fix(proxy/api/ndJsonStream): send header for empty iterables

Introduced by ed987e161

@xen-orchestra/proxy/src/app/mixins/api.mjs

@@ -15,24 +15,29 @@ import { createLogger } from '@xen-orchestra/log'
 const { debug, warn } = createLogger('xo:proxy:api')
 
 const ndJsonStream = asyncIteratorToStream(async function*(responseId, iterable) {
-  let headerSent = false
   try {
-    for await (const data of iterable) {
-      if (!headerSent) {
+    let cursor, iterator
+    try {
+      const getIterator = iterable[Symbol.iterator] ?? iterable[Symbol.asyncIterator]
+      iterator = getIterator.call(iterable)
+
+      cursor = await iterator.next()
       yield format.response(responseId, { $responseType: 'ndjson' }) + '\n'
-        headerSent = true
+    } catch (error) {
+      yield format.error(responseId, error)
+      throw error
     }
+
+    while (!cursor.done) {
       try {
-        yield JSON.stringify(data) + '\n'
+        yield JSON.stringify(cursor.value) + '\n'
       } catch (error) {
         warn('ndJsonStream, item error', { error })
       }
+      cursor = await iterator.next()
     }
   } catch (error) {
     warn('ndJsonStream, fatal error', { error })
-    if (!headerSent) {
-      yield format.error(responseId, error)
-    }
   }
 })
 
@@ -47,7 +52,7 @@ export default class Api {
       ctx.req.setTimeout(0)
 
       const profile = await app.authentication.findProfile({
-        authenticationToken: ctx.cookies.get('authenticationToken'),
+        authenticationToken: ctx.cookies.get('authenticationToken')
       })
       if (profile === undefined) {
         ctx.status = 401
@@ -126,14 +131,14 @@ export default class Api {
             }
           }.bind(this),
           {
-            description: 'returns the signatures of all available API methods',
-          },
+            description: 'returns the signatures of all available API methods'
+          }
         ],
         getServerVersion: [
           () => appVersion,
           {
-            description: 'returns the version of xo-server',
-          },
+            description: 'returns the version of xo-server'
+          }
         ],
         listMethods: [
           function*() {
@@ -143,8 +148,8 @@ export default class Api {
             }
           }.bind(this),
           {
-            description: 'returns the name of all available API methods',
-          },
+            description: 'returns the name of all available API methods'
+          }
         ],
         methodSignature: [
           ({ method: name }) => {
@@ -159,10 +164,10 @@ export default class Api {
           {
             description: 'returns the signature of an API method',
             params: {
-              method: { type: 'string' },
-            },
-          },
-        ],
+              method: { type: 'string' }
+            }
+          }
+        ]
       },
       test: {
         range: [
@@ -184,11 +189,11 @@ export default class Api {
             params: {
               start: { optional: true, type: 'number' },
               step: { optional: true, type: 'number' },
-              stop: { type: 'number' },
-            },
-          },
-        ],
-      },
+              stop: { type: 'number' }
+            }
+          }
+        ]
+      }
     })
   }
 
@@ -215,7 +220,7 @@ export default class Api {
         return required
       }),
 
-      type: 'object',
+      type: 'object'
     })
 
     const m = params => {

CHANGELOG.unreleased.md

@@ -27,3 +27,5 @@
 > - major: if the change breaks compatibility
 >
 > In case of conflict, the highest (lowest in previous list) `$version` wins.
+
+- @xen-orchestra/proxy patch