在JavaScript中是否有一种方法来检查字符串是否是URL?
regex被排除在外，因为URL很可能写成stackoverflow;也就是说，它可能没有。com, WWW或http。
当前回答
我一直用来验证URL“字符串”的一个函数是:
var matcher = /^(?:\w+:)?\/\/([^\s\.]+\.\S{2}|localhost[\:?\d]*)\S*$/;
function isUrl(string){
return matcher.test(string);
}
这个函数将返回一个布尔值，不管字符串是否是URL。
例子:
isUrl("https://google.com"); // true
isUrl("http://google.com"); // true
isUrl("http://google.de"); // true
isUrl("//google.de"); // true
isUrl("google.de"); // false
isUrl("http://google.com"); // true
isUrl("http://localhost"); // true
isUrl("https://sdfasd"); // false
其他回答
依赖库: https://www.npmjs.com/package/valid-url
import { isWebUri } from 'valid-url';
// ...
if (!isWebUri(url)) {
return "Not a valid url.";
}
我使用下面的函数来验证URL是否有http/https:
function isValidURL(string) { var res = string.match(/(http(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)/g); return (res !== null) }; var testCase1 = "http://en.wikipedia.org/wiki/Procter_&_Gamble"; console.log(isValidURL(testCase1)); // return true var testCase2 = "http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&docid=nIv5rk2GyP3hXM&tbnid=isiOkMe3nCtexM:&ved=0CAUQjRw&url=http%3A%2F%2Fanimalcrossing.wikia.com%2Fwiki%2FLion&ei=ygZXU_2fGKbMsQTf4YLgAQ&bvm=bv.65177938,d.aWc&psig=AFQjCNEpBfKnal9kU7Zu4n7RnEt2nerN4g&ust=1398298682009707"; console.log(isValidURL(testCase2)); // return true var testCase3 = "https://sdfasd"; console.log(isValidURL(testCase3)); // return false var testCase4 = "dfdsfdsfdfdsfsdfs"; console.log(isValidURL(testCase4)); // return false var testCase5 = "magnet:?xt=urn:btih:123"; console.log(isValidURL(testCase5)); // return false var testCase6 = "https://stackoverflow.com/"; console.log(isValidURL(testCase6)); // return true var testCase7 = "https://w"; console.log(isValidURL(testCase7)); // return false var testCase8 = "https://sdfasdp.ppppppppppp"; console.log(isValidURL(testCase8)); // return false
As has been noted the perfect regex is elusive but still seems to be a reasonable approach (alternatives are server side tests or the new experimental URL API). However the high ranking answers are often returning false for common URLs but even worse will freeze your app/page for minutes on even as simple a string as isURL('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'). It's been pointed out in some of the comments, but most probably haven't entered a bad value to see it. Hanging like that makes that code unusable in any serious application. I think it's due to the repeated case insensitive sets in code like ((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.?)+[a-z]{2,}|' .... Take out the 'i' and it doesn't hang but will of course not work as desired. But even with the ignore case flag those tests reject high unicode values that are allowed.
已经提到的最好的是:
function isURL(str) {
return /^(?:\w+:)?\/\/([^\s\.]+\.\S{2}|localhost[\:?\d]*)\S*$/.test(str);
}
That comes from Github segmentio/is-url. The good thing about a code repository is you can see the testing and any issues and also the test strings run through it. There's a branch that would allow strings missing protocol like google.com, though you're probably making too many assumptions then. The repository has been updated and I'm not planning on trying to keep up a mirror here. It's been broken up into separate tests to avoid RegEx redos which can be exploited for DOS attacks (I don't think you have to worry about that with client side js, but you do have to worry about your page hanging for so long that your visitor leaves your site).
在dperini/regex- webburl .js中，我还看到过另一个存储库，它可能更适合isURL，但它非常复杂。它有一个更大的有效和无效url的测试列表。上面的简单的一个仍然通过了所有的正面信息，只有一些奇怪的负面信息，如http://a.b--c.de/以及特殊的ip。
无论你选择哪一个，在使用浏览器的开发人员工具检查器时，通过这个函数运行它，这个函数是我从dperini/regex- webburl .js上的测试中改编的。
function testIsURL() {
//should match
console.assert(isURL("http://foo.com/blah_blah"));
console.assert(isURL("http://foo.com/blah_blah/"));
console.assert(isURL("http://foo.com/blah_blah_(wikipedia)"));
console.assert(isURL("http://foo.com/blah_blah_(wikipedia)_(again)"));
console.assert(isURL("http://www.example.com/wpstyle/?p=364"));
console.assert(isURL("https://www.example.com/foo/?bar=baz&inga=42&quux"));
console.assert(isURL("http://✪df.ws/123"));
console.assert(isURL("http://userid:password@example.com:8080"));
console.assert(isURL("http://userid:password@example.com:8080/"));
console.assert(isURL("http://userid@example.com"));
console.assert(isURL("http://userid@example.com/"));
console.assert(isURL("http://userid@example.com:8080"));
console.assert(isURL("http://userid@example.com:8080/"));
console.assert(isURL("http://userid:password@example.com"));
console.assert(isURL("http://userid:password@example.com/"));
console.assert(isURL("http://142.42.1.1/"));
console.assert(isURL("http://142.42.1.1:8080/"));
console.assert(isURL("http://➡.ws/䨹"));
console.assert(isURL("http://⌘.ws"));
console.assert(isURL("http://⌘.ws/"));
console.assert(isURL("http://foo.com/blah_(wikipedia)#cite-1"));
console.assert(isURL("http://foo.com/blah_(wikipedia)_blah#cite-1"));
console.assert(isURL("http://foo.com/unicode_(✪)_in_parens"));
console.assert(isURL("http://foo.com/(something)?after=parens"));
console.assert(isURL("http://☺.damowmow.com/"));
console.assert(isURL("http://code.google.com/events/#&product=browser"));
console.assert(isURL("http://j.mp"));
console.assert(isURL("ftp://foo.bar/baz"));
console.assert(isURL("http://foo.bar/?q=Test%20URL-encoded%20stuff"));
console.assert(isURL("http://مثال.إختبار"));
console.assert(isURL("http://例子.测试"));
console.assert(isURL("http://उदाहरण.परीक्षा"));
console.assert(isURL("http://-.~_!$&'()*+,;=:%40:80%2f::::::@example.com"));
console.assert(isURL("http://1337.net"));
console.assert(isURL("http://a.b-c.de"));
console.assert(isURL("http://223.255.255.254"));
console.assert(isURL("postgres://u:p@example.com:5702/db"));
console.assert(isURL("https://d1f4470da51b49289906b3d6cbd65074@app.getsentry.com/13176"));
//SHOULD NOT MATCH:
console.assert(!isURL("http://"));
console.assert(!isURL("http://."));
console.assert(!isURL("http://.."));
console.assert(!isURL("http://../"));
console.assert(!isURL("http://?"));
console.assert(!isURL("http://??"));
console.assert(!isURL("http://??/"));
console.assert(!isURL("http://#"));
console.assert(!isURL("http://##"));
console.assert(!isURL("http://##/"));
console.assert(!isURL("http://foo.bar?q=Spaces should be encoded"));
console.assert(!isURL("//"));
console.assert(!isURL("//a"));
console.assert(!isURL("///a"));
console.assert(!isURL("///"));
console.assert(!isURL("http:///a"));
console.assert(!isURL("foo.com"));
console.assert(!isURL("rdar://1234"));
console.assert(!isURL("h://test"));
console.assert(!isURL("http:// shouldfail.com"));
console.assert(!isURL(":// should fail"));
console.assert(!isURL("http://foo.bar/foo(bar)baz quux"));
console.assert(!isURL("ftps://foo.bar/"));
console.assert(!isURL("http://-error-.invalid/"));
console.assert(!isURL("http://a.b--c.de/"));
console.assert(!isURL("http://-a.b.co"));
console.assert(!isURL("http://a.b-.co"));
console.assert(!isURL("http://0.0.0.0"));
console.assert(!isURL("http://10.1.1.0"));
console.assert(!isURL("http://10.1.1.255"));
console.assert(!isURL("http://224.1.1.1"));
console.assert(!isURL("http://1.1.1.1.1"));
console.assert(!isURL("http://123.123.123"));
console.assert(!isURL("http://3628126748"));
console.assert(!isURL("http://.www.foo.bar/"));
console.assert(!isURL("http://www.foo.bar./"));
console.assert(!isURL("http://.www.foo.bar./"));
console.assert(!isURL("http://10.1.1.1"));}
然后测试这串a。
在你发布一个看起来很棒的正则表达式之前，看看Mathias Bynens对isURL正则表达式的比较，了解更多信息。
我认为使用本地URL API比@pavlo建议的复杂正则表达式模式更好。虽然它有一些缺点，但我们可以通过一些额外的代码来修复。对于以下有效url，此方法失败。
//cdn.google.com/script.js
我们可以预先添加缺失的协议来避免这种情况。它也无法检测以下无效的url。
http://w
http://..
那么为什么要检查整个url呢?我们可以检查定义域。我借用正则表达式从这里验证域。
function isValidUrl(string) {
if (string && string.length > 1 && string.slice(0, 2) == '//') {
string = 'http:' + string; //dummy protocol so that URL works
}
try {
var url = new URL(string);
return url.hostname && url.hostname.match(/^([a-z0-9])(([a-z0-9-]{1,61})?[a-z0-9]{1})?(\.[a-z0-9](([a-z0-9-]{1,61})?[a-z0-9]{1})?)?(\.[a-zA-Z]{2,4})+$/) ? true : false;
} catch (_) {
return false;
}
}
主机名属性是javascript:void(0)的空字符串，所以它也适用于此，你也可以添加IP地址验证器。我最喜欢坚持使用本地API，并希望它在不久的将来开始支持一切。
如果你也需要支持https://localhost:3000，那么使用[Devshed]s regex的修改版本。
function isURL(url) {
if(!url) return false;
var pattern = new RegExp('^(https?:\\/\\/)?'+ // protocol
'((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|'+ // domain name
'((\\d{1,3}\\.){3}\\d{1,3}))|' + // OR ip (v4) address
'localhost' + // OR localhost
'(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*'+ // port and path
'(\\?[;&a-z\\d%_.~+=-]*)?'+ // query string
'(\\#[-a-z\\d_]*)?$', 'i'); // fragment locator
return pattern.test(url);
}
