I am consuming the Twitter API and want to convert all URLs to hyperlinks.
What is the most effective way you've come up with to do this?
from
string myString = "This is my tweet check it out http://tinyurl.com/blah";
to
This is my tweet check it out <a href="http://tinyurl.com/blah">http://tinyurl.com/>blah</a>
Regular expressions are probably your friend for this kind of task:
Regex r = new Regex(@"(https?://[^\s]+)");
myString = r.Replace(myString, "<a href=\"$1\">$1</a>");
The regular expression for matching URLs might need a bit of work.
(https?://[^ ]+) becuase https is not that uncommon.I did this exact same thing with jquery consuming the JSON API here is the linkify function:
String.prototype.linkify = function() {
return this.replace(/[A-Za-z]+:\/\/[A-Za-z0-9-_]+\.[A-Za-z0-9-_:%&\?\/.=]+/, function(m) {
return m.link(m);
});
};
This is actually an ugly problem. URLs can contain (and end with) punctuation, so it can be difficult to determine where a URL actually ends, when it's embedded in normal text. For example:
http://example.com/.
is a valid URL, but it could just as easily be the end of a sentence:
I buy all my witty T-shirts from http://example.com/.
You can't simply parse until a space is found, because then you'll keep the period as part of the URL. You also can't simply parse until a period or a space is found, because periods are extremely common in URLs.
Yes, regex is your friend here, but constructing the appropriate regex is the hard part.
Check out this as well: Expanding URLs with Regex in .NET.
You can add some more control on this by using MatchEvaluator delegate function with regular expression: suppose i have this string:
find more on http://www.stackoverflow.com
now try this code
private void ModifyString()
{
string input = "find more on http://www.authorcode.com ";
Regex regx = new Regex(@"\b((http|https|ftp|mailto)://)?(www.)+[\w-]+(/[\w- ./?%&=]*)?");
string result = regx.Replace(input, new MatchEvaluator(ReplaceURl));
}
static string ReplaceURl(Match m)
{
string x = m.ToString();
x = "< a href=\"" + x + "\">" + x + "</a>";
return x;
}
/cheer for RedWolves
from: this.replace(/[A-Za-z]+://[A-Za-z0-9-]+.[A-Za-z0-9-:%&\?/.=]+/, function(m){...
see: /[A-Za-z]+://[A-Za-z0-9-]+.[A-Za-z0-9-:%&\?/.=]+/
There's the code for the addresses "anyprotocol"://"anysubdomain/domain"."anydomainextension and address",
and it's a perfect example for other uses of string manipulation. you can slice and dice at will with .replace and insert proper "a href"s where needed.
I used jQuery to change the attributes of these links to "target=_blank" easily in my content-loading logic even though the .link method doesn't let you customize them.
I personally love tacking on a custom method to the string object for on the fly string-filtering (the String.prototype.linkify declaration), but I'm not sure how that would play out in a large-scale environment where you'd have to organize 10+ custom linkify-like functions. I think you'd definitely have to do something else with your code structure at that point.
Maybe a vet will stumble along here and enlighten us.
