fix(pypi): prevent caching origin-bound rewritten index pages

src/index.js

@@ -555,6 +555,7 @@ async function handleRequest(request, env, ctx) {
                     /** @type {string | ReadableStream<Uint8Array> | null} */
                     let responseBody = response.body;
                     let rewrittenContentLength = null;
+                    let hasOriginBoundRewrite = false;
 
                     if (
                       shouldRewriteTextResponse(
@@ -575,6 +576,7 @@ async function handleRequest(request, env, ctx) {
                       );
                       responseBody = rewrittenText;
                       rewrittenContentLength = new TextEncoder().encode(rewrittenText).byteLength;
+                      hasOriginBoundRewrite = platform === 'pypi';
                     }
 
                     const headers = new Headers(response.headers);
@@ -586,6 +588,8 @@ async function handleRequest(request, env, ctx) {
                     if (!isGit && !isGitLFS && !isDocker && !isAI && !isHF) {
                       if (!canUseCache) {
                         headers.set('Cache-Control', 'no-store');
+                      } else if (hasOriginBoundRewrite) {
+                        headers.set('Cache-Control', 'no-store');
                       } else if (hasSensitiveHeaders) {
                         headers.set('Cache-Control', 'private, no-store');
                         const existingVary = headers.get('Vary');
@@ -629,6 +633,7 @@ async function handleRequest(request, env, ctx) {
                       !isDocker &&
                       !isAI &&
                       !isHF &&
+                      !hasOriginBoundRewrite &&
                       !hasSensitiveHeaders &&
                       request.method === 'GET' &&
                       response.ok &&

test/unit/worker-regressions.test.js

@@ -64,6 +64,27 @@ describe('Worker regression coverage', () => {
     expect(clearTimeoutSpy).toHaveBeenCalledWith(timeoutToken);
   });
 
+  it('does not cache host-bound PyPI rewritten HTML responses', async () => {
+    vi.spyOn(globalThis, 'fetch').mockResolvedValue(
+      new Response('<a href="https://files.pythonhosted.org/packages/demo.whl">demo</a>', {
+        status: 200,
+        headers: { 'Content-Type': 'text/html; charset=utf-8' }
+      })
+    );
+
+    const response = await worker.fetch(
+      new Request('https://mirror.example/pypi/simple/demo/'),
+      {},
+      executionContext
+    );
+
+    const body = await response.text();
+
+    expect(response.status).toBe(200);
+    expect(body).toContain('https://mirror.example/pypi/files/packages/demo.whl');
+    expect(response.headers.get('Cache-Control')).toBe('no-store');
+    expect(cacheDefault.put).not.toHaveBeenCalled();
+  });
   it('forwards body and content type for configured non-protocol POST requests', async () => {
     /** @type {{ url: string, method: string | undefined, body: string | null, contentType: string | null, cf: unknown }} */
     let observed = {