<?php
namespace Aws\EndpointV2;
use Aws\Api\Operation;
use Aws\Api\Service;
use Aws\Auth\Exception\UnresolvedAuthSchemeException;
use Aws\CommandInterface;
use Aws\MetricsBuilder;
use Closure;
use GuzzleHttp\Promise\Promise;
use function JmesPath\search;
/**
* Handles endpoint rule evaluation and endpoint resolution.
*
* IMPORTANT: this middleware must be added to the "build" step.
* Specifically, it must precede the 'builder' step.
*
* @internal
*/
class EndpointV2Middleware
{
const ACCOUNT_ID_PARAM = 'AccountId';
const ACCOUNT_ID_ENDPOINT_MODE_PARAM = 'AccountIdEndpointMode';
private static $validAuthSchemes = [
'sigv4' => 'v4',
'sigv4a' => 'v4a',
'none' => 'anonymous',
'bearer' => 'bearer',
'sigv4-s3express' => 'v4-s3express'
];
/** @var callable */
private $nextHandler;
/** @var EndpointProviderV2 */
private $endpointProvider;
/** @var Service */
private $api;
/** @var array */
private $clientArgs;
/** @var Closure */
private $credentialProvider;
/**
* Create a middleware wrapper function
*
* @param EndpointProviderV2 $endpointProvider
* @param Service $api
* @param array $args
* @param callable $credentialProvider
*
* @return Closure
*/
public static function wrap(
EndpointProviderV2 $endpointProvider,
Service $api,
array $args,
callable $credentialProvider
) : Closure
{
return function (callable $handler) use ($endpointProvider, $api, $args, $credentialProvider) {
return new self($handler, $endpointProvider, $api, $args, $credentialProvider);
};
}
/**
* @param callable $nextHandler
* @param EndpointProviderV2 $endpointProvider
* @param Service $api
* @param array $args
*/
public function __construct(
callable $nextHandler,
EndpointProviderV2 $endpointProvider,
Service $api,
array $args,
?callable $credentialProvider = null
)
{
$this->nextHandler = $nextHandler;
$this->endpointProvider = $endpointProvider;
$this->api = $api;
$this->clientArgs = $args;
$this->credentialProvider = $credentialProvider;
}
/**
* @param CommandInterface $command
*
* @return Promise
*/
public function __invoke(CommandInterface $command)
{
$nextHandler = $this->nextHandler;
$operation = $this->api->getOperation($command->getName());
$commandArgs = $command->toArray();
$providerArgs = $this->resolveArgs($commandArgs, $operation);
if (!empty($providerArgs[self::ACCOUNT_ID_PARAM])) {
$command->getMetricsBuilder()->append(MetricsBuilder::RESOLVED_ACCOUNT_ID);
}
$endpoint = $this->endpointProvider->resolveEndpoint($providerArgs);
if (!empty($authSchemes = $endpoint->getProperty('authSchemes'))) {
$this->applyAuthScheme(
$authSchemes,
$command
);
}
return $nextHandler($command, $endpoint);
}
/**
* Resolves client, context params, static context params and endpoint provider
* arguments provided at the command level.
*
* @param array $commandArgs
* @param Operation $operation
*
* @return array
*/
private function resolveArgs(array $commandArgs, Operation $operation): array
{
$rulesetParams = $this->endpointProvider->getRuleset()->getParameters();
if (isset($rulesetParams[self::ACCOUNT_ID_PARAM])
&& isset($rulesetParams[self::ACCOUNT_ID_ENDPOINT_MODE_PARAM])) {
$this->clientArgs[self::ACCOUNT_ID_PARAM] = $this->resolveAccountId();
}
$endpointCommandArgs = $this->filterEndpointCommandArgs(
$rulesetParams,
$commandArgs
);
$staticContextParams = $this->bindStaticContextParams(
$operation->getStaticContextParams()
);
$contextParams = $this->bindContextParams(
$commandArgs, $operation->getContextParams()
);
$operationContextParams = $this->bindOperationContextParams(
$commandArgs,
$operation->getOperationContextParams()
);
return array_merge(
$this->clientArgs,
$operationContextParams,
$contextParams,
$staticContextParams,
$endpointCommandArgs
);
}
/**
* Compares Ruleset parameters against Command arguments
* to create a mapping of arguments to pass into the
* endpoint provider for endpoint resolution.
*
* @param array $rulesetParams
* @param array $commandArgs
* @return array
*/
private function filterEndpointCommandArgs(
array $rulesetParams,
array $commandArgs
): array
{
$endpointMiddlewareOpts = [
'@use_dual_stack_endpoint' => 'UseDualStack',
'@use_accelerate_endpoint' => 'Accelerate',
'@use_path_style_endpoint' => 'ForcePathStyle'
];
$filteredArgs = [];
foreach($rulesetParams as $name => $value) {
if (isset($commandArgs[$name])) {
if (!empty($value->getBuiltIn())) {
continue;
}
$filteredArgs[$name] = $commandArgs[$name];
}
}
if ($this->api->getServiceName() === 's3') {
foreach($endpointMiddlewareOpts as $optionName => $newValue) {
if (isset($commandArgs[$optionName])) {
$filteredArgs[$newValue] = $commandArgs[$optionName];
}
}
}
return $filteredArgs;
}
/**
* Binds static context params to their corresponding values.
*
* @param $staticContextParams
*
* @return array
*/
private function bindStaticContextParams($staticContextParams): array
{
$scopedParams = [];
forEach($staticContextParams as $paramName => $paramValue) {
$scopedParams[$paramName] = $paramValue['value'];
}
return $scopedParams;
}
/**
* Binds context params to their corresponding values found in
* command arguments.
*
* @param array $commandArgs
* @param array $contextParams
*
* @return array
*/
private function bindContextParams(
array $commandArgs,
array $contextParams
): array
{
$scopedParams = [];
foreach($contextParams as $name => $spec) {
if (isset($commandArgs[$spec['shape']])) {
$scopedParams[$name] = $commandArgs[$spec['shape']];
}
}
return $scopedParams;
}
/**
* Binds context params to their corresponding values found in
* command arguments.
*
* @param array $commandArgs
* @param array $contextParams
*
* @return array
*/
private function bindOperationContextParams(
array $commandArgs,
array $operationContextParams
): array
{
$scopedParams = [];
foreach($operationContextParams as $name => $spec) {
$scopedValue = search($spec['path'], $commandArgs);
if ($scopedValue) {
$scopedParams[$name] = $scopedValue;
}
}
return $scopedParams;
}
/**
* Applies resolved auth schemes to the command object.
*
* @param $authSchemes
* @param $command
*
* @return void
*/
private function applyAuthScheme(
array $authSchemes,
CommandInterface $command
): void
{
$authScheme = $this->resolveAuthScheme($authSchemes);
$command['@context']['signature_version'] = $authScheme['version'];
if (isset($authScheme['name'])) {
$command['@context']['signing_service'] = $authScheme['name'];
}
if (isset($authScheme['region'])) {
$command['@context']['signing_region'] = $authScheme['region'];
} elseif (isset($authScheme['signingRegionSet'])) {
$command['@context']['signing_region_set'] = $authScheme['signingRegionSet'];
}
}
/**
* Returns the first compatible auth scheme in an endpoint object's
* auth schemes.
*
* @param array $authSchemes
*
* @return array
*/
private function resolveAuthScheme(array $authSchemes): array
{
$invalidAuthSchemes = [];
foreach($authSchemes as $authScheme) {
if ($this->isValidAuthScheme($authScheme['name'])) {
return $this->normalizeAuthScheme($authScheme);
}
$invalidAuthSchemes[$authScheme['name']] = false;
}
$invalidAuthSchemesString = '`' . implode(
'`, `',
array_keys($invalidAuthSchemes))
. '`';
$validAuthSchemesString = '`'
. implode('`, `', array_keys(
array_diff_key(self::$validAuthSchemes, $invalidAuthSchemes))
)
. '`';
throw new UnresolvedAuthSchemeException(
"This operation requests {$invalidAuthSchemesString}"
. " auth schemes, but the client currently supports {$validAuthSchemesString}."
);
}
/**
* Normalizes an auth scheme's name, signing region or signing region set
* to the auth keys recognized by the SDK.
*
* @param array $authScheme
* @return array
*/
private function normalizeAuthScheme(array $authScheme): array
{
/*
sigv4a will contain a regionSet property. which is guaranteed to be `*`
for now. The SigV4 class handles this automatically for now. It seems
complexity will be added here in the future.
*/
$normalizedAuthScheme = [];
if (isset($authScheme['disableDoubleEncoding'])
&& $authScheme['disableDoubleEncoding'] === true
&& $authScheme['name'] !== 'sigv4a'
&& $authScheme['name'] !== 'sigv4-s3express'
) {
$normalizedAuthScheme['version'] = 's3v4';
} else {
$normalizedAuthScheme['version'] = self::$validAuthSchemes[$authScheme['name']];
}
$normalizedAuthScheme['name'] = $authScheme['signingName'] ?? null;
$normalizedAuthScheme['region'] = $authScheme['signingRegion'] ?? null;
$normalizedAuthScheme['signingRegionSet'] = $authScheme['signingRegionSet'] ?? null;
return $normalizedAuthScheme;
}
private function isValidAuthScheme($signatureVersion): bool
{
if (isset(self::$validAuthSchemes[$signatureVersion])) {
if ($signatureVersion === 'sigv4a') {
return extension_loaded('awscrt');
}
return true;
}
return false;
}
/**
* This method tries to resolve an `AccountId` parameter from a resolved identity.
* We will just perform this operation if the parameter `AccountId` is part of the ruleset parameters and
* `AccountIdEndpointMode` is not disabled, otherwise, we will ignore it.
*
* @return null|string
*/
private function resolveAccountId(): ?string
{
if (isset($this->clientArgs[self::ACCOUNT_ID_ENDPOINT_MODE_PARAM])
&& $this->clientArgs[self::ACCOUNT_ID_ENDPOINT_MODE_PARAM] === 'disabled') {
return null;
}
if (is_null($this->credentialProvider)) {
return null;
}
$identityProviderFn = $this->credentialProvider;
$identity = $identityProviderFn()->wait();
return $identity->getAccountId();
}
}
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