tornado.auth — Third-party login with OpenID and OAuth

This module contains implementations of various third-party authentication schemes.

All the classes in this file are class mixins designed to be used with the tornado.web.RequestHandler class. They are used in two ways:

• On a login handler, use methods such as authenticate_redirect(), authorize_redirect(), and get_authenticated_user() to establish the user’s identity and store authentication tokens to your database and/or cookies.
• In non-login handlers, use methods such as facebook_request() or twitter_request() to use the authentication tokens to make requests to the respective services.

They all take slightly different arguments due to the fact all these services implement authentication and authorization slightly differently. See the individual service classes below for complete documentation.

Example usage for Google OAuth:

class GoogleOAuth2LoginHandler(tornado.web.RequestHandler,
                               tornado.auth.GoogleOAuth2Mixin):
    @tornado.gen.coroutine
    def get(self):
        if self.get_argument('code', False):
            user = yield self.get_authenticated_user(
                redirect_uri='http://your.site.com/auth/google',
                code=self.get_argument('code'))
            # Save the user with e.g. set_secure_cookie
        else:
            yield self.authorize_redirect(
                redirect_uri='http://your.site.com/auth/google',
                client_id=self.settings['google_oauth']['key'],
                scope=['profile', 'email'],
                response_type='code',
                extra_params={'approval_prompt': 'auto'})

Changed in version 4.0: All of the callback interfaces in this module are now guaranteed to run their callback with an argument of None on error. Previously some functions would do this while others would simply terminate the request on their own. This change also ensures that errors are more consistently reported through the Future interfaces.

Common protocols

These classes implement the OpenID and OAuth standards. They will generally need to be subclassed to use them with any particular site. The degree of customization required will vary, but in most cases overridding the class attributes (which are named beginning with underscores for historical reasons) should be sufficient.

class tornado.auth.OpenIdMixin

Abstract implementation of OpenID and Attribute Exchange.

Class attributes:

• _OPENID_ENDPOINT: the identity provider’s URI.

authenticate_redirect(callback_uri=None, ax_attrs=['name', 'email', 'language', 'username'], callback=None)

Redirects to the authentication URL for this service.

After authentication, the service will redirect back to the given callback URI with additional parameters including openid.mode.

We request the given attributes for the authenticated user by default (name, email, language, and username). If you don’t need all those attributes for your app, you can request fewer with the ax_attrs keyword argument.

Changed in version 3.1: Returns a Future and takes an optional callback. These are not strictly necessary as this method is synchronous, but they are supplied for consistency with OAuthMixin.authorize_redirect.

get_authenticated_user(callback, http_client=None)

Fetches the authenticated user data upon redirect.

This method should be called by the handler that receives the redirect from the authenticate_redirect() method (which is often the same as the one that calls it; in that case you would call get_authenticated_user if the openid.mode parameter is present and authenticate_redirect if it is not).

The result of this method will generally be used to set a cookie.

get_auth_http_client()

Returns the AsyncHTTPClient instance to be used for auth requests.

May be overridden by subclasses to use an HTTP client other than the default.

class tornado.auth.OAuthMixin

Abstract implementation of OAuth 1.0 and 1.0a.

See TwitterMixin below for an example implementation.

Class attributes:

• _OAUTH_AUTHORIZE_URL: The service’s OAuth authorization url.
• _OAUTH_ACCESS_TOKEN_URL: The service’s OAuth access token url.
• _OAUTH_VERSION: May be either “1.0” or “1.0a”.
• _OAUTH_NO_CALLBACKS: Set this to True if the service requires advance registration of callbacks.

Subclasses must also override the _oauth_get_user_future and _oauth_consumer_token methods.

authorize_redirect(callback_uri=None, extra_params=None, http_client=None, callback=None)

Redirects the user to obtain OAuth authorization for this service.

The callback_uri may be omitted if you have previously registered a callback URI with the third-party service. For some services (including Friendfeed), you must use a previously-registered callback URI and cannot specify a callback via this method.

This method sets a cookie called _oauth_request_token which is subsequently used (and cleared) in get_authenticated_user for security purposes.

Note that this method is asynchronous, although it calls RequestHandler.finish for you so it may not be necessary to pass a callback or use the Future it returns. However, if this method is called from a function decorated with gen.coroutine, you must call it with yield to keep the response from being closed prematurely.

Changed in version 3.1: Now returns a Future and takes an optional callback, for compatibility with gen.coroutine.

get_authenticated_user(callback, http_client=None)

Gets the OAuth authorized user and access token.

This method should be called from the handler for your OAuth callback URL to complete the registration process. We run the callback with the authenticated user dictionary. This dictionary will contain an access_key which can be used to make authorized requests to this service on behalf of the user. The dictionary will also contain other fields such as name, depending on the service used.

_oauth_consumer_token()

Subclasses must override this to return their OAuth consumer keys.

The return value should be a dict with keys key and secret.

_oauth_get_user_future(access_token, callback)

Subclasses must override this to get basic information about the user.

Should return a Future whose result is a dictionary containing information about the user, which may have been retrieved by using access_token to make a request to the service.

The access token will be added to the returned dictionary to make the result of get_authenticated_user.

For backwards compatibility, the callback-based _oauth_get_user method is also supported.

get_auth_http_client()

Returns the AsyncHTTPClient instance to be used for auth requests.

May be overridden by subclasses to use an HTTP client other than the default.

class tornado.auth.OAuth2Mixin

Abstract implementation of OAuth 2.0.

See FacebookGraphMixin or GoogleOAuth2Mixin below for example implementations.

Class attributes:

• _OAUTH_AUTHORIZE_URL: The service’s authorization url.
• _OAUTH_ACCESS_TOKEN_URL: The service’s access token url.

authorize_redirect(redirect_uri=None, client_id=None, client_secret=None, extra_params=None, callback=None, scope=None, response_type='code')

Redirects the user to obtain OAuth authorization for this service.

Some providers require that you register a redirect URL with your application instead of passing one via this method. You should call this method to log the user in, and then call get_authenticated_user in the handler for your redirect URL to complete the authorization process.

Changed in version 3.1: Returns a Future and takes an optional callback. These are not strictly necessary as this method is synchronous, but they are supplied for consistency with OAuthMixin.authorize_redirect.

oauth2_request(url, callback, access_token=None, post_args=None, **args)

Fetches the given URL auth an OAuth2 access token.

If the request is a POST, post_args should be provided. Query string arguments should be given as keyword arguments.

Example usage:

..testcode:

class MainHandler(tornado.web.RequestHandler,
                  tornado.auth.FacebookGraphMixin):
    @tornado.web.authenticated
    @tornado.gen.coroutine
    def get(self):
        new_entry = yield self.oauth2_request(
            "https://graph.facebook.com/me/feed",
            post_args={"message": "I am posting from my Tornado application!"},
            access_token=self.current_user["access_token"])

        if not new_entry:
            # Call failed; perhaps missing permission?
            yield self.authorize_redirect()
            return
        self.finish("Posted a message!")

New in version 4.3.

get_auth_http_client()

Returns the AsyncHTTPClient instance to be used for auth requests.

May be overridden by subclasses to use an HTTP client other than the default.

New in version 4.3.

Google

class tornado.auth.GoogleOAuth2Mixin

Google authentication using OAuth2.

In order to use, register your application with Google and copy the relevant parameters to your application settings.

• Go to the Google Dev Console at http://console.developers.google.com
• Select a project, or create a new one.
• In the sidebar on the left, select APIs & Auth.
• In the list of APIs, find the Google+ API service and set it to ON.
• In the sidebar on the left, select Credentials.
• In the OAuth section of the page, select Create New Client ID.
• Set the Redirect URI to point to your auth handler
• Copy the “Client secret” and “Client ID” to the application settings as {“google_oauth”: {“key”: CLIENT_ID, “secret”: CLIENT_SECRET}}

New in version 3.2.

get_authenticated_user(redirect_uri, code, callback)

Handles the login for the Google user, returning an access token.

The result is a dictionary containing an access_token field ([among others](https://developers.google.com/identity/protocols/OAuth2WebServer#handlingtheresponse)). Unlike other get_authenticated_user methods in this package, this method does not return any additional information about the user. The returned access token can be used with OAuth2Mixin.oauth2_request to request additional information (perhaps from https://www.googleapis.com/oauth2/v2/userinfo)

Example usage:

class GoogleOAuth2LoginHandler(tornado.web.RequestHandler,
                               tornado.auth.GoogleOAuth2Mixin):
    @tornado.gen.coroutine
    def get(self):
        if self.get_argument('code', False):
            access = yield self.get_authenticated_user(
                redirect_uri='http://your.site.com/auth/google',
                code=self.get_argument('code'))
            user = yield self.oauth2_request(
                "https://www.googleapis.com/oauth2/v1/userinfo",
                access_token=access["access_token"])
            # Save the user and access token with
            # e.g. set_secure_cookie.
        else:
            yield self.authorize_redirect(
                redirect_uri='http://your.site.com/auth/google',
                client_id=self.settings['google_oauth']['key'],
                scope=['profile', 'email'],
                response_type='code',
                extra_params={'approval_prompt': 'auto'})

Facebook

class tornado.auth.FacebookGraphMixin

Facebook authentication using the new Graph API and OAuth2.

get_authenticated_user(redirect_uri, client_id, client_secret, code, callback, extra_fields=None)

Handles the login for the Facebook user, returning a user object.

Example usage:

class FacebookGraphLoginHandler(tornado.web.RequestHandler,
                                tornado.auth.FacebookGraphMixin):
  @tornado.gen.coroutine
  def get(self):
      if self.get_argument("code", False):
          user = yield self.get_authenticated_user(
              redirect_uri='/auth/facebookgraph/',
              client_id=self.settings["facebook_api_key"],
              client_secret=self.settings["facebook_secret"],
              code=self.get_argument("code"))
          # Save the user with e.g. set_secure_cookie
      else:
          yield self.authorize_redirect(
              redirect_uri='/auth/facebookgraph/',
              client_id=self.settings["facebook_api_key"],
              extra_params={"scope": "read_stream,offline_access"})

facebook_request(path, callback, access_token=None, post_args=None, **args)

Fetches the given relative API path, e.g., “/btaylor/picture”

If the request is a POST, post_args should be provided. Query string arguments should be given as keyword arguments.

An introduction to the Facebook Graph API can be found at http://developers.facebook.com/docs/api

Many methods require an OAuth access token which you can obtain through authorize_redirect and get_authenticated_user. The user returned through that process includes an access_token attribute that can be used to make authenticated requests via this method.

Example usage:

..testcode:

class MainHandler(tornado.web.RequestHandler,
                  tornado.auth.FacebookGraphMixin):
    @tornado.web.authenticated
    @tornado.gen.coroutine
    def get(self):
        new_entry = yield self.facebook_request(
            "/me/feed",
            post_args={"message": "I am posting from my Tornado application!"},
            access_token=self.current_user["access_token"])

        if not new_entry:
            # Call failed; perhaps missing permission?
            yield self.authorize_redirect()
            return
        self.finish("Posted a message!")

The given path is relative to self._FACEBOOK_BASE_URL, by default “https://graph.facebook.com”.

This method is a wrapper around OAuth2Mixin.oauth2_request; the only difference is that this method takes a relative path, while oauth2_request takes a complete url.

Changed in version 3.1: Added the ability to override self._FACEBOOK_BASE_URL.

Twitter

class tornado.auth.TwitterMixin

Twitter OAuth authentication.

To authenticate with Twitter, register your application with Twitter at http://twitter.com/apps. Then copy your Consumer Key and Consumer Secret to the application settings twitter_consumer_key and twitter_consumer_secret. Use this mixin on the handler for the URL you registered as your application’s callback URL.

When your application is set up, you can use this mixin like this to authenticate the user with Twitter and get access to their stream:

class TwitterLoginHandler(tornado.web.RequestHandler,
                          tornado.auth.TwitterMixin):
    @tornado.gen.coroutine
    def get(self):
        if self.get_argument("oauth_token", None):
            user = yield self.get_authenticated_user()
            # Save the user using e.g. set_secure_cookie()
        else:
            yield self.authorize_redirect()

The user object returned by get_authenticated_user includes the attributes username, name, access_token, and all of the custom Twitter user attributes described at https://dev.twitter.com/docs/api/1.1/get/users/show

authenticate_redirect(callback_uri=None, callback=None)

Just like authorize_redirect, but auto-redirects if authorized.

This is generally the right interface to use if you are using Twitter for single-sign on.

Changed in version 3.1: Now returns a Future and takes an optional callback, for compatibility with gen.coroutine.

twitter_request(path, callback=None, access_token=None, post_args=None, **args)

Fetches the given API path, e.g., statuses/user_timeline/btaylor

The path should not include the format or API version number. (we automatically use JSON format and API version 1).

If the request is a POST, post_args should be provided. Query string arguments should be given as keyword arguments.

All the Twitter methods are documented at http://dev.twitter.com/

Many methods require an OAuth access token which you can obtain through authorize_redirect and get_authenticated_user. The user returned through that process includes an ‘access_token’ attribute that can be used to make authenticated requests via this method. Example usage:

class MainHandler(tornado.web.RequestHandler,
                  tornado.auth.TwitterMixin):
    @tornado.web.authenticated
    @tornado.gen.coroutine
    def get(self):
        new_entry = yield self.twitter_request(
            "/statuses/update",
            post_args={"status": "Testing Tornado Web Server"},
            access_token=self.current_user["access_token"])
        if not new_entry:
            # Call failed; perhaps missing permission?
            yield self.authorize_redirect()
            return
        self.finish("Posted a message!")