blocks|key|555298|text|我相信您可以执行以下操作来获得文件名的扩展名。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|555299|var+path+=+require('path')

path.extname('index.html')
//+returns
'.html'|code-block|syntax|javascript|555300|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I believe you can do the following to get the extension of a file name.

<pre><code>var path = require('path')

path.extname('index.html')
// returns
'.html'
</code></pre>

blocks|key|339313|text|//+you+can+send+full+url+here
function+getExtension(filename)+{
++++return+filename.split('.').pop();
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|339314|如果您使用的是express，请在配置中间件(bodyParser)时添加以下行|unstyled|339315|app.use(express.bodyParser({+keepExtensions:+true}));|339316|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>// you can send full url here
function getExtension(filename) {
 return filename.split('.').pop();
}
</code></pre>

If you are using express please add the following line when configuring middleware (bodyParser)

<pre><code>app.use(express.bodyParser({ keepExtensions: true}));
</code></pre>

blocks|key|339547|text|此解决方案支持查询字符串！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|339548|var+Url+=+require('url');
var+Path+=+require('path');

var+url+=+'http://i.imgur.com/Mvv4bx8.jpg?querystring=true';
var+result+=+Path.extname(Url.parse(url).pathname);+//+'.jpg'|code-block|syntax|javascript|339549|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This solution supports querystrings!

<pre><code>var Url = require('url');
var Path = require('path');

var url = 'http://i.imgur.com/Mvv4bx8.jpg?querystring=true';
var result = Path.extname(Url.parse(url).pathname); // '.jpg'
</code></pre>

blocks|key|555509|text|一种不需要要求的简单解决方案，解决了多周期延长问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|555510|var+filename+=+'file.with.long.extension';
var+ext+=+filename.substring(filename.indexOf('.'));+
//ext+=+'.with.long.extension'|code-block|syntax|javascript|555511|或者，如果您不想要前导圆点：|555512|var+filename+=+'file.with.long.extension';
var+ext+=+filename.substring(filename.indexOf('.')%2B1);+
//ext+=+'with.long.extension'|555513|确保测试文件也有一个扩展名。|555514|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

A simple solution without need for require which solves the multiple period extension problem:

<pre><code>var filename = 'file.with.long.extension';
var ext = filename.substring(filename.indexOf('.')); 
//ext = '.with.long.extension'
</code></pre>

Or if you don't want the leading dot:

<pre><code>var filename = 'file.with.long.extension';
var ext = filename.substring(filename.indexOf('.')+1); 
//ext = 'with.long.extension'
</code></pre>

Make sure to test that the file has an extension too.

blocks|key|339703|text|您可以使用path.parse(path)，例如|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|339704|const+path+=+require('path');
const+{+ext+}+=+path.parse('/home/user/dir/file.txt');|code-block|syntax|javascript|339705|entityMap|0|LINK|mutability|MUTABLE|url|https://nodejs.org/api/path.html#path_path_parse_path^0|5|G|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

You can use <a href="https://nodejs.org/api/path.html#path_path_parse_path" rel="nofollow noreferrer">path.parse(path)</a>, for example

<pre><code>const path = require('path');
const { ext } = path.parse('/home/user/dir/file.txt');
</code></pre>

blocks|key|339376|text|path.extname在大多数情况下都能做到这一点。但是，它将包含最后一个.之后的所有内容，包括查询字符串和http请求的散列片段：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|339377|var+path+=+require('path')
var+extname+=+path.extname('index.html?username=asdf')
//+extname+contains+'.html?username=asdf'|code-block|syntax|javascript|339378|在这种情况下，您需要尝试如下所示：|339379|var+regex+=+/[#\\?]/g;+//+regex+of+illegal+extension+characters
var+extname+=+path.extname('index.html?username=asdf');
var+endOfExt+=+extname.search(regex);
if+(endOfExt+>+-1)+{
++++extname+=+extname.substring(0,+endOfExt);
}
//+extname+contains+'.html'|339380|请注意，带有多个句点的扩展(如.tar.gz)在path.extname中根本不起作用。|339381|entityMap^0|0|C|12|1|0|0|0|0|F|7|O|C|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|10|8|@$9|11|A|12|B|C]|$9|13|A|14|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|R|$]]

<code>path.extname</code> will do the trick in most cases. However, it will include everything after the last <code>.</code>, including the query string and hash fragment of an http request:

<pre><code>var path = require('path')
var extname = path.extname('index.html?username=asdf')
// extname contains '.html?username=asdf'
</code></pre>

In such instances, you'll want to try something like this:

<pre><code>var regex = /[#\\?]/g; // regex of illegal extension characters
var extname = path.extname('index.html?username=asdf');
var endOfExt = extname.search(regex);
if (endOfExt &gt; -1) {
 extname = extname.substring(0, endOfExt);
}
// extname contains '.html'
</code></pre>

Note that extensions with multiple periods (such as <code>.tar.gz</code>), will not work at all with <code>path.extname</code>.

blocks|key|555446|text|var+fileName+=+req.files.upload.name;

var+arr+=+fileName.split('.');

var+extension+=+arr[length-1];|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|555447|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>var fileName = req.files.upload.name;

var arr = fileName.split('.');

var extension = arr[length-1];
</code></pre>

blocks|key|339659|text|导入extname以返回文件的扩展名：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|339660|import+{+extname+}+from+'path';
extname(file.originalname);|code-block|syntax|javascript|339661|其中，file是表单的文件'name‘|339662|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

import extname in order to return the extension the file:

<pre><code>import { extname } from 'path';
extname(file.originalname);
</code></pre>

where file is the file 'name' of form

blocks|key|339818|text|一个扩展了String.prototype的one+liner|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|339819|Object.defineProperty(String.prototype,+"ext",+{get:+function(x)+{return+this.split('.').pop()}})
str+=+'fox.fbx';
str.ext|code-block|syntax|javascript|339820|结果：|339821|​|339822|📷|atomic|339823|339824|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/21f73b16716f86b849838dbaf1fc1914.png|imageAlt^0|5|G|0|0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|14|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|15|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|16|8|@]|D|@]|E|$]]|$1|O|3|P|5|Q|7|17|8|@]|D|@$9|18|A|19|1|1A]]|E|$]]|$1|R|3|N|5|6|7|1B|8|@]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1C|8|@]|D|@]|E|$]]]|T|$U|$5|V|W|X|E|$Y|Z|10|-4]]]]

A one liner which extends <code>String.prototype</code>:
<pre><code>Object.defineProperty(String.prototype, &quot;ext&quot;, {get: function(x) {return this.split('.').pop()}})
str = 'fox.fbx';
str.ext
</code></pre>
Result:
<a href="https://i.stack.imgur.com/Bpxop.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Bpxop.png" alt="enter image description here" /></a>

blocks|key|555603|text|下面的函数拆分字符串并返回名称和扩展名，而不管扩展名中有多少个点。如果没有扩展，它将返回一个空字符串。以点和/或空格开头的名称也可以。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|555604|function+basext(name)+{
++name+=+name.trim()
++const+match+=+name.match(/%5E(\.%2B)/)
++let+prefix+=+''
++if+(match)+{
++++prefix+=+match[0]
++++name+=+name.replace(prefix,+'')
++}
++const+index+=+name.indexOf('.')
++const+ext+=+name.substring(index+%2B+1)
++const+base+=+name.substring(0,+index)+%7C%7C+ext
++return+[prefix+%2B+base,+base+===+ext+?+''+:+ext]
}

const+[base,+ext]+=+basext('hello.txt')|code-block|syntax|javascript|555605|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The following function splits the string and returns the name and extension no matter how many dots there are in the extension. It returns an empty string for the extension if there is none. Names that start with dots and/or white space work also.

<pre><code>function basext(name) {
 name = name.trim()
 const match = name.match(/^(\.+)/)
 let prefix = ''
 if (match) {
 prefix = match[0]
 name = name.replace(prefix, '')
 }
 const index = name.indexOf('.')
 const ext = name.substring(index + 1)
 const base = name.substring(0, index) || ext
 return [prefix + base, base === ext ? '' : ext]
}

const [base, ext] = basext('hello.txt')
</code></pre>

blocks|key|339718|text|试试这个|type|unstyled|depth|inlineStyleRanges|entityRanges|data|339719|const+path+=+require('path');

function+getExt(str)+{
++const+basename+=+path.basename(str);
++const+firstDot+=+basename.indexOf('.');
++const+lastDot+=+basename.lastIndexOf('.');
++const+extname+=+path.extname(basename).replace(/(\.[a-z0-9]%2B).*/i,+'$1');

++if+(firstDot+===+lastDot)+{
++++return+extname;
++}

++return+basename.slice(firstDot,+lastDot)+%2B+extname;
}

//+all+are+`.gz`
console.log(getExt('/home/charlike/bar/file.gz'));
console.log(getExt('/home/charlike/bar/file.gz~'));
console.log(getExt('/home/charlike/bar/file.gz%2Bcdf2'));
console.log(getExt('/home/charlike/bar/file.gz?quz=zaz'));

//+all+are+`.tar.gz`
console.log(getExt('/home/charlike/bar/file.tar.gz'));
console.log(getExt('/home/charlike/bar/file.tar.gz~'));
console.log(getExt('/home/charlike/bar/file.tar.gz%2Bcdf2'));
console.log(getExt('/home/charlike/bar/file.tar.gz?quz=zaz'));|code-block|syntax|javascript|339720|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this one

<pre class="lang-js prettyprint-override"><code>const path = require('path');

function getExt(str) {
 const basename = path.basename(str);
 const firstDot = basename.indexOf('.');
 const lastDot = basename.lastIndexOf('.');
 const extname = path.extname(basename).replace(/(\.[a-z0-9]+).*/i, '$1');

 if (firstDot === lastDot) {
 return extname;
 }

 return basename.slice(firstDot, lastDot) + extname;
}

// all are `.gz`
console.log(getExt('/home/charlike/bar/file.gz'));
console.log(getExt('/home/charlike/bar/file.gz~'));
console.log(getExt('/home/charlike/bar/file.gz+cdf2'));
console.log(getExt('/home/charlike/bar/file.gz?quz=zaz'));

// all are `.tar.gz`
console.log(getExt('/home/charlike/bar/file.tar.gz'));
console.log(getExt('/home/charlike/bar/file.tar.gz~'));
console.log(getExt('/home/charlike/bar/file.tar.gz+cdf2'));
console.log(getExt('/home/charlike/bar/file.tar.gz?quz=zaz'));

</code></pre>

Im creating a file upload function in node.js with express 3.

I would like to grab the file extension of the image. so i can rename the file and then append the file extension to it.

<pre><code>app.post('/upload', function(req, res, next) {
 var is = fs.createReadStream(req.files.upload.path),
 fileExt = '', // I want to get the extension of the image here
 os = fs.createWriteStream('public/images/users/' + req.session.adress + '.' + fileExt);
});
</code></pre>

How can i get the extension of the image in node.js?

Node.js get file extension

中间件

我正在用Express3在node.js中创建一个文件上传功能。我想抓取图像的文件扩展名。因此，我可以重命名该文件，然后将文件扩展名附加到该文件。app.post('/upload', function(req, res, next) {    var is = fs.createReadStream(req.files.upload.path),        fileExt = '', // 

问Node.js get文件扩展名
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