Authenticators

RestSharp includes authenticators for basic HTTP, OAuth1 and token-based (JWT and OAuth2).

There are two ways to set the authenticator: client-wide or per-request.

Set the client-wide authenticator by assigning the Authenticator property of RestClientOptions:

var options = new RestClientOptions("https://example.com") {
    Authenticator = new HttpBasicAuthenticator("username", "password")
};
var client = new RestClient(options);

To set the authenticator per-request, assign the Authenticator property of RestRequest:

var request = new RestRequest("/api/users/me") {
    Authenticator = new HttpBasicAuthenticator("username", "password")
};
var response = await client.ExecuteAsync(request, cancellationToken);

Basic authentication

The HttpBasicAuthenticator allows you pass a username and password as a basic Authorization header using a base64 encoded string.

var options = new RestClientOptions("https://example.com") {
    Authenticator = new HttpBasicAuthenticator("username", "password")
};
var client = new RestClient(options);

OAuth1

For OAuth1 authentication the OAuth1Authenticator class provides static methods to help generate an OAuth authenticator. OAuth1 authenticator will add the necessary OAuth parameters to the request, including signature.

The authenticator will use HMAC SHA1 to create a signature by default. Each static function to create the authenticator allows you to override the default and use another method to generate the signature.

Request token

Getting a temporary request token is the usual first step in the 3-legged OAuth1 flow. Use OAuth1Authenticator.ForRequestToken function to get the request token authenticator. This method requires a consumerKey and consumerSecret to authenticate.

var options = new RestClientOptions("https://api.twitter.com") {
    Authenticator = OAuth1Authenticator.ForRequestToken(consumerKey, consumerSecret)
};
var client = new RestClient(options);
var request = new RestRequest("oauth/request_token");

The response should contain the token and the token secret, which can then be used to complete the authorization process. If you need to provide the callback URL, assign the CallbackUrl property of the authenticator to the callback destination.

Access token

Getting an access token is the usual third step in the 3-legged OAuth1 flow. This method retrieves an access token when provided consumerKey, consumerSecret, oauthToken, and oauthTokenSecret. If you don't have a token for this call, you need to make a call to get the request token as described above.

var authenticator = OAuth1Authenticator.ForAccessToken(
    consumerKey, consumerSecret, oauthToken, oauthTokenSecret
);
var options = new RestClientOptions("https://api.twitter.com") {
    Authenticator = authenticator
};
var client = new RestClient(options);
var request = new RestRequest("oauth/access_token");

If the second step in 3-leg OAuth1 flow returned a verifier value, you can use another overload of ForAccessToken:

var authenticator = OAuth1Authenticator.ForAccessToken(
    consumerKey, consumerSecret, oauthToken, oauthTokenSecret, verifier
);

The response should contain the access token that can be used to make calls to protected resources.

For refreshing access tokens, use one of the two overloads of ForAccessToken that accept sessionHandle.

Protected resource

When the access token is available, use ForProtectedResource function to get the authenticator for accessing protected resources.

var authenticator = OAuth1Authenticator.ForAccessToken(
    consumerKey, consumerSecret, accessToken, accessTokenSecret
);
var options = new RestClientOptions("https://api.twitter.com/1.1") {
    Authenticator = authenticator
};
var client = new RestClient(options);
var request = new RestRequest("statuses/update.json", Method.Post)
        .AddParameter("status", "Hello Ladies + Gentlemen, a signed OAuth request!")
        .AddParameter("include_entities", "true");

xAuth

xAuth is a simplified version of OAuth1. It allows sending the username and password as x_auth_username and x_auth_password request parameters and directly get the access token. xAuth is not widely supported, but RestSharp still allows using it.

Create an xAuth authenticator using OAuth1Authenticator.ForClientAuthentication function:

var authenticator = OAuth1Authenticator.ForClientAuthentication(
    consumerKey, consumerSecret, username, password
);

0-legged OAuth

The access token authenticator can be used in 0-legged OAuth scenarios by providing null for the consumerSecret.

var authenticator = OAuth1Authenticator.ForAccessToken(
    consumerKey, null, oauthToken, oauthTokenSecret
);

OAuth2

RestSharp has two very simple authenticators to send the access token as part of the request.

OAuth2UriQueryParameterAuthenticator accepts the access token as the only constructor argument, and it will send the provided token as a query parameter oauth_token.

OAuth2AuthorizationRequestHeaderAuthenticator has two constructors. One only accepts a single argument, which is the access token. The other constructor also allows you to specify the token type. The authenticator will then add an Authorization header using the specified token type or OAuth as the default token type, and the token itself.

For example:

var authenticator = new OAuth2AuthorizationRequestHeaderAuthenticator(
    token, "Bearer"
);
var options = new RestClientOptions("https://example.com") {
    Authenticator = authenticator
};
var client = new RestClient(options);

The code above will tell RestSharp to send the bearer token with each request as a header. Essentially, the code above does the same as the sample for JwtAuthenticator below.

As those authenticators don't do much to get the token itself, you might be interested in looking at our sample OAuth2 authenticator, which requests the token on its own.

JWT

The JWT authentication can be supported by using JwtAuthenticator. It is a very simple class that can be constructed like this:

var authenticator = new JwtAuthenticator(myToken);
var options = new RestClientOptions("https://example.com") {
    Authenticator = authenticator
};
var client = new RestClient(options);

For each request, it will add an Authorization header with the value Bearer <your token>.

As you might need to refresh the token from, you can use the SetBearerToken method to update the token.

Custom authenticator

You can write your own implementation by implementing IAuthenticator and registering it with your RestClient:

var authenticator = new SuperAuthenticator(); // implements IAuthenticator
var options = new RestClientOptions("https://example.com") {
    Authenticator = authenticator
};
var client = new RestClient(options);

The Authenticate method is the very first thing called upon calling RestClient.Execute or RestClient.Execute<T>. It gets the RestRequest currently being executed giving you access to every part of the request data (headers, parameters, etc.)

You can find an example of a custom authenticator that fetches and uses an OAuth2 bearer token here.