docspec-docx-reader 1.21.5

DOCX to DocSpec event stream reader
Documentation

docspec-docx-reader

DOCX to DocSpec event stream reader

Word documents, unwrapped as they flow. docspec-docx-reader parses a .docx archive with quick-xml and zip and emits DocSpec events one at a time — and from from_path, in constant memory, whatever the file's size. Streaming, like the rest of DocSpec. (See the Manifesto for why.)

Add it

[dependencies]
docspec-docx-reader = "1"
docspec-core = "1"

What it handles today

  • Paragraphs (<w:p>) and direct text (<w:t> inside <w:r>)
  • Line breaks (<w:br>, including w:type="page" and w:type="column" — all emit LineBreak)
  • Tabs (<w:tab> — emitted as a Text event containing the single character "\t")
  • Tables (<w:tbl>, <w:tr>, <w:tc>) — structural events. Horizontal cell merging via <w:gridSpan> is emitted as colspan. Header rows via <w:trPr><w:tblHeader/></w:trPr> are emitted as StartTableHeader (with scope: Column) for cells in the contiguous header band at the top of the outermost table. Nested tables emit all cells as StartTableCell (header rows in nested tables are not supported). Vertical merging via <w:vMerge> is NOT yet supported — rowspan information is lost.
  • Run properties (<w:rPr>): <w:b> (bold), <w:i> (italic), <w:u> (underline — any w:val other than none), <w:strike> (strikethrough), <w:dstrike> (double-strike, collapses to strikethrough), <w:vertAlign> (subscript and superscript only; baseline resets to neither). These are emitted as deferred StartTextStyle { kind, id: None } / EndTextStyle wrapper events around the first run content, not as fields on Text events. Empty styled runs emit no style wrapper events; multiple <w:t> elements in one styled run share a single wrapper span.
  • Run color properties (<w:rPr>):
    • <w:color w:val="HEX"> — foreground (text) color. Emitted as StartTextStyle { kind: TextColor(Color::Rgb { r, g, b }) }. w:val="auto" and non-hex values are silently dropped. Black (0,0,0) is preserved by the reader; whether to treat it as "default color" is writer policy.
    • <w:highlight w:val="namedColor"> — highlight color using the 17-entry ECMA-376 named palette. Emitted as StartTextStyle { kind: Mark(Color::Rgb { r, g, b }) }. w:val="none" and unknown names are silently dropped.
    • <w:shd w:val="..." w:color="..." w:fill="..."> — shading, used as a fallback highlight when <w:highlight> is absent. The visible color is resolved per ECMA-376 §17.3.5 / §17.18.78: for w:val of nil or clear (No Pattern) the visible color is w:fill alone; for w:val="solid" (100% Fill Pattern) w:color covers the area (falling back to w:fill when absent); for all other patterns (pct10…pct95, *Stripe, *Cross, etc.) the rendered color is approximated by w:fill. A missing w:val is malformed per the XSD and is defensively treated as clear. Emitted as StartTextStyle { kind: Mark(Color::Rgb { r, g, b }) }. An effective color of "auto" (consumer default per spec) or a missing attribute is silently dropped.
  • Paragraph properties (<w:pPr>): <w:jc> (alignment — left/start to Left, right/end to Right, center to Center, both/distribute to Justify)
  • Heading-style paragraphs (<w:pStyle> resolving to Title → level 1, or to any style name matching heading N for N ≥ 1) emit StartHeading { level } / EndHeading instead of StartParagraph / EndParagraph. Style inheritance via basedOn is followed when resolving the style name.
  • Block-quote-style paragraphs (<w:pStyle> resolving to Quote, Block Text, Block Quote, Block Quotation, or Intense Quote) emit StartBlockQuote / EndBlockQuote instead of StartParagraph / EndParagraph.
  • Code-styled paragraphs (paragraph styles whose name resolves to Source Code, SourceCode, or Codeblock) emit StartPreformatted / EndPreformatted. Consecutive code-styled paragraphs are consolidated into one preformatted block with LineBreak events between paragraph boundaries. The character style Verbatim Char is recognized as inline code at the run level only and never promotes a paragraph to preformatted.
  • Lists (<w:p> with <w:numPr>): ordered (Decimal/LowerAlpha/UpperAlpha/LowerRoman/UpperRoman) and unordered (Disc) — emitted as Start*ListItem/End*ListItem with id (numId stringified), level (ilvl), start, and style_type. Per-level classification: same numId can mix ordered and unordered levels. Any plain paragraph without <w:numPr> (including empty paragraphs) closes the open list immediately and emits as a top-level paragraph; styled non-numbered paragraphs still emit their dedicated StartHeading, StartBlockQuote, or StartPreformatted events instead. Counter continuity within a single numId/ilvl is preserved across intervening paragraphs per OOXML §17.9.17: the counter increments for each paragraph at that level "sequential or not". The first item of a numId/ilvl emits start: Some(1). Items that immediately follow the previous item at the same level with no intervening non-list content emit start: None (sequential continuation). Items that resume after any break (table, paragraph, heading, or other non-list content between two items at the same level) emit start: Some(N) where N is the effective counter value. Two list items with different numIds at the same level produce two distinct lists, each with its own counter starting at 1. The list also closes at a heading, block quote, preformatted block, table boundary, table-cell boundary, or end of document.
  • Empty <w:rPr/> and <w:pPr/> are treated as no properties (default style / alignment None)
  • A <w:rPr> or <w:pPr> that appears after content in the same parent is silently ignored (per the OOXML spec, both must be the first child element)
  • Hyperlinks (<w:hyperlink>): resolved via word/_rels/document.xml.rels and emitted as StartLink/EndLink events around inline content. Supports external URL targets (both Strict and Transitional OOXML relationship Type URIs), anchor-only links (w:anchor without r:id emits #fragment), and tooltips (w:tooltip → StartLink.title, XML-decoded). When the relationship cannot be resolved, the link wrapper is dropped and content passes through as plain runs.
  • Structured Document Tags (<w:sdt>) — the content of an SDT is emitted normally. The property containers <w:sdtPr> and <w:sdtEndPr> are dropped.
  • Tracked insertions and moves (<w:ins>, <w:moveTo>) — the inserted/moved-in content is emitted (accept-changes semantics).
  • DrawingML images (<w:drawing>) — emitted as Event::Image. See Image Support below.
  • VML images (<w:pict> containing <v:imagedata>) — emitted as Event::Image. Alt text precedence: o:title attribute on <v:imagedata> (non-empty) falls back to alt attribute on parent <v:shape>. Multiple <v:imagedata> in one <w:pict> emit multiple Image events in document order. <v:group> wrappers are transparent.
  • Emits: StartDocument, StartHeading, EndHeading, StartBlockQuote, EndBlockQuote, StartParagraph, StartPreformatted, StartTextStyle, Text, EndTextStyle, LineBreak, EndParagraph, EndPreformatted, StartTable, StartTableRow, StartTableCell, StartTableHeader, EndTableHeader, EndTableCell, EndTableRow, EndTable, StartLink, EndLink, StartOrderedListItem, EndOrderedListItem, StartUnorderedListItem, EndUnorderedListItem, Image, EndDocument
  • Symbol font character normalization for Wingdings, Wingdings 2, Wingdings 3, Webdings, and Symbol fonts — codepoints are mapped to their Unicode equivalents; unmapped codepoints are dropped
  • Compression: Stored and Deflated only
  • Suppressing empty headings, block quotes, and paragraphs: the reader emits these by design (see empty_paragraph_still_emits_start_end and sibling tests in tests/reader.rs). To hide empty StartHeading/EndHeading, StartBlockQuote/EndBlockQuote, and StartParagraph/EndParagraph pairs in your pipeline, wrap the reader in docspec_core::SkipEmptyBlocks. The docspec CLI and HTTP server apply this filter by default; library consumers opt in by wrapping their EventSource.

Color and Highlight Precedence

When both <w:highlight> and <w:shd w:fill> appear in the same <w:rPr>, <w:highlight> wins. The <w:shd> fill is ignored for that run.

No-Collapse Rule

Adjacent runs with the same color emit separate StartTextStyle/EndTextStyle pairs. The reader maintains per-run discipline and does not merge consecutive runs, even when their style properties are identical.

Style references (resolved, not on the denylist)

Two elements look like they should belong to the denylist below, but are actually resolved through the styles table — the surrounding content is emitted normally:

  • <w:rStyle> (run-level style references) — resolved via apply_resolved_rpr_style. Style values that classify as Code promote the run to TextStyleKind::Code; other values contribute no style metadata, but the run's text is still emitted.
  • <w:pStyle> values other than the heading, block-quote, and code-style names listed in "What it handles today" — the paragraph emits as StartParagraph with no style metadata, and its content is emitted normally.

Out of scope (subtree silently dropped)

The XML elements listed below are the reader's denylist — their entire subtree is silently dropped during parsing. Any element NOT listed (whether a known structural tag like <w:p> or an unknown extension) is processed normally; the reader just continues into its children.

  • Run formatting not listed above: <w:sz>, <w:szCs>, <w:caps>, <w:smallCaps>, <w:position>, <w:spacing>, <w:kern>, <w:lang>, <w:noProof>
  • <w:rFonts> (general font tracking is not exposed as events, except for symbol font resolution (Wingdings, Wingdings 2, Wingdings 3, Webdings, Symbol) which is used internally to normalize codepoints to Unicode)
  • themeColor / themeTint / themeShade attributes on <w:color> and <w:shd> are silently dropped. The reader parses styles.xml for style classification, but does not load or resolve theme colors from theme1.xml.
  • Revision tracking (<w:rPrChange>, <w:pPrChange>)
  • Advanced paragraph layout beyond alignment: <w:ind>, <w:tabs>, <w:framePr>, <w:sectPr>
  • <w:rPr> nested inside <w:pPr> (paragraph mark / pilcrow run properties)
  • BiDi-aware logical alignment (start/end flipping based on paragraph direction is not tracked)
  • Math (m:rPr) and DrawingML (a:rPr) namespaces
  • Vertical cell merging (<w:vMerge>) — every cell still emits with rowspan: None; covered cells emit as ordinary StartTableCell events (visual merge is lost)
  • Header rows in nested tables — only the outermost table honors <w:tblHeader>
  • Table-level property exceptions (<w:tblPrEx>) — silently ignored (consistent with <w:tblPr>)
  • Table, row, and cell visual properties (<w:tblPr>, <w:trPr> visual fields, <w:tcPr> visual fields, <w:tblGrid>) — silently dropped
  • <mc:Fallback> (inside <mc:AlternateContent>) — subtree dropped to deduplicate images that appear in both the modern <w:drawing> (in <mc:Choice>) and the legacy <w:pict> (in <mc:Fallback>).
  • Comments, footnotes, headers, footers
  • Document metadata
  • Tracked deletions and moves-from (<w:del>, <w:moveFrom>) — silently dropped (accept-changes semantics). Their text content uses <w:delText> which is not part of the reader's text-matching set.
  • Structured document tag properties (<w:sdtPr>, <w:sdtEndPr>) — metadata containers; subtree dropped.
  • Field-code hyperlinks (<w:fldChar> + <w:instrText>HYPERLINK ...): legacy form not currently supported; only the modern <w:hyperlink> element is recognized.

Lists (V1 cuts)

The following list features are intentionally out of scope for V1:

  • No <w:start> element parsing — start comes from the effective per-numId/ilvl paragraph counter, not explicit OOXML start overrides
  • No <w:lvlOverride> resolution — abstractNum's level definitions are authoritative
  • No picture bullets (<w:lvlPicBulletId>) — picture-bullet levels emit Disc
  • No style-linked lists (<w:numStyleLink>, <w:styleLink>) — fall back to Decimal defaults
  • <w:multiLevelType> is ignored — per-level <w:numFmt> is authoritative (§17.9.12)
  • No per-level marker text (<w:lvlText>) — not parsed
  • No level-specific font, color, or indent
  • No per-level resolution for synthesised phantom levels — when the first authored item appears at ilvl > 0, intermediate levels inherit the target item's ordered/unordered classification and use Decimal/Disc defaults instead of resolving each phantom level's own numFmt

Image Support

<w:drawing> elements are parsed and emit Event::Image. The source field is one of two variants:

  • Embedded image (r:embed): ImageSource::Asset(handle) where handle.asset_id() returns "zip://word/media/image1.png". The asset ID is the resolved ZIP entry path with a zip:// scheme prefix. Call handle.stream_to(&mut buf) to stream the raw bytes, or handle.content_type() to get the MIME type.
  • External image (r:link): ImageSource::Uri { uri: "<url>" }. The URL is passed through verbatim from the relationship target.

When both r:embed and r:link appear on the same blip, r:embed wins.

A relationship marked TargetMode="External" is honored even when referenced via r:embed — the reader emits ImageSource::Uri in that case, matching Word and LibreOffice behavior.

If the relationship ID cannot be resolved (missing or malformed rels), the reader emits ImageSource::Asset(handle) where handle.asset_id() returns the raw relationship ID with no zip:// prefix. Writers should apply their own missing-asset policy.

wp:docPr/@descr maps to Event::Image.alt. The title field is always None in this release.

VML images (<w:pict> containing <v:imagedata>) are also supported, using the same asset resolution as DrawingML images. V1 limitations: VML positioning attributes (style, w10:wrap, w10:anchorlock), <v:textbox> text content, and inline image bytes via <w:binData> (referenced from <v:imagedata src="wordml://..."/>) are silently dropped.

Asset Handles

Each ImageSource::Asset(handle) carries an Arc<dyn AssetHandle> that holds everything needed to resolve the asset. Call methods directly on the handle:

use docspec_docx_reader::{DocxReader, EventSource};
use docspec_core::{Event, ImageSource};

let mut reader = DocxReader::from_path("document.docx")?;
while let Some(event) = reader.next_event()? {
    if let Event::Image { source: ImageSource::Asset(handle), .. } = &event {
        let mut buf = Vec::new();
        handle.stream_to(&mut buf)?;
        // buf now contains the raw image bytes
    }
}
# Ok::<(), docspec_core::Error>(())

Streaming Guarantee

Memory use depends on which constructor you call:

  • from_path: streams word/document.xml in constant memory — O(1) regardless of document size. Use this when processing large files or when memory is constrained.
  • from_reader: buffers word/document.xml into memory — O(N) in document size. Use from_path when constant memory is required.

In both cases, _rels/.rels and word/_rels/document.xml.rels are fully read into memory at package-open time (typical combined size < 10 KB even for large documents). The internal event queue remains bounded regardless of document size or hyperlink count.

Read a DOCX

use docspec_docx_reader::{DocxReader, EventSource};

let mut reader = DocxReader::from_path("document.docx")?;
while let Some(event) = reader.next_event()? {
    println!("{event:?}");
}
# Ok::<(), docspec_core::Error>(())

Related

  • Architecture — pipeline design, event model decisions, and pointers to the in-code event reference
  • docspec-core on docs.rs — every event variant, field, and well-formedness rule