This is the official Google API Client Library for PHP, providing a unified interface to call Google APIs such as Drive, YouTube, Books, and many others. It handles authentication (API keys, OAuth2 web flow, service accounts), HTTP requests via Guzzle, batching, media uploads (simple, multipart, resumable), retries with exponential backoff, caching, and model serialization. The library is in maintenance mode: critical bugs and security issues are addressed, but no new features are added. It is a mature, well-tested library with extensive documentation and examples. The architecture centers around a `Google\Client` object that manages authentication and HTTP, and generated service classes (from `google/apiclient-services`) that map to specific Google APIs. The codebase is well-structured, uses modern PHP (8.0+), and follows PSR standards. Key reusable components include a standalone URI Template parser and a generic retry runner with exponential backoff.
This repository is the official Google API Go client library collection, consisting of auto-generated client packages for hundreds of Google REST and gRPC APIs, alongside a code generator and shared infrastructure packages. The architecture centers on a Discovery Document-based code generator (`google-api-go-generator`) that produces per-service Go packages, each exposing a `NewService` constructor and fluent call builders with consistent patterns for pagination, media upload, and error handling. Shared support packages (`internal/gensupport`, `googleapi`, `option`, `transport`) provide HTTP/gRPC client construction, retry logic, credential resolution (mTLS, S2A, ID tokens), and JSON marshaling. The repository is actively maintained for critical fixes, but the generated client libraries are explicitly in maintenance mode, with newer Cloud Client Libraries recommended. Key entry points include `option.ClientOption` for client configuration, `transport/http.NewClient` and `transport/grpc.Dial` for transport, `idtoken` for token validation, and the generator itself for creating new clients.