在做運營後臺的時候,不免會收到運營導出數據的需求,我們一般先從db裏發數據取出來,做一些簡單的數據。讓後echo到server,再到瀏覽器。
所以一般可能會這樣
class ConcreteController {
public function actionDownload() {
$request = new Request();
$model = new ConcreteModel();
$data = $model->getAllData($request); //取出所有數據
$this->exportData($dataReader, 'txt.csv');
exit;
}
private function exportData($data, $filename) {
$file = '/tmp/Concrete.exportData.'.time().'csv';
$this->putToFile($data, $file);
$this->download($filename, $file, true);
}
private function putToFile($data,$file) {
$isFirst = true;
$fp = fopen($file, 'wb');
foreach($dataReader as $key => $row) {
if($isFirst) {
$isFirst = false;
fputcsv($fp, array_keys($row));
}
fputcsv($fp, $row);
}
fclose($fp);
}
private function download($filename, $file, $rmFile=false) {
$this->downloadHeader($filename);
$d = file_get_contents($file);
echo mb_convert_encoding($d, 'gbk', 'utf-8');
if($rmFile) {
unlink($file);
}
}
protected function downloadHeader($filename) {
header("Content-Type: application/force-download");
header("Content-Disposition: attachment; filename={$filename}");
}
}
但是到取出的數據量很大的時候可能會有問題,優化的方法有很多,比如用PDO::query查詢數據後只獲取一個部分結果集,迭代獲取全部結果,把數據輸出到瀏覽器的時候輸出一部分,就flush一部分,或者先把數據寫到磁盤裏,然後用X-sendfile技術結合sever來下載一個靜態的文件.
我這裏不想把文件寫到磁盤上,就不用x-sendfile了,結合前面把數組變成csv字符串的方法,可以這麼弄
class ConcreteController {
public function actionDownload() {
$request = new Request();
$model = new ConcreteModel();
$dataReader = $model->exportData($request); //dataReader是一個 實現了 Traversable 接口,可用foreach 遍歷的數據集對象
$this->exportData($dataReader, 'test.csv');
exit;
}
private function exportData($dataReader, $filename) {
$this->downloadHeader($filename);
list($isFirst, $i, $limit) = array(true, 0, 1000);
foreach($dataReader as $key => $row) {
if($isFirst) {
$isFirst = false;
++$i;
echo CsvHelper::strPutCsv(array_keys($row));
}
echo CsvHelper::strPutCsv($row);
if(++$i > $limit) {
$i = 0;
ob_flush();
flush();
}
}
}
protected function downloadHeader($filename) {
header("Content-Type: application/force-download");
header("Content-Disposition: attachment; filename={$filename}");
}
}