Render repository wikis

Wikis are one of the last parts of GitHub still served as plain Rails
HTML, with no embedded JSON to read, so this scrapes the markup: a page
and any older revision of it, the _Sidebar and _Footer a wiki can
define, and the page index. Every page is already in the sidebar of
every page, since the "Show N more pages" button only unhides the rest,
so linking the whole wiki costs no second request.

Routes mirror GitHub's and resolve in its order, so an underscore name
reserved for its own actions (_pages, _history, _new, _edit) can never
be mistaken for a page; the ones we don't serve fall through to the
usual redirect. A slug reaches us decoded and has to be encoded again
rather than interpolated the way a ref is, or a page named C# would
truncate at the fragment.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013rQG1io1i4GJQW5RFcXNGd

1 files changed, 32 insertions, 0 deletions

diff --git a/cgithub/src/app.ts b/cgithub/src/app.ts
index 33b408e..956a8cb 100644
--- a/cgithub/src/app.ts
+++ b/cgithub/src/app.ts
@@ -16,6 +16,8 @@ import {
   getGitHubReleases,
   getGitHubRepo,
   getGitHubTree,
+  getGitHubWiki,
+  getGitHubWikiPages,
   GitHubHTTPError,
   RedirectError,
 } from "./scraper.ts";
@@ -146,6 +148,36 @@ export function createApp(eta: Eta) {
     return new Response(response.body, { headers: { "Content-Type": contentType } });
   });
 
+  // GitHub's own wiki URLs, in the order it resolves them: names beginning with
+  // an underscore are reserved for its actions (_pages, _new, _edit, ...), so a
+  // page can never be mistaken for one.
+  app.get("/:owner/:repo/wiki", async (c) => {
+    const { owner, repo } = c.req.param();
+    return tryRender(c, "wiki.eta", getGitHubWiki(owner, repo));
+  });
+
+  app.get("/:owner/:repo/wiki/_pages", async (c) => {
+    const { owner, repo } = c.req.param();
+    return tryRender(c, "wikiPages.eta", getGitHubWikiPages(owner, repo));
+  });
+
+  // An older revision of a page renders exactly like its current one.
+  app.get("/:owner/:repo/wiki/:page/:oid", async (c) => {
+    const { owner, repo, page, oid } = c.req.param();
+    if (page.startsWith("_") || !/^[0-9a-f]{40}$/.test(oid)) {
+      return redirectToGitHub(c, githubUrlFor(c));
+    }
+    return tryRender(c, "wiki.eta", getGitHubWiki(owner, repo, page, oid));
+  });
+
+  app.get("/:owner/:repo/wiki/:page", async (c) => {
+    const { owner, repo, page } = c.req.param();
+    if (page.startsWith("_")) {
+      return redirectToGitHub(c, githubUrlFor(c));
+    }
+    return tryRender(c, "wiki.eta", getGitHubWiki(owner, repo, page));
+  });
+
   app.get("/:owner/:repo/issues", async (c) => {
     const { owner, repo } = c.req.param();
     const q = c.req.query("q");