OAuth Client for C++: liboauth Library for Authorization

OAuth Client for C++: liboauthcpp Library

In modern web development, integration with external APIs via the OAuth protocol has become the de facto standard. For C++ developers, creating a reliable OAuth client can be a non-trivial task due to the lack of built-in support in the standard library. liboauthcpp is a lightweight, cross-platform C++ library that provides ready-made mechanisms for working with OAuth 1.0a and partial support for OAuth 2.0. It is ideal for embedding in desktop applications, server utilities, and IoT devices where performance and minimal dependencies are critical.

Key Features

• OAuth 1.0a Support — full implementation of HMAC-SHA1 and RSA-SHA1 signatures.
• Basic OAuth 2.0 Mechanisms — obtaining Authorization Code and Client Credentials (without Refresh Token).
• Minimal Dependencies — requires only a C++11/14 compiler and OpenSSL (or an alternative crypto provider).
• Cross-Platform — works on Linux, macOS, Windows (MinGW/MSVC).
• Simple API — intuitive classes OAuthClient, OAuthToken, OAuthRequest.

Installation

The recommended installation method is via the vcpkg package system or building from source:

# Via vcpkgvcpkg install liboauthcpp

# Or build from GitHubgit clone https://github.com/lyokato/liboauthcpp.gitcd liboauthcppmkdir build && cd buildcmake .. -DCMAKE_INSTALL_PREFIX=/usr/localmake && sudo make install

After installation, include the header file and link with the library:

#include <oauthcpp/oauthcpp.hpp>// Linking: -loauthcpp -lssl -lcrypto

Example: OAuth 1.0a (Twitter API)

Let's look at a classic scenario — sending a tweet via the Twitter API v1.1 using OAuth 1.0a:

#include <iostream>#include <oauthcpp/oauthcpp.hpp>#include <curl/curl.h>  // For HTTP transport

int main() {    // 1. Initialize credentials    oauthcpp::OAuthClient client(        "YOUR_CONSUMER_KEY",        "YOUR_CONSUMER_SECRET",        oauthcpp::OAuthClient::HttpMethod::POST    );

    // 2. Set user tokens (obtained previously)    oauthcpp::OAuthToken accessToken(        "USER_ACCESS_TOKEN",        "USER_TOKEN_SECRET"    );    client.setToken(accessToken);

    // 3. Form the request    std::string url = "https://api.twitter.com/1.1/statuses/update.json";    oauthcpp::OAuthRequest request(url);    request.addParameter("status", "Hello from C++ OAuth client!");

    // 4. Sign the request    std::string signedUrl = client.sign(request);

    // 5. Send via libcurl    CURL* curl = curl_easy_init();    curl_easy_setopt(curl, CURLOPT_URL, signedUrl.c_str());    curl_easy_setopt(curl, CURLOPT_POST, 1L);    // ... configure SSL and handle response    curl_easy_perform(curl);    curl_easy_cleanup(curl);

    return 0;}

Example: OAuth 2.0 (Google API)

To work with OAuth 2.0, use the simplified OAuth2Client mechanism (included in liboauthcpp):

#include <iostream>#include <oauthcpp/oauth2.hpp>

int main() {    oauthcpp::OAuth2Client client(        "YOUR_CLIENT_ID",        "YOUR_CLIENT_SECRET",        "https://oauth2.googleapis.com/token"    );

    // Obtain token via Authorization Code    std::string authCode = "AUTH_CODE_FROM_REDIRECT";    oauthcpp::OAuthToken token = client.getAccessToken(authCode,         "https://your-app.com/callback");

    std::cout << "Access Token: " << token.getAccessToken() << std::endl;    std::cout << "Expires in: " << token.getExpiresIn() &