Read RSS feed from the web

Hi Ele,

I think this best way to approach this is with the XML libname and an XML map.

You can assign your RSS feed to a library like this:

libname rss xml xmlfileref=rss_feed xmlmap=xml_map;

Where "bounce" and "xml_map" are filenames you've set up.

You an create XMl maps using the SAS XML Mapper tool, details of which can be found in the following paper: http://www2.sas.com/proceedings/sugi29/119-29.pdf

One thing you'll notice quite quickly if you try to map this RSS feed is that it doesn't have a unique top level element. This is a problem, as SAS expects one.

You can get around this by re-formatting the XML before reading it in throug the map, the simplest approach is just to delete all lines until you find a useful top level element.

A basic program to do all this would look a bit like this:

/* Simple program to read useful information out of an RSS fee (XML) */
%let feed_url = %nrstr(http://www.xing.com/generated/rss/de-net27452-rssfeed2.0.xml); 
filename rss_feed url "&feed_url" debug lrecl=32000;

/* Bounce the rss onto a temporary file and remove all the lines until we find a useful root element*/
filename bounce temp lrecl=32000;
data _NULL_;
    retain delete 1;
    file bounce;
    infile rss_feed;
    input;
    if _INFILE_ = "<channel>" then delete = 0; * Change this flag to stop deleting records;
    if delete = 0 then put _INFILE_;
run;

/* Define an XML map to read in the data */
filename xml_map temp;
data _xml_map;
    file xml_map;
    put
            '<?xml version="1.0" encoding="windows-1252" ?>'
        /   '<SXLEMAP xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="TreeMap" version="1.2" xsi:noNamespaceSchemaLocation="http://www.sas.com/xml/schema/sxle12.xsd">'
        /   '    <TABLE name="items">'
        /   '       <TABLE-PATH syntax="XPath">/channel/item</TABLE-PATH>'
              /   '        <COLUMN name="ID" class="ordinal">'
              /   '           <INCREMENT-PATH syntax="XPath">/channel/item</INCREMENT-PATH>'
              /   '           <TYPE>numeric</TYPE>'
              /   '           <DATATYPE>integer</DATATYPE>'
              /   '        </COLUMN>'
        /   '        <COLUMN name="title">'
        /   '            <PATH syntax="XPath">/channel/item/title</PATH>'
        /   '            <TYPE>character</TYPE>'
        /   '            <DATATYPE>string</DATATYPE>'
        /   '            <LENGTH>200</LENGTH>'
        /   '        </COLUMN>'
        /   '    </TABLE>'
        /   '</SXLEMAP>'
    ;
run;

/* Read the parsed data into SAS */
libname rss xml xmlfileref=bounce xmlmap=xml_map;
proc sql;
    create table items as
    select *
    from rss_get.items
    ;
quit;

Oh yes, you can define a column with "class=ordinal" to count elements too!

Hope that helps, -- Will