Google APIs

Overview

Google APIs are typically deployed as API services that are hosted under different DNS names. One API service may implement multiple APIs and multiple versions of the same API.

Google APIs use Protocol Buffers version 3 (proto3) as their Interface Definition Language (IDL) to define the API interface and the structure of the payload messages. The same interface definition is used for both REST and RPC versions of the API, which can be accessed over different wire protocols.

There are several ways of accessing Google APIs:

1. JSON over HTTP: You can access all Google APIs directly using JSON over HTTP, using Google API client library or third-party API client libraries.

2. Protocol Buffers over gRPC: You can access Google APIs published in this repository through GRPC, which is a high-performance binary RPC protocol over HTTP/2. It offers many useful features, including request/response multiplex and full-duplex streaming.

3. Google Cloud Client Libraries: You can use these libraries to access Google Cloud APIs. They are based on gRPC for better performance and provide idiomatic client surface for better developer experience.

Repository Structure

This repository uses a directory hierarchy that reflects the Google API product structure. In general, every API has its own root directory, and each major version of the API has its own subdirectory. The proto package names exactly match the directory: this makes it easy to locate the proto definitions and ensures that the generated client libraries have idiomatic namespaces in most programming languages. Alongside the API directories live the configuration files for GAPIC generators.

The preview/ subdirectory is a nested API root dedicated to API surfaces that are explicitly in preview. This is a subset of APIs found in the root of the repository. These must not be consumed alongside API protos found in the root of the repository. Generally, do not depend on these protos directly.

NOTE: The major version of an API is used to indicate breaking change to the API.