WikiExporter

These are LionKimbro's notes on developing a wiki exporter.

Date: 2004-02-12
Inkscape version: 0.40
Target: Oddmuse

That is, a system so that you can load from and save to a wiki.

The wiki targetted by this exporter is Oddmuse. We have an upload script for it.

I imagine it should be possible to use the Wiki XML-RPC interfaces as well, in the future, though they are usually turned off.

odd_output.inx

This file goes in: /usr/share/inkscape/extensions

<inkscape-extension>
  <name>Oddwiki Output</name>
  <id>org.inkscape.output.odd</id>
  <dependency type="executable" location="extensions">svg2oddmuse.sh</dependency>
  <output>
     <extension>.odd</extension>
     <mimetype>image/x-svgz</mimetype>
     <filetypename>Oddmuse Wiki POST (*.odd)</filetypename>
     <filetypetooltip>Oddmuse Wiki proxy (SVG, PNG of Drawing)</filetypetooltip>
     <dataloss>FALSE</dataloss>
  </output>
  <script>
     <command reldir="extensions">svg2oddmuse.sh</command>
     <helper_extension>org.inkscape.output.svg.inkscape</helper_extension>
  </script>
</inkscape-extension>

What data am I receiving from Inkscape?

To see what you're getting from Inkscape, create the following script, and call it: svg2oddmuse.sh

#!/bin/bash
echo "hello, world" > /tmp/eraseme.txt
echo "invocation: $@"
echo
echo "$1:"
cat "$1"
echo "- - - - - - - - - - - - - - - - - - - - - - - - - - - -"
env

It appears that no environment variables are being set. The first (and only) argument is the location of a file in /tmp that contains the Inkscape SVG data.

Now what?

The strategy is this:

• create a directory, representing the wiki
• place a file in the directory, "oddmuse.txt", representing necessary details about the wiki
• when the user saves a file to the directory (.odd extension,) do the following:
  • push the SVG to the wiki
  • render a PNG, and push the PNG to the wiki
  • perhaps append the name of the wikipage containing the SVG to a page on the wiki

We don't have command-line access (bash argument, environment variable) to the filename or directory it was saved in. But we CAN get this data from the Inkscape SVG.

The <svg> element has attributes:

• "sodipodi:docbase" -- path up to the save location
• "sodpodi:docname" -- filaname, including extension (".odd", in this case)

Inkscape Export process

• User hits "Save" in "Save As" dialog
• Inkscape writes a file with a random name to /tmp
• Inkscape calls export bash script, with /tmp file as only argument
• Whatever bash outputs to /dev/stdout, Inkscape records to the file chosen by the user.

Inkscape SVG Attributes

Here's a Python script that outputs <svg> attributes:

svgattrs.py:

#!/usr/bin/python2.3
"""Expose Inkscape SVG attributes.

Read an Inkscape SVG from stdin.
Output attributes to the "<svg>" element to stdout.
"""

import sys
import xml.sax


class InkscapeSvgHandler(xml.sax.ContentHandler):

    """Print attributes to svg element."""

    def startElement(self, name, attrs):
        if name == "svg":
            for (k,v) in attrs.items():
                print k + " " + v


if __name__ == "__main__":
    parser = xml.sax.make_parser()
    parser.setContentHandler(InkscapeSvgHandler())
    parser.parse(sys.stdin)
    sys.exit(0)

You can use it like so:

DOCNAME=`cat "$1" | ./svgattrs.py | grep -e "^sodipodi:docname" | cut -d" " -f2`
DOCBASE=`cat "$1" | ./svgattrs.py | grep -e "^sodipodi:docbase" | cut -d" " -f2`