XML / Perl: Perl CGI script returning XML

[Mrs Kensington]

I'm trying to make a perl script that returns XML instead of HTML.

my script currently looks like this...

#!/usr/bin/perl

#
#print xml info
print "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n";
print "<programlist>\n";
print "</programlist>\n";

which creates the following xml file

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<programlist>
</programlist>

this works fine if i save the output to a file and view it in a browser however if i run the perl script in my browser I get a "500 Internal Server Error".

Looking at the apache error log i get

malformed header from script. Bad header=<?xml version="1.0" encoding=": /usr/local/apache/cgi-bin/getChannels.pl

does anyone know how to stop this???

Thanks for your help

Mrs K

[jeffmott]

You need to print out an HTTP Content-Type header before your content. For HTML it would be

print "Content-Type: text/html\n\n";

I would assume that XML is

print "Content-Type: text/xml\n\n";

but I'm not certain.

[CornedBee]

XML has two main MIME types: text/xml and application/xml. I'm not sure which is to be used for which, but I think text/xml is for XML files that are pure data, while application/xml is for XML languages that actually instruct an app to do something.

Example for text/xml:

<storelist>
  <item>
    <name>Chair</name>
    <amount>32</amount>
  </item>
  <item>
    <name>Table</name>
    <amount>5</amount>
  </item>
</storelist>

Examples for application/xml are XHTML and SVG. Those have their own MIME types though: XHTML uses application/xhtml+xml and SVG uses image/svg+xml.

I'm sure this is explained in greater detail in the XML specification.
www.w3.org

[CornedBee]

Here's the IETF RFC that explains them.
http://www.ietf.org/rfc/rfc2376.txt

This document also has some stuff to say about the default handling of text/* types. For practical considerations, if you use text/xml, you MUST either use us-ascii as character set or specify the encoding explicitly, as in
print "Content-Type: text/xml; charset=\"UTF-16\"\n\n";