredMeta)
+		if err := bFiles.Put([]byte(filename), data); err != nil {
+			return err
+		}
+
+		indexKey := []byte(expiredMeta.ExpiresAt.Format(time.RFC3339) + "_" + filename)
+		return bIndex.Put(indexKey, []byte(filename))
+	}); err != nil {
+		t.Fatalf("DB Update failed: %v", err)
+	}
+
+	app.CleanStorage()
+
+	if _, err := os.Stat(path); !os.IsNotExist(err) {
+		t.Error("Cleanup failed to remove expired large file")
+	}
+
+	if err := app.DB.View(func(tx *bbolt.Tx) error {
+		bFiles := tx.Bucket([]byte(DBBucketName))
+		if v := bFiles.Get([]byte(filename)); v != nil {
+			t.Error("Cleanup failed to remove metadata")
+		}
+
+		bIndex := tx.Bucket([]byte(DBBucketIndexName))
+		indexKey := []byte(expiredMeta.ExpiresAt.Format(time.RFC3339) + "_" + filename)
+		if v := bIndex.Get(indexKey); v != nil {
+			t.Error("Cleanup failed to remove index entry")
+		}
+		return nil
+	}); err != nil {
+		t.Fatalf("DB View failed: %v", err)
+	}
+}
+
+func TestSaveChunk_EncryptsData(t *testing.T) {
+	tmpDir := t.TempDir()
+	app := &App{
+		Conf:   Config{StorageDir: tmpDir},
+		Logger: discardLogger(),
+	}
+
+	uid := "test-encrypt-chunk"
+	plaintext := make([]byte, 1024)
+	if _, err := rand.Read(plaintext); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := app.saveChunk(uid, 0, bytes.NewReader(plaintext)); err != nil {
+		t.Fatalf("saveChunk failed: %v", err)
+	}
+
+	path := filepath.Join(tmpDir, TempDirName, uid, "0")
+	fileData, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("ReadFile failed: %v", err)
+	}
+
+	if bytes.Equal(fileData, plaintext) {
+		t.Fatal("Chunk stored as plaintext!")
+	}
+	if bytes.Contains(fileData, plaintext) {
+		t.Fatal("Chunk contains plaintext!")
+	}
+
+	expectedSize := crypto.KeySize + len(plaintext) + 16
+	if len(fileData) != expectedSize {
+		t.Errorf("Unexpected file size. Want %d, got %d", expectedSize, len(fileData))
+	}
+}
+
+func TestSequentialChunkReader_RestoresData(t *testing.T) {
+	tmpDir := t.TempDir()
+	app := &App{
+		Conf:   Config{StorageDir: tmpDir},
+		Logger: discardLogger(),
+	}
+
+	uid := "test-restore"
+	data1 := []byte("chunk one data")
+	data2 := []byte("chunk two data")
+
+	if err := app.saveChunk(uid, 0, bytes.NewReader(data1)); err != nil {
+		t.Fatal(err)
+	}
+	if err := app.saveChunk(uid, 1, bytes.NewReader(data2)); err != nil {
+		t.Fatal(err)
+	}
+
+	reader := &SequentialChunkReader{
+		app:   app,
+		uid:   uid,
+		total: 2,
+	}
+	defer func() {
+		if err := reader.Close(); err != nil {
+			t.Errorf("Failed to close reader: %v", err)
+		}
+	}()
+
+	restored, err := io.ReadAll(reader)
+	if err != nil {
+		t.Fatalf("ReadAll failed: %v", err)
+	}
+
+	expected := append(data1, data2...)
+	if !bytes.Equal(restored, expected) {
+		t.Errorf("Restored data mismatch.\nWant: %s\nGot:  %s", expected, restored)
+	}
+}

internal/app/upload.go

@@ -0,0 +1,269 @@
+package app
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"errors"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/skidoodle/safebin/internal/crypto"
+)
+
+var reUploadID = regexp.MustCompile(`^[a-zA-Z0-9]{10,50}$`)
+
+func (app *App) HandleUpload(writer http.ResponseWriter, request *http.Request) {
+	limit := (app.Conf.MaxMB * MegaByte) + MegaByte
+	request.Body = http.MaxBytesReader(writer, request.Body, limit)
+
+	mr, err := request.MultipartReader()
+	if err != nil {
+		app.SendError(writer, request, http.StatusBadRequest)
+		return
+	}
+
+	var filename string
+	var partReader io.Reader
+
+	for {
+		part, err := mr.NextPart()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			app.SendError(writer, request, http.StatusBadRequest)
+			return
+		}
+
+		if part.FormName() == "file" {
+			filename = part.FileName()
+			partReader = part
+			break
+		}
+	}
+
+	if partReader == nil {
+		app.SendError(writer, request, http.StatusBadRequest)
+		return
+	}
+
+	tmp, err := os.CreateTemp(filepath.Join(app.Conf.StorageDir, TempDirName), "up_*")
+	if err != nil {
+		app.Logger.Error("Failed to create temp file", "err", err)
+		app.SendError(writer, request, http.StatusInternalServerError)
+		return
+	}
+	tmpPath := tmp.Name()
+
+	defer func() {
+		_ = tmp.Close()
+		if removeErr := os.Remove(tmpPath); removeErr != nil && !os.IsNotExist(removeErr) {
+			app.Logger.Error("Failed to remove temp file", "err", removeErr)
+		}
+	}()
+
+	ephemeralKey := make([]byte, crypto.KeySize)
+	if _, err := rand.Read(ephemeralKey); err != nil {
+		app.Logger.Error("Failed to generate ephemeral key", "err", err)
+		app.SendError(writer, request, http.StatusInternalServerError)
+		return
+	}
+
+	pr, pw := io.Pipe()
+	hasher := sha256.New()
+	errChan := make(chan error, 1)
+
+	go func() {
+		_, err := io.Copy(io.MultiWriter(hasher, pw), partReader)
+		_ = pw.CloseWithError(err)
+		errChan <- err
+	}()
+
+	streamer, err := crypto.NewGCMStreamer(ephemeralKey)
+	if err != nil {
+		_ = pr.Close()
+		app.Logger.Error("Failed to create streamer", "err", err)
+		app.SendError(writer, request, http.StatusInternalServerError)
+		return
+	}
+
+	if err := streamer.EncryptStream(tmp, pr); err != nil {
+		_ = pr.Close()
+		app.Logger.Error("Failed to encrypt stream", "err", err)
+		app.SendError(writer, request, http.StatusInternalServerError)
+		return
+	}
+
+	if err := <-errChan; err != nil {
+		if errors.Is(err, http.ErrMissingBoundary) || strings.Contains(err.Error(), "request body too large") {
+			app.SendError(writer, request, http.StatusRequestEntityTooLarge)
+		} else {
+			app.Logger.Error("Failed to read/hash upload", "err", err)
+			app.SendError(writer, request, http.StatusInternalServerError)
+		}
+		return
+	}
+
+	convergentKey := hasher.Sum(nil)[:crypto.KeySize]
+
+	if _, err := tmp.Seek(0, 0); err != nil {
+		app.Logger.Error("Seek failed", "err", err)
+		app.SendError(writer, request, http.StatusInternalServerError)
+		return
+	}
+
+	info, _ := tmp.Stat()
+	decryptor := crypto.NewDecryptor(tmp, streamer.AEAD, info.Size())
+
+	app.finalizeUpload(writer, request, decryptor, convergentKey, filename)
+}
+
+func (app *App) HandleChunk(writer http.ResponseWriter, request *http.Request) {
+	const MaxChunkBody = UploadChunkSize + (1 << 20)
+	request.Body = http.MaxBytesReader(writer, request.Body, MaxChunkBody)
+
+	uid := request.FormValue("upload_id")
+	idx, err := strconv.Atoi(request.FormValue("index"))
+	if err != nil {
+		app.SendError(writer, request, http.StatusBadRequest)
+		return
+	}
+
+	maxChunks := int((app.Conf.MaxMB*MegaByte)/MinChunkSize) + ChunkSafetyMargin
+
+	if !reUploadID.MatchString(uid) || idx > maxChunks || idx < 0 {
+		app.SendError(writer, request, http.StatusBadRequest)
+		return
+	}
+
+	file, _, err := request.FormFile("chunk")
+	if err != nil {
+		if strings.Contains(err.Error(), "request body too large") {
+			app.SendError(writer, request, http.StatusRequestEntityTooLarge)
+			return
+		}
+		app.SendError(writer, request, http.StatusBadRequest)
+		return
+	}
+	defer func() {
+		if closeErr := file.Close(); closeErr != nil {
+			app.Logger.Error("Failed to close chunk file", "err", closeErr)
+		}
+	}()
+
+	if err := app.saveChunk(uid, idx, file); err != nil {
+		app.Logger.Error("Failed to save chunk", "err", err)
+		app.SendError(writer, request, http.StatusInternalServerError)
+	}
+}
+
+func (app *App) HandleFinish(writer http.ResponseWriter, request *http.Request) {
+	uid := request.FormValue("upload_id")
+	total, err := strconv.Atoi(request.FormValue("total"))
+	if err != nil {
+		app.SendError(writer, request, http.StatusBadRequest)
+		return
+	}
+
+	maxChunks := int((app.Conf.MaxMB*MegaByte)/MinChunkSize) + ChunkSafetyMargin
+
+	if !reUploadID.MatchString(uid) || total > maxChunks || total <= 0 {
+		app.SendError(writer, request, http.StatusBadRequest)
+		return
+	}
+
+	defer func() {
+		if err := os.RemoveAll(filepath.Join(app.Conf.StorageDir, TempDirName, uid)); err != nil {
+			app.Logger.Error("Failed to remove chunk dir", "err", err)
+		}
+	}()
+
+	var totalSize int64
+	for i := range total {
+		info, err := os.Stat(filepath.Join(app.Conf.StorageDir, TempDirName, uid, strconv.Itoa(i)))
+		if err != nil {
+			app.Logger.Error("Missing chunk", "index", i, "err", err)
+			app.SendError(writer, request, http.StatusBadRequest)
+			return
+		}
+		chunkContentSize := info.Size() - crypto.KeySize
+		if chunkContentSize < 0 {
+			app.SendError(writer, request, http.StatusBadRequest)
+			return
+		}
+		totalSize += chunkContentSize
+	}
+
+	if totalSize > (app.Conf.MaxMB * MegaByte) {
+		app.Logger.Warn("Upload exceeded quota", "uid", uid, "size", totalSize)
+		app.SendError(writer, request, http.StatusRequestEntityTooLarge)
+		return
+	}
+
+	hasher := sha256.New()
+	for i := range total {
+		rc, err := app.openChunkDecryptor(uid, i)
+		if err != nil {
+			app.Logger.Error("Failed to open chunk for hashing", "index", i, "err", err)
+			app.SendError(writer, request, http.StatusInternalServerError)
+			return
+		}
+		if _, err := io.Copy(hasher, rc); err != nil {
+			_ = rc.Close()
+			app.Logger.Error("Failed to hash chunk", "index", i, "err", err)
+			app.SendError(writer, request, http.StatusInternalServerError)
+			return
+		}
+		_ = rc.Close()
+	}
+
+	convergentKey := hasher.Sum(nil)[:crypto.KeySize]
+
+	multiSrc := &SequentialChunkReader{
+		app:   app,
+		uid:   uid,
+		total: total,
+	}
+	defer func() {
+		if err := multiSrc.Close(); err != nil {
+			app.Logger.Error("Failed to close sequential reader", "uid", uid, "err", err)
+		}
+	}()
+
+	app.finalizeUpload(writer, request, multiSrc, convergentKey, request.FormValue("filename"))
+}
+
+func (app *App) finalizeUpload(writer http.ResponseWriter, request *http.Request, src io.Reader, key []byte, filename string) {
+	ext := filepath.Ext(filename)
+	id := crypto.GetID(key, ext)
+	finalPath := filepath.Join(app.Conf.StorageDir, id)
+
+	if info, err := os.Stat(finalPath); err == nil {
+		if err := app.RegisterFile(id, info.Size()); err != nil {
+			app.Logger.Error("Failed to update metadata for existing file", "err", err)
+		}
+		app.RespondWithLink(writer, request, key, filename)
+		return
+	}
+
+	if err := app.encryptAndSave(src, key, finalPath); err != nil {
+		app.Logger.Error("Encryption failed", "err", err)
+		app.SendError(writer, request, http.StatusInternalServerError)
+		return
+	}
+
+	if info, err := os.Stat(finalPath); err == nil {
+		if err := app.RegisterFile(id, info.Size()); err != nil {
+			app.Logger.Error("Failed to save metadata", "err", err)
+		}
+	} else {
+		app.Logger.Error("Failed to stat new file", "err", err)
+	}
+
+	app.RespondWithLink(writer, request, key, filename)
+}

internal/crypto/crypto.go

@@ -6,27 +6,34 @@ import (
 	"crypto/sha256"
 	"encoding/base64"
 	"encoding/binary"
+	"errors"
+	"fmt"
 	"io"
 )
 
 const (
 	GCMChunkSize = 64 * 1024
 	NonceSize    = 12
+	KeySize      = 16
+	IDSize       = 9
 )
 
-func DeriveKey(r io.Reader) ([]byte, error) {
-	h := sha256.New()
-	if _, err := io.Copy(h, r); err != nil {
-		return nil, err
+func DeriveKey(reader io.Reader) ([]byte, error) {
+	hasher := sha256.New()
+
+	if _, err := io.Copy(hasher, reader); err != nil {
+		return nil, fmt.Errorf("failed to copy to hasher: %w", err)
 	}
-	return h.Sum(nil)[:16], nil
+
+	return hasher.Sum(nil)[:KeySize], nil
 }
 
 func GetID(key []byte, ext string) string {
-	h := sha256.New()
-	h.Write(key)
-	h.Write([]byte(ext))
-	return base64.RawURLEncoding.EncodeToString(h.Sum(nil)[:9])
+	hasher := sha256.New()
+	hasher.Write(key)
+	hasher.Write([]byte(ext))
+
+	return base64.RawURLEncoding.EncodeToString(hasher.Sum(nil)[:IDSize])
 }
 
 type GCMStreamer struct {
@@ -34,37 +41,46 @@ type GCMStreamer struct {
 }
 
 func NewGCMStreamer(key []byte) (*GCMStreamer, error) {
-	b, err := aes.NewCipher(key)
+	block, err := aes.NewCipher(key)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to create cipher: %w", err)
 	}
-	g, err := cipher.NewGCM(b)
+
+	gcm, err := cipher.NewGCM(block)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to create GCM: %w", err)
 	}
-	return &GCMStreamer{AEAD: g}, nil
+
+	return &GCMStreamer{AEAD: gcm}, nil
 }
 
 func (g *GCMStreamer) EncryptStream(dst io.Writer, src io.Reader) error {
 	buf := make([]byte, GCMChunkSize)
-	var chunkIdx uint64 = 0
+	var chunkIdx uint64
+
 	for {
-		n, err := io.ReadFull(src, buf)
-		if n > 0 {
+		bytesRead, err := io.ReadFull(src, buf)
+		if bytesRead > 0 {
 			nonce := make([]byte, NonceSize)
 			binary.BigEndian.PutUint64(nonce[4:], chunkIdx)
-			ciphertext := g.AEAD.Seal(nil, nonce, buf[:n], nil)
+
+			ciphertext := g.AEAD.Seal(nil, nonce, buf[:bytesRead], nil)
+
 			if _, werr := dst.Write(ciphertext); werr != nil {
-				return werr
+				return fmt.Errorf("failed to write ciphertext: %w", werr)
 			}
+
 			chunkIdx++
 		}
-		if err == io.EOF || err == io.ErrUnexpectedEOF {
+
+		if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {
 			break
 		}
+
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to read source: %w", err)
 		}
 	}
+
 	return nil
 }

internal/crypto/crypto_test.go

@@ -0,0 +1,152 @@
+package crypto_test
+
+import (
+	"bytes"
+	"crypto/rand"
+	"io"
+	"testing"
+
+	"github.com/skidoodle/safebin/internal/crypto"
+)
+
+func TestDeriveKey(t *testing.T) {
+	data := []byte("some random file content")
+	reader := bytes.NewReader(data)
+
+	key1, err := crypto.DeriveKey(reader)
+	if err != nil {
+		t.Fatalf("DeriveKey failed: %v", err)
+	}
+
+	if len(key1) != 16 {
+		t.Errorf("Expected key length 16, got %d", len(key1))
+	}
+
+	if _, err := reader.Seek(0, 0); err != nil {
+		t.Fatalf("Seek failed: %v", err)
+	}
+	key2, err := crypto.DeriveKey(reader)
+	if err != nil {
+		t.Fatalf("DeriveKey failed second time: %v", err)
+	}
+
+	if !bytes.Equal(key1, key2) {
+		t.Error("DeriveKey is not deterministic")
+	}
+}
+
+func TestGetID(t *testing.T) {
+	key := make([]byte, 16)
+	ext := ".txt"
+	id1 := crypto.GetID(key, ext)
+	id2 := crypto.GetID(key, ext)
+
+	if id1 != id2 {
+		t.Error("GetID is not deterministic")
+	}
+
+	if len(id1) == 0 {
+		t.Error("GetID returned empty string")
+	}
+}
+
+func TestEncryptDecryptStream(t *testing.T) {
+	payloadSize := (64 * 1024) * 3
+	payload := make([]byte, payloadSize)
+	if _, err := rand.Read(payload); err != nil {
+		t.Fatalf("rand.Read payload failed: %v", err)
+	}
+
+	key := make([]byte, 16)
+	if _, err := rand.Read(key); err != nil {
+		t.Fatalf("rand.Read key failed: %v", err)
+	}
+
+	var encryptedBuf bytes.Buffer
+	streamer, err := crypto.NewGCMStreamer(key)
+	if err != nil {
+		t.Fatalf("Failed to create streamer: %v", err)
+	}
+
+	if err := streamer.EncryptStream(&encryptedBuf, bytes.NewReader(payload)); err != nil {
+		t.Fatalf("EncryptStream failed: %v", err)
+	}
+
+	encryptedReader := bytes.NewReader(encryptedBuf.Bytes())
+	decryptor := crypto.NewDecryptor(encryptedReader, streamer.AEAD, int64(encryptedBuf.Len()))
+
+	decrypted := make([]byte, payloadSize)
+	n, err := io.ReadFull(decryptor, decrypted)
+	if err != nil {
+		t.Fatalf("ReadFull failed: %v", err)
+	}
+
+	if n != payloadSize {
+		t.Errorf("Expected %d bytes, got %d", payloadSize, n)
+	}
+
+	if !bytes.Equal(payload, decrypted) {
+		t.Error("Decrypted content does not match original payload")
+	}
+}
+
+func TestDecryptorSeeking(t *testing.T) {
+	chunkSize := 64 * 1024
+	payload := make([]byte, chunkSize*4)
+	for i := range len(payload) {
+		payload[i] = byte(i % 255)
+	}
+
+	key := make([]byte, 16)
+	if _, err := rand.Read(key); err != nil {
+		t.Fatalf("rand.Read key failed: %v", err)
+	}
+
+	var encryptedBuf bytes.Buffer
+	streamer, _ := crypto.NewGCMStreamer(key)
+	if err := streamer.EncryptStream(&encryptedBuf, bytes.NewReader(payload)); err != nil {
+		t.Fatalf("EncryptStream failed: %v", err)
+	}
+
+	r := bytes.NewReader(encryptedBuf.Bytes())
+	d := crypto.NewDecryptor(r, streamer.AEAD, int64(encryptedBuf.Len()))
+
+	tests := []struct {
+		name   string
+		offset int64
+		whence int
+		read   int
+	}{
+		{"Start of file", 0, io.SeekStart, 100},
+		{"Middle of chunk 1", 1000, io.SeekStart, 100},
+		{"Start of chunk 2", int64(chunkSize), io.SeekStart, 100},
+		{"Middle of chunk 2", int64(chunkSize) + 50, io.SeekStart, 100},
+		{"Near end", int64(len(payload)) - 10, io.SeekStart, 10},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			pos, err := d.Seek(tc.offset, tc.whence)
+			if err != nil {
+				t.Fatalf("Seek failed: %v", err)
+			}
+			if pos != tc.offset {
+				t.Errorf("Expected pos %d, got %d", tc.offset, pos)
+			}
+
+			buf := make([]byte, tc.read)
+			n, err := io.ReadFull(d, buf)
+			if err != nil {
+				t.Fatalf("Read failed: %v", err)
+			}
+			if n != tc.read {
+				t.Errorf("Expected %d bytes, got %d", tc.read, n)
+			}
+
+			expected := payload[tc.offset : tc.offset+int64(tc.read)]
+			if !bytes.Equal(buf, expected) {
+				t.Errorf("Data mismatch at offset %d", tc.offset)
+			}
+		})
+	}
+}

internal/crypto/reader.go

@@ -4,34 +4,43 @@ import (
 	"crypto/cipher"
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"io"
 )
 
+var ErrInvalidWhence = errors.New("invalid whence")
+var ErrNegativeBias = errors.New("negative bias")
+
 type Decryptor struct {
-	rs     io.ReadSeeker
+	readSeeker io.ReadSeeker
 	aead       cipher.AEAD
 	size       int64
 	offset     int64
+	phyOffset  int64
 }
 
-func NewDecryptor(rs io.ReadSeeker, aead cipher.AEAD, encryptedSize int64) *Decryptor {
+func NewDecryptor(readSeeker io.ReadSeeker, aead cipher.AEAD, encryptedSize int64) *Decryptor {
 	overhead := int64(aead.Overhead())
-	fullBlocks := encryptedSize / (GCMChunkSize + overhead)
-	remainder := encryptedSize % (GCMChunkSize + overhead)
+	chunkWithOverhead := int64(GCMChunkSize) + overhead
 
-	plainSize := (fullBlocks * GCMChunkSize)
+	fullBlocks := encryptedSize / chunkWithOverhead
+	remainder := encryptedSize % chunkWithOverhead
+
+	plainSize := fullBlocks * GCMChunkSize
 	if remainder > overhead {
 		plainSize += (remainder - overhead)
 	}
 
 	return &Decryptor{
-		rs:   rs,
+		readSeeker: readSeeker,
 		aead:       aead,
 		size:       plainSize,
+		offset:     0,
+		phyOffset:  -1,
 	}
 }
 
-func (d *Decryptor) Read(p []byte) (int, error) {
+func (d *Decryptor) Read(buf []byte) (int, error) {
 	if d.offset >= d.size {
 		return 0, io.EOF
 	}
@@ -40,25 +49,37 @@ func (d *Decryptor) Read(p []byte) (int, error) {
 	overhang := d.offset % GCMChunkSize
 
 	overhead := int64(d.aead.Overhead())
-	actualChunkSize := int64(GCMChunkSize + overhead)
+	actualChunkSize := int64(GCMChunkSize) + overhead
 
-	_, err := d.rs.Seek(chunkIdx*actualChunkSize, io.SeekStart)
-	if err != nil {
-		return 0, err
+	targetOffset := chunkIdx * actualChunkSize
+
+	if d.phyOffset != targetOffset {
+		if _, err := d.readSeeker.Seek(targetOffset, io.SeekStart); err != nil {
+			return 0, fmt.Errorf("failed to seek: %w", err)
+		}
+		d.phyOffset = targetOffset
 	}
 
 	encrypted := make([]byte, actualChunkSize)
-	n, err := io.ReadFull(d.rs, encrypted)
-	if err != nil && err != io.ErrUnexpectedEOF {
-		return 0, err
+
+	bytesRead, err := io.ReadFull(d.readSeeker, encrypted)
+	if bytesRead > 0 {
+		d.phyOffset += int64(bytesRead)
+	}
+
+	if err != nil && !errors.Is(err, io.ErrUnexpectedEOF) {
+		return 0, fmt.Errorf("failed to read encrypted data: %w", err)
 	}
 
 	nonce := make([]byte, NonceSize)
+	if chunkIdx < 0 {
+		return 0, fmt.Errorf("invalid chunk index")
+	}
 	binary.BigEndian.PutUint64(nonce[4:], uint64(chunkIdx))
 
-	plaintext, err := d.aead.Open(nil, nonce, encrypted[:n], nil)
+	plaintext, err := d.aead.Open(nil, nonce, encrypted[:bytesRead], nil)
 	if err != nil {
-		return 0, err
+		return 0, fmt.Errorf("failed to decrypt: %w", err)
 	}
 
 	if overhang >= int64(len(plaintext)) {
@@ -66,7 +87,7 @@ func (d *Decryptor) Read(p []byte) (int, error) {
 	}
 
 	available := plaintext[overhang:]
-	nCopied := copy(p, available)
+	nCopied := copy(buf, available)
 	d.offset += int64(nCopied)
 
 	return nCopied, nil
@@ -74,6 +95,7 @@ func (d *Decryptor) Read(p []byte) (int, error) {
 
 func (d *Decryptor) Seek(offset int64, whence int) (int64, error) {
 	var abs int64
+
 	switch whence {
 	case io.SeekStart:
 		abs = offset
@@ -82,11 +104,14 @@ func (d *Decryptor) Seek(offset int64, whence int) (int64, error) {
 	case io.SeekEnd:
 		abs = d.size + offset
 	default:
-		return 0, errors.New("invalid whence")
+		return 0, ErrInvalidWhence
 	}
+
 	if abs < 0 {
-		return 0, errors.New("negative bias")
+		return 0, ErrNegativeBias
 	}
+
 	d.offset = abs
+
 	return abs, nil
 }

main.go

@@ -2,35 +2,54 @@ package main
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log/slog"
 	"net/http"
 	"os"
 	"os/signal"
+	"path/filepath"
 	"syscall"
-	"time"
 
 	"github.com/skidoodle/safebin/internal/app"
+	"github.com/skidoodle/safebin/web"
 )
 
 func main() {
 	cfg := app.LoadConfig()
-	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelDebug}))
+	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
+		Level:     slog.LevelDebug,
+		AddSource: true,
+	}))
 
 	logger.Info("Initializing Safebin Server",
 		"storage_dir", cfg.StorageDir,
 		"max_file_size", fmt.Sprintf("%dMB", cfg.MaxMB),
 	)
 
-	if err := os.MkdirAll(fmt.Sprintf("%s/tmp", cfg.StorageDir), 0700); err != nil {
+	tmpDir := filepath.Join(cfg.StorageDir, app.TempDirName)
+	if err := os.MkdirAll(tmpDir, app.PermUserRWX); err != nil {
 		logger.Error("Failed to initialize storage directory", "err", err)
 		os.Exit(1)
 	}
 
+	db, err := app.InitDB(cfg.StorageDir)
+	if err != nil {
+		logger.Error("Failed to initialize database", "err", err)
+		os.Exit(1)
+	}
+	defer func() {
+		if err := db.Close(); err != nil {
+			logger.Error("Failed to close database", "err", err)
+		}
+	}()
+
 	application := &app.App{
 		Conf:   cfg,
 		Logger: logger,
-		Tmpl:   app.ParseTemplates(),
+		Tmpl:   app.ParseTemplates(web.Assets),
+		Assets: web.Assets,
+		DB:     db,
 	}
 
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
@@ -41,13 +60,15 @@ func main() {
 	srv := &http.Server{
 		Addr:         cfg.Addr,
 		Handler:      application.Routes(),
-		ReadTimeout:  10 * time.Minute,
-		WriteTimeout: 10 * time.Minute,
+		ReadTimeout:  app.ServerTimeout,
+		WriteTimeout: app.ServerTimeout,
+		IdleTimeout:  app.ServerTimeout,
 	}
 
 	go func() {
 		application.Logger.Info("Server is ready and listening", "addr", cfg.Addr)
-		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+
+		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
 			application.Logger.Error("Server failed to start", "err", err)
 			os.Exit(1)
 		}
@@ -56,10 +77,12 @@ func main() {
 	<-ctx.Done()
 	application.Logger.Info("Shutting down gracefully...")
 
-	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), app.ShutdownTimeout)
 	defer cancel()
+
 	if err := srv.Shutdown(shutdownCtx); err != nil {
 		application.Logger.Error("Forced shutdown", "err", err)
 	}
+
 	application.Logger.Info("Server stopped")
 }

web/app.js

@@ -50,7 +50,7 @@ async function handleUpload(file) {
   $("busy-state").classList.remove("hidden");
   $("p-bar-container").classList.add("visible");
 
-  const uploadID = Math.random().toString(36).substring(2, 15);
+  const uploadID = Array.from(window.crypto.getRandomValues(new Uint8Array(16)), (b) => b.toString(16).padStart(2, "0")).join("");
   const chunkSize = 1024 * 1024 * 8;
   const total = Math.ceil(file.size / chunkSize);
 

web/embed.go

@@ -0,0 +1,6 @@
+package web
+
+import "embed"
+
+//go:embed *.html *.css *.js *.ico
+var Assets embed.FS

web/layout.html

@@ -1,11 +1,12 @@
-{{define "base"}}
+{{define "layout"}}
 <!doctype html>
 <html lang="en">
     <head>
         <meta charset="UTF-8" />
         <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+        <link rel="icon" type="image/vnd.microsoft.icon" href="/static/favicon.ico" />
         <title>safebin</title>
-        <link rel="stylesheet" href="/static/css/style.css" />
+        <link rel="stylesheet" href="/static/style.css" />
     </head>
     <body>
         <div class="container">
@@ -28,9 +29,18 @@
                 <div class="dim cli-label">CLI Usage</div>
                 <pre class="cli-pre">curl -F file=@yourfile {{.Host}}</pre>
             </section>
+            <footer class="footer">
+                <div class="dim">
+                    {{if eq .Version "dev"}}
+                    <a href="https://github.com/skidoodle/safebin" target="_blank" rel="noopener noreferrer">dev</a>
+                    {{else}}
+                    <a href="https://github.com/skidoodle/safebin/releases/tag/v{{.Version}}" target="_blank" rel="noopener noreferrer">v{{.Version}}</a>
+                    {{end}}
+                </div>
+            </footer>
         </div>
         <input type="file" id="file-input" class="hidden" />
-        <script src="/static/js/app.js"></script>
+        <script src="/static/app.js"></script>
     </body>
 </html>
 {{end}}

web/style.css

@@ -237,10 +237,26 @@ button {
     display: none !important;
 }
 
+.footer {
+    margin-top: 20px;
+    text-align: center;
+    opacity: 0.5;
+}
+
+.footer a {
+    color: inherit;
+    text-decoration: none;
+}
+
+.footer a:hover {
+    text-decoration: underline;
+}
+
 @media (max-width: 400px) {
     .github-btn span {
         display: none;
     }
+
     .github-btn {
         padding: 6px;
     }