ruby regex with quotes - ruby-on-rails

I'm trying to pass more than one regex parameter for parts of a string that needs to be replaced. Here's the string:
str = "stands in hall "Let's go get to first period everyone" Students continue moving to seats."
Here is the expected string:
str = "stands in hall "Let's go get to first period everyone" Students continue moving to seats."
This is what I tried:
str.gsub(/'|"/, "'" => "\'", """ => "\"")
This is what I got:
"stands in hall \"Let's go get to first period everyone\" Students continue moving to seats."
How do I get the quotes in while sending in two regex parameters using gsub?


This is an HTML unescaping problem.
require 'cgi'
CGI.unescape_html(str)
This gives you the correct answer.


From my comments on this question:
Your updated version is correct. The only reason the slashes are in your final line of code is that it's an escape sequence so that you don't mistakenly think the first slash is used to terminate the string. Try assigning your output and printing it:
str1 = str.gsub(/'|"/, "'" => "\'", """ => "\"")
puts str1
and you'll see that the slashes are gone when str1 is printed using puts.
The difference is that autoevaluating variables within irb (which is what I assume you're doing to execute this sample code) automatically calls the inspect method, which for string variables shows the string in its entirety.


Because I did not understand unescaping characters I found an alternative solution that might be the "rails-way"
Can you use <%= raw 'some_html' %>
My final solution ended up being this instead of messy regex and requiring CGI
<%= raw evidence_score.description %>
Unescaping HTML string in Rails

Related

Rails remove '\' from json response

json response
{"skill"=>"{\"dept_id\"=>\"01\", \"user_id\"=>\"001\", \"level_cd\"=>\"04_swim\", \"first_name\"=>\"rohit\", \"last_name\"=>\"patel\", \"dept_full_name\"=>\"swiming\", \"rank\"=>\"04_swim\"}, {\"dept_id\"=>\"02\", \"user_id\"=>\"002\", \"level_cd\"=>\"04_swim\", \"first_name\"=>\"ranjit\", \"last_name\"=>\"shinde\", \"dept_full_name\"=>\"running\", \"rank\"=>\"03_run\"}, {\"dept_id\"=>\"04\", \"user_id\"=>\"004\", \"level_cd\"=>\"02_jump\", \"first_name\"=>\"kedar\", \"last_name\"=>\"patil\", \"dept_full_name\"=>\"jumping\", \"rank\"=>\"02_jump\"}, {\"dept_id\"=>\"05\", \"user_id\"=>\"005\", \"level_cd\"=>\"03_run\", \"first_name\"=>\"kapil\", \"last_name\"=>\"bote\", \"dept_full_name\"=>\"Hammer\", \"rank\"=>\"03_run\"}"
How to remove only \ from this response
expected output is
"skill"=>{"dept_id"=>"01", "user_id"=>"001", "level_cd"=>"04_swim", "first_name"=>"rohit", "last_name"=>"patel", "dept_full_name"=>"swiming", "rank"=>"04_swim"}, {"dept_id"=>"02", "user_id"=>"002", "level_cd"=>"04_swim", "first_name"=>"ranjit", "last_name"=>"shinde", "dept_full_name"=>"running", "rank"=>"03_run"}, {"dept_id"=>"04", "user_id"=>"004", "level_cd"=>"02_jump", "first_name"=>"kedar", "last_name"=>"patil", "dept_full_name"=>"jumping", "rank"=>"02_jump"}, {"dept_id"=>"05", "user_id"=>"005", "level_cd"=>"03_run", "first_name"=>"kapil", "last_name"=>"bote", "dept_full_name"=>"Hammer", "rank"=>"03_run"}

There are currently no backslashes in the string. The backslash is only there because the context is within a double quoted string context.
If you want to use a double quote in double quoted string context you need to escape it with a backslash, otherwise the compiler thinks you want to end the string.
"John Doe said: "Hello Word!""
The above is not valid. The " before Hello World! will end the string. Meaning that Hello World! will not be in string context and Ruby tries to parse Hello and World as constants.
To prevent this from happening you escape the " with a backslash \.
"John Doe said: \"Hello Word!\""
\" will be interpreted as one " character. There is no backslash present within the resulting string. See the Ruby literals documentation.
When using single quotes for string delimiters there is no need to escape the double quotes (but you do need to escape single quotes). The above could also be written as:
'John Doe said: "Hello Word!"'
Similarly your data can be written as:
{"skill"=>'{"dept_id"=>"01", "user_id"=>"001", "level_cd"=>"04_swim", "first_name"=>"rohit", "last_name"=>"patel", "dept_full_name"=>"swiming", "rank"=>"04_swim"}, {"dept_id"=>"02", "user_id"=>"002", "level_cd"=>"04_swim", "first_name"=>"ranjit", "last_name"=>"shinde", "dept_full_name"=>"running", "rank"=>"03_run"}, {"dept_id"=>"04", "user_id"=>"004", "level_cd"=>"02_jump", "first_name"=>"kedar", "last_name"=>"patil", "dept_full_name"=>"jumping", "rank"=>"02_jump"}, {"dept_id"=>"05", "user_id"=>"005", "level_cd"=>"03_run", "first_name"=>"kapil", "last_name"=>"bote", "dept_full_name"=>"Hammer", "rank"=>"03_run"}'
The above clearly demonstrates that there are no backslash characters present in the string.
However the string is not JSON. I suggest changing the server response if possible. You can eval the current response, but I would advise not to use eval ever (eval is evil). If the server would send malicious Ruby code, eval will execute it without any issues and might corrupt your machine.

Looks like the hash example needs to end with an } to be valid. So I added it in my example. Further more it looks to be a collection of records, but it also looks like it's missing a list. If it were inside a list it would be valid but as the example stands now, it is not a valid hash.
But let's say just for fun, I did want to take the string and put it inside an array. Maybe something like this:
data = {"skill"=>"{\"dept_id\"=>\"01\", \"user_id\"=>\"001\", \"level_cd\"=>\"04_swim\", \"first_name\"=>\"rohit\", \"last_name\"=>\"patel\", \"dept_full_name\"=>\"swiming\", \"rank\"=>\"04_swim\"}, {\"dept_id\"=>\"02\", \"user_id\"=>\"002\", \"level_cd\"=>\"04_swim\", \"first_name\"=>\"ranjit\", \"last_name\"=>\"shinde\", \"dept_full_name\"=>\"running\", \"rank\"=>\"03_run\"}, {\"dept_id\"=>\"04\", \"user_id\"=>\"004\", \"level_cd\"=>\"02_jump\", \"first_name\"=>\"kedar\", \"last_name\"=>\"patil\", \"dept_full_name\"=>\"jumping\", \"rank\"=>\"02_jump\"}, {\"dept_id\"=>\"05\", \"user_id\"=>\"005\", \"level_cd\"=>\"03_run\", \"first_name\"=>\"kapil\", \"last_name\"=>\"bote\", \"dept_full_name\"=>\"Hammer\", \"rank\"=>\"03_run\"}"}
parsed_data = data["skill"].split("}, ").map{|x| x.end_with?("\"") ? x + '}' : x}.map{|x| eval(x)}
puts parsed_data
{"dept_id"=>"01", "user_id"=>"001", "level_cd"=>"04_swim", "first_name"=>"rohit", "last_name"=>"patel", "dept_full_name"=>"swiming", "rank"=>"04_swim"}
{"dept_id"=>"02", "user_id"=>"002", "level_cd"=>"04_swim", "first_name"=>"ranjit", "last_name"=>"shinde", "dept_full_name"=>"running", "rank"=>"03_run"}
{"dept_id"=>"04", "user_id"=>"004", "level_cd"=>"02_jump", "first_name"=>"kedar", "last_name"=>"patil", "dept_full_name"=>"jumping", "rank"=>"02_jump"}
{"dept_id"=>"05", "user_id"=>"005", "level_cd"=>"03_run", "first_name"=>"kapil", "last_name"=>"bote", "dept_full_name"=>"Hammer", "rank"=>"03_run"}
Now with the data in an array you can convert it to json if you'd like
require 'json'
2.6.5 :007 > parsed_data.to_json
=> "[{\"dept_id\":\"01\",\"user_id\":\"001\",\"level_cd\":\"04_swim\",\"first_name\":\"rohit\",\"last_name\":\"patel\",\"dept_full_name\":\"swiming\",\"rank\":\"04_swim\"},{\"dept_id\":\"02\",\"user_id\":\"002\",\"level_cd\":\"04_swim\",\"first_name\":\"ranjit\",\"last_name\":\"shinde\",\"dept_full_name\":\"running\",\"rank\":\"03_run\"},{\"dept_id\":\"04\",\"user_id\":\"004\",\"level_cd\":\"02_jump\",\"first_name\":\"kedar\",\"last_name\":\"patil\",\"dept_full_name\":\"jumping\",\"rank\":\"02_jump\"},{\"dept_id\":\"05\",\"user_id\":\"005\",\"level_cd\":\"03_run\",\"first_name\":\"kapil\",\"last_name\":\"bote\",\"dept_full_name\":\"Hammer\",\"rank\":\"03_run\

String is getting enclosed by \ in the params

In my get request, I am sending the parameter like this localhost:3000/home?q="item1 item2"
But in the server params if I observe the q. It changes like this.
"\"item1 item2\""
However I don't want the extra \" in the starting and ending of string, is there any thing I am doing wrong while sending the request?
The scenario is the same even when q="item1+item2"

First of all, there are no \" characters in the string, it is just a way how Rails quotes " strings in logs. In reality, the string has a value of "item1 item2" and the " characters are part of it.
Second, if you don't want the " to be there, you can either just not send it - see #Sudipta Mondal:
localhost:3000/home?q=item1%20item2
or if you need to send it, then remove it afterwards in the controller:
params[:q].to_s[1..-2]
which will remove first and last character, or:
params[:q].gsub /"/, ""
which will remove all occurences of the ".

The value of q parameter in the URL should be: localhost:3000/home?q=item1+item2

#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("\\", "\\\\")')

Regex in Ruby: expression not found

I'm having trouble with a regex in Ruby (on Rails). I'm relatively new to this.
The test string is:
http://www.xyz.com/017010830343?$ProdLarge$
I am trying to remove "$ProdLarge$". In other words, the $ signs and anything between.
My regular expression is:
\$\w+\$
Rubular says my expression is ok. http://rubular.com/r/NDDQxKVraK
But when I run my code, the app says it isn't finding a match. Code below:
some_array.each do |x|
logger.debug "scan #{x.scan('\$\w+\$')}"
logger.debug "String? #{x.instance_of?(String)}"
x.gsub!('\$\w+\$','scl=1')
...
My logger debug line shows a result of "[]". String is confirmed as being true. And the gsub line has no effect.
What do I need to correct?

Use /regex/ instead of 'regex':
> "http://www.xyz.com/017010830343?$ProdLarge$".gsub(/\$\w+\$/, 'scl=1')
=> "http://www.xyz.com/017010830343?scl=1"

Don't use a regex for this task, use a tool designed for it, URI. To remove the query:
require 'uri'
url = URI.parse('http://www.xyz.com/017010830343?$ProdLarge$')
url.query = nil
puts url.to_s
=> http://www.xyz.com/017010830343
To change to a different query use this instead of url.query = nil:
url.query = 'scl=1'
puts url.to_s
=> http://www.xyz.com/017010830343?scl=1
URI will automatically encode values if necessary, saving you the trouble. If you need even more URL management power, look at Addressable::URI.

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]

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