The json ingredient is designed to extend EPrints 3.4 by adding a new JSON-based Compound MetaField to EPrints.

Like a Compound field, this field is designed to have a number of subfields which are all stored and displayed under the same parent field. However, unlike the Compound field, instead of storing each one in its own field or table, we store all the subfields in a single database field as a JSON string.

Installation

This module requires the HTML::Entities and JSON::Parse libraries installed.

Usage

The field works by providing a json_config parameter, for example:

{ name => "fieldname", type => "json", json_config => [
		{
			name => "subfield1",
			type => "text"
		},
		{
			name => "subfield2",
			type => "number"
		},
		{
			name => "subfield3",
			type => "richtext"
		},
		{
			name => "subfield4",
			type => "namedset"
			set_name => "example_set"
		}
	],
}

The json_config parameter is required.

Field types

For the subfield type, the following fields are currently compatible:

• text
• number
• longtext
• boolean
• richtext
• namedset

namedset expects a set_name parameter provided

These all render as their standard EPrints counterparts would, however are rendered by JavaScript instead of the standard EPrints form renderer.

The corresponding phrases for each subfield are in the format:

• eprint_fieldname_${fieldname}_${subfieldname}
• eprint_fieldhelp_${fieldname}_${subfieldname}

The same convention is used for the ep_eprint classes added to inputs

Table view

The JSON field can also be used to render a table, with a fixed number of rows. In this scenario, the JSON string stored is a JSON array.

Use render_table to turn on the table mode, and table_row_count to specify the number of rows.

In some tables, you may want to skip certain subfields - e.g. the third row doesn't have subfield 3. If the value of the subfield is __json_field_control__skip, the subfield will not render.

If using resizeable richtext in your tables, you can use the reset button to put the fields/table columns back to their default size.

List view

The JSON field can also be used to display the fields in multiple columns, instead of the standard one-after-the-other. This is helpful in scenarios where you have lots of small fields, e.g. a series of boolean checkboxes.

Use display_as_list to turn on the list mode, and display_as_list_cols to specify the number of columns you want.

Other parameters

You can also specify the following:

• richtext_init_fun - determines the function which initialises the TinyMCE richtext field. Default is initTinyMCE, as defined in 98_richtext.js

Lookup

You can provide an input_lookup_url as per standard MetaFields.

When added, each subfield will have lookup capabilities. It will send the following as parameters to the input_lookup_url

• q - the query
• field - the json field name
• json_field - the subfield name, per the json_config

A basic CGI script that accepts these parameters and uses them to lookup on a particular subfield is provided.

Authors: Richard Cook, EPrints Services

EPrints 3.4 is supplied by EPrints Services.