I've got this regex pattern from WMD showdown.js file.
/<((https?|ftp|dict):[^'">\s]+)>/gi
and the code is:
text = text.replace(/<((https?|ftp|dict):[^'">\s]+)>/gi,"$1");
But when I set text to http://www.google.com, it does not anchor it, it returns the original text value as is (http://www.google.com).
P.S: I've tested it with RegexPal and it does not match.
Your code is searching for a url wrapped in <> like: <http://www.google.com>: RegexPal.
Just change it to /((https?|ftp|dict):[^'">\s]+)/gi if you don't want it to search for the <>: RegexPal
As long as you know your url's start with http:// or https:// or whatever you can use:
/((https?|s?ftp|dict|www)(://)?)[A-Za-z0-9.\-]+)/gi
The expression will match till it encounters a character not allowed in the URL i.e. is not A-Za-z\.\-. It will not however detect anything of the form google.com or anything that comes after the domain name like parameters or sub directory paths etc. If that is your requirement that you can simply choose to terminate the terminating condition as you have above in your regex.
I know it seems pointless but it may be useful if you want the display name to be something abbreviated rather than the whole url in case of complex urls.
You could use:
var re = /(http|https|ftp|dict)(:\/\/\S+?)(\.?\s|\.?$)/gi;
with:
el.innerHTML = el.innerHTML.replace(re, '<a href=\'$1$2\'>$1$2<\/a>$3');
to also match URLs at the end of sentences.
But you need to be very careful with this technique, make sure the content of the element is more or less plain text and not complex markup. Regular expressions are not meant for, nor are they good at, processing or parsing HTML.
Related
I wrote a RegExp to grab and encode URLs in JavaScript.
This works fine but, it introduced a bug into my app.
I have a span Element which is used to display Emojis like this:
<span style="background:url(http://localhost/res/emo/face/E004.png)"></span>
Now, I'm using this Regular Expression to grab and convert anything URL into actual HTML clickable links:
/((https?:\/\/)?[\w-]+(\.[\w-]+)+\.?(:\d+)?(\/\S*)?)/ig
This ended up encoding the emoji URL into a clickable link.
Can anyone adjust that Code to Ignore URLs inside Elements or embedded Objects???
Please I need help!
This is the code:
var urlRegex = /((https?:\/\/)?[\w-]+(\.[\w-]+)+\.?(:\d+)?(\/\S*)?)/ig;
return txt.replace(urlRegex, function (url) {
var hyperlink = url;
if(!hyperlink.match('^https?:\/\/')) {
hyperlink = 'http://' + hyperlink;
}
return `${url}`;
});
I don't that the URLS inside
<span style="background:url(http://localhost/res/emo/face/E004.png)"></span>
were touched.
You would need to use negative look behind, which has limited support in JavaScript. (see here https://stackoverflow.com/a/50434875/6853740)
Simply adding negative look behind to your existing regex still doesn't work as expected:
((?<!url\()(https?:\/\/)?[\w-]+(\.[\w-]+)+\.?(:\d+)?(\/\S*)?) still matches "E004.png" in your example. Even other URL regexs from this post (What is the best regular expression to check if a string is a valid URL?) also match that. You may need to consider only looking for links that start with http:// or https:// which may help you recraft a regex that will only match full URLs.
I have a bit of a strange one here, I basically have a large chunk of text which may or may not contain links to images.
So lets say it does I have a pattern which will extract the image url fine, however once a match is found it is replaced with a element with the link as the src. Now the problem is there may be multiple matches within the text and this is where it gets tricky. As the url pattern will now match the src tags url, which will basically just enter an infinite loop.
So is there a way to ONLY match in regex if it doesnt start with a pattern like ="|=' ? as then it would match the url in something like:
some image http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=6
but not
some image <img src="http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=6">
I am not sure if it is possible, but if it is could someone point me in the right direction? A replace by itself will not suffice in this scenario as the url matched needs to be used elsewhere too so it needs to be used like a capture.
The main scenarios I need to account for are:
Many links in one block of varied text
A single link without any other text
A single link with other varied text
== edit ==
Here is the current regex I am using to match urls:
(\b(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*(?:png|jpeg|jpg|gif|bmp))
== edit 2 ==
Just so everyone understands why I cannot use the /g command here is an answer which explains the issue, if I could use this /g like I originally tried then it would make things a lot simpler.
Javascript regex multiple captures again
What you are looking for is a negative look behind, but Javascript doesn't support any kind of look behinds, so you will either have to use a callback function to check what was matched and make sure it is not preceded by a ' or ", or you can use the following regex:
(?:^|[^"'])(\b(https?|ftp|file):\/\/[-a-zA-Z0-9+&##\/%?=~_|!:,.;]*(?:png|jpeg|jpg|gif|bmp))
which has a single problem, that is in the case of a successful match it will catch one more character, the one right before the (\b(https?|ftp|file) pattern in the input, but I think you can deal with this easily.
Regex101 Demo
Using the /ig command at the end should work... the g is for global replace and the i is for case-insensitivity, which is necessary as you've only got A-Z instead of a-zA-Z.
Using the following vanilla JS appears to work for me (see jsfiddle)...
var test="some image http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=6 some image http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=6 some image http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=6";
var re = new RegExp(/(\b(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*(?:png|jpeg|jpg|gif|bmp))/ig);
document.getElementById("output").innerHTML = test.replace(re,"<img src=\"$1\"/>");
Although, what it does highlight is that the query string part of the URL (the ?v=6 is not being picked up with your RegEx).
For jQuery, it would be (see jsfiddle)...
$(document).ready(function(){
var test="some image http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=6 some image http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=6 some image http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=6";
var re = new RegExp(/(\b(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*(?:png|jpeg|jpg|gif|bmp))/ig);
$("#output").html(test.replace(re,"<img src=\"$1\"/>"));
});
Update
Just in case my example of using the same image URL in the example doesn't convince you - it also works with different URLs... see this jsfiddle update
var test="http://cdn.sstatic.net/stackoverflow/img/sprites.png?v=6 http://cdn.sstatic.net/serverfault/img/sprites.png?v=7";
var re = new RegExp(/(\b(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*(?:png|jpeg|jpg|gif|bmp))/ig);
document.getElementById("output").innerHTML = test.replace(re,"<img src=\"$1\"/>");
Couldn't you just see if there is a whitespace in front of the url, instead of that word-boundary? seems to work, although you will have to remove the matched whitespace later.
(\s(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*(?:png|jpeg|jpg|gif|bmp))
http://rubular.com/r/9wSc0HNWas
Edit: Damn, too slow :) I'll still leave this here as my regex is shorter ;)
as was said by freefaller, you might use /g flag to just find all matches in one go, if exec is not a must.
otherwise: you can add (="|=')? to the beginning of your regex, and check if $1 is undefined. if it is undefined, then it was not started with a ="|=' pattern
I'm trying to validate a field to allow relative and absolute urls. I'm using the regex from this post but it is allowing spaces in the url.
var urlRegex = new RegExp(/(\/?[\w-]+)(\/[\w-]+)*\/?|(((http|ftp|https):\/\/)?[\w-]+(\.[\w-]+)+([\w.,#?^=%&:\/~+#-]*[\w#?^=%&\/~+#-])?)/gi);
Example:
// this should work
this/will/work.aspx?say=hello
http://www.example.com/this/will/work.aspx?say=hello
// this shouldn't work but does
and/this will also work/even though it shouldn't
and/this-shouldn't/but it does/also
The code below is what I was originally using to validate just absolute urls and it was working perfectly. If I remember properly, I pulled it from the jquery source. If this could be modified to also accept relative urls that would be perfect, but this is out of my league.
var urlRegex = new RegExp(/^(https?|ftp):\/\/(((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:)*#)?(((\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5]))|((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?)(:\d*)?)(\/((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|#)+(\/(([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|#)*)*)?)?(\?((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|#)|[\uE000-\uF8FF]|\/|\?)*)?(\#((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|#)|\/|\?)*)?$/i);
I think you just need to anchor the pattern so that it has to match the whole string:
var urlRegex = /^(\/?[\w-]+)(\/[\w-]+)*\/?|(((http|ftp|https):\/\/)?[\w-]+(\.[\w-]+)+([\w.,#?^=%&:\/~+#-]*[\w#?^=%&\/~+#-])?)$/gi;
The leading ^ and trailing $ means that the pattern has to match the entire string instead of just some part of it.
edit that said, the pattern has other problems. First, those HTML entities for & (&) need to be just "&". The slashes don't need to be escaped in [] groups, and we don't need the "g" suffix. That leaves us with:
var urlRegex = /^(?:(\/?[\w-]+)(\/[\w-]+)*\/?|(((http|ftp|https):\/\/)?[\w-]+(\.[\w-]+)*([\w.,#?^=%&:/~+#-]*[\w#?^=%&/~+#-])?))$/i;
edit again - oops also need to wrap the whole thing.
I wrote an article about URI validation complete with code snippets for all the various URI components as defined by RFC3986 here:
Regular Expression URI Validation
You may find what you are looking for there. Note however that almost any string represents a valid URI - even an empty string!
I would like to convert any instances of a hashtag in a String into a linked URL:
#hashtag -> should have "#hashtag" linked.
This is a #hashtag -> should have "#hashtag" linked.
This is a [url=http://www.mysite.com/#name]named anchor[/url] -> should not be linked.
This isn't a pretty way to use quotes -> should not be linked.
Here is my current code:
String.prototype.parseHashtag = function() {
return this.replace(/[^&][#]+[A-Za-z0-9-_]+(?!])/, function(t) {
var tag = t.replace("#","")
return t.link("http://www.mysite.com/tag/"+tag);
});
};
Currently, this appears to fix escaped characters (by excluding matches with the amperstand), handles named anchors, but it doesn't link the #hashtag if it's the first thing in the message, and it seems to grab include the 1-2 characters prior to the "#" in the link.
Halp!
How about the following:
/(^|[^&])#([A-Za-z0-9_-]+)(?![A-Za-z0-9_\]-])/g
matches the hashtags in your example. Since JavaScript doesn't support lookbehind, it tries to either match the start of the string or any character except & before the hashtag. It captures the latter so it can later be replaced. It also captures the name of the hashtag.
So, for example:
subject.replace(/(^|[^&])#([A-Za-z0-9_-]+)(?![A-Za-z0-9_\]-])/g, "$1http://www.mysite.com/tag/$2");
will transform
#hashtag
This is a #hashtag and this one #too.
This is a [url=http://www.mysite.com/#name]named anchor[/url]
This isn't a pretty way to use quotes
into
http://www.mysite.com/tag/hashtag
This is a http://www.mysite.com/tag/hashtag and this one http://www.mysite.com/tag/too.
This is a [url=http://www.mysite.com/#name]named anchor[/url]
This isn't a pretty way to use quotes
This probably isn't what t.link() (which I don't know) would have returned, but I hope it's a good starting point.
There is an open-source Ruby gem to do this sort of thing (hashtags and #usernames) called twitter-text. You might get some ideas and regexes from that, or try out this JavaScript port.
Using the JavaScript port, you'll want to just do:
var linked = TwitterText.auto_link_hashtags(text, {hashtag_url_base: "http://www.mysite.come/tag/"});
Tim, your solution was almost perfect. Here's what I ended up using:
subject.replace(/(^| )#([A-Za-z0-9_-]+)(?![A-Za-z0-9_\]-])/g, "$1#$2");
The only change is the first conditional, changed it to match the beginning of the string or a space character. (I tried \s, but that didn't work at all.)
Related (but slightly different):
Javascript Regex: surround #_____, #_____, and http://______ with anchor tags in one pass?
I would like to surround all instances of #_______, #________, and http://________ with anchor tags. Multiple passes is fine with me.
For example, consider this Twitter message:
The quick brown fox #Spreadthemovie jumps over the lazy dog #cow, http://bit.ly/bC9Dy
Running it with the desired regex pattern would yield:
The quick brown fox #Spreadthemovie jumps over the lazy
dog #cow, http://bit.ly/bC9Dy
Only surround words that start with #, # or http:// so that dog#gmail.com would not become dog#gmail.com. Also, note how "#cow," turned into "<a href=urlB>#cow</a>," ... I only want alpha-numeric characters to be on the end of each anchor tagged substring. Also notice the href attribute.
If possible, please include actual javascript code with the regex pattern and replace function.
Many thanks! This problem has been plaguing me for a while
In my code I got similar function, you can take a look and change it to fit your needs:
function checkChatUrl($matches)
{
if(strpos($matches[0],'http://www.xxx.pl/?task=forum')!==false) $n='>forum';
elseif(strpos($matches[0],'http://www.xxx.pl')!==false) $n='>xxx';
elseif(strpos($matches[0],'db.php')!==false) return "";
elseif(strpos($matches[0],'%22')!==false) return "";
else $n=">".substr($matches[1].$matches[2],0,10).((strlen($matches[1].$matches[2])>10)?'..':'');
return "<a href='http://$matches[1]$matches[2]' target=_blank $n</a>";
}
$text=preg_replace_callback("/\bhttp:\/\/([\w\.]+)([\#\,\/\~\?\&\=\;\-\w+\.\/]+)\b/i",'checkChatUrl',$text);
This was designed for url links on chat, it makes its name shorter and for some urls uses prepared shortcuts.
str.replace(
/(\s|^)([##])([\w\d]+)|(http:\/\/\S+)/g,
'$1$2$3$4'
);
For matching # and # tags, I'd suggest using the \w metapattern (matches word characters - so it'll match digits and letters, but not whitespace/punctuation). Thus, you'd want something like the following patterns to pull out the matched items:
(#\w+)
(#\w+)
For matching URLs, a simple but naive pattern would be to just match http:// followed by any non-whitespace:
(http://\S+)
However, there are certain characters not valid in URLs that would get captured by this. A more sophisticated pattern that only allows characters which are valid in URLs would be the following:
(http://[a-zA-Z0-9+$_.+!*'(),#/-]+)
Here is a revised answer based on the revised question. You should actually put the revision/comment on the original question.
It uses 3 patterns for 3 actions and chains them. It uses the word boundary pattern (\b\B) as appropriate instead of (^|\s). This picks up patterns separated by punctuation and no space, eg #tweet,#tag
<script type=text/javascript>
function addTags(str) {
return str.replace(/\B(#)(\w+)/g, '<a href"//twitter.com=/$2">$1$2</a>')
.replace(/\B(#)(\w+)/g, '$1$2')
.replace(/\b(http:\S+[^,.])/g, '$1')
;
}
function testTags() {
document.getElementById('outstr').innerHTML =
document.getElementById('outtxt').innerHTML =
addTags(document.getElementById('instr').value);
}
</script>
<input type=text size=100 id="instr" value="#begin ignore#email.com and then #cow to http://mysite.com and also http://yoursite.com."><br>
<p><textarea id="outtxt" cols=90></textarea>
<p id=outstr></p>
<p><button onclick="testTags();">TEST</button>
I tested it with the above.
One important thing!
Make sure you are aware of the possible risks in doing naive replacement on links.
Do not allow users to insert arbitrary HTML on your site. The name of the XSS game is sanitizing user input. If you stick to a whitelist based approach -- only allow input that you know to be good, and immediately discard anything else -- then you're usually well on your way to solving any XSS problems you might have.
Naïve replacement counts as allowing inserting arbitrary HTML on you site.
At the very least, try to make sure that the resulting <a href=''> does not start with javascipt:, as you'd be open to Cross-Site Request Forgeries.