wagtail-traverse

Utilities for traversing Wagtail StreamField and StreamValue objects.

Installation

pip install wagtail-traverse

Usage

This is a set of two functions:

• traverse_block(block, parent=None) walks a StreamField's block definition tree (the schema, not page data).

  Given a root block, it yields back (path, block) tuples for every block reachable from that root, including the root itself. This is intended to be used to discover what block types and paths can exist in a StreamField.

  from wagtailtraverse import traverse_block
  
  streamfield = MyPage._meta.get_field("body")
  for child_name in streamfield.stream_block.child_blocks:
      for path, block in traverse_block(
          streamfield.stream_block.child_blocks[child_name]
      ):
          print(f"{path}: {block.__class__.__name__}")

  For a page with a body field containing heading, paragraph, and a hero StructBlock that has an image and caption, this would print:

  heading: CharBlock
  paragraph: RichTextBlock
  hero: StructBlock
  hero.image: ImageChooserBlock
  hero.caption: CharBlock
  

• traverse_value(value, parent=None) walks the value of a StreamField on a page.

  It yields (path, bound_block) tuples for every block in the stream value, recursing into StreamValues, StructValues, ListValues, and TypedTables. This is intended to be used for deeply inspecting or migrating the content stored in a StreamField.

  from wagtail_traverse import traverse_value
  
  page = MyPage.objects.get(slug="example")
  for path, bound_block in traverse_value(page.body):
      print(f"{path}: {bound_block.block.__class__.__name__} = {bound_block.value}")

Paths

Both functions produce dotted path strings like hero.image or section.list.item that describe where a block sits in the tree.

License

This project is licensed under the MIT License. See LICENSE for details.

These functions originate in the wagtail-content-audit library as part of a block usage auditing. I have broken them out in this small utility library for convenience, since the ability to traverse StreamFields and their values is something I occasionally have found need to do.