Suppose we have a Plone website on a remote Internet-facing box but back in the office we're crunching through numbers and we discover we want to update the News section, say, with a new article. Ordinarily, through the Plone UI we'd:

1. log in
2. navigate to /News
3. select Add News Item from a pulldown menu
4. fill in all the fields including the Title which becomes part of the URL
5. click Save
6. then finally select Publish from the pulldown

That seems quite a lot of work for wget or curl.

Well, it turns out that you can do the majority (if not all of it) in a single command line HTTP GET so long as you fill in all the hidden fields that have been accumulating as you performed those steps remembering to handle all the HTML/URI/shell escaping required.

If you have a lot of data to shuffle about (or fear the escape mechanisms required) you might be able to push a text file containing your news article up to the remote server and then have Plone read the contents of the file and add the news article itself.

For that, we need to add an External Method to Plone which is incredibly simple.

A little bit more involved is how we invoke the External Method and what the External Method does when it is invoked.