Aspose.Note FOSS for Python — Knowledge Base

How to Traverse the OneNote Document DOM in Python

Aspose.Note FOSS for Python represents a OneNote section file as a tree of typed Python objects. Understanding how to traverse this tree efficiently is the foundation for all content extraction tasks. This guide covers all three traversal approaches: GetChildNodes, direct iteration, and DocumentVisitor.

The Document Object Model

The OneNote DOM is a strict tree:

Document
  ├── Page
  │     ├── Title
  │     │     ├── TitleText (RichText)
  │     │     ├── TitleDate (RichText)
  │     │     └── TitleTime (RichText)
  │     └── Outline
  │           └── OutlineElement
  │                 ├── RichText
  │                 ├── Image
  │                 ├── AttachedFile
  │                 └── Table
  │                       └── TableRow
  │                             └── TableCell
  │                                   └── RichText / Image
  └── Page  (next page ...)

Every node inherits from Node. Nodes that have children inherit from CompositeNode.

Method 1: GetChildNodes (Recursive, Type-Filtered)

CompositeNode.GetChildNodes(Type) performs a recursive depth-first search of the entire subtree and returns a flat list of all nodes matching the given type. This is the most convenient approach for content extraction:

from aspose.note import Document, RichText, Image, Table, AttachedFile

doc = Document("MyNotes.one")

##All RichText nodes anywhere in the document
texts = doc.GetChildNodes(RichText)
print(f"RichText nodes: {len(texts)}")

##All images
images = doc.GetChildNodes(Image)
print(f"Image nodes: {len(images)}")

##All tables
tables = doc.GetChildNodes(Table)
print(f"Table nodes: {len(tables)}")

##All attachments
attachments = doc.GetChildNodes(AttachedFile)
print(f"AttachedFile nodes: {len(attachments)}")

Scope the search to a single page by calling GetChildNodes on Page instead of Document:

from aspose.note import Document, Page, RichText

doc = Document("MyNotes.one")
for page in doc.GetChildNodes(Page):
    page_texts = page.GetChildNodes(RichText)
    print(f"  Page has {len(page_texts)} text nodes")

Method 2: Direct Child Iteration

for child in node iterates the immediate children of a CompositeNode. Use this when you need one specific level of the hierarchy:

from aspose.note import Document

doc = Document("MyNotes.one")

##Direct children of Document are Pages
for page in doc:
    title = (
        page.Title.TitleText.Text
        if page.Title and page.Title.TitleText
        else "(untitled)"
    )
    print(f"Page: {title}")
    # Direct children of Page are Outlines (and optionally Title)
    for child in page:
        print(f"  {type(child).__name__}")

Method 3: DocumentVisitor

DocumentVisitor provides a visitor pattern for structured traversal. Override only the VisitXxxStart/End methods you need. The visitor is dispatched by calling doc.Accept(visitor):

from aspose.note import (
    Document, DocumentVisitor, Page, Title,
    Outline, OutlineElement, RichText, Image,
)

class StructurePrinter(DocumentVisitor):
    def __init__(self):
        self._depth = 0

    def _indent(self):
        return "  " * self._depth

    def VisitPageStart(self, page: Page) -> None:
        t = page.Title.TitleText.Text if page.Title and page.Title.TitleText else "(untitled)"
        print(f"{self._indent()}Page: {t!r}")
        self._depth += 1

    def VisitPageEnd(self, page: Page) -> None:
        self._depth -= 1

    def VisitOutlineStart(self, outline) -> None:
        self._depth += 1

    def VisitOutlineEnd(self, outline) -> None:
        self._depth -= 1

    def VisitRichTextStart(self, rt: RichText) -> None:
        if rt.Text.strip():
            print(f"{self._indent()}Text: {rt.Text.strip()!r}")

    def VisitImageStart(self, img: Image) -> None:
        print(f"{self._indent()}Image: {img.FileName!r} ({img.Width}x{img.Height}pts)")

doc = Document("MyNotes.one")
doc.Accept(StructurePrinter())

Available Visitor Methods

Method pair	Node type
`VisitDocumentStart/End`	`Document`
`VisitPageStart/End`	`Page`
`VisitTitleStart/End`	`Title`
`VisitOutlineStart/End`	`Outline`
`VisitOutlineElementStart/End`	`OutlineElement`
`VisitRichTextStart/End`	`RichText`
`VisitImageStart/End`	`Image`

Navigating Up the Tree

Every node exposes ParentNode and a Document property to navigate upward:

from aspose.note import Document, RichText

doc = Document("MyNotes.one")
for rt in doc.GetChildNodes(RichText):
    parent = rt.ParentNode   # OutlineElement, TableCell, Title, etc.
    root = rt.Document       # always the Document root
    print(f"  '{rt.Text.strip()!r}' parent={type(parent).__name__}")
    break

Child Management Methods

CompositeNode also exposes in-memory child management (useful for programmatic document construction, though write-back to .one is not supported):

Method	Description
`node.FirstChild`	First direct child or `None`
`node.LastChild`	Last direct child or `None`
`node.AppendChildLast(child)`	Add child at end
`node.AppendChildFirst(child)`	Add child at start
`node.InsertChild(index, child)`	Insert at position
`node.RemoveChild(child)`	Remove a child

Count Nodes With a Visitor

from aspose.note import Document, DocumentVisitor, Page, RichText, Image

class Counter(DocumentVisitor):
    def __init__(self):
        self.pages = self.texts = self.images = 0

    def VisitPageStart(self, page: Page) -> None:
        self.pages += 1

    def VisitRichTextStart(self, rt: RichText) -> None:
        self.texts += 1

    def VisitImageStart(self, img: Image) -> None:
        self.images += 1

doc = Document("MyNotes.one")
c = Counter()
doc.Accept(c)
print(f"Pages={c.pages}  RichText={c.texts}  Images={c.images}")

Choosing the Right Traversal Method

Scenario	Best approach
Find all nodes of one type (e.g. all RichText)	`GetChildNodes(RichText)`
Iterate direct children only	`for child in node`
Walk the tree with context (depth, parent state)	`DocumentVisitor`
Navigate from content up to the parent or root	`node.ParentNode` / `node.Document`

Related Resources: