One of These Days

Ruby Day 10 Uri

04 Jul 2010

Today we will take a brief look at Ruby’s Uniform Resource Identifier (URI) class in order to handle a wider range of requests in our web server. Currently, if we enter a URL such as ‘http://localhost:8080/test.html’ into our web browser we will receive a request that looks like ‘GET /index.html HTTP/1.1’. If we want to send any extra parameters such as an id (http://localhost:8080/test.html?id=123) then our server will naively assume that the file we are requesting is named ‘index.html?id=123’, and so it will not be able to find it.

 

  		




  
    

      
    

    
By treating the request as an HTTP URI, we can interpret the request more intelligently, separating it into the filename and the query parameters.

  		
  
    

  		




  
    

      
    

    
We can modify our worker class like so

  		
  
    
file = request.split(' ')[1]
file = '.' + file

uri =  URI.split(file)
file = uri[5]
query = uri[7]

  		




  
    

      
    

    
The ‘split’ method will take a URL and split it up into 9 components which will be explained by using the URL ‘http://www.google.com/index.html?user=123’ as an example

  		
  
    

  		




  
    

      
    

    
Scheme – http
Userinfo – nil
Host – www.google.com
Port – 80
Registry – nil
Path – /index.html
Opaque – nil
Query = user=123
Fragment – nil

  		
  
    

  		




  
    

      
    

    
(Userinfo, registry, opaque and fragment are not likely to be used for an HTTP request so we can ignore them.)

  		
  
    

  		




  
    

      
    

    
The two components we are interested in are path and query, elements 5 and 7 respectively. By passing the middle part of our GET request to the split method, we can grab the 2 elements we need. ‘uri[5]’ contains the file we want, so that will be passed to the File class. ‘uri[7]’ contains the query parameters which can be dealt with later on.