plone.app.textfield 1.0b2

Text field with MIME type support

Introduction

This package provides a zope.schema style field type called RichText which can be used to store a value with a related MIME type. The value can be transformed to an output MIME type, for example to transform from structured text to HTML.

To use the field, place it in a schema like so:

from plone.app.textfield import RichText
from zope.interface import Interface

class ITest(Interface):

    bodyText = RichText(
            title=u"Body text",
            default_mime_type='text/structured',
            output_mime_type='text/html',
            allowed_mime_types=('text/structured', 'text/plain',),
            default=u"Default value"
        )

This specifies the default MIME type of text content as well as the default output type, and a tuple of allowed types. All these values are optional. The default MIME type is ‘text/html’, and the default output type is ‘text/x-html-safe’. By default, allowed_mime_types is None, which means no validation will take place on the allowed MIME type.

Note that the default value here is set to a unicode string, which will be considered to be of the default MIME type. This value is converted to a RichTextValue object (see below) on field initialisation, so the default property will be an object of this type.

The field actually stores an object of type plone.app.textfield.value.RichTextValue. This object has the following attributes:

raw (read/write)

The raw value as a unicode string. This value is stored in a ZODB blob.

mimeType (read/write)

The MIME type of the raw text.

output (read-only)

A unicode string that represents the value transformed to the default output MIME type. This is not stored in a BLOB. May be None if the transformation could not be completed successfully.

readonly (read-only)

The value may be read-only. A common example is the default property on the field, if set. In this case, setting the raw value or MIME type will result in a TypeError. Use the copy() method to get back a new copy that is not in read-only mode.

The idea is that the raw value is used in edit controls or if a different transformation is required. The output value is stored in a non-BLOB string, because it is expected to be commonly used (e.g. as the body text of a page- like object) and should thus be loaded with the object.

The RichTextValue is not a persistent object, but is expected to be set as an attribute of a persistent object. It will notify its parent (via the _p_changed protocol) when it is modified. The parent will be set correctly when the field’s set() method is used. Otherwise, set it yourself.

Transformation takes place using an ITransformer adapter. The default implementation uses Plone’s portal_transforms tool to convert form one MIME type to another. Note that Products.PortalTransforms must be installed for this to work, otherwise no default ITransformer adapter is registered. You can use the [portaltransforms] extra to add a Products.PortralTransforms dependency.

The package also contains a plone.supermodel export/import handler, which will be configured if plone.supermodel is installed. You can use the [supermodel] extra to add a plone.supermodel dependency.

Finally, a z3c.form widget will be installed if z3c.form is installed. The [widget] extra will pull this dependency in if nothing else does.

See field.txt for more details about the field’s behaviour, and handler.txt for more details about the plone.supermodel handler.

Changelog

1.0b2 - 2009-09-21

• Store the raw value in a separate persistent object in the ZODB instead of in a BLOB. This avoids potential problems with having thousands of small BLOB files, which would not be very space efficient on many filesystems. [optilude]

• Make the RichTextValue immutable. This greatly simplifies the code and avoids the need to keep track of the parent object. [optilude]

1.0b1 - 2009-09-17

• Initial release