From: Aaron Patterson <aaron@...>
Date: 2007-09-02T04:15:19+09:00
Subject: Re: Parsing query parameters from hyperlink

On Sun, Sep 02, 2007 at 04:00:20AM +0900, Robert Klemme wrote:
> On 01.09.2007 19:34, lrlebron@gmail.com wrote:
> >I am trying to parse strings like this
> ><a href='showmono.asp?cpnum=1022&ampmonotype=comb' target='main'>
> >
> >I need to get the cpnum value (555)
> >
> >I am using the following function
> >
> >def get_drugId(link)
> >     arrParts = link.html.split('?')
> >     cpnum = arrParts[1].split('&amp')
> >     cpnumparts= cpnum[0].split("=")
> >     drugId = cpnumparts[1]
> >  end
> >
> >but I imagine there is a simpler way to do this. Also, I would like
> >something more flexible that would return all the query parameters (if
> >there are more than one) in an array or a hash.
> >
> >Any ideas?
> 
> The std lib:
> 
> require 'uri'
> 
> irb(main):006:0> u=URI.parse("http://foo/bar?dodo=1&dada=2")
> => #<URI::HTTP:0x3ff9814a URL:http://foo/bar?dodo=1&dada=2>
> irb(main):007:0> u.query
> => "dodo=1&dada=2"
> irb(main):008:0> u.query.split('&')
> => ["dodo=1", "dada=2"]
> ...

Query strings are allowed to use semicolons as delimeters, not to
mention you must handle multiple values per key. I recommend using the
CGI library with the URI library:

  irb(main):001:0> require 'uri'
  => true
  irb(main):002:0> require 'cgi'
  => true
  irb(main):003:0> CGI.parse(URI.parse('http://foo/?a=b&b=c').query)
  => {"a"=>["b"], "b"=>["c"]}
  irb(main):004:0> CGI.parse(URI.parse('http://foo/?a=b;b=c').query)
  => {"a"=>["b"], "b"=>["c"]}
  irb(main):005:0> CGI.parse(URI.parse('http://foo/?b=a;b=c').query)
  => {"b"=>["a", "c"]}
  irb(main):006:0>

-- 
Aaron Patterson
http://tenderlovemaking.com/