PHP - 安全的方式来下载大文件？ [英] PHP - Safe way to download large files?

问题描述

信息

有很多方法可以在PHP中下载文件， file_get_contents + file_put_contents ， fopen ，< a href =http://php.net/manual/en/function.readfile.php =nofollow> readfile 和cURL。

There are many ways to download files in PHP, file_get_contents + file_put_contents, fopen, readfile and cURL.

问题？

• 当有一个大文件时，让我们说500 MB来自另一个服务器/域， 正确的方式下载安全吗？如果连接失败，它应该找到位置，如果它包含错误，请继续或重新下载文件。


• 它将在网站上使用，而不是在php.exe shell中。 li>
  

• When having a large file, let's say 500 MB from another server / domain, what is the "correct" way to downloaded it safe? If connection failes it should find the position and continue OR download the file again if it contains errors.
• It's going to be used on a web site, not in php.exe shell.

我到目前为止所想到的

• 我已经阅读过有关进度条的AJAX解决方案，但我真正寻找的是一个PHP解决方案。


• 我不需要缓冲文件像file_get_contents这样的字符串。这可能也是使用内存。


• 我也读过有关内存问题。不要使用这么多内存的解决方案可能会被优先使用。

概念

如果结果为false，这是我想要的。

This is sort of what I want if the result is false.

function download_url( $url, $filename ) {
    // Code
    $success['success'] = false;
    $success['message'] = 'File not found';
    return $success;
}

推荐答案

文件可以在这里展示从php stdin 保存大文件，但没有显示如何使用http范围复制文件

The easiest way to copy large files can be demonstrated here Save large files from php stdin but the does not shows how to copy files with http range

$url = "http://REMOTE_FILE";
$local = __DIR__ . "/test.dat";

try {
    $download = new Downloader($url);
    $download->start($local); // Start Download Process
} catch (Exception $e) {
    printf("Copied %d bytes\n", $pos = $download->getPos());
}

当出现异常时，您可以继续下一个文件下载点， p>

When an Exception occur you can resume the file download for the last point

$download->setPos($pos);

使用类

class Downloader {
    private $url;
    private $length = 8192;
    private $pos = 0;
    private $timeout = 60;

    public function __construct($url) {
        $this->url = $url;
    }

    public function setLength($length) {
        $this->length = $length;
    }

    public function setTimeout($timeout) {
        $this->timeout = $timeout;
    }

    public function setPos($pos) {
        $this->pos = $pos;
    }

    public function getPos() {
        return $this->pos;
    }

    public function start($local) {
        $part = $this->getPart("0-1");

        // Check partial Support
        if ($part && strlen($part) === 2) {
            // Split data with curl
            $this->runPartial($local);
        } else {
            // Use stream copy
            $this->runNormal($local);
        }
    }

    private function runNormal($local) {
        $in = fopen($this->url, "r");
        $out = fopen($local, 'w');
        $pos = ftell($in);
        while(($pos = ftell($in)) <= $this->pos) {
            $n = ($pos + $this->length) > $this->length ? $this->length : $this->pos;
            fread($in, $n);
        }
        $this->pos = stream_copy_to_stream($in, $out);
        return $this->pos;
    }

    private function runPartial($local) {
        $i = $this->pos;
        $fp = fopen($local, 'w');
        fseek($fp, $this->pos);
        while(true) {
            $data = $this->getPart(sprintf("%d-%d", $i, ($i + $this->length)));

            $i += strlen($data);
            fwrite($fp, $data);

            $this->pos = $i;
            if ($data === - 1)
                throw new Exception("File Corupted");

            if (! $data)
                break;
        }

        fclose($fp);
    }

    private function getPart($range) {
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $this->url);
        curl_setopt($ch, CURLOPT_RANGE, $range);
        curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_TIMEOUT, $this->timeout);
        $result = curl_exec($ch);
        $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        // Request not Satisfiable
        if ($code == 416)
            return false;

            // Check 206 Partial Content
        if ($code != 206)
            return - 1;

        return $result;
    }
}

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