feat: add an x-redirected-url header to inform clients of redirects (#7)

middleware.js

@@ -39,6 +39,7 @@ const exposeHeaders = [
   'transfer-encoding',
   'vary',
   'x-github-request-id',
+  'x-redirected-url',
 ]
 const allowMethods = [
   'POST',
@@ -108,6 +109,11 @@ module.exports = ({ origin, insecure_origins = [], authorization = noop } = {})
       }
     }
 
+    // GitHub uses user-agent sniffing for git/* and changes its behavior which is frustrating
+    if (!headers['user-agent'] || !headers['user-agent'].startsWith('git/')) {
+      headers['user-agent'] = 'git/@isomorphic-git/cors-proxy'
+    }
+
     let p = u.path
     let parts = p.match(/\/([^\/]*)\/(.*)/)
     let pathdomain = parts[1]
@@ -128,6 +134,9 @@ module.exports = ({ origin, insecure_origins = [], authorization = noop } = {})
         if (f.headers.has(h)) {
           res.setHeader(h, f.headers.get(h))
         }
+        if (f.redirected) {
+          res.setHeader('x-redirected-url', f.url)
+        }
       }
       f.body.pipe(res)
     })

package.json

@@ -23,7 +23,7 @@
     "micro": "^9.3.3",
     "micro-cors": "0.1.1",
     "minimisted": "^2.0.0",
-    "node-fetch": "^2.3.0",
+    "node-fetch": "^2.6.0",
     "tree-kill": "^1.2.1"
   },
   "now": {