How can I detect if a cookie exists using the Ruby programming language?

Question

I know how to read cookies using CGI and Ruby but the problem is, if I try to read cookies.value[0] when it does not exists, it breaks my program. So I need to check if the cookie is there to read first. I can't find this answer anywhere on the internet.

Please help, thank you, Henry.

Answer 1

The Ruby CGI doc says:

HTTP Cookies are automatically parsed from the request. They are available from the cookies() accessor, which returns a hash from cookie name to CGI::Cookie object.

If that's the case, then the cookies are simply stored in a regular hash. You can use the regular Hash API to check for the presence of the target cookie, including Hash.key?():

if cgi.cookies().key?("mycookie")
  p "Cookie value is #{cgi.cookies()["mycookie"].value}"
else
  p "Cookie does not exist."
end

Answer 2

Hey Craig, for some reason It won't let me comment again so I have to leave an answer to my own question, I think it's because I've booted in to Ubuntu to test the code. It works great by the way! thank you so much.

I'm using a piece of code so when someone logs in, my ruby creates a cookie and then if the cookie exists, my website doesnt show a log in form, but a welcome 'username' instead.

I have this problem, which is, it detects the cookie fine if all the files are in the CGI bin which is where the cookie is created, but if I try to detect my cookie from another folder, it just doesn't ever seem to register it is there. Do you know why? I have a feeling it is something to do with the cookie path :(