From 15c1caf41fa240fb95268ebf1c58d00196d19451 Mon Sep 17 00:00:00 2001
From: skidoodle <contact@albert.lol>
Date: Wed, 13 Dec 2023 10:53:22 +0100
Subject: [PATCH] pdf proxy

---
 pnpm-lock.yaml             |  1 +
 src/pages/api/erettsegi.ts | 15 +++++++++----
 src/pages/api/proxy.ts     | 43 ++++++++++++++++++++++++++++++++++++++
 src/pages/api/validate.ts  |  9 +++++---
 4 files changed, 61 insertions(+), 7 deletions(-)
 create mode 100644 src/pages/api/proxy.ts

diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 58fe935..e3e5785 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -3705,6 +3705,7 @@ packages:
 
   /glob@7.2.3:
     resolution: {integrity: sha512-nFR0zLpU2YCaRxwoCJvL6UvCH2JFyFVIvwTLsIf21AuHlMskA1hhTdk+LlYJtOlYt9v6dvszD2BGRqBL+iQK9Q==}
+    requiresBuild: true
     dependencies:
       fs.realpath: 1.0.0
       inflight: 1.0.6
diff --git a/src/pages/api/erettsegi.ts b/src/pages/api/erettsegi.ts
index dc5293b..9aba86b 100644
--- a/src/pages/api/erettsegi.ts
+++ b/src/pages/api/erettsegi.ts
@@ -9,7 +9,14 @@ export default function handler(req: NextApiRequest, res: NextApiResponse) {
     szint: string
   }
 
+  const secure = req.headers['x-forwarded-proto'] === 'https'
+  const protocol = secure ? 'https' : 'http'
+  const address = req.headers.host
+
   const baseUrl = `https://dload-oktatas.educatio.hu/erettsegi/feladatok_${ev}${idoszak}_${szint}/`
+  const proxiedUrl = `${protocol}://${address}/api/proxy?link=${encodeURIComponent(
+    baseUrl
+  )}`
 
   const missingParams = []
   if (!ev) missingParams.push('ev')
@@ -68,13 +75,13 @@ export default function handler(req: NextApiRequest, res: NextApiResponse) {
     case 'infoism':
     case 'digkult':
       flZipUrl = `${baseUrl}${prefix}${forras}_${shortev}${honap}_${feladat}.zip`
-      flPdfUrl = `${baseUrl}${prefix}_${shortev}${honap}_${feladat}.pdf`
+      flPdfUrl = `${proxiedUrl}${prefix}_${shortev}${honap}_${feladat}.pdf`
       utZipUrl = `${baseUrl}${prefix}${megoldas}_${shortev}${honap}_${utmutato}.zip`
-      utPdfUrl = `${baseUrl}${prefix}_${shortev}${honap}_${utmutato}.pdf`
+      utPdfUrl = `${proxiedUrl}${prefix}_${shortev}${honap}_${utmutato}.pdf`
       break
     default:
-      flPdfUrl = `${baseUrl}${prefix}_${shortev}${honap}_${feladat}.pdf`
-      utPdfUrl = `${baseUrl}${prefix}_${shortev}${honap}_${utmutato}.pdf`
+      flPdfUrl = `${proxiedUrl}${prefix}_${shortev}${honap}_${feladat}.pdf`
+      utPdfUrl = `${proxiedUrl}${prefix}_${shortev}${honap}_${utmutato}.pdf`
       break
   }
 
diff --git a/src/pages/api/proxy.ts b/src/pages/api/proxy.ts
new file mode 100644
index 0000000..827b8b8
--- /dev/null
+++ b/src/pages/api/proxy.ts
@@ -0,0 +1,43 @@
+import type { NextApiRequest, NextApiResponse } from 'next'
+
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse
+) {
+  const { link } = req.query as { link: string }
+  let missingParam: string | null = null
+  if (!link) {
+    missingParam = 'link'
+  }
+
+  if (missingParam) {
+    return res.status(400).json({ error: `Hiányzó paraméter: ${missingParam}` })
+  }
+
+  const domain = link.split('/')[2]
+  if (domain !== 'dload-oktatas.educatio.hu') {
+    return res.status(400).json({ error: 'Érvénytelen link' })
+  }
+
+  try {
+    const response = await fetch(link, { method: 'GET' })
+
+    if (response.headers.get('content-type') !== 'application/pdf') {
+      return res.status(400).json({ error: 'Érvénytelen link' })
+    }
+
+    if (response.ok) {
+      res.setHeader('Content-Type', 'application/pdf')
+      const arrayBuffer: ArrayBuffer = await response.arrayBuffer()
+      const pdfBuffer: Buffer = Buffer.from(arrayBuffer)
+      res.send(pdfBuffer)
+    } else {
+      res
+        .status(response.status)
+        .json({ error: 'Hiba történt a lekérés során.' })
+    }
+  } catch (error) {
+    console.error(error)
+    res.status(500).json({ error: 'Internal Server Error' })
+  }
+}
diff --git a/src/pages/api/validate.ts b/src/pages/api/validate.ts
index 5c29c60..0c8eb7c 100644
--- a/src/pages/api/validate.ts
+++ b/src/pages/api/validate.ts
@@ -14,8 +14,11 @@ export default async function handler(
     return res.status(400).json({ error: `Hiányzó paraméter: ${MissingParam}` })
   }
 
-  const domain = link.split('/')[2]
-  if (domain !== 'dload-oktatas.educatio.hu') {
+  const secure = req.headers['x-forwarded-proto'] === 'https'
+  const protocol = secure ? 'https' : 'http'
+  const address = req.headers.host
+
+  if (!link.startsWith(`${protocol}://${address}`)) {
     return res.status(400).json({ error: 'Érvénytelen link' })
   }
 
@@ -24,6 +27,6 @@ export default async function handler(
     const status = response.status
     res.status(200).json({ status })
   } catch (error) {
-    res.status(500).json({ error: 'Hiányzó paraméterek:' })
+    res.status(500).json({ error: 'Internal Server Error' })
   }
 }