Javascript Node.js - 文件系统获取文件类型，2012 年左右的解决方案
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Node.js - File System get file type, solution around year 2012
提问by noob
I need to get the file type of a file with the help of node.js to set the content type. I know I can easily check the file extension but I've also got files without extension which should have the content type image/png, text/htmlaso.
我需要在 node.js 的帮助下获取文件的文件类型来设置内容类型。我知道我可以轻松检查文件扩展名，但我也有没有扩展名的文件，这些文件应该具有内容类型image/png，text/htmlaso。
This is my code (I know it doesn't make much sense but that's the base I need):
这是我的代码（我知道它没有多大意义，但这是我需要的基础）：
var http = require("http"),
fs = require("fs");
http.createServer(function(req, res) {
var data = "";
try {
/*
* Do not use this code!
* It's not async and it has a security issue.
* The code style is also bad.
*/
data = fs.readFileSync("/home/path/to/folder" + req.url);
var type = "???"; // how to get the file type??
res.writeHead(200, {"Content-Type": type});
} catch(e) {
data = "404 Not Found";
res.writeHead(404, {"Content-Type": "text/plain"});
}
res.write(data);
res.end();
}).listen(7000);
I haven't found a function for that in the APIso I would be happy if anyone can tell me how to do it.
我还没有在API 中找到一个函数，所以如果有人能告诉我怎么做，我会很高兴。
采纳答案by ThiefMaster
Have a look at the mmmagic module. It is a libmagic binding and seems to do exactly what you want.
看看mmmagic 模块。它是一个 libmagic 绑定，似乎完全符合您的要求。
回答by 250R
There is a helper library for looking up mime types https://github.com/broofa/node-mime
有一个帮助库用于查找 mime 类型https://github.com/broofa/node-mime
var mime = require('mime');
mime.getType('/path/to/file.txt'); // => 'text/plain'
But it still uses the extension for lookup though
但它仍然使用扩展名进行查找
回答by Daniel Baulig
You should have a look at the command line tool file(Linux). It attempts to guess the filetype based on the first couple of bytes of the file. You can use child_process.spawnto run it from within node.
你应该看看命令行工具file（Linux）。它尝试根据文件的前几个字节猜测文件类型。您可以使用child_process.spawn从节点内运行它。
回答by timoxley
You want to be looking up the mime type, and thankfully node has a handy library just for that:
你想查找 mime 类型，幸好 node 有一个方便的库：
https://github.com/bentomas/node-mime#readme
https://github.com/bentomas/node-mime#readme
edit:
编辑：
You should probably look into a static asset server and not be setting any of this stuff yourself. You can use expressto do this really easily, or there's a whole host of static file modules, e.g. ecstatic. On the other hand you should probably use nginx to serve static files anyway.
您可能应该查看静态资产服务器，而不是自己设置任何这些东西。您可以使用express非常轻松地完成此操作，或者有大量静态文件模块，例如ecstatic。另一方面，您可能应该使用 nginx 来提供静态文件。
回答by Stephen Paul
回答by Andrea Girardi
I used this:
我用过这个：
npm install mime-types
And, inside the code:
而且，在代码中：
var mime = require('mime-types');
tmpImg.contentType = mime.lookup(fileImageTmp);
Where fileImageTmp is the copy of image stored on the file system (in this case tmp).
其中 fileImageTmp 是存储在文件系统上的图像副本（在本例中为 tmp）。
The result I can see is: image/jpeg
我能看到的结果是：image/jpeg
