Yii2 setDownloadHeaders()不工作

Question

代码

public function actionExport() {
  ini_set('memory_limit','32M');
  $whileAgo = date('Y-m-d', time() - 2*24*60*60); // 7-9 seems to be the limit for # days before the 30s timeout 
  $agkn = AdGroupKeywordNetwork::find()
    ->select(['field1', 'field2', ...])
    ->where(['>', 'event_date', $whileAgo])->asArray()->each(10000);
  $dateStamp = date('Y-m-d');
  Yii::$app->response->setDownloadHeaders("stats_$dateStamp.csv", 'text/csv');
  echo 'id,ad_group_keyword_id,keyword,network_id,quality,event_date,clicks,cost,impressions,position,ebay_revenue,prosperent_revenue'.PHP_EOL;
  // flush(); // gives us 55s more // doesn't work with gzip
  foreach ($agkn as $row) {
    echo join(',', $row).PHP_EOL;
    // flush();
  }
}

测试结果：

$ time (curl -sv -b 'PHPSESSID=ckg8l603vpls8jgj6h49d32tq0' http://localhost:81/web/ad-group-keyword-network/export | head)
...
< HTTP/1.1 200 OK
< Transfer-Encoding: chunked
< Content-Type: text/html; charset=UTF-8
<
{ [8277 bytes data]
id,ad_group_keyword_id,keyword,network_id,quality,event_date,clicks,cost,impressions,position,ebay_revenue,prosperent_revenue
9690697,527322,ray ban predator,1,6,2015-11-22,0,0.00,1,5.0,,

它也不会在浏览器中下载CSV文件。它没有设置头文件。怎么啦？

参考：http://www.yiiframework.com/doc-2.0/yii-web-response.html#setDownloadHeaders()-detail

Answer 1

这是因为php在第一次回显时发送报头，而在Yii之前发送报头。有一些方法可以解决这个问题。

• 将输出收集到缓冲区，然后发送。

Yii::$app->response->setDownloadHeaders("stats_$dateStamp.csv"，‘文本/csv’)；$data = 'id，ad_group_keyword_id，keyword，network_id，quality，event_date，clicks，cost，impressions，position，ebay_revenue，prosperent_id‘.PHP_EOL；foreach ($agkn as $row) { $data .= join('，'，$row).PHP_EOL；} return $data；

• 如果输出太大，内存无法容纳，则可能会将数据存储到临时文件。然后发送文件并删除临时文件。这种情况下不需要手动设置header。

$filePath = tempnam(sys_get_temp_dir()，'export')；$fp = fopen($filePath，'w')；if ($fp) {fput($fp，...)；} fclose($fp)；return Yii::$app->response->sendFile($filePath，"stats_$dateStamp.csv") ->on(\yii\web\Response::EVENT_AFTER_SEND，function($event) { unlink($event->data)；}，$filePath);