fix: improve cancel logic in openAi model

The cancel of a request was not working correctly.
With the changes the cancelToken is better taken into account.

packages/ai-openai/src/node/openai-language-model.ts

@@ -69,6 +69,9 @@ export class OpenAiModel implements LanguageModel {
         if (request.response_format?.type === 'json_schema' && this.supportsStructuredOutput()) {
             return this.handleStructuredOutputRequest(openai, request);
         }
+        if (cancellationToken?.isCancellationRequested) {
+            return { text: '' };
+        }
 
         let runner: ChatCompletionStream;
         const tools = this.createTools(request);
@@ -95,42 +98,57 @@ export class OpenAiModel implements LanguageModel {
 
         let runnerEnd = false;
 
-        let resolve: (part: LanguageModelStreamResponsePart) => void;
+        let resolve: ((part: LanguageModelStreamResponsePart) => void) | undefined;
         runner.on('error', error => {
             console.error('Error in OpenAI chat completion stream:', error);
             runnerEnd = true;
-            resolve({ content: error.message });
+            resolve?.({ content: error.message });
         });
         // we need to also listen for the emitted errors, as otherwise any error actually thrown by the API will not be caught
         runner.emitted('error').then(error => {
             console.error('Error in OpenAI chat completion stream:', error);
             runnerEnd = true;
-            resolve({ content: error.message });
+            resolve?.({ content: error.message });
         });
         runner.emitted('abort').then(() => {
-            // do nothing, as the abort event is only emitted when the runner is aborted by us
+            // cancel async iterator
+            runnerEnd = true;
         });
         runner.on('message', message => {
             if (message.role === 'tool') {
-                resolve({ tool_calls: [{ id: message.tool_call_id, finished: true, result: this.getCompletionContent(message) }] });
+                resolve?.({ tool_calls: [{ id: message.tool_call_id, finished: true, result: this.getCompletionContent(message) }] });
             }
             console.debug('Received Open AI message', JSON.stringify(message));
         });
         runner.once('end', () => {
             runnerEnd = true;
             // eslint-disable-next-line @typescript-eslint/no-explicit-any
-            resolve(runner.finalChatCompletion as any);
+            resolve?.(runner.finalChatCompletion as any);
         });
+        if (cancellationToken?.isCancellationRequested) {
+            return { text: '' };
+        }
         const asyncIterator = {
             async *[Symbol.asyncIterator](): AsyncIterator<LanguageModelStreamResponsePart> {
                 runner.on('chunk', chunk => {
-                    if (chunk.choices[0]?.delta) {
+                    if (cancellationToken?.isCancellationRequested) {
+                        resolve = undefined;
+                        return;
+                    }
+                    if (resolve && chunk.choices[0]?.delta) {
                         resolve({ ...chunk.choices[0]?.delta });
                     }
                 });
                 while (!runnerEnd) {
+                    if (cancellationToken?.isCancellationRequested) {
+                        throw new Error('Iterator canceled');
+                    }
                     const promise = new Promise<LanguageModelStreamResponsePart>((res, rej) => {
                         resolve = res;
+                        cancellationToken?.onCancellationRequested(() => {
+                            rej(new Error('Canceled'));
+                            runnerEnd = true; // Stop the iterator
+                        });
                     });
                     yield promise;
                 }