Regex URL not validating as expected in Dart [duplicate] - dart

I have the following regex in JavaScript regex
(https?|ftp)://([-A-Z0-9.]+)(/[-A-Z0-9+&##/%=~_|!:,.;]*)?(\?[A-Z0-9+&##/%=~_|!:‌​,.;]*)?
It attempts to validate and empty space/s or a URL.
Yet when I attempt to use it in Dart RegExp
that uses a Perle flavour regex, it does not validates.
Any help is appreciated.


Your pattern doesn't look for lowercase characters. Either you add a-z to the respective character groups or you use caseSenstivie: false as shown in the code.
var urlPattern = r"(https?|ftp)://([-A-Z0-9.]+)(/[-A-Z0-9+&##/%=~_|!:,.;]*)?(\?[A-Z0-9+&##/%=~_|!:‌​,.;]*)?";
var result = new RegExp(urlPattern, caseSensitive: false).firstMatch('https://www.google.com');
If the result is != null a match was found.
Your pattern doesn't find http: URLs (only https or ftp) neither www.google.com.
Your statement about 'empty space' might apply to your email regexp you had in your question originally but not to your URL regexp you added in your comment.

Related

#HttpContext.Current.User.Identity.Name not showing backslash

Super Simple. Only issues I find are people getting null. Which I obvi fixed. But where is the backslash???!!
params.me = '#HttpContext.Current.User.Identity.Name';
This returns
"domainUserName" <- Browser
"domain\\UserName" <- Debugging
What I expect is
"domain\UserName" <- Browser
Any ideas?

Based on your comments you are using the following code to show the user name:
alert('#HttpContext.Current.User.Identity.Name');
#HttpContext.Current.User.Identity.Nameis a string that can contain "\" backslash character. This character is considered as a escape character in javascript as it is in C# as well.
You need to escape the "\" character in the string before passing it to Javascript like that:
alert('#HttpContext.Current.User.Identity.Name.Replace("\\", "\\\\")')

How to deal with dynamic urls with special characters like single quote?

I am generating dynamic an "a href" html tag on my asp page. Also the url is dynamic. Sometimes there are special characters inside the url and the hyperlink is not working. For example when there is an single quote:
http://myCompany.com/'s-hertog.aspx
How can I fix this that the dynamic url always will work?
I already try this, but is not working:
string hyperLinkHtml = string.Format("<span class=\"bw-NewsQueryWebpart-BodyItemTitle\"><a href='{0}' >{1}</a>", HttpUtility.UrlEncode(newsItem.Url), newsItem.Title);

I found the solution by my self. I changed the single quotes to double quotes in the string.format:
string hyperLinkHtml = string.Format("<span class=\"bw-NewsQueryWebpart-BodyItemTitle\"><a href=\"{0}\" >{1}</a>", HttpUtility.UrlEncode(newsItem.Url), newsItem.Title);

string manipulation in ruby on rails

I have a string of the format,
/d.phpsoft_id=369242&url=http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk
and i need to edit this string using regular expression that the result string should start from http: ie the resultatnt string should be
http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk
please help

For these types of situations, I prefer to go with readily available tools that will help provide a solution or at the very least will point me in the right direction. My favourite for regex is txt2re because it will output example code in many languages, including ruby.
After running your string through the parser and selecting httpurl for matching, it output:
txt='/d.phpsoft_id=369242&url=http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk'
re1='.*?' # Non-greedy match on filler
re2='((?:http|https)(?::\\/{2}[\\w]+)(?:[\\/|\\.]?)(?:[^\\s"]*))' # HTTP URL 1
re=(re1+re2)
m=Regexp.new(re,Regexp::IGNORECASE);
if m.match(txt)
httpurl1=m.match(txt)[1];
puts "("<<httpurl1<<")"<< "\n"
end

str = "/d.phpsoft_id=369242&url=http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk"
str.spl­it("url=")­[1]

Simple Answer
You need to do following
str = "/d.phpsoft_id=369242&url=http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk"
start=str.index('http://')
resultant=str[start,str.length]

How do I scan url for a specific string with spaces and special characters?

I'm using stringscanner on my request URL in order to get the name of the user's currently selected category, but I've been having difficulty dealing with spaces and special characters.
request.url.scan(/\?category=\w+/).to_s.gsub('?category=', '')
URL examples followed by result
http://localhost:3000/search?category=dog&search=&utf8=%E2%9C%93 => ["dog"]
http://localhost:3000/search?category=dog.com&search=&utf8=%E2%9C%93 => ["dog"]
http://localhost:3000/search?category=dog+cat&search=&utf8=%E2%9C%93 => ["dog"]
I'm trying to get ["dog"] ["dog.com"] and ["dog cat"], but am currently stuck. Any ideas?
Note: Considering removing spaces from categories and replacing them with dashes as multiple spaces could be problematic, but if it's possible to create one function to rule them all, that would be awesome.

This is Rails, is there a reason you're not just using params[:category]?

If you are trying to extract params then you could use parse_query :
uri = "http://localhost:3000/search?category=dog+cat&search=&utf8=%E2%9C%93"
result = Rack::Utils.parse_query(URI(uri).query) #=> {"category"=>"dog cat", "search"=>"", "utf8"=>"\xE2\x9C\x93"}
result["category"] #=> dog cat

Why does this regex check return true for this string?

I need a regex that will determine if a string is a tweet URL. I've got this
Regexp.new(/http:|https:\/\/(twitter\.com\/.*\/status\/.*|twitter\.com\/.*\/statuses\/.*|www\.twitter\.com\/.*\/status\/.*|www\.twitter\.com\/.*\/statuses\/.*|mobile\.twitter\.com\/.*\/status\/.*|mobile\.twitter\.com\/.*\/statuses\/.*)/i)
Why does it return true for the following?
"http://i.stack.imgur.com/QdOS0.jpg".match(Regexp.new(/http:|https:\/\/(twitter\.com\/.*\/status\/.*|twitter\.com\/.*\/statuses\/.*|www\.twitter\.com\/.*\/status\/.*|www\.twitter\.com\/.*\/statuses\/.*|mobile\.twitter\.com\/.*\/status\/.*|mobile\.twitter\.com\/.*\/statuses\/.*)/i))? true : false
=> true

http: will always match a URL starting with http:
Try the following:
/https?:\/\/(twitter\.com\/.*\/status\/.*|twitter\.com\/.*\/statuses\/.*|www\.twitter\.com\/.*\/status\/.*|www\.twitter\.com\/.*\/statuses\/.*|mobile\.twitter\.com\/.*\/status\/.*|mobile\.twitter\.com\/.*\/statuses\/.*)/i
The question mark will make the s optional, thus matching http or https.

Your regex could be abbreviated like :
#^https?://(:?www\.|mobile\.)?twitter\.com/.*?/status(:?es)?/.*#i
explanation:
# regex delimiter
^ start of line
https? http or https
:// ://
(:? start of non capture group
www\.|mobile\. www. or mobile.
)? end of group
twitter\.com/ twitter.com
.*? any number of any char not greedy
/status /status
(:?es)? non capture group that contains possibly `es`
/.* / followed by any number of any char
$ end of string
#i delimiter and case insensitive

No need for regular expressions here (as usual).
require 'uri'
uri = URI.parse("http://www.twitter.com/status/12345")
p uri.host.split('.')[-2] == 'twitter' # returns true
More docs at: http://ruby-doc.org/stdlib/

You should group your OR-Clauses, like this:
(http:|https:)
Additionally, it wouldn't hurt to specify beginning and end of it:
^(http:|https:).*$

The start of your regex specifies an option of just 'http:', which naturally matches the URL you are testing. Depending on how strict you need your check to be, you could just remove the http/https parts from the start of the regex.

While many other answers show you a better regex, the answer is because /foo|bar/ will match either foo or bar, and what you wrote was /http:|.../, hence all URLs will be matched.
See #giraff's answer for how you could have written the alternation to do what you expect, or #M42's or #Koraktor's answers for a better regexp.
And as posted in the comments, note that you can write a regex literal as %r{...} instead of /.../, which is nice when you want to use / characters in your regex without escaping them.

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