**Note:** For browserless Twitter authentication, you can use the OXTwitter specialized class which can do Twitter XAuth. You will need to additionally provide your Twitter login credentials (username & password) before calling *link()*.
### Handling Signals
O2 is an asynchronous library. It will send signals at various stages of authentication and request processing.
To handle these signals, implement the following slots in your code:
void onLinkedChanged() {
// Linking (login) state has changed.
// Use o1->linked() to get the actual state
}
void onLinkingFailed() {
// Login has failed
}
void onLinkingSucceeded() {
// Login has succeeded
}
void onOpenBrowser(const QUrl *url) {
// Open a web browser or a web view with the given URL.
// The user will interact with this browser window to
// enter login name, password, and authorize your application
// to access the Twitter account
}
void onCloseBrowser() {
// Close the browser window opened in openBrowser()
}
### Logging In
To log in (e.g. to link your application to the OAuth service), call the link() method:
o1->link();
This initiates the authentication sequence. Your signal handlers above will be called at various stages. Lastly, if linking succeeds, onLinkingSucceeded() will be called.
### Logging Out
To log out, call the unlink() method:
o1->unlink();
Logging out always succeeds, and requires no user interaction.
### Sending Authenticated Requests
Once linked, you can start sending authenticated requests to the service. We start with a simple example of sending a text-only tweet or as it's known in Twitter docs, a 'status update'.
First we need a Qt network manager and an O1 requestor object:
QNetworkAccessManager *manager = new QNetworkAccessManager(this);
O1Requestor *requestor = new O1Requestor(manager, o1, this);
O2 provides simple storage classes for writing OAuth tokens in a persistent location. Currently, a QSettings based backing store **O2SettingsStore** is provided in O2. O2SettingsStore keeps all token values in an encrypted form. You have to specify the encryption key to use while constructing the object:
O0SettingsStore settings = new O0SettingsStore("myencryptionkey");
// Set the store before starting OAuth, i.e before calling link()
o1->setStore(settings);
...
You can also create it with your customized QSettings object. O2SettingsStore will then use that QSettings object for storing the tokens:
O0SettingsStore settings = new O0SettingsStore(mySettingsObject, "myencryptionkey");
Once set, O2SettingsStore takes ownership of the QSettings object.
**Note:** If you do not specify a storage object to use, O2 will create one by default (which QSettings based), and use it. In such a case, a default encryption key is used for encrypting the data.
### Extra OAuth Tokens
Some OAuth service providers provide additional information in the access token response. Eg: Twitter returns 2 additional tokens in it's access token response - *screen_name* and *user_id*.
O2 provides all such tokens via the property - *extraTokens*. You can query this property after a successful OAuth exchange, i.e after the *linkingSucceeded()* signal has been emitted.
## More Examples
The *examples* folder contains complete example applications:
Name | Description
:-- | :--
facebookdemo | Command line application authenticating with Facebook
sialis | QT Quick Twitter client using OAuth 1
twitterdemo | Command line client for authenticating with Twitter and posting status updates. Uses OAuth 1 or Twitter XAuth
