security.md

Authentication & Security

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Most GitHub services do not require authentication, but some do. For example the methods that allow you to change properties on Repositories and some others. Therefore this step is facultative.

Authenticate

GitHub provides some different ways of authentication. This API implementation implements three of them which are handled by one function:

$client->authenticate($usernameOrToken, $password, $method);

$usernameOrToken is, of course, the username (or in some cases token/client ID, more details you can find below), and guess what should contain $password. The $method can contain one of the three allowed values:

Supported methods

• Github\AuthMethod::CLIENT_ID - https://developer.github.com/v3/#oauth2-keysecret
• Github\AuthMethod::ACCESS_TOKEN - https://developer.github.com/v3/#oauth2-token-sent-in-a-header
• Github\AuthMethod::JWT - https://developer.github.com/apps/building-github-apps/authenticating-with-github-apps/#authenticating-as-a-github-app

The required value of $password depends on the chosen $method. For Github\AuthMethod::CLIENT_ID, Github\AuthMethod::ACCESS_TOKEN and Github\AuthMethod::JWT methods you should provide the API token in $usernameOrToken variable ($password is omitted in this particular case).

The Github\AuthMethod::JWT authentication method sends the specified JSON Web Token in an Authorization header.

After executing the $client->authenticate($usernameOrToken, $secret, $method); method using correct credentials, all further requests are done as the given user.

Authenticating as an Integration

To authenticate as an integration you need to supply a JSON Web Token with Github\AuthMethod::JWT to request and installation access token which is then usable with Github\AuthMethod::ACCESS_TOKEN. Github´s integration authentication docs describe the flow in detail. It´s important for integration requests to use the custom Accept header application/vnd.github.machine-man-preview.

The following sample code authenticates as an installation using lcobucci/jwt 4.1 to generate a JSON Web Token (JWT).

use Github\HttpClient\Builder;
use Lcobucci\JWT\Configuration;
use Lcobucci\JWT\Encoding\ChainedFormatter;
use Lcobucci\JWT\Signer\Key\LocalFileReference;
use Lcobucci\JWT\Signer\Rsa\Sha256;

$builder = new Builder();

$github = new Github\Client($builder, 'machine-man-preview');

$config = Configuration::forSymmetricSigner(
    new Sha256(),
    LocalFileReference::file('path/to/integration.private-key.pem')
);

$now = new \DateTimeImmutable();
$jwt = $config->builder(ChainedFormatter::withUnixTimestampDates())
    ->issuedBy($integrationId)
    ->issuedAt($now)
    ->expiresAt($now->modify('+1 minute'))
    ->getToken($config->signer(), $config->signingKey())
;

$github->authenticate($jwt->toString(), null, Github\AuthMethod::JWT)

The $integrationId you can find in the about section of your github app. The $installationId you can find by installing the app and using the id in the url.