A Dexterity Intro for Recovering Archetypes Addicts

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This talk covers the basics of building content types with Dexterity, and how it compares to doing so with Archetypes; what sorts of tasks Dexterity is best suited for, and which ones it isn't ready …

This talk covers the basics of building content types with Dexterity, and how it compares to doing so with Archetypes; what sorts of tasks Dexterity is best suited for, and which ones it isn't ready for yet
* an update on the most recent improvements to Dexterity

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  • 1. A Dexterity Intro for Recovering Archetypes Addicts David Glick Plone Symposium East, 2010
  • 2. What is a content type?
  • 3. ZODB stores objects
  • 4. Content type (or portal_type) categorizes objects Page Something Else
  • 5. Schema (what sort of data can be stored)
  • 6. Workflow (who can do things when)
  • 7. Custom view templates (what it looks like)
  • 8. Miscellaneous settings • Placeful restrictions • Comments • Searchability • Per-type portlet assignments • etc.
  • 9. History Lesson http://commons.wikimedia.org/wiki/File:1893_Nina_Pinta_Santa_Maria_replicas.jpg
  • 10. Content Management Framework (CMF) • Underlying framework for registering types, assigning workflow • CMFDefault contains sample types which used to be used by Plone • Not schema-based
  • 11. Archetypes • Schema-based form generation • Basis of Plone's current default content types (ATContentTypes) • Not going away anytime soon
  • 12. Dexterity Martin Aspeli
  • 13. Goals http://www.fickr.com/photos/paul-w-locke/1662634481/sizes/m/
  • 14. Make filesystem content type development sane
  • 15. Make through-the-web content type development possible
  • 16. Make it possible to switch back and forth between the 2
  • 17. Philosophy http://www.fickr.com/photos/ulrichsson/3519217737/
  • 18. Reuse over reinvention
  • 19. Small over big Pro duc ts .Arc he ty pe s plone.app.dexterity base classes metadata plone.behavior felds schema plone.directives.* plone.autoform widgets plo ne .de x te rity storage plone.supermodel z3c.form reference engine plone.schemaeditor plone.app.relations
  • 20. Natural interaction over excessive generality understanding time
  • 21. Real code over generated code
  • 22. Zope 3 over Zope 2
  • 23. Automated testing over wishful thinking
  • 24. Example: Photo Gallery (example.dexgallery in the collective) • Photo Gallery content type • Photo content type • Tagging • Geolocation
  • 25. Rapid Development Archetypes Dexterity • ArchGenXML • collective.dexteritypaste • ZopeSkel $ bin/zopeskel dexterity • Though-the-web content type creation
  • 26. TTW type development
  • 27. Exporting a type • GenericSetup export for now; better UI coming :)
  • 28. Base class Archetypes Dexterity • BaseObject, usually via • plone.dexterity.content.Item or plone.dexterity.content.Container ATContentTypes • fewer mixins • many mixins • custom subclasses • typically need a custom typically unneeded subclass
  • 29. Schemas Archetypes Dexterity • unique schema format • Zope 3 schemas • define a schema, assign it • Can also be represented in to the content class's a unique XML schema 'schema' attribute format • Associated with a content type via the FTI in portal_types
  • 30. Filesystem roundtripping We b File s y s te m Zope 3 Schema Schema as Python interface Content Editing py Schema Editing xml xml External GenericSetup tools import/export XML schema in XML schema FTI on flesystem
  • 31. Schemas Archetypes Dexterity From content/photo.py: From content/photo.py: PhotoSchema = atapi.Schema(( class IPhoto(form.Schema): # (fields here) # (fields here) )) From profles/default/types/photo.xml: schemata.finalizeATCTSchema(PhotoSchema, moveDiscussion=False) <property name="schema"> example.dexgallery.dexterity.content.photo. class Photo(base.ATCTContent): IPhoto implements(IPhoto) </property> meta_type = "Photo" schema = PhotoSchema
  • 32. Accessing fields Archetypes Dexterity • obj.getField('fieldname') • obj.fieldname .get(obj) (values are simply stored • obj.getFieldname() as attributes) (magically generated • Use property descriptors if accessor on the content you need custom accessor/ class) mutator logic • __getattr__ makes sure to get default value from schema if there's no attribute stored yet
  • 33. Field security • Controlled access (from RestrictedPython) • Implemented using __allow_access_to_unprotected_subobjects__ Archetypes Dexterity • Read/write permissions • Read/write permissions can be specified per field can be specified per field in the schema in the schema
  • 34. Caption field (rich text) Archetypes Dexterity From content/photo.py: From content/photo.py: atapi.TextField('caption', from plone.app.textfield import RichText required = False, searchable = True, caption = RichText( storage = title = _(u'Caption'), atapi.AnnotationStorage(migrate=True), required = False, validators = ) ('isTidyHtmlWithCleanup',), default_content_type = 'text/html', default_output_type = 'text/x-html- safe', widget = atapi.RichWidget( label = _(u'Caption'), ), ),
  • 35. Photo field (image) Archetypes from plone.app.blob.field import ImageField ImageField('image', required = True, storage = atapi.AnnotationStorage(migrate=True), languageIndependent = True, swallowResizeExceptions = zconf.swallowImageResizeExceptions.enable, pil_quality = zconf.pil_config.quality, pil_resize_algo = zconf.pil_config.resize_algo, max_size = zconf.ATNewsItem.max_image_dimension, validators = (('isNonEmptyFile', V_REQUIRED), ('checkNewsImageMaxSize', V_REQUIRED)), widget = atapi.ImageWidget( label = _(u'Photo'), show_content_type = False ), ), Dexterity from plone.namedfile.field import NamedBlobImage image = NamedBlobImage( title = _(u'Photo'), )
  • 36. Image scaling • Now supports arbitrary sizes, e.g. <img tal:defne="scale photo_obj/@ @ images" tal:replace="structure python:scale.scale('image', width=1200, height=300, direction='keep').tag()"/> • (supported for both Archetypes and Dexterity in Plone 4)
  • 37. Tags field (relations) Archetypes Dexterity From content/photo.py: From content/photo.py: atapi.ReferenceField( from z3c.relationfield.schema import 'tags', RelationList, RelationChoice storage=atapi.AnnotationStorage(), tags = RelationList( widget=atapi.ReferenceWidget( title = _(u'Tags'), label=_(u"Tags"), default = [], ), value_type=RelationChoice( required=False, title = _(u'Tag'), relationship='photo_tag', source = ObjPathSourceBinder( allowed_types=('Document',), navigation_tree_query = {'path': multiValued=True, {'query':'/'}}, ), portal_type = 'Document', ), ), required = False, )
  • 38. Content tree widget
  • 39. Indexing fields • similar for both • for Dexterity you may need to implement your own SearchableText indexer, e.g. from plone.indexer import indexer @indexer(IPhoto) def SearchableText(obj): return ' '.join([obj.Title(), obj.Description(), obj.caption.output])
  • 40. Custom views Archetypes Dexterity • default: base_view.cpt • default: view class in • add a skin layer template plone.dexterity.browser.view or browser view, register • add a skin layer template or in the FTI browser view, register in the FTI
  • 41. Grok-style configuration • Configuration via directives inline with code, instead of via ZCML declarations. e.g. from five import grok class View(grok.View): grok.context(IPhoto) grok.require('zope2.View') • Supported but not required
  • 42. Custom forms Archetypes Dexterity • difficult • full power of z3c.form (write custom forms that reference fields from the type's schema) • or, use grok directives on the schema to influence how fields appear in all forms (e.g., custom widget, etc.)
  • 43. Adding items Archetypes Dexterity • Autogenerated factory • z3c.form add form method • Default works in many • In Plone, portal_factory cases, but can be replaced prevents premature by setting add_view_expr creation and indexing in the FTI • No content is constructed until the form is submitted
  • 44. Extending content types Archetypes Dexterity • archetypes.schemaextender • “behaviors” • “schema extender” adapters • can provide additional can provide additional fields fields • “schema modifier” adapters • can mark the content item can make arbitrary changes with a particular interface to a schema • can be turned on/off through the web for each content type
  • 45. Behaviors s ubc la s s ing s c he m a be ha v io rs schema e x te ns io n ATFile schema model schema schema schema Deco thumbnail schema layout image ATFile Dexterity versioned File name from CustomATFile ATFile title geolocatable ratings
  • 46. Geolocation behavior
  • 47. Geolocation behavior • Adds a geolocation field • Provides an adapter to store the value of that field in an annotation • Marks the item with IGeolocatableMarker • Some adapters so that Products.Maps knows how to get a geolocation from an item with IGeolocatableMarker
  • 48. Registering a type Archetypes Dexterity • registerType() after class • Just GenericSetup definition magically (profiles/default/types/ generates Zope 2-style [Type_Id].xml) factory methods • boilerplate in __init__.py finds types and completes registration • type configuration in GenericSetup profile references the factory method
  • 49. """Main product initializer from zope.i18nmessageid import MessageFactory """ _ = MessageFactory('example.dexgallery') from zope.i18nmessageid import MessageFactory from example.dexgallery.archetypes import config from Products.Archetypes import atapi from Products.CMFCore import utils # Define a message factory for when this product is internationalised. # This will be imported with the special name "_" in most modules. Strings # like _(u"message") will then be extracted by i18n tools for translation. archetypesMessageFactory = MessageFactory('example.dexgallery.archetypes') def initialize(context): """Initializer called when used as a Zope 2 product. This is referenced from configure.zcml. Regstrations as a "Zope 2 product" is necessary for GenericSetup profiles to work, for example. Here, we call the Archetypes machinery to register our content types with Zope and the CMF. """ # Retrieve the content types that have been registered with Archetypes # This happens when the content type is imported and the registerType() # call in the content type's module is invoked. Actually, this happens # during ZCML processing, but we do it here again to be explicit. Of # course, even if we import the module several times, it is only run # once. content_types, constructors, ftis = atapi.process_types( atapi.listTypes(config.PROJECTNAME), config.PROJECTNAME) # Now initialize all these content types. The initialization process takes # care of registering low-level Zope 2 factories, including the relevant # add-permission. These are listed in config.py. We use different # permissions for each content type to allow maximum flexibility of who # can add which content types, where. The roles are set up in rolemap.xml # in the GenericSetup profile. for atype, constructor in zip(content_types, constructors): utils.ContentInit('%s: %s' % (config.PROJECTNAME, atype.portal_type), content_types=(atype, ), permission=config.ADD_PERMISSIONS[atype.portal_type], extra_constructors=(constructor,), ).initialize(context)
  • 50. Status report / roadmap http://www.fickr.com/photos/brianatwebbmoto/2392041992/sizes/m/
  • 51. Core functionality
  • 52. Schema serialization
  • 53. Automatic form generation
  • 54. Portlet assignments
  • 55. Content rules
  • 56. Relations • Support for referencing Dexterity content from AT content is in progress
  • 57. Widgets • Not as rich as Archetypes yet, but better than formlib. We have autocomplete, browse-for-content, file/image upload.
  • 58. TTW schema editing
  • 59. Image & file support (via plone.namedfile)
  • 60. Text transform support (via plone.app.textfield)
  • 61. WebDAV support
  • 62. Versioning & staging • In progress
  • 63. TTW behavior creation
  • 64. Automatic migration from Archetypes content
  • 65. Multi-lingual content • Some discussion, but no code yet.
  • 66. Link integrity checks
  • 67. Upcoming releases • First beta release was on Apr. 20 • But, being used in production • Future releases will support upgrades
  • 68. Compatibility • Plone 3 • Plone 4
  • 69. Performance
  • 70. Further information • Installation howto: http://plone.org/products/dexterity/documentation/how -to/install • Dexterity manual: http://plone.org/products/dexterity/documentation/man ual/developer-manual • Behaviors manual: http://plone.org/products/dexterity/documentation/man ual/behaviors
  • 71. Example Code • example.dexterity • example.conference • example.dexgallery (in the collective)
  • 72. Thanks to everyone who has contributed to making Dexterity a reality! http://www.fickr.com/photos/torley/2862255105/
  • 73. Getting involved • Google Code project: http://code.google.com/p/dexterity/ • Google Group: http://groups.google.com/group/dexterity- development