feat: add x-error header

src/index.js

@@ -36,7 +36,7 @@ export default {
         return daResp({ status: 400 });
       }
       console.error('Error computing context', e);
-      return daResp({ status: 500 });
+      return daResp({ status: 500, error: e.message });
     }
 
     const { users, authorized, key } = daCtx;

src/storage/object/get.js

@@ -89,7 +89,10 @@ export default async function getObject(
           etag: e.ETag || conditionalHeaders?.ifNoneMatch,
         };
       }
-      return { body: '', status, contentLength: 0 };
+      const error = status >= 500 ? e.message : undefined;
+      return {
+        body: '', status, contentLength: 0, ...(error ? { error } : {}),
+      };
     }
   }
   // HEAD request path - uses presigned URL with fetch
@@ -141,6 +144,9 @@ export default async function getObject(
     if (status === 304 || status === 412) {
       return { body: '', status, contentLength: 0 };
     }
-    return { body: '', status, contentLength: 0 };
+    const error = status >= 500 ? e.message : undefined;
+    return {
+      body: '', status, contentLength: 0, ...(error ? { error } : {}),
+    };
   }
 }

src/storage/object/move.js

@@ -80,15 +80,15 @@ export default async function moveObject(env, daCtx, details) {
           // eslint-disable-next-line no-console
           console.error('Move partial failure', r.reason);
         });
-        return { body: JSON.stringify({ error: 'partial_failure', failed: failed.length }), status: 500 };
+        return { body: JSON.stringify({ error: 'partial_failure', failed: failed.length }), status: 500, error: failed[0]?.reason?.message };
       }
       results.push(...settled.map((r) => r.value));
 
       ContinuationToken = NextContinuationToken;
     } catch (e) {
       // eslint-disable-next-line no-console
       console.error('Move failed', e);
-      return { body: JSON.stringify({ error: 'move_failed' }), status: 500 };
+      return { body: JSON.stringify({ error: 'move_failed' }), status: 500, error: e.message };
     }
   } while (ContinuationToken);
 

src/storage/version/audit.js

@@ -278,6 +278,6 @@ export async function writeAuditEntry(env, ctx, repo, fileId, entry, attempt = 0
   } catch (e) {
     // eslint-disable-next-line no-console
     console.error('writeAuditEntry failed', e);
-    return { status: 500 };
+    return { status: 500, error: e.message };
   }
 }

src/storage/version/put.js

@@ -69,7 +69,7 @@ export async function putVersion(config, {
     // Cancel the body stream if it wasn't consumed (e.g. R2 rejected via 100-continue on 412).
     // Without this, Cloudflare Workers logs "non-retryable streaming request" warnings.
     if (Body?.cancel) Body.cancel();
-    return { status };
+    return { status, ...(status >= 500 ? { error: e.message } : {}) };
   }
 }
 
@@ -189,7 +189,7 @@ export async function putObjectWithVersion(
 
       // eslint-disable-next-line no-console
       if (status >= 500) console.error('Failed to put object (in object with version)', e);
-      return { status, metadata: { id: ID } };
+      return { status, metadata: { id: ID }, ...(status >= 500 ? { error: e.message } : {}) };
     }
   }
 
@@ -319,7 +319,7 @@ export async function putObjectWithVersion(
 
     // eslint-disable-next-line no-console
     if (status >= 500) console.error('Failed to version (in object with version)', e);
-    return { status, metadata: { id: ID } };
+    return { status, metadata: { id: ID }, ...(status >= 500 ? { error: e.message } : {}) };
   }
 }
 
@@ -335,7 +335,7 @@ export async function postObjectVersionWithLabel(label, env, daCtx) {
   }, true);
 
   if (resp.status !== 200) return { status: resp.status };
-  if (!resp.versionCreated) return { status: 500 };
+  if (!resp.versionCreated) return { status: 500, error: 'Version was not created' };
   return { status: 201 };
 }
 

src/utils/daResp.js

@@ -30,12 +30,13 @@ export default function daResp({
   metadata,
   etag,
   continuationToken,
+  error,
 }, ctx = null) {
   const headers = new Headers();
   headers.append('Access-Control-Allow-Origin', '*');
   headers.append('Access-Control-Allow-Methods', 'HEAD, GET, PUT, POST, DELETE');
   headers.append('Access-Control-Allow-Headers', '*');
-  headers.append('Access-Control-Expose-Headers', 'X-da-actions, X-da-child-actions, X-da-acltrace, X-da-id, da-continuation-token, ETag');
+  headers.append('Access-Control-Expose-Headers', 'X-da-actions, X-da-child-actions, X-da-acltrace, X-da-id, da-continuation-token, ETag, x-error');
   headers.append('Content-Type', normalizeCharset(contentType));
   if (contentLength) {
     headers.append('Content-Length', contentLength);
@@ -55,6 +56,10 @@ export default function daResp({
     headers.append('da-continuation-token', continuationToken);
   }
 
+  if (status >= 500 && error) {
+    headers.append('x-error', error);
+  }
+
   if (ctx?.aclCtx && status < 500) {
     headers.append('X-da-actions', `/${ctx.key}=${[...ctx.aclCtx.actionSet]}`);
 

test/storage/object/move.test.js

@@ -118,6 +118,7 @@ describe('Move', () => {
     const resp = await moveObject({}, ctx, { source: 'somewhere', destination: 'somedest' });
 
     assert.strictEqual(resp.status, 500);
+    assert.strictEqual(resp.error, 'R2 throttled');
     const body = JSON.parse(resp.body);
     assert.strictEqual(body.error, 'move_failed');
   });
@@ -161,6 +162,7 @@ describe('Move', () => {
 
     // a.html (from initialKeys) throws, b.html succeeds — one failure, one success
     assert.strictEqual(resp.status, 500);
+    assert.strictEqual(resp.error, 'R2 throttled');
     const body = JSON.parse(resp.body);
     assert.strictEqual(body.error, 'partial_failure');
     assert.strictEqual(body.failed, 1);

test/storage/version/audit.test.js

@@ -511,6 +511,7 @@ describe('Version Audit', () => {
       });
 
       assert.strictEqual(result.status, 500);
+      assert.strictEqual(result.error, 'server error');
     });
 
     it('appends three entries when edit then version then edit (version breaks time window)', async () => {
@@ -851,6 +852,7 @@ describe('Version Audit', () => {
       });
 
       assert.strictEqual(result.status, 500, 'persistent 412 must surface as 500 after one retry');
+      assert.strictEqual(result.error, 'precondition failed');
     });
   });
 });

test/storage/version/put.test.js

@@ -228,6 +228,7 @@ describe('Version Put', () => {
     const mockCtx = { users: [{ email: 'blah@acme.com' }] };
     const resp = await putObjectWithVersion(mockEnv, mockCtx, mockUpdate, true);
     assert.equal(500, resp.status);
+    assert.strictEqual(resp.error, 'testing 123');
   });
 
   it('Put Object With Version store content', async () => {
@@ -788,9 +789,11 @@ describe('Version Put', () => {
     s3Client = s3client2;
     const resp2 = await putVersion({}, { Body: 'hello' });
     assert.equal(500, resp2.status);
+    assert.strictEqual(resp2.error, 'Test error2');
     s3Client = s3client3;
     const resp3 = await putVersion({}, { Body: 'hello' });
     assert.equal(500, resp3.status);
+    assert.strictEqual(resp3.error, 'Test error3');
   });
 
   it('Test putVersion preserves ContentType', async () => {
@@ -2298,6 +2301,7 @@ describe('Version Put', () => {
 
     const resp = await postObjectVersion(req, env, ctx);
     assert.equal(500, resp.status);
+    assert.strictEqual(resp.error, 'Version was not created');
   });
 
   it('postObjectVersion returns 201 when version is successfully created', async () => {
@@ -2965,6 +2969,7 @@ describe('Version Put', () => {
 
       // No label means shouldCreateVersionObject is false → versionCreated stays false → 500
       assert.strictEqual(resp.status, 500);
+      assert.strictEqual(resp.error, 'Version was not created');
     });
   });
 
@@ -3066,6 +3071,7 @@ describe('Version Put', () => {
       const resp = await postObjectVersionWithLabel('My Label', {}, daCtx);
 
       assert.strictEqual(resp.status, 500, 'must return 500 when version was not created');
+      assert.strictEqual(resp.error, 'Version was not created');
     });
   });
 });

test/utils/daResp.test.js

@@ -28,7 +28,7 @@ describe('DA Resp', () => {
     assert.strictEqual('*', resp.headers.get('Access-Control-Allow-Origin'));
     assert.strictEqual('HEAD, GET, PUT, POST, DELETE', resp.headers.get('Access-Control-Allow-Methods'));
     assert.strictEqual('*', resp.headers.get('Access-Control-Allow-Headers'));
-    assert.strictEqual('X-da-actions, X-da-child-actions, X-da-acltrace, X-da-id, da-continuation-token, ETag', resp.headers.get('Access-Control-Expose-Headers'));
+    assert.strictEqual('X-da-actions, X-da-child-actions, X-da-acltrace, X-da-id, da-continuation-token, ETag, x-error', resp.headers.get('Access-Control-Expose-Headers'));
     assert.strictEqual('text/plain; charset=utf-8', resp.headers.get('Content-Type'));
     assert.strictEqual('777', resp.headers.get('Content-Length'));
     assert.strictEqual('/foo/bar.html=read,write', resp.headers.get('X-da-actions'));
@@ -49,7 +49,7 @@ describe('DA Resp', () => {
     assert.strictEqual('*', resp.headers.get('Access-Control-Allow-Origin'));
     assert.strictEqual('HEAD, GET, PUT, POST, DELETE', resp.headers.get('Access-Control-Allow-Methods'));
     assert.strictEqual('*', resp.headers.get('Access-Control-Allow-Headers'));
-    assert.strictEqual('X-da-actions, X-da-child-actions, X-da-acltrace, X-da-id, da-continuation-token, ETag', resp.headers.get('Access-Control-Expose-Headers'));
+    assert.strictEqual('X-da-actions, X-da-child-actions, X-da-acltrace, X-da-id, da-continuation-token, ETag, x-error', resp.headers.get('Access-Control-Expose-Headers'));
     assert.strictEqual('application/json', resp.headers.get('Content-Type'));
     assert(!resp.headers.get('Content-Length'));
     assert.strictEqual('/foo/blah.html=read', resp.headers.get('X-da-actions'));
@@ -69,6 +69,13 @@ describe('DA Resp', () => {
     assert(resp.headers.get('X-da-child-actions') === null);
     assert(resp.headers.get('X-da-acltrace') === null);
     assert(resp.headers.get('X-da-id') === null);
+    assert(resp.headers.get('x-error') === null);
+  });
+
+  it('test 500 with error message', () => {
+    const resp = daResp({ status: 500, error: 'Something went wrong' });
+    assert.strictEqual(500, resp.status);
+    assert.strictEqual('Something went wrong', resp.headers.get('x-error'));
   });
 
   it('normalizes text/html to include charset=utf-8', () => {
@@ -136,7 +143,7 @@ describe('DA Resp', () => {
     const ctx = { key: 'foo/bar.html', aclCtx };
     const resp = daResp({ status: 200, body: 'foobar' }, ctx);
     assert.strictEqual(200, resp.status);
-    assert.strictEqual('X-da-actions, X-da-child-actions, X-da-acltrace, X-da-id, da-continuation-token, ETag', resp.headers.get('Access-Control-Expose-Headers'));
+    assert.strictEqual('X-da-actions, X-da-child-actions, X-da-acltrace, X-da-id, da-continuation-token, ETag, x-error', resp.headers.get('Access-Control-Expose-Headers'));
     assert.strictEqual('/haha/hoho/**=read,write', resp.headers.get('X-da-child-actions'));
   });
 });