在CakePHP中将标题设置为内容图像 [英] Setting the header to be content image in CakePHP

问题描述

我在控制器中写一个动作，在某种情况下，我想直接输出原始图像数据，并且想要设置标题内容类型。但是我认为标题已经由CakePHP早期设置了（我将设置为false）。

I am writing an action in a controller where in a certain case, I want to output raw image data directly, and want to set the header content-type appropriate. However I think the header is already being set earlier by CakePHP (I am setting render to be false).

有没有办法解决这个问题？感谢！

Is there a way to get around this? Thanks!

推荐答案

如前所述，当 render false 。当心，任何代码做一个echo将发送头（除非你使用输出缓冲）。这包括来自PHP（警告等）的邮件。

As said before, CakePHP does not send headers when render is false. Beware though, that any code doing an 'echo' will send headers (except you are using output-buffering). This includes messages from PHP (warnings etc.).

发送文件可以有多种方式，但有两种基本方式：

Sending the file can be done in numerous ways, but there are two basic ways:

function send_file_using_plain_php($filename) {
    // Avoids hard to understand error-messages
    if (!file_exists($filename)) {
        throw RuntimeException("File $filename not found");
    }

    $fileinfo = new finfo(FILEINFO_MIME);
    $mime_type = $fileinfo->file($filename); 
    // The function above also returns the charset, if you don't want that:
    $mime_type = reset(explode(";", $mime_type));
    // gets last element of an array

    header("Content-Type: $mime_type");
    header("Content-Length: ".filesize($filename));
    readfile($filename);
}

使用X-Sendfile并让Web服务器提供文件

Use X-Sendfile and have the Webserver serve the file

// This was only tested with nginx

function send_file_using_x_sendfile($filename) {
    // Avoids hard to understand error-messages
    if (!file_exists($filename)) {
        throw RuntimeException("File $filename not found");
    }

    $fileinfo = new finfo(FILEINFO_MIME);
    $mime_type = $fileinfo->file($filename); 
    // The function above also returns the charset, if you don't want that:
    $mime_type = reset(explode(";", $mime_type));
    // gets last element of an array

    header("Content-Type: $mime_type");
    // The slash makes it absolute (to the document root of your server)
    // For apache and lighttp use:
    header("X-Sendfile: /$filename");
    // or for nginx: header("X-Accel-Redirect: /$filename");

}

第一个函数占用一个PHP进程/数据正在发送，并且不支持范围请求或其他高级HTTP功能。

The first function occupies one PHP-process / thread while the data is being send and supports no Range-Requests or other advanced HTTP-features. This should therefore only be used with small files, or on very small sites.

使用X-Sendfile你可以得到所有的，但你需要知道哪个网络服务器正在运行，甚至可能需要更改配置。特别是在使用lighttp或nginx时，这在性能上是有利的，因为这些网络服务器极其擅长从磁盘提供静态文件。

Using X-Sendfile you get all that, but you need to know which webserver is running and maybe even a change to the configuration is needed. Especially when using lighttp or nginx this really pays off performance-wise, because these webservers are extremly good at serving static files from disk.

这两个函数都支持文档 - web服务器的根。在nginx中有所谓的内部位置（http://wiki.nginx.org/HttpCoreModule#internal）。这些可以与 X-Accel-Redirect -Header一起使用。甚至可以进行速率限制，请查看 http://wiki.nginx.org/XSendfile 。

Both functions support files not in the document-root of the webserver. In nginx there are so called "internal locations" (http://wiki.nginx.org/HttpCoreModule#internal). These can be used with the X-Accel-Redirect-Header. Even rate-throtteling is possible, have a look at http://wiki.nginx.org/XSendfile.

如果您使用apache，则有mod_xsendfile，它实现第二个函数所需的功能。

If you use apache, there is mod_xsendfile, which implements the feature needed by the second function.

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