composer require guzzlehttp/guzzle //用composer安装最新guzzle，当前是6.3版

$client = new GuzzleHttp\Client(); //初始化客户端
$response = $client->get('http://httpbin.org/get', [
   'query' => [ //get查询字符串参数组
    'a' => '参数a的值',
    'b' => '参数b的值',
   ],
   'timeout' => 3.14 //设置请求超时时间
  ]);
  
//  与上面一条等价
//  $response = $client->request('GET','http://httpbin.org/get', [
//   'query' => [  
//    'a' => '参数a的值',
//    'b' => '参数b的值',
//   ],
//   'timeout' => 3.14 
//  ]);

$body = $response->getBody(); //获取响应体，对象
$bodyStr = (string)$body; //对象转字串,这就是请求返回的结果
echo $bodyStr;

$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');

$client = new GuzzleHttp\Client();
//普通表单`application/x-www-form-urlencoded`的POST请求
$response = $client->post('http://httpbin.org/post', [
 'form_params' => [  //参数组
  'a' => 'aaa',
  'b' => 'bbb',
  'nested_field' => [ //参数允许嵌套多层
   'A' => 'AAA',
   'B' => 'BBB',
  ]
 ],
]);
  
  //包含文件上传的表单`multipart/form-data`的POST请求
//  $response = $client->post('http://httpbin.org/post', [
//   'multipart' => [ //注意这个参数组的键名与前一个不同
//    [
//     'name' => 'a', //字段名
//     'contents' => 'aaa' //对应的值
//    ],
//    [
//     'name' => 'upload_file_name', //文件字段名
//     'contents' => fopen('/data/test.md', 'r') //文件资源
//    ],
//   ]
//  ]);
  
  $body = $response->getBody(); //获取响应体，对象
  $bodyStr = (string)$body; //对象转字串
  echo $bodyStr;