<?php
/*
* Copyright 2015 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
namespace Google\Auth;
use Google\Auth\Credentials\ImpersonatedServiceAccountCredentials;
use Google\Auth\Credentials\InsecureCredentials;
use Google\Auth\Credentials\ServiceAccountCredentials;
use Google\Auth\Credentials\UserRefreshCredentials;
use RuntimeException;
use UnexpectedValueException;
/**
* CredentialsLoader contains the behaviour used to locate and find default
* credentials files on the file system.
*/
abstract class CredentialsLoader implements
FetchAuthTokenInterface,
UpdateMetadataInterface
{
const TOKEN_CREDENTIAL_URI = 'https://oauth2.googleapis.com/token';
const ENV_VAR = 'GOOGLE_APPLICATION_CREDENTIALS';
const WELL_KNOWN_PATH = 'gcloud/application_default_credentials.json';
const NON_WINDOWS_WELL_KNOWN_PATH_BASE = '.config';
const MTLS_WELL_KNOWN_PATH = '.secureConnect/context_aware_metadata.json';
const MTLS_CERT_ENV_VAR = 'GOOGLE_API_USE_CLIENT_CERTIFICATE';
/**
* @param string $cause
* @return string
*/
private static function unableToReadEnv($cause)
{
$msg = 'Unable to read the credential file specified by ';
$msg .= ' GOOGLE_APPLICATION_CREDENTIALS: ';
$msg .= $cause;
return $msg;
}
/**
* @return bool
*/
private static function isOnWindows()
{
return strtoupper(substr(PHP_OS, 0, 3)) === 'WIN';
}
/**
* Load a JSON key from the path specified in the environment.
*
* Load a JSON key from the path specified in the environment
* variable GOOGLE_APPLICATION_CREDENTIALS. Return null if
* GOOGLE_APPLICATION_CREDENTIALS is not specified.
*
* @return array<mixed>|null JSON key | null
*/
public static function fromEnv()
{
$path = getenv(self::ENV_VAR);
if (empty($path)) {
return null;
}
if (!file_exists($path)) {
$cause = 'file ' . $path . ' does not exist';
throw new \DomainException(self::unableToReadEnv($cause));
}
$jsonKey = file_get_contents($path);
return json_decode((string) $jsonKey, true);
}
/**
* Load a JSON key from a well known path.
*
* The well known path is OS dependent:
*
* * windows: %APPDATA%/gcloud/application_default_credentials.json
* * others: $HOME/.config/gcloud/application_default_credentials.json
*
* If the file does not exist, this returns null.
*
* @return array<mixed>|null JSON key | null
*/
public static function fromWellKnownFile()
{
$rootEnv = self::isOnWindows() ? 'APPDATA' : 'HOME';
$path = [getenv($rootEnv)];
if (!self::isOnWindows()) {
$path[] = self::NON_WINDOWS_WELL_KNOWN_PATH_BASE;
}
$path[] = self::WELL_KNOWN_PATH;
$path = implode(DIRECTORY_SEPARATOR, $path);
if (!file_exists($path)) {
return null;
}
$jsonKey = file_get_contents($path);
return json_decode((string) $jsonKey, true);
}
/**
* Create a new Credentials instance.
*
* @param string|string[] $scope the scope of the access request, expressed
* either as an Array or as a space-delimited String.
* @param array<mixed> $jsonKey the JSON credentials.
* @param string|string[] $defaultScope The default scope to use if no
* user-defined scopes exist, expressed either as an Array or as a
* space-delimited string.
*
* @return ServiceAccountCredentials|UserRefreshCredentials|ImpersonatedServiceAccountCredentials
*/
public static function makeCredentials(
$scope,
array $jsonKey,
$defaultScope = null
) {
if (!array_key_exists('type', $jsonKey)) {
throw new \InvalidArgumentException('json key is missing the type field');
}
if ($jsonKey['type'] == 'service_account') {
// Do not pass $defaultScope to ServiceAccountCredentials
return new ServiceAccountCredentials($scope, $jsonKey);
}
if ($jsonKey['type'] == 'authorized_user') {
$anyScope = $scope ?: $defaultScope;
return new UserRefreshCredentials($anyScope, $jsonKey);
}
if ($jsonKey['type'] == 'impersonated_service_account') {
$anyScope = $scope ?: $defaultScope;
return new ImpersonatedServiceAccountCredentials($anyScope, $jsonKey);
}
throw new \InvalidArgumentException('invalid value in the type field');
}
/**
* Create an authorized HTTP Client from an instance of FetchAuthTokenInterface.
*
* @param FetchAuthTokenInterface $fetcher is used to fetch the auth token
* @param array<mixed> $httpClientOptions (optional) Array of request options to apply.
* @param callable $httpHandler (optional) http client to fetch the token.
* @param callable $tokenCallback (optional) function to be called when a new token is fetched.
* @return \GuzzleHttp\Client
*/
public static function makeHttpClient(
FetchAuthTokenInterface $fetcher,
array $httpClientOptions = [],
callable $httpHandler = null,
callable $tokenCallback = null
) {
$middleware = new Middleware\AuthTokenMiddleware(
$fetcher,
$httpHandler,
$tokenCallback
);
$stack = \GuzzleHttp\HandlerStack::create();
$stack->push($middleware);
return new \GuzzleHttp\Client([
'handler' => $stack,
'auth' => 'google_auth',
] + $httpClientOptions);
}
/**
* Create a new instance of InsecureCredentials.
*
* @return InsecureCredentials
*/
public static function makeInsecureCredentials()
{
return new InsecureCredentials();
}
/**
* export a callback function which updates runtime metadata.
*
* @return callable updateMetadata function
* @deprecated
*/
public function getUpdateMetadataFunc()
{
return [$this, 'updateMetadata'];
}
/**
* Updates metadata with the authorization token.
*
* @param array<mixed> $metadata metadata hashmap
* @param string $authUri optional auth uri
* @param callable $httpHandler callback which delivers psr7 request
* @return array<mixed> updated metadata hashmap
*/
public function updateMetadata(
$metadata,
$authUri = null,
callable $httpHandler = null
) {
if (isset($metadata[self::AUTH_METADATA_KEY])) {
// Auth metadata has already been set
return $metadata;
}
$result = $this->fetchAuthToken($httpHandler);
$metadata_copy = $metadata;
if (isset($result['access_token'])) {
$metadata_copy[self::AUTH_METADATA_KEY] = ['Bearer ' . $result['access_token']];
} elseif (isset($result['id_token'])) {
$metadata_copy[self::AUTH_METADATA_KEY] = ['Bearer ' . $result['id_token']];
}
return $metadata_copy;
}
/**
* Gets a callable which returns the default device certification.
*
* @throws UnexpectedValueException
* @return callable|null
*/
public static function getDefaultClientCertSource()
{
if (!$clientCertSourceJson = self::loadDefaultClientCertSourceFile()) {
return null;
}
$clientCertSourceCmd = $clientCertSourceJson['cert_provider_command'];
return function () use ($clientCertSourceCmd) {
$cmd = array_map('escapeshellarg', $clientCertSourceCmd);
exec(implode(' ', $cmd), $output, $returnVar);
if (0 === $returnVar) {
return implode(PHP_EOL, $output);
}
throw new RuntimeException(
'"cert_provider_command" failed with a nonzero exit code'
);
};
}
/**
* Determines whether or not the default device certificate should be loaded.
*
* @return bool
*/
public static function shouldLoadClientCertSource()
{
return filter_var(getenv(self::MTLS_CERT_ENV_VAR), FILTER_VALIDATE_BOOLEAN);
}
/**
* @return array{cert_provider_command:string[]}|null
*/
private static function loadDefaultClientCertSourceFile()
{
$rootEnv = self::isOnWindows() ? 'APPDATA' : 'HOME';
$path = sprintf('%s/%s', getenv($rootEnv), self::MTLS_WELL_KNOWN_PATH);
if (!file_exists($path)) {
return null;
}
$jsonKey = file_get_contents($path);
$clientCertSourceJson = json_decode((string) $jsonKey, true);
if (!$clientCertSourceJson) {
throw new UnexpectedValueException('Invalid client cert source JSON');
}
if (!isset($clientCertSourceJson['cert_provider_command'])) {
throw new UnexpectedValueException(
'cert source requires "cert_provider_command"'
);
}
if (!is_array($clientCertSourceJson['cert_provider_command'])) {
throw new UnexpectedValueException(
'cert source expects "cert_provider_command" to be an array'
);
}
return $clientCertSourceJson;
}
}