ftw.jsondump 1.0.0

Partials

The JSON is built using “partials”, which are merged into one dict.

There are various default partials:

• metadata partial, providing infos such as _type and _class

• fields partial extracting Archetypes and Dexterity field data

• uid partial, providing the UID in _uid

• localroles partial, extracting the local roles

• workflow partial, providing the _workflow_chain and the _workflow_history

• properties partial, providing local properties in _properties

• interfaces partial, extracting the directly provided interfaces in _directly_provided

Selecting partials

The desired partials can be selected when extracting the JSON:

from ftw.jsondump.interfaces import IJSONRepresentation
from zope.component import getMultiAdapter

json_representation = getMultiAdapter((context, request), IJSONRepresentation)
print json_representation.json(only=['fields', 'metadata'])
print json_representation.json(exclude=['localroles'])

File blob data The file data is extracted by default as base64 encoded string and embedded in the JSON document.

This fieldata can be excluded with the filedata configuration:

from ftw.jsondump.interfaces import IJSONRepresentation
from zope.component import getMultiAdapter

json_representation = getMultiAdapter((context, request), IJSONRepresentation)
print json_representation.json(filedata=False)

For doing custom things with the filedata, a callback can be used:

from ftw.jsondump.interfaces import IJSONRepresentation
from zope.component import getMultiAdapter

def file_callback(context, fieldname, data, filename, mimetype, jsondata):
    with open('./tmp/' + filename, 'w+b') as target:
      target.write(data)

json_representation = getMultiAdapter((context, request), IJSONRepresentation)
print json_representation.json(file_callback=file_callback)

Creating custom partials

Custom partials can easily be registered as adapter:

configure.zcml:

<adapter factory=".partial.CustomAnnotations" name="custom_annotations" />

partial.py:

from ftw.jsondump.interfaces import IPartial
from my.package.interfaces import ICustomContent
from zope.annotation import IAnnotations
from zope.component import adapts
from zope.interface import Interface
from zope.interface import implements

class CustomAnnotations(object):
    implements(IPartial)
    adapts(ICustomContent, Interface)


    def __init__(self, context, request):
        self.context = context
        self.request = request

    def __call__(self, config):
        annotations = IAnnotations(self.context)
        return {'_custom_annotations': dict(annotations.get('custom_config'))}

Field data extractors

The Archetypes and Dexterity partial use field data extractor adapters for extracting the field data and converting it to a JSON serializable value.

Custom extractors can easily be registered for custom fields:

configure.zcml:

<adapter factory=".extractor.CustomFieldExtractor" />

extractor.py:

from ftw.jsondump.interfaces import IFieldExtractor
from my.package import ICustomField
from zope.component import adapts
from zope.interface import implements
from zope.interface import Interface


class CustomFieldExtractor(object):
    implements(IFieldExtractor)
    adapts(Interface, Interface, ICustomField)

    def __init__(self, context, request, field):
        self.context = context
        self.request = request
        self.field = field

    def extract(self, name, data, config):
        value = self.field.get(self.context)
        value = value.prepare_for_serialization()
        data.update({name: value})