130 lines
4.3 KiB
Markdown
130 lines
4.3 KiB
Markdown
# Angel3 OAuth2 Handler
|
|
|
|
|
|
(<https://dart.dev/null-safety>)
|
|
[](https://gitter.im/angel_dart/discussion)
|
|
[](https://github.com/dukefirehawk/angel/tree/master/packages/auth_oauth2/LICENSE)
|
|
|
|
Angel3 library for authenticating users with remote identity providers via OAuth2, i.e. Facebook, Google, Azure AD, etc.
|
|
|
|
## Usage
|
|
|
|
First, create an options object:
|
|
|
|
```dart
|
|
configureServer(Angel app) async {
|
|
// Load from a Map, i.e. app config:
|
|
var opts = ExternalAuthOptions.fromMap(app.configuration['auth0'] as Map);
|
|
|
|
// Create in-place:
|
|
var opts = ExternalAuthOptions(
|
|
clientId: '<client-id>',
|
|
clientSecret: '<client-secret>',
|
|
redirectUri: Uri.parse('<callback>'));
|
|
}
|
|
```
|
|
|
|
After getting authenticated against the remote server, we need to be able to identify users within our own application.
|
|
|
|
```dart
|
|
typedef OAuth2Verifier = FutureOr<User> Function(oauth2.Client, RequestContext, ResponseContext);
|
|
|
|
/// You might use a pure function to create a verifier that queries a
|
|
/// given service.
|
|
OAuth2Verifier oauth2verifier(Service<User> userService) {
|
|
return (client) async {
|
|
var response = await client.get('https://api.github.com/user');
|
|
var ghUser = json.decode(response.body);
|
|
var id = ghUser['id'] as int;
|
|
|
|
var matchingUsers = await mappedUserService.index({
|
|
'query': {'github_id': id}
|
|
});
|
|
|
|
if (matchingUsers.isNotEmpty) {
|
|
// Return the corresponding user, if it exists.
|
|
return matchingUsers.first;
|
|
} else {
|
|
// Otherwise,create a user
|
|
return await mappedUserService.create(User(githubId: id));
|
|
}
|
|
};
|
|
}
|
|
```
|
|
|
|
Now, initialize an `OAuth2Strategy`, using the options and verifier. You'll also need to provide a name for this instance of the strategy. Consider using the name of the remote authentication provider (ex. `facebook`).
|
|
|
|
```dart
|
|
configureServer(Angel app) {
|
|
auth.strategies['github'] = OAuth2Strategy(
|
|
options,
|
|
authorizationEndpoint,
|
|
tokenEndpoint,
|
|
yourVerifier,
|
|
|
|
// This function is called when an error occurs, or the user REJECTS the request.
|
|
(e, req, res) async {
|
|
res.write('Ooops: $e');
|
|
await res.close();
|
|
},
|
|
);
|
|
}
|
|
```
|
|
|
|
Lastly, connect it to an `AngelAuth` instance, and wire it up to an `Angel` server. Set up two routes:
|
|
|
|
1. Redirect users to the external provider
|
|
2. Acts as a callback and handles an access code
|
|
|
|
In the case of the callback route, you may want to display an HTML page that closes a popup window. In this case, use `confirmPopupAuthentication`, which is bundled with `package:angel3_auth`, as a `callback` function:
|
|
|
|
```dart
|
|
configureServer(Angel app) async {
|
|
// ...
|
|
var auth = AngelAuth<User>();
|
|
auth.strategies['github'] = oauth2Strategy;
|
|
|
|
// Redirect
|
|
app.get('/auth/github', auth.authenticate('github'));
|
|
|
|
// Callback
|
|
app.get('/auth/github/callback', auth.authenticate(
|
|
'github',
|
|
AngelAuthOptions(callback: confirmPopupAuthentication())
|
|
));
|
|
|
|
// Connect the plug-in!!!
|
|
await app.configure(auth);
|
|
}
|
|
```
|
|
|
|
## Custom Scope Delimiter
|
|
|
|
This package should work out-of-the-box for most OAuth2 providers, such as Github or Dropbox. However, if your OAuth2 scopes are separated by a delimiter other than the default (`' '`), you can add it in the `OAuth2Strategy` constructor:
|
|
|
|
```dart
|
|
configureServer(Angel app) async {
|
|
OAuth2Strategy(..., delimiter: ' ');
|
|
}
|
|
```
|
|
|
|
## Handling non-JSON responses
|
|
|
|
Many OAuth2 providers do not follow the specification, and do not return `application/json` responses.
|
|
|
|
You can add a `getParameters` callback to parse the contents of any arbitrary response:
|
|
|
|
```dart
|
|
OAuth2Strategy(
|
|
// ...
|
|
getParameters: (contentType, body) {
|
|
if (contentType.type == 'application') {
|
|
if (contentType.subtype == 'x-www-form-urlencoded')
|
|
return Uri.splitQueryString(body);
|
|
else if (contentType.subtype == 'json') return JSON.decode(body);
|
|
}
|
|
|
|
throw FormatException('Invalid content-type $contentType; expected application/x-www-form-urlencoded or application/json.');
|
|
}
|
|
);
|
|
```
|