SilvaFind is a Silva extension to allow easy creation of search forms, both
for use by authors in the ZMI, and by users of the public site. Simple
schemas can be defined to indicate which fields should be searchable.

Authors can add a 'Silva Find' object anywhere, and define which fields to
make searchable by end users of the public site, and/or which fields to
limit to a preset value.

For example the default global schema that SilvaFind installs
(globalschema.py) looks as follows::

    from Products.Silva.i18n import translate as _

    from Products.SilvaFind.schema import SearchSchema
    from Products.SilvaFind.schema import ResultsSchema

    from Products.SilvaFind.schema import ResultField
    from Products.SilvaFind.schema import FullTextCriterionField
    from Products.SilvaFind.schema import MetadataCriterionField
    from Products.SilvaFind.schema import MetatypeCriterionField
    from Products.SilvaFind.schema import DateRangeMetadataCriterionField

    globalSearchSchema = SearchSchema([
        MetatypeCriterionField(),
        FullTextCriterionField(),
        MetadataCriterionField('silva-content', 'maintitle'),
        MetadataCriterionField('silva-content', 'shorttitle'),
        DateRangeMetadataCriterionField('silva-extra', 'publicationtime'),
        ])
   
    globalResultsSchema = ResultsSchema([
        ResultField('get_title', _('Title')),
        ])

The resultschema defines what fields get shown in the list of results, by
default as columns in a results table. There are currently 3 types of
resultfields (plain vanilla, metatype and metadata), and it is not hard to
make your own. See schema.py for how that is done.

The following SearchField types exist for now, and of course it is possible
to roll your own::

    MetatypeCriterionField: allows the content that is to be searched, to be
        restricted to certain (one or more) content types.

    FulltextCriterionField: allows the fulltext of the content item to be
        searched.

    MetadataCriterionField: allows a specific metadata field of a specific
        metadata set to be searched.

    DateRangeMetadataCriterionField: allows a specific datetime based
        metadata field of a specific metadata set to be searched, using a 
        date range.


Making your own is as simple as creating a different SearchSchema and
ResultsSchema in your extension, and registering it in the install.py of
your extension. You can replace the global default search schema as
follows, assuming myVeryOwnSearchSchema is a valid SearchSchema object::

    def register_search_schema(root):
        root.service_find.search_schema = myVeryOwnSearchSchema
        root.service_find.manage_delObjects(['default'])
        SilvaFind.manage_addSilvaFind(
            root.service_find, 'default', 'Default search')
        default = root.service_find.default
        for field in root.service_find.getSearchSchema().getFields():
            fieldName = field.getName()
            default.shownFields[fieldName] = True
        default._p_changed = True

If your extension defines its own metadata-set, making the fields in
that set searchable by putting them in your schema is trivially easy::

    myVeryOwnSearchSchema = SearchSchema([
        
        ...
    
        MetadataCriterionField('my-metadataset', 'my-field1'),
        MetadataCriterionField('my-metadataset', 'my-field2'),
        
        ...

        ])

For a good example of how to customize and use SilvaFind from your own
extension, see SilvaDLCMS, which you can find here: 

svn co https://infrae.com/svn/dlcms/SilvaDLCMS/trunk/ SilvaDLCMS

and look at searchschema.py


