PHP文件下载后无法读取

Question

您好，我有一个脚本可以创建文件并将其存储在服务器上。该文件以 UTF-8 编码，是 cmap 软件的一种 xml 文件。

如果我直接从服务器打开文件，则没有问题并且可以读取该文件。

当用户访问特定网址时，我强制下载此文件。下载后，cmap 软件将无法读取该文件。我必须进入我的文本编辑器（notepad++）并将编码从 UTF-8 更改为 UTF-8 without BOM。

我发送了错误的标头吗？php 在下载文件时是否对文件做了什么？

对此的任何建议将不胜感激。

欢呼

编辑

抱歉，几个不同的类涉及大量代码。我已经包含了用于将文件发送到浏览器的代码：

function exportCMAP()
{   
    $serializer = new Serializer();
    $serializer->serializeCmap();

    header("Cache-Control: public");
    header("Content-Description: File Transfer");
    header("Content-Disposition: attachment; filename=export.cxl");
    header("Content-Type: x-cmap/text-xml");
    header("Content-Transfer-Encoding: binary");

    readfile("temp/export.cxl");
}

如果需要生成 xml（使用 XMLWriter）的代码，我也可以发布它。

编辑

按照此处的要求，生成 xml 的代码 - 它位于另一个类中：

        function serializeCmap()
    {

        $storeManager = new StoreManager();         
        $linkedNodes = $storeManager->getLinkedNodes();

        $namespaces = Array();

        $writer = new XMLWriter();

        $writer->openMemory();
        $writer->setIndent(4); 

        $writer->startDocument('1.0', 'utf-8');

            $writer->startElement('cmap');

                $writer->writeAttribute('xmlns', 'http://cmap.ihmc.us/xml/cmap/');
                $writer->writeAttribute('dc', 'http://purl.org/dc/elements/1.1/');

            $writer->startElement('res-meta');

                $writer->writeElement("dc:title", "Full schema for Cmap");
                $writer->writeElement("dc:description", "Description Goes Here");

            $writer->endElement();  

            $writer->startElement('map');

                $writer->startElement('concept-list');

                    foreach($linkedNodes['nodes'] as $node=>$id) {

                        $writer->startElement('concept');

                            $writer->writeAttribute("id", $id);
                            $writer->writeAttribute("label", $node);

                        $writer->endElement();
                    }

                $writer->endElement();

                $writer->startElement('linking-phrase-list');

                    foreach($linkedNodes['phrases'] as $phrase=>$id) {

                        $writer->startElement('linking-phrase');

                            $writer->writeAttribute("id", $id);
                            $writer->writeAttribute("label", $phrase);

                        $writer->endElement();
                    }

                $writer->endElement();

                $writer->startElement('connection-list');

                    foreach($linkedNodes['connections'] as $key=>$val) {

                        $writer->startElement('connection');

                            $writer->writeAttribute("from-id", $val['from']);
                            $writer->writeAttribute("to-id", $val['phrase']);

                        $writer->endElement();

                        $writer->startElement('connection');

                            $writer->writeAttribute("from-id", $val['phrase']);
                            $writer->writeAttribute("to-id", $val['to']);

                        $writer->endElement();
                    }

                $writer->endElement();

            $writer->endElement();

        $writer->endElement();

        $writer->endDocument();

        file_put_contents("temp/export.cxl",$writer->outputMemory());
    }

Answer 1

您应该添加两件重要的事情：

1. 测试 HTTP 标头是否尚未发送，并且
2. 确保没有比以下之一更多的输出 readfile.

所以试试这个：

function exportCMAP() {
    if (headers_sent()) {
        // HTTP header has already been sent
        return false;
    }
    // clean buffer(s)
    while (ob_get_level() > 0) {
        ob_end_clean();
    }
    header("Cache-Control: public");
    header("Content-Description: File Transfer");
    header("Content-Disposition: attachment; filename=export.cxl");
    header("Content-Type: x-cmap/text-xml");
    header("Content-Transfer-Encoding: binary");
    readfile("temp/export.cxl");
    // avoid any further output
    exit;
}