php - 食欲池: Wait for Requests

是否可以使Guzzle池等待请求？

现在，我可以将请求动态添加到池中，但是一旦池为空，就将停止(显然)。

当我同时处理10个左右的页面时，这是一个问题，因为在处理结果HTML页面并添加新链接之前，我的请求数组将为空。

这是我的发电机:

$generator = function () {
  while ($request = array_shift($this->requests)) {
    if (isset($request['page'])) {
      $key = 'page_' . $request['page'];
    } else {
      $key = 'listing_' . $request['listing'];
    }

    yield $key => new Request('GET', $request['url']);
  }
  echo "Exiting...\n";
  flush();
};

而我的游泳池:

$pool = new Pool($this->client, $generator(), [
  'concurrency' => function() {
    return max(1, min(count($this->requests), 2));
  },
  'fulfilled' => function ($response, $index) {
      // new requests may be added to the $this->requests array here
  }
  //...
]);

$promise = $pool->promise();
$promise->wait();

@Alexey Shockov回答后编辑的代码:

$generator = function() use ($headers) {
  while ($request = array_shift($this->requests)) {
    echo 'Requesting ' . $request['id'] . ': ' . $request['url'] . "\r\n";

    $r = new Request('GET', $request['url'], $headers);

    yield 'id_' . $request['id'] => $this->client->sendAsync($r)->then(function($response, $index) {
      echo 'In promise fulfillment ' . $index . "\r\n";
    }, function($reason, $index) {
      echo 'in rejected: ' . $index . "\r\n";
    });
  }
};

$promise = \GuzzleHttp\Promise\each_limit($generator(), 10, function() {
  echo 'fullfilled' . "\r\n";
  flush();
}, function($err) {
  echo 'rejected' . "\r\n";
  echo $err->getMessage();
  flush();
});
$promise->wait();

最佳答案

不幸的是，您不能使用生成器来做到这一点，只能使用自定义迭代器。

我准备了 a gist with the full example ，但是主要思想是创建一个Iterator，它将以两种方式更改其状态(结束后可以再次变得有效)。

psysh中的ArrayIterator的示例:

>>> $a = new ArrayIterator([1, 2])
=> ArrayIterator {#186
     +0: 1,
     +1: 2,
   }
>>> $a->current()
=> 1
>>> $a->next()
=> null
>>> $a->current()
=> 2
>>> $a->next()
=> null
>>> $a->valid()
=> false
>>> $a[] = 2
=> 2
>>> $a->valid()
=> true
>>> $a->current()
=> 2

考虑到这个想法，我们可以将这样的动态迭代器传递给Guzzle并让其完成工作:

// MapIterator mainly needed for readability.
$generator = new MapIterator(
    // Initial data. This object will be always passed as the second parameter to the callback below
    new \ArrayIterator(['http://google.com']),
    function ($request, $array) use ($httpClient, $next) {
        return $httpClient->requestAsync('GET', $request)
            ->then(function (Response $response) use ($request, $array, $next) {
                // The status code for example.
                echo $request . ': ' . $response->getStatusCode() . PHP_EOL;
                // New requests.
                $array->append($next->shift());
                $array->append($next->shift());
            });
    }
);
// The "magic".
$generator = new ExpectingIterator($generator);
// And the concurrent runner.
$promise = \GuzzleHttp\Promise\each_limit($generator, 5);
$promise->wait();

如我之前所说，的完整示例在the gist 中，其中包括MapIterator和ExpectingIterator。

关于php - 食欲池: Wait for Requests，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/42754389/