Since these components are little known I'd like to give a brief introduction of the great set of open source OAI-PMH components that Infrae has developed.
What is OAI-PMH? It's the Open Archives Initiative Protocol for Metadata Harvesting. This is an XML and HTTP based protocol for harvesting large amounts of metadata from so-called data providers. Data providers are sites on the web that are interested in exposing some metadata collection to the world. Other systems can then harvest this information and do something with it; analyze it, index it, present it, and so on.
While its potential uses are many, the main use of OAI-PMH is by many academic libraries in the world. Universities have large amounts of papers written all the time, and this is a way for the university library to publish information on the papers (the title, who wrote it, where to get it, and so on).
Infrae has been working for some years to build a great set of OAI-PMH tools. We have the following:
I can confidently say that if you need anything done with OAI-PMH, especially in a Python or Zope environment, this set of tools (together called the OAI Pack) is a good base to start from. And let Infrae know if you need help!