Resolve git lfs pointers

Author: colebemis

netlify/edge-functions/git-lfs-file.ts

@@ -0,0 +1,54 @@
+/// <reference lib="deno.ns" />
+
+import type { Config } from "https://edge.netlify.com"
+
+export default async (request: Request) => {
+  switch (request.method) {
+    case "GET":
+      return await get(request)
+    default:
+      return new Response("Method not allowed", { status: 405 })
+  }
+}
+
+/** Resolve a Git LFS pointer to a file URL */
+async function get(request: Request) {
+  try {
+    const url = new URL(request.url)
+    const repo = url.searchParams.get("repo")
+    const pointer = url.searchParams.get("pointer")
+    const authorization = request.headers.get("Authorization")
+
+    if (!repo || !pointer || !authorization) {
+      throw new Error("Invalid request")
+    }
+
+    const oid = pointer.match(/oid sha256:(?<oid>[a-f0-9]{64})/)?.groups?.oid
+    const size = parseInt(pointer.match(/size (?<size>\d+)/)?.groups?.size ?? "0")
+
+    const response = await fetch(`https://github.com/${repo}.git/info/lfs/objects/batch`, {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+        Accept: "application/vnd.git-lfs+json",
+        Authorization: authorization,
+      },
+      body: JSON.stringify({
+        operation: "download",
+        transfers: ["basic"],
+        objects: [{ oid, size }],
+      }),
+    })
+
+    const json = await response.json()
+    const href = json.objects[0].actions.download.href
+
+    return new Response(href, { status: 200 })
+  } catch (error) {
+    return new Response(`Error: ${error.message}`, { status: 500 })
+  }
+}
+
+export const config: Config = {
+  path: "/git-lfs-file",
+}

netlify/edge-functions/github-auth.ts

@@ -5,8 +5,9 @@ import type { Config } from "https://edge.netlify.com"
 // Reference: https://docs.github.com/en/apps/oauth-apps/building-oauth-apps/authorizing-oauth-apps
 export default async (request: Request) => {
   try {
-    const code = new URL(request.url).searchParams.get("code")
-    const state = new URL(request.url).searchParams.get("state")
+    const url = new URL(request.url)
+    const code = url.searchParams.get("code")
+    const state = url.searchParams.get("state")
 
     const response = await fetch("https://github.com/login/oauth/access_token", {
       method: "POST",

src/components/file-preview.tsx

@@ -24,10 +24,6 @@ export function FilePreview({ path, alt = "" }: FilePreviewProps) {
     // If file is already cached, don't fetch it again
     if (file) return
 
-    // Use ignore flag to avoid race conditions
-    // Reference: https://react.dev/reference/react/useEffect#fetching-data-with-effects
-    let ignore = false
-
     async function loadFile() {
       if (!githubUser || !githubRepo) return
       console.log(githubUser, githubRepo)
@@ -46,12 +42,11 @@ export function FilePreview({ path, alt = "" }: FilePreviewProps) {
           url = URL.createObjectURL(file)
         }
 
-        if (!ignore) {
-          setFile(file)
-          setUrl(url)
-          // Cache the file and its URL
-          fileCache.set(path, { file, url })
-        }
+        setFile(file)
+        setUrl(url)
+
+        // Cache the file and its URL
+        fileCache.set(path, { file, url })
       } catch (error) {
         console.error(error)
       } finally {
@@ -60,10 +55,6 @@ export function FilePreview({ path, alt = "" }: FilePreviewProps) {
     }
 
     loadFile()
-
-    return () => {
-      ignore = true
-    }
   }, [file, githubUser, githubRepo, path])
 
   if (!file) {

src/utils/git-lfs.ts

@@ -22,36 +22,24 @@ export async function resolveGitLfsPointer({
 }) {
   const text = await file.text()
 
-  // Parse the Git LFS pointer
-  const oid = text.match(/oid sha256:(?<oid>[a-f0-9]{64})/)?.groups?.oid
-  const size = text.match(/size (?<size>\d+)/)?.groups?.size
-
-  if (!oid || !size) {
-    throw new Error("Invalid Git LFS pointer")
-  }
-
-  // Fetch the file URL from GitHub
-  // TODO: Use proxy to avoid CORS issues
   const response = await fetch(
-    `https://github.com/${githubRepo.owner}/${githubRepo.name}.git/info/lfs/objects/batch`,
+    `/git-lfs-file?repo=${githubRepo.owner}/${githubRepo.name}&pointer=${text}`,
     {
-      method: "POST",
       headers: {
-        "Content-Type": "application/json",
-        Accept: "application/vnd.git-lfs+json",
         Authorization: `Bearer ${githubUser.token}`,
       },
-      body: JSON.stringify({
-        operation: "download",
-        transfers: ["basic"],
-        objects: [{ oid, size }],
-      }),
     },
   )
 
-  const json = await response.json()
+  if (!response.ok) {
+    throw new Error("Unable to resolve Git LFS pointer")
+  }
+
+  const url = await response.text()
 
-  console.log(json)
+  if (!url) {
+    throw new Error("Unable to resolve Git LFS pointer")
+  }
 
-  return ""
+  return url
 }