从URL字符串中提取多种模式

Question

I have a URL string:

http://localhost:3000/user/event?profile_id=2&profile_type=UserProfile

I want to extract "2" and "UserProfile", where these can change.

I tried to use both match and scan but neither is returning results:

url = "http://localhost:3000/user/event?profile_id=2&profile_type=UserProfile"
m = /http(s)?:\/\/(.)+\/user\/event?profile_id=(\d)&profile_type=(\w)/.match(url)
=> nil 

url.scan /http(s)?:\/\/(.)+\/user\/event?profile_id=(\d)&profile_type=(\w)/
=> [] 

Any idea what I might be doing wrong?

Answer 1

Don't use a pattern to try to do this. URL ordering of the query parameters can change, and isn't position dependent, which would instantly break a pattern.

Instead, use a tool designed for the purpose, like the built-in URI :

require 'uri'

uri = URI.parse('http://localhost:3000/user/event?profile_id=2&profile_type=UserProfile')

Hash[URI::decode_www_form(uri.query)].values_at('profile_id', 'profile_type') 
# => ["2", "UserProfile"]

By doing it that way you are guaranteed to always receive the right value in the expected order, making it easy to assign them:

profile_id, profile_type = Hash[URI::decode_www_form(uri.query)].values_at('profile_id', 'profile_type')

Here are the intermediate steps so you can see what's happening:

uri.query # => "profile_id=2&profile_type=UserProfile"
URI::decode_www_form(uri.query) # => [["profile_id", "2"], ["profile_type", "UserProfile"]]
Hash[URI::decode_www_form(uri.query)] # => {"profile_id"=>"2", "profile_type"=>"UserProfile"}

Answer 2

match = url.match(/https?:\/\/.+?\/user\/event\?profile_id=(\d)&profile_type=(\w+)/)
p match.captures[0] #=> '2'
p match.captures[1] #=> 'UserProfile'

In your expression:

/http(s)?:\/\/(.)+\/user\/event?profile_id=(\d)&profile_type=(\w)/

EVERYTHING you put inside () is captured in a regular expression. There's no need to put the s in parentheses because ? will act only on the preceding character. Also, there's no need for the (.) because, again, the + will act only on the preceding character. Also, (\\w) should be (\\w+) which basically says: One or more characters (and 'UserProfile' is 1 or more characters.