Editing How to write plugins (section)

=== Types of Plugin ===

There are a number of different kinds of plugin for EPrints. You can find a comprehensive list of [[Perl_lib/EPrints/Plugin/|types of plugins here]]. The most of common of those are... 

==== Export Plugin ====

These are used to export the data in a variety of formats. A number of tutorials have been created to help you create your own export plugins:

* [[Contribute:_Plugins/ExportPluginsHello| Export Plugin Tutorial 1: "Hello, World!"]]
* [[Contribute:_Plugins/ExportPluginsList| Export Plugin Tutorial 2: List handling]]
* [[Contribute:_Plugins/ExportPluginsHTML| Export Plugin Tutorial 3: HTML]]
* [[Contribute:_Plugins/ExportPluginsExcel| Export Plugin Tutorial 4: Excel]]
* [[Contribute:_Plugins/ExportPluginsZip| Export Plugin Tutorial 5: Zip]]

==== Import Plugin ====

These are used to import data into a repository. They can take datafiles directly, or they can take an ID of a record that can be retrieved in a known way, or a URL of a file, or... whatever.

These are a bit trickier to write than export plugins as parsing data is harder than just "print"ing it, but they are still reasonably straight forward. To get you started a small selection of tutorials has been written:

* [[Contribute:_Plugins/ImportPluginsCSV| Import Plugin Tutorial 1: CSV]]
* [[Contribute:_Plugins/ImportPluginsAWS| Import Plugin Tutorial 2: Amazon Web Services]]

==== Screen Plugin ====

These handle (almost) all the user interface screens. Pages like "Review" and "Profile" are just built-in plugins. You can add your own very easily. 

Examples you could create...
* Birds Eye View - a view of various statistics on the database, all in one page.
* Spellchecking Tab - an additional tab in the item control page which checks the spelling on certain fields.
* Bulk Delete tool - a tool which takes a list of eprintid's and deletes them all in a fell swoop.

Look at the existing Screen Plugins for an idea of how they work. They can be very simple.

* [[How to make a Screen for the Admin Section]]
* [[How to make a Screen perform Actions]]

==== Input Component Plugin ====

These handle how the workflow components are rendered. Built in components include the default (one field) component, the multiple fields component, the upload component, the subject component (which does pretty things to a field of type "subject") and the XHTML component. You can add your own or sub-class existing ones.

==== Convert Plugin ====

These are used for two things, currently.

* Converting the full text of documents into utf-8 text for search indexing
* Converting images and pdfs into thumbnails and previews

Some examples you could create:

* RTF to utf-8 to allow rich text documents to be indexed.
* Powerpoint to Thumbnail to allow thumbnail and previews of powerpoint slides
* Video to Thumbnail/Preview to make a still preview of a video file.