Convert CCPA requests to proper format (#981)

CCPA uses a different format than GenAi. This adds conversion code to get it to the right format.

Note that this doesn't work against the current ccpa staging server, The changes it needs are in cl/770266927

3 files changed, 434 insertions, 17 deletions

diff --git a/packages/core/src/code_assist/ccpaServer.ts b/packages/core/src/code_assist/ccpaServer.ts
index 7a542db4..3ef8b084 100644
--- a/packages/core/src/code_assist/ccpaServer.ts
+++ b/packages/core/src/code_assist/ccpaServer.ts
@@ -19,10 +19,10 @@ import {
   CountTokensResponse,
   EmbedContentParameters,
 } from '@google/genai';
-import { Readable } from 'stream';
 import * as readline from 'readline';
-import type { ReadableStream } from 'node:stream/web';
 import { ContentGenerator } from '../core/contentGenerator.js';
+import { CcpaResponse, toCcpaRequest, fromCcpaResponse } from './converter.js';
+import { PassThrough } from 'node:stream';
 
 // TODO: Use production endpoint once it supports our methods.
 export const CCPA_ENDPOINT =
@@ -38,19 +38,25 @@ export class CcpaServer implements ContentGenerator {
   async generateContentStream(
     req: GenerateContentParameters,
   ): Promise<AsyncGenerator<GenerateContentResponse>> {
-    return await this.streamEndpoint<GenerateContentResponse>(
+    const resps = await this.streamEndpoint<CcpaResponse>(
       'streamGenerateContent',
-      req,
+      toCcpaRequest(req, this.projectId),
     );
+    return (async function* (): AsyncGenerator<GenerateContentResponse> {
+      for await (const resp of resps) {
+        yield fromCcpaResponse(resp);
+      }
+    })();
   }
 
   async generateContent(
     req: GenerateContentParameters,
   ): Promise<GenerateContentResponse> {
-    return await this.callEndpoint<GenerateContentResponse>(
+    const resp = await this.callEndpoint<CcpaResponse>(
       'generateContent',
-      req,
+      toCcpaRequest(req, this.projectId),
     );
+    return fromCcpaResponse(resp);
   }
 
   async onboardUser(
@@ -92,11 +98,6 @@ export class CcpaServer implements ContentGenerator {
       responseType: 'json',
       body: JSON.stringify(req),
     });
-    if (res.status !== 200) {
-      throw new Error(
-        `Failed to fetch from ${method}: ${res.status} ${res.data}`,
-      );
-    }
     return res.data as T;
   }
 
@@ -114,15 +115,10 @@ export class CcpaServer implements ContentGenerator {
       responseType: 'stream',
       body: JSON.stringify(req),
     });
-    if (res.status !== 200) {
-      throw new Error(
-        `Failed to fetch from ${method}: ${res.status} ${res.data}`,
-      );
-    }
 
     return (async function* (): AsyncGenerator<T> {
       const rl = readline.createInterface({
-        input: Readable.fromWeb(res.data as ReadableStream<Uint8Array>),
+        input: res.data as PassThrough,
         crlfDelay: Infinity, // Recognizes '\r\n' and '\n' as line breaks
       });
 
diff --git a/packages/core/src/code_assist/converter.test.ts b/packages/core/src/code_assist/converter.test.ts
new file mode 100644
index 00000000..4536d65f
--- /dev/null
+++ b/packages/core/src/code_assist/converter.test.ts
@@ -0,0 +1,222 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import { toCcpaRequest, fromCcpaResponse, CcpaResponse } from './converter.js';
+import {
+  GenerateContentParameters,
+  GenerateContentResponse,
+  FinishReason,
+  BlockedReason,
+} from '@google/genai';
+
+describe('converter', () => {
+  describe('toCcpaRequest', () => {
+    it('should convert a simple request with project', () => {
+      const genaiReq: GenerateContentParameters = {
+        model: 'gemini-pro',
+        contents: [{ role: 'user', parts: [{ text: 'Hello' }] }],
+      };
+      const ccpaReq = toCcpaRequest(genaiReq, 'my-project');
+      expect(ccpaReq).toEqual({
+        model: 'gemini-pro',
+        project: 'my-project',
+        request: {
+          contents: [{ role: 'user', parts: [{ text: 'Hello' }] }],
+          systemInstruction: undefined,
+          cachedContent: undefined,
+          tools: undefined,
+          toolConfig: undefined,
+          labels: undefined,
+          safetySettings: undefined,
+          generationConfig: undefined,
+        },
+      });
+    });
+
+    it('should convert a request without a project', () => {
+      const genaiReq: GenerateContentParameters = {
+        model: 'gemini-pro',
+        contents: [{ role: 'user', parts: [{ text: 'Hello' }] }],
+      };
+      const ccpaReq = toCcpaRequest(genaiReq);
+      expect(ccpaReq).toEqual({
+        model: 'gemini-pro',
+        project: undefined,
+        request: {
+          contents: [{ role: 'user', parts: [{ text: 'Hello' }] }],
+          systemInstruction: undefined,
+          cachedContent: undefined,
+          tools: undefined,
+          toolConfig: undefined,
+          labels: undefined,
+          safetySettings: undefined,
+          generationConfig: undefined,
+        },
+      });
+    });
+
+    it('should handle string content', () => {
+      const genaiReq: GenerateContentParameters = {
+        model: 'gemini-pro',
+        contents: 'Hello',
+      };
+      const ccpaReq = toCcpaRequest(genaiReq);
+      expect(ccpaReq.request.contents).toEqual([
+        { role: 'user', parts: [{ text: 'Hello' }] },
+      ]);
+    });
+
+    it('should handle Part[] content', () => {
+      const genaiReq: GenerateContentParameters = {
+        model: 'gemini-pro',
+        contents: [{ text: 'Hello' }, { text: 'World' }],
+      };
+      const ccpaReq = toCcpaRequest(genaiReq);
+      expect(ccpaReq.request.contents).toEqual([
+        { role: 'user', parts: [{ text: 'Hello' }] },
+        { role: 'user', parts: [{ text: 'World' }] },
+      ]);
+    });
+
+    it('should handle system instructions', () => {
+      const genaiReq: GenerateContentParameters = {
+        model: 'gemini-pro',
+        contents: 'Hello',
+        config: {
+          systemInstruction: 'You are a helpful assistant.',
+        },
+      };
+      const ccpaReq = toCcpaRequest(genaiReq);
+      expect(ccpaReq.request.systemInstruction).toEqual({
+        role: 'user',
+        parts: [{ text: 'You are a helpful assistant.' }],
+      });
+    });
+
+    it('should handle generation config', () => {
+      const genaiReq: GenerateContentParameters = {
+        model: 'gemini-pro',
+        contents: 'Hello',
+        config: {
+          temperature: 0.8,
+          topK: 40,
+        },
+      };
+      const ccpaReq = toCcpaRequest(genaiReq);
+      expect(ccpaReq.request.generationConfig).toEqual({
+        temperature: 0.8,
+        topK: 40,
+      });
+    });
+
+    it('should handle all generation config fields', () => {
+      const genaiReq: GenerateContentParameters = {
+        model: 'gemini-pro',
+        contents: 'Hello',
+        config: {
+          temperature: 0.1,
+          topP: 0.2,
+          topK: 3,
+          candidateCount: 4,
+          maxOutputTokens: 5,
+          stopSequences: ['a'],
+          responseLogprobs: true,
+          logprobs: 6,
+          presencePenalty: 0.7,
+          frequencyPenalty: 0.8,
+          seed: 9,
+          responseMimeType: 'application/json',
+        },
+      };
+      const ccpaReq = toCcpaRequest(genaiReq);
+      expect(ccpaReq.request.generationConfig).toEqual({
+        temperature: 0.1,
+        topP: 0.2,
+        topK: 3,
+        candidateCount: 4,
+        maxOutputTokens: 5,
+        stopSequences: ['a'],
+        responseLogprobs: true,
+        logprobs: 6,
+        presencePenalty: 0.7,
+        frequencyPenalty: 0.8,
+        seed: 9,
+        responseMimeType: 'application/json',
+      });
+    });
+  });
+
+  describe('fromCcpaResponse', () => {
+    it('should convert a simple response', () => {
+      const ccpaRes: CcpaResponse = {
+        response: {
+          candidates: [
+            {
+              index: 0,
+              content: {
+                role: 'model',
+                parts: [{ text: 'Hi there!' }],
+              },
+              finishReason: FinishReason.STOP,
+              safetyRatings: [],
+            },
+          ],
+        },
+      };
+      const genaiRes = fromCcpaResponse(ccpaRes);
+      expect(genaiRes).toBeInstanceOf(GenerateContentResponse);
+      expect(genaiRes.candidates).toEqual(ccpaRes.response.candidates);
+    });
+
+    it('should handle prompt feedback and usage metadata', () => {
+      const ccpaRes: CcpaResponse = {
+        response: {
+          candidates: [],
+          promptFeedback: {
+            blockReason: BlockedReason.SAFETY,
+            safetyRatings: [],
+          },
+          usageMetadata: {
+            promptTokenCount: 10,
+            candidatesTokenCount: 20,
+            totalTokenCount: 30,
+          },
+        },
+      };
+      const genaiRes = fromCcpaResponse(ccpaRes);
+      expect(genaiRes.promptFeedback).toEqual(ccpaRes.response.promptFeedback);
+      expect(genaiRes.usageMetadata).toEqual(ccpaRes.response.usageMetadata);
+    });
+
+    it('should handle automatic function calling history', () => {
+      const ccpaRes: CcpaResponse = {
+        response: {
+          candidates: [],
+          automaticFunctionCallingHistory: [
+            {
+              role: 'model',
+              parts: [
+                {
+                  functionCall: {
+                    name: 'test_function',
+                    args: {
+                      foo: 'bar',
+                    },
+                  },
+                },
+              ],
+            },
+          ],
+        },
+      };
+      const genaiRes = fromCcpaResponse(ccpaRes);
+      expect(genaiRes.automaticFunctionCallingHistory).toEqual(
+        ccpaRes.response.automaticFunctionCallingHistory,
+      );
+    });
+  });
+});
diff --git a/packages/core/src/code_assist/converter.ts b/packages/core/src/code_assist/converter.ts
new file mode 100644
index 00000000..c7b0e7c7
--- /dev/null
+++ b/packages/core/src/code_assist/converter.ts
@@ -0,0 +1,199 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  Content,
+  ContentListUnion,
+  ContentUnion,
+  GenerateContentConfig,
+  GenerateContentParameters,
+  GenerateContentResponse,
+  GenerationConfigRoutingConfig,
+  MediaResolution,
+  Candidate,
+  ModelSelectionConfig,
+  GenerateContentResponsePromptFeedback,
+  GenerateContentResponseUsageMetadata,
+  Part,
+  SafetySetting,
+  PartUnion,
+  SchemaUnion,
+  SpeechConfigUnion,
+  ThinkingConfig,
+  ToolListUnion,
+  ToolConfig,
+} from '@google/genai';
+
+export interface CcpaRequest {
+  model: string;
+  project?: string;
+  request: CcpaGenerateContentRequest;
+}
+
+interface CcpaGenerateContentRequest {
+  contents: Content[];
+  systemInstruction?: Content;
+  cachedContent?: string;
+  tools?: ToolListUnion;
+  toolConfig?: ToolConfig;
+  labels?: Record<string, string>;
+  safetySettings?: SafetySetting[];
+  generationConfig?: CcpaGenerationConfig;
+}
+
+interface CcpaGenerationConfig {
+  temperature?: number;
+  topP?: number;
+  topK?: number;
+  candidateCount?: number;
+  maxOutputTokens?: number;
+  stopSequences?: string[];
+  responseLogprobs?: boolean;
+  logprobs?: number;
+  presencePenalty?: number;
+  frequencyPenalty?: number;
+  seed?: number;
+  responseMimeType?: string;
+  responseSchema?: SchemaUnion;
+  routingConfig?: GenerationConfigRoutingConfig;
+  modelSelectionConfig?: ModelSelectionConfig;
+  responseModalities?: string[];
+  mediaResolution?: MediaResolution;
+  speechConfig?: SpeechConfigUnion;
+  audioTimestamp?: boolean;
+  thinkingConfig?: ThinkingConfig;
+}
+
+export interface CcpaResponse {
+  response: VertexResponse;
+}
+
+interface VertexResponse {
+  candidates: Candidate[];
+  automaticFunctionCallingHistory?: Content[];
+  promptFeedback?: GenerateContentResponsePromptFeedback;
+  usageMetadata?: GenerateContentResponseUsageMetadata;
+}
+
+export function toCcpaRequest(
+  req: GenerateContentParameters,
+  project?: string,
+): CcpaRequest {
+  return {
+    model: req.model,
+    project,
+    request: toCcpaGenerateContentRequest(req),
+  };
+}
+
+export function fromCcpaResponse(res: CcpaResponse): GenerateContentResponse {
+  const inres = res.response;
+  const out = new GenerateContentResponse();
+  out.candidates = inres.candidates;
+  out.automaticFunctionCallingHistory = inres.automaticFunctionCallingHistory;
+  out.promptFeedback = inres.promptFeedback;
+  out.usageMetadata = inres.usageMetadata;
+  return out;
+}
+
+function toCcpaGenerateContentRequest(
+  req: GenerateContentParameters,
+): CcpaGenerateContentRequest {
+  return {
+    contents: toContents(req.contents),
+    systemInstruction: maybeToContent(req.config?.systemInstruction),
+    cachedContent: req.config?.cachedContent,
+    tools: req.config?.tools,
+    toolConfig: req.config?.toolConfig,
+    labels: req.config?.labels,
+    safetySettings: req.config?.safetySettings,
+    generationConfig: toCcpaGenerationConfig(req.config),
+  };
+}
+
+function toContents(contents: ContentListUnion): Content[] {
+  if (Array.isArray(contents)) {
+    // it's a Content[] or a PartsUnion[]
+    return contents.map(toContent);
+  }
+  // it's a Content or a PartsUnion
+  return [toContent(contents)];
+}
+
+function maybeToContent(content?: ContentUnion): Content | undefined {
+  if (!content) {
+    return undefined;
+  }
+  return toContent(content);
+}
+
+function toContent(content: ContentUnion): Content {
+  if (Array.isArray(content)) {
+    // it's a PartsUnion[]
+    return {
+      role: 'user',
+      parts: toParts(content),
+    };
+  }
+  if (typeof content === 'string') {
+    // it's a string
+    return {
+      role: 'user',
+      parts: [{ text: content }],
+    };
+  }
+  if ('parts' in content) {
+    // it's a Content
+    return content;
+  }
+  // it's a Part
+  return {
+    role: 'user',
+    parts: [content as Part],
+  };
+}
+
+function toParts(parts: PartUnion[]): Part[] {
+  return parts.map(toPart);
+}
+
+function toPart(part: PartUnion): Part {
+  if (typeof part === 'string') {
+    // it's a string
+    return { text: part };
+  }
+  return part;
+}
+
+function toCcpaGenerationConfig(
+  config?: GenerateContentConfig,
+): CcpaGenerationConfig | undefined {
+  if (!config) {
+    return undefined;
+  }
+  return {
+    temperature: config.temperature,
+    topP: config.topP,
+    topK: config.topK,
+    candidateCount: config.candidateCount,
+    maxOutputTokens: config.maxOutputTokens,
+    stopSequences: config.stopSequences,
+    responseLogprobs: config.responseLogprobs,
+    logprobs: config.logprobs,
+    presencePenalty: config.presencePenalty,
+    frequencyPenalty: config.frequencyPenalty,
+    seed: config.seed,
+    responseMimeType: config.responseMimeType,
+    responseSchema: config.responseSchema,
+    routingConfig: config.routingConfig,
+    modelSelectionConfig: config.modelSelectionConfig,
+    responseModalities: config.responseModalities,
+    mediaResolution: config.mediaResolution,
+    speechConfig: config.speechConfig,
+    audioTimestamp: config.audioTimestamp,
+    thinkingConfig: config.thinkingConfig,
+  };
+}