ac_oauth2_client

Description:

ac oauth2 client

Unopinionated OAuth 2.0 client #
An unopinionated RFC-compliant OAuth 2.0 client which doesn't make assumption on anything.
Features #
What it implements :

Authorization Code Grant (RFC-6749 §4.1);
Implicit Grant (RFC-6749 §4.2);
Resource Owner Password Credentials Grant (RFC-6749 §4.3);
Client Credentials Grant (RFC-6749 §4.4);
Extension Grants (RFC-6749 §4.5);
Access Token Refreshing (RFC-6749 §6)
Token Revocation (RFC-7009)

What it will NOT implement :

The actual HTTP requests to the server, although it gives you data to make requests and it transforms the responses.
A way to present the web page to the user and retrieve the redirection URI for the Authorization Code Grant and Implicit Grant types. You can either use a WebView (for development/debugging purpose only) or spawn an external browser to present the web page and use deep-link to retrieve the redirected URI.

Usage #
Usage description assume you have some knowledge of the OAuth 2.0 authentications flows and the data involved.
HTTP request handler #
A typical implementation with the http package will look like this :
import 'package:http/http.dart' as http;

class MyHttpRequestHandler
implements OAuth2HttpRequestHandler {
Future<OAuth2HttpResponse> post(
Uri url,
Map<String, String> headers,
Map<String, String> formData,
) async {
final response = await http.post(
url,
headers: headers,
body: Uri(queryParameters: formData).query,
);

return OAuth2HttpResponse(
status: response.statusCode,
formData: Uri.splitQueryString(response.body),
);
}
}
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or if you use the ac_fetch package :
class MyHttpRequestHandler
implements OAuth2HttpRequestHandler {
Future<OAuth2HttpResponse> post(
Uri url,
Map<String, String> headers,
Map<String, String> formData,
) {
final options = FetchOptions(
method: 'POST',
url: url,
headers: headers,
);

final response = await fetchWithStructuredData(options, formData);

return OAuth2HttpResponse(
status: response.status,
formData: response.ok
? await response.waitStructuredData()
: null,
);
}
}
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Authorization Code Grant #
Generating the authorization URL
final authorizationEndpoint =
Uri.parse('https://www.example.com/oauth/authorize');

final clientCredentialsIdentifier =
OAuth2ClientCredentialsIdentifier(
identifier: '<client_id>',
authentication: OAuth2ClientAuthenticationSecret(
secret: '<client_secret>',
),
);

// Optionally you can define a random state.
final state = OAuth2State.random();

// Optionally, for those providers which allow multiple redirection URI,
// you can pass the redirect URI.
// Or, for those who only allow one redirection URI, they may make this
// parameter mandatory.
final redirectUri = Uri.parse('my-app://deeplink');

// Optionally pass the desired OAuth 2.0 scopes
final scopes = ['read', 'write'];

// Optionally pass custom parameters
final customParameters = <String, String>{
'my-provider-custom-parameter': 'value',
}

final url = OAuth2Client.composeAuthorizationCodeGrantUrl(
authorizationEndpoint: authorizationEndpoint,
clientCredentialsIdentifier: clientCredentialsIdentifier,
state: state,
redirectUri: redirectUri,
scopes: scopes,
customParameters: customParameters,
);

// ... present url to the user
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Parsing the redirection URI
// the redirection URI you got back from authorization
Uri redirectionUri;

// the state you passed to composeAuthorizationCodeGrantUrl
OAuth2State? state;

final result = OAuth2Client.parseAuthorizationCodeGrantRedirectionUri(
redirectionUri: redirectionUri,
state: state,
);

// the authorization code, only valid for a few minutes,
// which allows creation of tokens.
print(result.code);
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Token Grant from Authorization Code
final tokenEndpoint =
Uri.parse('https://www.example.com/oauth/token');

// the redirectUri you used as parameter to composeAuthorizationCodeGrantUrl.
Uri? originalRedirectUri;

// optionally pass some custom parameters
Map<String, String>? customParameters;

final result = await OAuth2Client.authorizationCodeTokenGrant(
requestHandler: MyHttpRequestHandler(),
tokenEndpoint: tokenEndpoint,
clientCredentials: clientCredentialsIdentifier,
authorizationCode: authorizationResult.code,
originalRedirectUri: originalRedirectUri,
customParameters: customParameters,
);

print(result.accessToken);
print(result.expiresIn);
print(result.refreshToken);
// ...
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Refreshing an Access Token #
final tokenEndpoint =
Uri.parse('https://www.example.com/oauth/token');

final clientCredentials =
OAuth2ClientCredentialsIdentifier(
identifier: '<client_id>',
authentication: OAuth2ClientAuthenticationSecret(
secret: '<client_secret>',
),
);

// probably retrieved from OAuth2TokenGrantResult.refreshToken
final refreshToken = '<refresh_token>';

// Optionally pass the desired OAuth 2.0 scopes
OAuth2Scopes? scopes = ['read'];

// optionally pass some custom parameters
Map<String, String>? customParameters;

final result = await OAuth2Client.refreshToken(
requestHandler: MyHttpRequestHandler(),
tokenEndpoint: tokenEndpoint,
clientCredentials: clientCredentials,
refreshToken: refreshToken,
scopes: scopes,
customParameters: customParameters,
);

// new access token
print(result.accessToken);
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Revoking a token #
final revocationEndpoint =
Uri.parse('https://www.example.com/oauth/revoke');

final token = '<access_or_refresh_token>';

// optionally, give an hint to the server which token
// you want to revoke
OAuth2TokenType? tokenTypeHint;

// optionally pass some custom parameters
Map<String, String>? customParameters;

await OAuth2Client.revokeToken(
requestHandler: MyHttpRequestHandler(),
revocationEndpoint: revocationEndpoint,
clientCredentials: clientCredentials,
token: token,
tokenTypeHint: tokenTypeHint,
customParameters: customParameters,
);
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License

For personal and professional use. You cannot resell or redistribute these repositories in their original state.

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