Display PDF blobs

GitHub renders a PDF with a viewer of its own and so ships no content for
one, leaving the blob view with nothing to show. Its raw bytes come as
application/octet-stream, which browsers download rather than display, so
serve them from a new embed route that retypes them and point an <object>
at that.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BErPR92xppzGFXkPqXPYj2

1 files changed, 26 insertions, 0 deletions

diff --git a/cgithub/src/app.ts b/cgithub/src/app.ts
index 9781a98..33b408e 100644
--- a/cgithub/src/app.ts
+++ b/cgithub/src/app.ts
@@ -10,6 +10,7 @@ import {
   getGitHubLatestCommit,
   getGitHubOwner,
   getGitHubPulls,
+  getGitHubRaw,
   getGitHubRefs,
   getGitHubRelease,
   getGitHubReleases,
@@ -120,6 +121,31 @@ export function createApp(eta: Eta) {
     );
   });
 
+  // This is not a native GitHub route, but instead it lets us render blob
+  // content whose raw headers prevent hotlinking.
+  app.get("/:owner/:repo/embed/:type/:branch/:path{.*}", async (c) => {
+    const { owner, repo, type, branch, path } = c.req.param();
+
+    if (type !== "pdf") {
+      return c.notFound();
+    }
+
+    let response: Response;
+    try {
+      response = await getGitHubRaw(owner, repo, branch, path);
+    } catch (e) {
+      c.status(e instanceof GitHubHTTPError ? (e.status as StatusCode) : 500);
+      return c.body(null);
+    }
+
+    let contentType = response.headers.get("Content-Type");
+    if (contentType === null || contentType === "application/octet-stream") {
+      contentType = "application/pdf";
+    }
+
+    return new Response(response.body, { headers: { "Content-Type": contentType } });
+  });
+
   app.get("/:owner/:repo/issues", async (c) => {
     const { owner, repo } = c.req.param();
     const q = c.req.query("q");