Question

这似乎是一个关于noobs的问题，但我想确切地知道当用户点击下载按钮时开始下载需要什么代码。假设我有这个网页和一个包含用户设置的过滤器（即选择日期范围）的表单，当他点击下载按钮时，在他的硬盘上创建了一个csv文档。我必须与哪个模块进行通信才能启动下载，文件具有此扩展名并包含X数据。我听说你必须在HTTP标题中设置一些字段，但我不太清楚我应该怎么做。

编辑：文件下载现在可以使用，但我的文件现在包含以前在页面上写的所有html以及要下载的数据。这是我的代码片段。为了便于阅读，我删除了很多语句

# Handler class which handles the page /Download 
class downloadsHandler(webapp2.RequestHandler):

def get(self):

    # write download page on the browser
    template = JINJA_ENVIRONMENT.get_template('/pages/download.html')
    self.response.write(template.render(template_values))

    # data to download
    buf = getLatestdata()

    # size of data
    size  = sys.getsizeof(buf)

    # set HTTP headers to notify server of download
    self.response.headers["Content-Type"] = "text/csv"
    self.response.headers["Cache-Control"] = "no-cache, must-revalidate"
    self.response.headers["Content-Disposition"] = "attachment; filename=kioskData.csv"
    self.response.headers["Content-Length"] = size
    self.response.headers["Content-Transfer-Encoding"] = "binary"

    # generate download
    self.response.write(buf)

如何告诉浏览器只包含要下载的数据？

Answer 1

你应该让下载按钮指向一个PHP文件（如果使用PHP），它将以下行作为标题

<?php
    header('Content-type: text/csv');
    header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
    header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past
    header('Content-Disposition: attachment; filename="filename.csv"');
?>

希望这有帮助！

更新：动态添加示例CSV文件

<?php
    echo "This is a CSV file generated by PHP code on the fly";
    // Let's print the column headers on first row
    echo "ID,Name,Type\r\n";
    echo "1,John,1\r\n";
    echo "2,Doe,2\r\n";

    header('Content-type: text/csv');
    header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
    header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past
    header('Content-Disposition: attachment; filename="filename.csv"');
?>

Answer 2

我使用以下内容下载和查看文件（支持的位置）。此代码支持在用户设备上重命名文件。

<?php

getFile("test.csv");

function getFile($file, $mode="download", $outfile=""){
    // File Exists?
    if (file_exists($file)){
        // Parse Info / Get Extension
        $fsize = filesize($file);
        $path_parts = pathinfo($file);
        $ext = strtolower($path_parts["extension"]);

        // Determine Content Type
        switch ($ext) {
            case "pdf": $ctype="application/pdf"; break;
            case "exe": $ctype="application/octet-stream"; break;
            case "zip": $ctype="application/zip"; break;
            case "doc": $ctype="application/msword"; break;
            case "xls": $ctype="application/vnd.ms-excel"; break;
            case "ppt": $ctype="application/vnd.ms-powerpoint"; break;
            case "gif": $ctype="image/gif"; break;
            case "png": $ctype="image/png"; break;
            case "jpeg":
            case "jpg": $ctype="image/jpg"; break;
            case "jpg": $ctype="image/jpg"; break;
            case "csv": $ctype="text/csv"; break;
                    // video
            case "3gp": $ctype='video/3gpp'; break;
            case "3g2": $ctype='video/3g2'; break;
            case "avi": $ctype='video/avi'; break;
            case "mp4": $ctype='video/mp4'; break;
            case "ogv": $ctype='video/ogg'; break;
            case "asf": $ctype='video/asf'; break;
            case "mov": $ctype='video/quicktime'; break;            
            default: $ctype="application/force-download";
        }

        header("Pragma: public"); // required
        header("Expires: 0");
        header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
        header("Cache-Control: private",false); // required for certain browsers
        header("Content-Type: $ctype");

        $outfile = ($outfile=="" ? basename($file) : basename($outfile));
        if ($mode == "view"){
            // View file
            header('Content-Disposition: inline; filename='.$outfile);
        } 
        else {
            // Download file
            header('Content-Disposition: attachment; filename='. $outfile);
        }

        header("Content-Transfer-Encoding: binary");
        header("Content-Length: ".$fsize);

        if (ob_get_length() > 0 ) {
                    ob_clean();
                    flush();
        }
        readfile( $file );
    } 
    else {
        echo('File Not Found: ' . $file);
    }
} 
?>

Answer 3

确定。所以现在一切正常。我必须清除包含当前页面的html数据的输出流

self.response.clear()

在设置标题之前。这将生成一个仅包含缓冲区内容的csv文件

如何在用户点击时生成下载

3 个答案: