zms._objattrs

_objattrs.py - ZMS Object Attributes Management

The _objattrs module is central to ZMS's content management architecture, implementing the meta-object model that enables flexible attribute handling for arbitrary content types. It encapsulates logic for content-object traversal, attribute access, and child-node handling, providing reusable behaviors shared by the ZMS runtime.

Key Functionality:

• Attribute retrieval, defaults, and access with multilingual and blob field support

• Form input generation (text areas, select menus, file uploads, rich text editors, etc.)

• Value formatting and validation including blob handling and datetime parsing

• Multilingual support with language-specific fallback behavior

• Object activation status determination based on active flags and datetime attributes

• Object versioning integration for preview vs. live version management

• Blob field management (images/files) with upload, preview, and manipulation support

• AJAX endpoints for autocomplete and dynamic form updates

• Attribute cloning and synchronization across object instances

  ObjAttrs: Mixin class providing attribute access, form rendering, and manipulation methods for ZMS content objects. Enables getting/setting attributes, generating form fields, and managing multilingual content.

  ObjAttrsManager: Manager class for synchronizing and maintaining the centralized attribute metadata dictionary (dObjAttrs) across the ZMS instance. Coordinates attribute definitions from the meta-object model with actual object instances.

Core Functions:

• getobjattrdefault(obj, obj_attr, lang): Returns the default value for an object attribute based on datatype, considering translation status and special handling for the 'active' attribute.
• getobjattr(self, obj, obj_attr, lang): Retrieves an object attribute value with fallback to primary language for mono-lingual attributes and default value resolution.
• setobjattr(self, obj, obj_attr, value, lang): Assigns a value to an object attribute, handling blob field callbacks.
• cloneobjattr(self, src, dst, obj_attr, lang): Copies an attribute value from source to destination object with proper handling of complex datatypes, blobs, lists, and dictionaries.

Architecture:

• The module integrates with:
  • ZMS meta-object model for attribute definitions
  • Object versioning system for preview/live state management
  • Blob field management for media handling
  • Multilingual content system with per-language attribute variants
  • AJAX framework for dynamic form interactions
  • PIL (Python Imaging Library) for image manipulation via pilutil
• Attribute Types Supported:
  • Text/Rich Text: Standard text, DTML, TAL expressions, rich text editors
  • Media: Images and files with upload, preview, resize, and crop capabilities
  • Numeric: Integers, floats, and currency amounts
  • Temporal: Date, time, datetime with format parsing
  • Structured: Lists, dictionaries with XML serialization
  • Selection: Select menus, multiselect, autocomplete with custom options
  • Security: Password fields with proper handling
  • Utility: Identifiers, URLs, coverage (i18n), status tracking
• Multilingual Features:
  • Per-language attribute variants with fallback chains
  • Coverage tracking for attribute availability by language
  • Translation status awareness affecting default values
  • Language-specific form field generation and rendering
• Special Attributes:
  • active: Boolean activation flag with multilingual support
  • attr_active_start/end: Datetime-based activation windows with cache expiration
  • created_uid/dt: Creation metadata
  • change_uid/dt: Modification tracking with multilingual support
  • change_history: Audit trail of modifications
  • Version tracking: master, major, minor version numbers
  • work_*: Workflow state attributes
  • internal_dict: Internal metadata storage

License: GNU General Public License v2 or later, Organization: ZMS Publishing