4.2.3 multishop.php 

multishop.php makes use of PHP`s event based XML parser. While an XML file could 

have been manually parsed, there was nothing to be gained in this instance by reinventing 

the  wheel.  The  parser  takes  much  of  the  work  out  of  traversing  an  XML  file  and 

extracting values from it, and it also makes it easier to adapt to different XML document 

hierarchies. Its key feature is flexibility, which it needs to deal with a HTTP query string 

such as: 

   DESC= 

   &MAKE=compaq 

   &MODEL= 

   &PRICE=2500 

   &xml%2F1722_KIELTY.xml=on 

   &xml%2F1437_Killian.xml=on 

   &xml%2F13755_Killory.xml=on 

From the start, one can see that the string is separable into two logical sections. The first 

deals with specific search parameters. This example string having come from the  smart 

form   on  queries.php, it would seem that the user wishes to browse through all of the 

shops in a certain area which sell Compaq computers for not more than  2,500. In this 

case, there are three shops which lie in the appropriate area. Assuming that queries.php 

has correctly responded to a search for  computers  or something similar, these should all 

be computer shops. 

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