Intro

    ATReferenceBrowserWidget is an add-on to Archtetypes. It adds a new reference widget
that allows you to search or browse the portal when creating references.
This new widget inherits from the standard reference widget so you can use all it's 
properties.

When you use this widget, there are two buttons presented for each widget. One
that opens a popup-window that let's you do the search/browsing and one that
let's you clear the reference or selected references (will be in effect after the
form's Save). 

The popop window basically consists of two parts. The top half is a search form and 
the bottom half is the browser/search results part. Both parts can be turned off or on
using the widget's properties.

The search part has additional configuration in the widget (see properties below).

Properties

    The popup window can be configured using the following widget properties:

    * default_search_index: when a user searches in the popup, this index is used by default

    * show_indexes: in the popup, when set to True, a drop-down list is shown with the index to be
used for searching. If set to False, default_search_index will be used.

    * size: in case of single-select widget, the default is set to 30. In case of multi-select, default is 8.

    * available_indexes: optional dictionary that lists all the indexes that can be used 
for searching. Format: {'<catalog index>':'<friendly name'>, ... } The friendly name
is what the end-users sees to make the indexes more sensible for him. If you do not use this 
property then all the indexes will be shown (I think nobody should allow this to happen!).

    * allow_search: shows the search section in the popup

    * allow_sorting: allows you change the order of referenced objects (requires multiValued=1)
    
    * allow_browse: shows the browse section in the popup
    
    * startup_directory: directory where the popup opens. Optional. When omitted, the current folder
      is used or in the case where a property refwidget_startupdirectories under site_properties is found
      it is searched for a startup_directory.

      Property is a lines field having the following
      format:
        path1:path2
      path1 is the path where all widgets being under it set startup_directory
      to path2 if no startup_directory is set.

    * image_portal_types: specify a list of image portal_types. Instances of
      these portal types are being previewed within the popup widget

    * image_method: specifies the name of a method that is added to the image
      URL to preview the image in a particular resolution (e.g. 'mini' for
      thumbnails)

    * show_review_state: allows you to display the workflow state for objects (off by default)

    * show_path: display the relative path (relative to the portal object) of referenced objects 

    * only_for_review_states: items are only referencable if their workflow state matches the ones
      a specified (default: None = no filtering by workflow state) 

    * history_length: enable a history feature that show the paths of the last N visited folders
      (default : 0 = no history)
      
    * force_close_on_insert: closes the popup when the user choses insert. This overrides the behavior in multiselect mode.

    * base_query: defines query terms that will apply to all searches, mainly useful to create specific restrictions when allow_browse=0.  Can be either a dictonary with query parameters, or the name of a method or callable available in cotext that will return such a dictionary.
    
This add-on comes with an example content type that uses this widget. You can enable the installation
of the type by uncommenting the appropriate line in Install.py under Extension. See ATReferenceBrowserDemo.py.

Installing

    Copy this folder and its subfolders in your products directory and install it using
the Quickinstaller in your Plone portal.

This product requires Archetypes 1.3+

Design notes

    Both the templates (widget and popup) are prototypes. There are still some inline styles, 
especially in the popup because I didn't want to tweak with plone's css stuff and I 
didn't want to do hacking and tricking to incorporate a stylesheet myself. 
So, that's still a point of interest.

Furthermore I made some design decisions. Right now, in the popup window, all objects are shown (when
browsing) and objects that may be referenced to are bold and the other objects are greyed out.
I chose to show the non-referenceable objects too because they may be an important 
part of the context that help the user search for the desired objects to browse to.
Another thing that I chose for is that in case of a multi-value widget, the popup remains open so that you
can continue to add references without having to reopen the popup over and over again. Problem is that
you have to close the window yourself. This may change if it turns out to be an annoyance.

A thing that is more related to forms in general is that the items in the multiselect listbox need to be
selected before Save is clicked otherwise only the selected items are submitted. That kinda sucks
usability-wise because now the user basically has to make two selections: first by choosing the items in the
popup and secondly by selecting them again in the listbox. Right now I made it so that the items are selected
by default but if the user starts clicking in the list, then there might be an issue. Btw, the inandout widget
has the same problem.
Best would be to select all the items in a script just before the form is submitted so that the complete list
is submitted. But that requires changes in the base_edit form I think. But it's something to think about since
there are now already two widgets that needs to be prepared like this (inandout and this one, haven't looked
at picklist though, could have the same problem).

Anyway, have fun with it and if you have suggestions please let me know. If you see problems, please fix
them when you can.

Danny Bloemendaal
danny.bloemendaal@companion.nl
