feat: Initialize LangChain with OpenAI integration and comprehensive API #76
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Fixes NexGenStudioDev#20 - Created LangChain service with ChatOpenAI - Added runSimplePrompt, runUserPrompt, runCustomTemplate, streamPrompt methods - Created LangChain controller with 5 API endpoints - Added health check, test, and chat endpoints - Configured environment variables (OPENAI_API_KEY, OPENAI_MODEL) - Created comprehensive documentation - No hardcoded secrets, production-ready code
Summary of ChangesHello @morningstarxcdcode, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed! This pull request introduces a significant enhancement by integrating LangChain with OpenAI, establishing a robust foundation for AI-powered functionalities. It sets up a dedicated service layer to manage AI interactions, exposes several new API endpoints for diverse AI operations such as chat and custom template execution, and includes comprehensive documentation to guide developers through the setup and usage of these new capabilities. This strategic addition paves the way for future advanced AI applications, including Retrieval-Augmented Generation (RAG) implementations. Highlights
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Code Review
This pull request introduces a comprehensive LangChain integration with OpenAI, providing a solid foundation for building AI-powered features. The changes include a well-structured service layer (langchain.service.ts), corresponding controller and routes, and excellent documentation (LANGCHAIN_SETUP.md). The implementation is clean and covers various use cases like simple prompts, template-based generation, and streaming. My review includes suggestions to improve error handling, response parsing, and information disclosure in the health check endpoint for enhanced robustness and security.
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Pull request overview
This PR implements a comprehensive LangChain integration with OpenAI ChatGPT, providing a reusable service layer and HTTP endpoints for AI-powered applications. The implementation adds 5 new API endpoints for health checks, testing, chat, prompts, and custom templates, with extensive documentation.
Key Changes:
- LangChain service with ChatOpenAI integration supporting simple prompts, custom templates, and streaming responses
- Five RESTful API endpoints for AI operations (health, test, chat, prompt, template)
- Environment configuration for OpenAI API key and model selection with validation schema updates
Reviewed changes
Copilot reviewed 8 out of 9 changed files in this pull request and generated 11 comments.
Show a summary per file
| File | Description |
|---|---|
| docs/LANGCHAIN_SETUP.md | Comprehensive 467-line documentation covering setup, API usage, troubleshooting, and best practices |
| LocalMind-Backend/src/validator/env.ts | Added OPENAI_MODEL schema validation with default value, updated arrow function formatting |
| LocalMind-Backend/src/services/langchain.service.ts | Core LangChain service with ChatOpenAI integration and 4 main methods for AI operations |
| LocalMind-Backend/src/routes/app.ts | Registered LangChainRouter in the application routes |
| LocalMind-Backend/src/api/v1/LangChain/langchain.routes.ts | Defined 5 routes for LangChain operations (health, test, chat, prompt, template) |
| LocalMind-Backend/src/api/v1/LangChain/langchain.controller.ts | Controller with handlers for all 5 endpoints with input validation and error handling |
| LocalMind-Backend/pnpm-lock.yaml | Updated dependency lock file with @langchain/openai@1.2.0 and related packages |
| LocalMind-Backend/package.json | Added @langchain/openai@1.2.0 dependency and upgraded bcrypt to 6.0.0 |
| LocalMind-Backend/.env.example | Added OPENAI_MODEL configuration example |
Files not reviewed (1)
- LocalMind-Backend/pnpm-lock.yaml: Language not supported
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1 participant
Closes #20
Summary
Complete LangChain initialization with OpenAI ChatGPT integration, reusable service layer, and HTTP endpoints for building AI-powered applications.
Changes
Files