How to use nodeXML on the gateway side

The implementation of a gateway should simply make HTTP requests to the nodexml.php script on the nodes of interest and then manage the XML output received. It is possible to specify complex research requests, as explained below.
On the gateway side, it is possible to query a node wher nodeXML is active. It is possible to use an SQL-like language. An example is

http://yourserver.yourdomain/nodexml/nodexml.php?q=select+message+from+myname&html=yes

nodeXML will produce a result which follows the structure of the previously defined message.xml map. html=yes has the effect to convert XML output to HTML, in order to visualise it with common browsers. In order to get pure XML results, just cut this option.

Let's now describe how to use research parameters; consider the query

http://yourserver.yourdomain/nodexml/nodexml.php?q=select+message+from+myname+where+tag1=val1+AND+(tag2=val2+OR+tag3=val3)

A gateway can use a WHERE branch with AND, OR, NOT and parenthesis At the moment, as this is a prototype implementation, nodeXML can only support = as comparison operator. Future developments will address the problem of defining and implementing a more powerful boolean language.