javascript 如何通过 URL 下载文件然后获取其名称
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How to download a file via URL then get its name
提问by HarryJ2213
This is for a userscript I'm making with JS+jQuery. I'm wondering if it's possible to find the filename given the URL.
这是我用 JS+jQuery 制作的用户脚本。我想知道是否有可能找到给定 URL 的文件名。
It's in the form of:
它的形式如下：
http://example.org/download.php?action=download&id=1234
and then that link downloads a file such as "cat.jpg".
然后该链接会下载一个文件，例如“cat.jpg”。
How do I find out what the file name is called? I don't need to actually save the file on the users computer - just need to find the name of the file.
我如何找出文件名的名称？我不需要实际将文件保存在用户计算机上 - 只需要找到文件的名称。
I'm open to using any JS library - but I need to make sure that the file isn't actually saved in the users computer (or maybe it's just saved in a temp folder somewhere).
我愿意使用任何 JS 库 - 但我需要确保该文件实际上并未保存在用户计算机中（或者它可能只是保存在某个临时文件夹中）。
回答by dfsq
The simple thing you can do is to make HEAD request, so that you don't actually download the file but only response headers. From there you get Content-Dispositionheader which contains filenamefield.
您可以做的最简单的事情是发出 HEAD 请求，这样您就不会实际下载文件，而只会下载响应标头。从那里你得到Content-Disposition包含filename字段的标题。
Something like this in jQuery:
在 jQuery 中是这样的：
$.ajax({
type: "HEAD",
url: 'http://example.org/download.php?action=download&id=1234',
success: function(message, text, response) {
var header = response.getResponseHeader('Content-Disposition');
console.log(header);
}
});
headervariable will be something like attachment; filename="image.jpg". Now it's easy to extract filename part:
header变量将类似于attachment; filename="image.jpg". 现在很容易提取文件名部分：
var filename = header.match(/filename="(.+)"/)[1]; // image.jpg
