README

This library uses Guzzle (guzzlehttp/guzzle, version 6.x) and provides the foundations to create fully-featured web service clients by abstracting Guzzle HTTP requests and responses into higher-level commands and results. A middleware system, analogous to — but separate from — the one in the HTTP layer may be used to customize client behavior when preparing commands into requests and processing responses into results.

Commands

Key-value pair objects representing an operation of a web service. Commands have a name and a set of parameters.

Results

Key-value pair objects representing the processed result of executing an operation of a web service.

Installing

This project can be installed using Composer:

composer require guzzlehttp/command

For Guzzle 5, use composer require guzzlehttp/command:0.8.*. The source code for the Guzzle 5 version is available on the 0.8 branch <https://github.com/guzzle/command/tree/0.8>_.

Note: If Composer is not installed globally <https://getcomposer.org/doc/00-intro.md#globally>_, then you may need to run the preceding Composer commands using php composer.phar (where composer.phar is the path to your copy of Composer), instead of just composer.

Service Clients

Service Clients are web service clients that implement the GuzzleHttp\Command\ServiceClientInterface and use an underlying Guzzle HTTP client (GuzzleHttp\Client) to communicate with the service. Service clients create and execute commands (GuzzleHttp\Command\CommandInterface), which encapsulate operations within the web service, including the operation name and parameters. This library provides a generic implementation of a service client: the GuzzleHttp\Command\ServiceClient class.

Instantiating a Service Client

@TODO Add documentation

• ServiceClient's constructor
• Transformer functions ($commandToRequestTransformer and $responseToResultTransformer)
• The HandlerStack

Executing Commands

Service clients create command objects using the getCommand() method.

$commandName = 'foo';
$arguments = ['baz' => 'bar'];
$command = $client->getCommand($commandName, $arguments);

After creating a command, you may execute the command using the execute() method of the client.

$result = $client->execute($command);

The result of executing a command will be a GuzzleHttp\Command\ResultInterface object. Result objects are ArrayAccess-ible and contain the data parsed from HTTP response.

Service clients have magic methods that act as shortcuts to executing commands by name without having to create the Command object in a separate step before executing it.

$result = $client->foo(['baz' => 'bar']);

Asynchronous Commands

@TODO Add documentation

• -Async suffix for client methods
• Promises

// Create and execute an asynchronous command.
$command = $command = $client->getCommand('foo', ['baz' => 'bar']);
$promise = $client->executeAsync($command);

// Use asynchronous commands with magic methods.
$promise = $client->fooAsync(['baz' => 'bar']);

@TODO Add documentation

• wait()-ing on promises.

$result = $promise->wait();

echo $result['fizz']; //> 'buzz' 

Concurrent Requests

@TODO Add documentation

• executeAll()
• executeAllAsync().
• Options (fulfilled, rejected, concurrency)

Middleware: Extending the Client

Middleware can be added to the service client or underlying HTTP client to implement additional behavior and customize the Command-to-Result and Request-to-Response lifecycles, respectively.

Todo

• Middleware system and command vs request layers
• The HandlerStack