发送请求

你可以使用Guzzle的 GuzzleHttp\ClientInterface 对象来发送请求。

创建客户端

use GuzzleHttp\Client;
$client = new Client([
    // Base URI is used with relative requests
    'base_uri' => 'http://httpbin.org',
    // You can set any number of default request options.
    'timeout'  => 2.0,
]);

Client对象可以接收一个包含参数的数组：

base_uri

(string|UriInterface) 基URI用来合并到相关URI，可以是一个字符串或者UriInterface的实例，当提供了相关uri，将合并到基URI，遵循的规则请参考 RFC 3986, section 2 章节。

// Create a client with a base URI
$client = new GuzzleHttp\Client(['base_uri' => 'https://foo.com/api/']);
// Send a request to https://foo.com/api/test
$response = $client->request('GET', 'test');
// Send a request to https://foo.com/root
$response = $client->request('GET', '/root');

不想阅读RFC 3986？这里有一些关于 base_uri 与其他URI处理器的快速例子：

handler

传输HTTP请求的(回调)函数。 该函数被调用的时候包含 Psr7\Http\Message\RequestInterface 以及参数数组，必须返回 GuzzleHttp\Promise\PromiseInterface ，成功时满足 Psr7\Http\Message\ResponseInterface 。 handler 是一个构造方法，不能在请求参数里被重写。

...

(混合) 构造方法中传入的其他所有参数用来当作每次请求的默认参数。

发送请求

Client对象的方法可以很容易的发送请求：

$response = $client->get('http://httpbin.org/get');
$response = $client->delete('http://httpbin.org/delete');
$response = $client->head('http://httpbin.org/get');
$response = $client->options('http://httpbin.org/get');
$response = $client->patch('http://httpbin.org/patch');
$response = $client->post('http://httpbin.org/post');
$response = $client->put('http://httpbin.org/put');

你可以创建一个请求，一切就绪后将请求传送给client：

use GuzzleHttp\Psr7\Request;
$request = new Request('PUT', 'http://httpbin.org/put');
$response = $client->send($request, ['timeout' => 2]);

Client对象为传输请求提供了非常灵活的处理器方式，包括请求参数、每次请求使用的中间件以及传送多个相关请求的基URI。

你可以在 Handlers and Middleware 页面找到更多关于中间件的内容。

异步请求

你可以使用Client提供的方法来创建异步请求：

$promise = $client->getAsync('http://httpbin.org/get');
$promise = $client->deleteAsync('http://httpbin.org/delete');
$promise = $client->headAsync('http://httpbin.org/get');
$promise = $client->optionsAsync('http://httpbin.org/get');
$promise = $client->patchAsync('http://httpbin.org/patch');
$promise = $client->postAsync('http://httpbin.org/post');
$promise = $client->putAsync('http://httpbin.org/put');

你也可以使用Client的 sendAsync() and requestAsync() 方法：

use GuzzleHttp\Psr7\Request;
// Create a PSR-7 request object to send
$headers = ['X-Foo' => 'Bar'];
$body = 'Hello!';
$request = new Request('HEAD', 'http://httpbin.org/head', $headers, $body);
// Or, if you don't need to pass in a request instance:
$promise = $client->requestAsync('GET', 'http://httpbin.org/get');

这些方法返回了Promise对象，该对象实现了由 Guzzle promises library 提供的 Promises/A+ spec ，这意味着你可以使用 then() 来调用返回值，成功使用 Psr\Http\Message\ResponseInterface 处理器，否则抛出一个异常。

use Psr\Http\Message\ResponseInterface;
use GuzzleHttp\Exception\RequestException;
$promise = $client->requestAsync('GET', 'http://httpbin.org/get');
$promise->then(
    function (ResponseInterface $res) {
        echo $res->getStatusCode() . "\n";
    },
    function (RequestException $e) {
        echo $e->getMessage() . "\n";
        echo $e->getRequest()->getMethod();
    }
);

并发请求

你可以使用Promise和异步请求来同时发送多个请求：

use GuzzleHttp\Client;
use GuzzleHttp\Promise;
$client = new Client(['base_uri' => 'http://httpbin.org/']);
// Initiate each request but do not block
$promises = [
    'image' => $client->getAsync('/image'),
    'png'   => $client->getAsync('/image/png'),
    'jpeg'  => $client->getAsync('/image/jpeg'),
    'webp'  => $client->getAsync('/image/webp')
];
// Wait on all of the requests to complete.
$results = Promise\unwrap($promises);
// You can access each result using the key provided to the unwrap
// function.
echo $results['image']->getHeader('Content-Length');
echo $results['png']->getHeader('Content-Length');

当你想发送不确定数量的请求时，可以使用 GuzzleHttp\Pool 对象：

use GuzzleHttp\Pool;
use GuzzleHttp\Client;
use GuzzleHttp\Psr7\Request;
$client = new Client();
$requests = function ($total) {
    $uri = 'http://127.0.0.1:8126/guzzle-server/perf';
    for ($i = 0; $i < $total; $i++) {
        yield new Request('GET', $uri);
    }
};
$pool = new Pool($client, $requests(100), [
    'concurrency' => 5,
    'fulfilled' => function ($response, $index) {
        // this is delivered each successful response
    },
    'rejected' => function ($reason, $index) {
        // this is delivered each failed request
    },
]);
// Initiate the transfers and create a promise
$promise = $pool->promise();
// Force the pool of requests to complete.
$promise->wait();