Chess Game API Example

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Authentication Using OAuth

OAuth (Open Authorization) is an industry-standard protocol for authorization, allowing third-party services to access a user’s data without exposing their credentials. This section outlines how to authenticate using OAuth in our API.

Overview

Our API supports OAuth 2.0 for authentication, which allows users to grant limited access to their resources without sharing their credentials directly with the third-party application.

Authorization Flow

OAuth 2.0 defines several grant types for different use cases. The most common flow for web applications is the Authorization Code Grant. Here’s a brief overview of the flow:

  • Authorization Request: The client application redirects the user to the authorization server’s authorization endpoint, where the user is prompted to log in and grant permissions to the client.
  • Authorization Grant: Upon successful authentication and authorization, the authorization server redirects the user back to the client application with an authorization code.
  • Token Request: The client application exchanges the authorization code for an access token by making a request to the authorization server’s token endpoint.
  • Access Resource: The client application can now access protected resources on behalf of the user using the access token.

Authentication Endpoints

Authorization Endpoint: https://example.com/oauth/authorize

Parameters:

response_type: Must be set to code. client_id: The client’s unique identifier. redirect_uri: The URL to which the authorization server will redirect the user after authorization. scope: The requested scope of access. state: A random value generated by the client to prevent CSRF attacks.

Token Endpoint: https://example.com/oauth/token

Parameters:

grant_type: Must be set to authorization_code. code: The authorization code received from the authorization server. redirect_uri: The same redirect URI used in the authorization request. client_id: The client’s unique identifier. client_secret: The client’s secret key.

Example

Step 1: Authorization Request

GET /oauth/authorize?
response_type=code&
client_id=CLIENT_ID&
redirect_uri=REDIRECT_URI&
scope=read_write&
state=STATE

Step 2: Authorization Response

Upon successful authorization, the authorization server redirects the user back to the client application’s redirect URI with an authorization code.

GET /redirect_uri?code=AUTHORIZATION_CODE&state=STATE

Step 3: Token Request

POST /oauth/token HTTP/1.1
Host: example.com
Content-Type: application/x-www-form-urlencoded

grant_type=authorization_code&
code=AUTHORIZATION_CODE&
redirect_uri=REDIRECT_URI&
client_id=CLIENT_ID&
client_secret=CLIENT_SECRET

Step 4: Token Response

Upon successful token exchange, the authorization server responds with an access token.

{
  "access_token": "ACCESS_TOKEN",
  "token_type": "Bearer",
  "expires_in": 3600,
  "refresh_token": "REFRESH_TOKEN"
}

Refreshing Tokens

Access tokens may expire after a certain period. To obtain a new access token without requiring the user to log in again, clients can use the refresh token provided during the authorization process.

Security Considerations

Always use HTTPS to secure communication between the client application and the authorization server. Protect sensitive information, such as client secrets and access tokens, from unauthorized access. Implement CSRF protection by validating the state parameter during the authorization flow.

Conclusion

OAuth 2.0 provides a secure and standardized way to authorize access to resources without sharing credentials. By following the authorization flow and best practices outlined in this documentation, developers can securely integrate with our API using OAuth authentication.