Regular expressions redirection - c#

I want to set redirection from
www.somesite.com/products/dynamicstring/randomtext1/randomtext2
to www.somesite.com/products/dynamicstring
Is it possible to do that through Regex ?
It means if my incming url is
www.somesite.com/products/myproducts/test1/test2 it should redirect to www.somesite.com/products/myproducts/
just briefing more about this :
#TomLord i am using HttpContext.Current.Response.RedirectPermanent(matchingDefinition.To) i have all the redirects "From" and "To" in a class object, in the form of REGEX expressions.Example in From "/product/*" and To "/products" , i am reading these object and trying to redirect them, but i am not able to redirect something like /products/dynamicstring/randomtext1/ to /products/dynamicstring where dynamic string is random string , i dont find any regular expression which can be use to do this. For example /products/samples/randomtext1 should redirect to /products/samples/

Redirection cannot be done with regex alone. Google a bit what is a regular expression in reality. The short answer is: it's string-like expression that describes search pattern. So it can't redirect, not even replace a substring with substring or do anything else then match and capture parts of the matched string.
That being said, regex can help us do what you wanna. I am gonna assume you can use Javascript, cause I can't put a solution in every language. I am also gonna assume you will try to go over the code not copy paste and press enter. If you only need that hire a programmer. If you use another language, principle should be the same:
obtain URL
define regex
use capture group to extract the part of your URL that you need
construct a new URL
redirect to it
While matching the URLs in general is a fair bit more complex, like:
^(?:https?://)?(?:[\w]+\.)(?:\.?[\w]{2,})+$
As long as you are sure you will only be getting URLs and in the format you wanna, we will do it far simpler.
Basically, let's say you have:
some text with 2 dots that ends in com
then a /products/dynamicstring/
then text
then /
then text
As a regex that is:
/\w*.\w*.com\/products\/dynamicstring\/\w*\/\w*/g
Curde matching is done, but we still need to add a capture group we will use to extract part of the string we need:
/(\w*.\w*.com\/products\/)dynamicstring\/\w*\/\w*/g
Oke, now let's leverage this regex to do rest of the work:
Define regex:
var regex = /\w*.\w*.com\/products\/dynamicstring\/\w*\/\w*/g;
Get current URL. If you already have URL use it.
var currUrl = window.location.href;
Extract capture group from string:
var match = regex.exec(currUrl);
Use that to get a new URL from old one:
var redirectUrl = match[1] + myproducts/
Finally, we redirect with:
window.location.replace(redirectUrl);
I wrote all this straight from my head so I recommend you go over each step, look how it works, read some documentation about functions used. You might find an error as well as learn a lot.

Related

How can I transform this url with REGEX?

I have a dynamic web app built using DotNetNuke that uses the following url format:
/SeoDummy.aspx?template={VAR1}&keywords={VAR2}
My user friendly url format is like this:
http://domain.com/.{VAR1}/{VAR2}
I am really terrible with REGEX and need to somehow detect when the user friendly url is requested and rewrite it with the dynamic web app url. I have tried the following, but It is not catching it on the site, it is just 404'ing:
.*/^([^/]+)/([^/]+)/?$
I am sure you that know regex will find my attempt silly, but regex is my kryptonite!
Thanks for any help that can be offered.
Since you are using some custom url,I guess regex would be better than using URI class
In your regex you have misplaced ^..The regex should be
^https?://domain[.]com/[.]([^/]+)/([^/]+)/?$
I have not tested this, but give it a shot and tell me how it works out:
domain[.]com/\.([^/]+)/([^/]+)/?$
It looks like you had it mostly right except for the first carat, marking the beginning of the string... which is impossible since you specified .* right in front of it! Also you missed the period in front of {VAR1} (unless that is a typo?).
I also wouldn't put .* at the beginning because then you could be capturing VAR1 = domain.com, VAR2 = something that is actually VAR1
If you want to become immune to your kryptonite, then this website is really good for looking up stuff:
http://www.regular-expressions.info/reference.html

Deal with '#' through regex

Quick question , I have been trying to match any word containing a '#' from a string list and remove it, but I don't know how to handle it . been playing around on http://regexhero.net/tester/ trying but to no avail.
Essentially if it comes across #ff or wha#s up i will just regex.replace them.
any ideas on the Regular expression to use?.
Thanks.
Don't use regex - just use string.replace - it's a lot faster.
I have a previous answer that covers some hashtag matching approaches.
In summary, if you are pulling statuses containing hashtags from Twitter, you no longer need to find them yourself. You can now specify the include_entities parameter to have Twitter automatically call out mentions, links, and hashtags (if the method you are calling, like statuses/show supports this parameter.
If you just need the regular expression to locate the hashtags and capture it's elements, Twitter provides it in an open source library that contains the following pattern.
(^|[^0-9A-Z&/]+)(#|\uFF03)([0-9A-Z_]*[A-Z_]+[a-z0-9_\\u00c0-\\u00d6\\u00d8-\\u00f6\\u00f8-\\u00ff]*)
More detail and additional links are provided in the original answer.
So you're trying to remove any words containing a #?
If so, give this a try...
\w*#\w*
And replace with nothing, like so...
http://regexhero.net/tester/?id=cda1e713-bdab-4aa2-b63d-a87e9b2c9bce
apple# orange ban#ana becomes orange
But if you're simply trying to remove all instances of #, then String.Replace is the better choice. myString = myString.Replace("#", "");

Conditional Regex Replace in C# without MatchEvaluator

So, Im trying to make a program to rename some files. For the most part, I want them to look like this,
[Testing]StupidName - 2[720p].mkv
But, I would like to be able to change the format, if so desired. If I use MatchEvaluators, you would have to recompile every time. Thats why I don't want to use the MatchEvaluator.
The problem I have is that I don't know how, or if its possible, to tell Replace that if a group was found, include this string. The only syntax for this I have ever seen was something like (?<group>:data), but I can't get this to work. Well if anyone has an idea, im all for it.
EDIT:
Current Capture Regexes =
^(\[(?<FanSub>[^\]\)\}]+)\])?[. _]*(?<SeriesTitle>[\w. ]*?)[. _]*\-[. _]*(?<EpisodeNumber>\d+)[. _]*(\-[. _]*(?<EpisodeName>[\w. ]*?)[. _]*)?([\[\(\{](?<MiscInfo>[^\]\)\}]*)[\]\)\}][. _]*)*[\w. ]*(?<Extension>\.[a-zA-Z]+)$
^(?<SeriesTitle>[\w. ]*?)[. _]*[Ss](?<SeasonNumber>\d+)[Ee](?<EpisodeNumber>\d+).*?(?<Extension>\.[a-zA-Z]+)$
^(?<SeriesTitle>[\w. ]*?)[. _]*(?<SeasonNumber>\d)(?<EpisodeNumber>\d{2}).*?(?<Extension>\.[a-zA-Z]+)$
Current Replace Regex = [${FanSub}]${SeriesTitle} - ${EpisodeNumber} [${MiscInfo}]${Extension}
Using Regex.Replace, the file TestFile 101.mkv, I get []TestFile - 1[].mkv. What I want to do is make it so that [] is only included if the group FanSub or MiscInfo was found.
I can solve this with a MatchEvaluator because I actually get to compile a function. But this would not be a easy solution for users of the program. The only other idea I have to solve this is to actually make my own Regex.Replace function that accepts special syntax.
It sounds like you want to be able to specify an arbitrary format dynamically rather than hard-code it into your code.
Perhaps one solution is to break your filename parts into specific groups then pass in a replacement pattern that takes advantage of those group names. This would give you the ability to pass in different replacement patterns which return the desired filename structure using the Regex.Replace method.
Since you didn't explain the categories of your filename I came up with some random groups to demonstrate. Here's a quick example:
string input = "Testing StupidName Number2 720p.mkv";
string pattern = #"^(?<Category>\w+)\s+(?<Name>.+?)\s+Number(?<Number>\d+)\s+(?<Resolution>\d+p)(?<Extension>\.mkv)$";
string[] replacePatterns =
{
"[${Category}]${Name} - ${Number}[${Resolution}]${Extension}",
"${Category} - ${Name} - ${Number} - ${Resolution}${Extension}",
"(${Number}) - [${Resolution}] ${Name} [${Category}]${Extension}"
};
foreach (string replacePattern in replacePatterns)
{
Console.WriteLine(Regex.Replace(input, pattern, replacePattern));
}
As shown in the sample, named groups in the pattern, specified as (?<Name>pattern), are referred to in the replacement pattern by ${Name}.
With this approach you would need to know the group names beforehand and pass these in to rearrange the pattern as needed.

Regular expression to define format of backup filenames

In the application I am currently working on, I have an option to create automatic backups of a certain file on the hard disk. What I would like to do is offer the user the possibility to configure the name of the file and its extension.
For example, the backup filename could be something like : "backup_month_year_username.bak". I had the idea to save the format in the form of a regular expression. For the example above, the regexp would look like :
"^backup_(?<Month>\d{2})_(?<Year>\d{2})_(?<Username>\w).(?<extension>bak)$"
I thought about using regex because I will also have to browse through the directory of backuped files to delete those older than a certain date. The main trouble I have now is how to create a filename using the regex. In a way I should replace the tags with the information. I could do that using regex.replace and another regex, but I feel it's a big weird doing that and it might be a better way.
Thanks
[Edit] Maybe I wasn't really clear in the first go, but the idea is of course that the user (in this case an admin that will know regex syntax) will have the possibility to modify the form of the filename, that's all the idea behind it[/Edit]
... and if the regex changes, it is next to impossible to reconstruct a string from a given regex.
Edit:
Create some predefined "place-holders": %u could be the user's name, %y could be the year, etc.:
backup_%m_%y_%u.bak
and then simple replace the %? with their actual values.
It sounds like you're trying to use the regular expression to create the file name from a pattern which the user should be able to specify.
Regular expressions can - AFAIK - not be used to create output, but only to validate input, so you'd have the user specify two things:
a file name production pattern like Bart suggested
a validation pattern in form of a regular expression that helps you split the file names into their parts
EDIT
By the way, your sample regex contains an error: The "." is use for "any character", also \w only matches one word character, so I guess you meant to write
"^backup_(?<Month>\d{2})_(?<Year>\d{2})_(?<Username>\w+)\.(?<extension>bak)$"
If the filename is always in this form, there is no reason for a regex, as it's easier to process with string.Split ...
With Bart's solution it is easy enough to split (using string.Split) the generated file name using underscore as the delimiter, to get back the information.
Ok, I think I have found a way to use only the regex. As I am using groups to get the information, I will use another regular expression to match the regular expression and replace the groups with the value:
Regex rgx = new Regex("\(\?\<Month\>.+?\)");
rgx.Replace("^backup_(?<Month>\d{2})_(?<Year>\d{2})_(?<Username>\w+)\.(?<extension>bak)$"
, DateTime.Now.Month.ToString());
Ok, it's really a hack, but at least it works and I have only one pattern defined by the user. It might not work if the regex is too complex, but I think I can deal with that problem.
What do you think?

C# Need to locate web addresses using REGEX is that possible?

C# Need to locate web addresses using REGEX is that possible?
Basically I need to parse a string prior to loading it into a WebBrowser
myString = "this is an example string http://www.google.com , and I need to make the link clickable";
webBrow.DocumentText = myString;
Basically what I want to happen is a replace of the web address so that it looks like a hyperlink, and do this with any address pulled in to the string. I would need to replace the web address so that web address would read like
<a href='web address'>web address</a>
This would allow me to have the links clickable..
Any Ideas?
new Regex(#"https?://([-\w\.]+)+(:\d+)?(/([\w/_\.]*(\?\S+)?)?)?").Match(myString)
It's possible depending on how strict or permissive you want your parsing to be.
As a first cut, you can try #"\bhttp://\S+" which will match any string starting with "http://" at a word boundary (non-word character, such as whitespace or punctuation).
To search using a regex and replace all occurrences with your custom text, you could use the Regex.Replace method.
You may want to read up on Regular Expression Language Elements to learn more.

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