如何将网址与正则表达式匹配？

Question

We want to check if a URL matches mail.google.com or mail.yahoo.com (also a subdomain of them is accepted) but not a URL which contains this string after a question mark. We also want the strings "mail.google.com" and "mail.yahoo.com" to come before the third slash of the URL, for example https://mail.google.com/ is accepted, https://www.facebook.com/mail.google.com/ is not accepted, and https://www.facebook.com/?mail=https://mail.google.com/ is also not accepted. https://mail.google.com.au/ is also not accepted. Is it possible to do it with regular expressions?

var possibleURLs = /^[^\?]*(mail\.google\.com|mail\.yahoo\.com)\//gi;
var url;
// assign a value to var url.
if (url.match(possibleURLs) !== null) {
    // Do something...
}

Currently this will match both https://mail.google.com/ and https://www.facebook.com/mail.google.com/ , but we don't want to match https://www.facebook.com/mail.google.com/ .

Edit : I want to match any protocol (any string which doesn't contain "?" and "/" ) followed by a slash "/" twice (the string and the slash can both be twice), then any string which doesn't contain "?" and "/" (if it's not empty, it must end with a dot "." ), and then (mail\\.google\\.com|mail\\.yahoo\\.com)\\/ . Case insensitive.

Answer 1

Not being funny - but why must it be a regular expression?

Is there are reason why you couldn't simplify the process using URL (or webkitURL in Chrome and Safari) - the URL constructor simply takes a string and then contains properties for each part of the URL. Whether it supports all the host types that you want to support, I don't know.

Granted, you might still need a regex after that (although really you'd just be checking that the hostname ends with either yahoo.com or google.com), but you would just be running it against the hostname of the URL object rather than the whole URI.

The API is not ubiquitous, but seems reasonably well supported and, anyway, if this is client-side validation then I hope you're checking it on the server, too, because sidestepping javascript validation is easy.

Answer 2

^([-a-z]+://|^cid:|^//)([^/\?]+\.)?mail\.(google|yahoo)\.com/

Should do the trick

The first ^ means "match beginning of line", the second negates the allowed characters, thus making a slash / not allowed.

Nb. You still have to escape the slashes, or use it as a string in new RegExp(string) :

new RegExp('^([-a-z]+://|^cid:|^//)([^/\?]+\.)?mail\.(google|yahoo)\.com/')

Answer 3

How about

^[a-z]+:\/\/([^.\/]+\.)*mail\.(google|yahoo).com\/

Regex Example Link

• ^ Anchors the regex at the start of the string

• [az]+ Matches the protocol. If you want a specific set of protocols, then (https?|ftp) may do the work

• ([^.\\/]+\\.)* matches the subdomin part

Answer 4

好的，我发现它适用于：

var possibleURLs = /^([^\/\?]*\/){2}([^\.\/\?]+\.)*(mail\.google\.com|mail\.yahoo\.com)\//gi;