fastrag.ingestion.steps.parsing.trafilatura#

Main-content extraction for arbitrary web pages, via Trafilatura.

HtmlParser removes page furniture by CSS selector, which works when a site marks its chrome up with <nav>/<footer> and fails on the many that build it out of anonymous ``div``s. DocusaurusParser solves that for one site generator. This parser solves it heuristically for any page: Trafilatura scores the DOM by text density and link ratio to find the article, so no per-site selector is needed, at the price of the usual heuristic risk of dropping a block a selector would have kept.

Module Attributes

METADATA_FIELDS

Page metadata Trafilatura extracts that is carried into Document.metadata when present, rather than into the embedded text.

Classes

TrafilaturaParser(*[, favor_precision, ...])

Extract a web page's main content as Markdown, with no per-site selectors.

fastrag.ingestion.steps.parsing.trafilatura.METADATA_FIELDS: tuple[str, ...] = ('title', 'author', 'date', 'description', 'sitename')#: Page metadata Trafilatura extracts that is carried into Document.metadata when present, rather than into the embedded text.

class fastrag.ingestion.steps.parsing.trafilatura.TrafilaturaParser(*, favor_precision=False, favor_recall=False, include_tables=True, include_links=True, include_images=False, include_comments=False, prune_xpath=(), encoding=None, cache=None, policy=None)[source]#

Bases: Parser

Extract a web page’s main content as Markdown, with no per-site selectors.

Trafilatura locates the article heuristically and discards navigation, sidebars, footers, and related-link blocks around it. Relative links are resolved against the source’s URI, and the page’s title, author, date, description, and site name travel in Document.metadata.

from fastrag.ingestion.steps.parsing import (
    ParserRouter,
    TrafilaturaParser,
    html_filter,
)

parser = ParserRouter(cache=cache).route(
    html_filter, TrafilaturaParser(favor_precision=True)
)

Parameters:

favor_precision (bool)
favor_recall (bool)
include_tables (bool)
include_links (bool)
include_images (bool)
include_comments (bool)
prune_xpath (Sequence[str])
encoding (str | None)
cache (CacheStore | Literal[False] | None)
policy (Policy | None)

content_format: ContentFormat = 'markdown'#: The ContentFormat this parser’s documents carry by default, stamped by build_document() into metadata["content_format"]. Override on a subclass whose output is always one format (HtmlParser/DocusaurusParser set MARKDOWN); pass content_format= to a single build_document() call instead for a parser whose output format depends on its own configuration.

accepted_media_types: frozenset[str] | None = frozenset({'application/xhtml+xml', 'text/html'})#: None retains legacy permissiveness; MIME patterns may use type/*.

config()[source]#

This parser’s cache-identity configuration.

Every option changes what a given page’s bytes parse into, so all of them are part of the fingerprint.

Return type:: Mapping[str, Any]

async transform(item, context)[source]#

Yield one Markdown document per page, or nothing if it has no content.

Parameters:

item (Source)
context (ExecutionContext)

Return type:

AsyncIterator[Document]

build_document(source, content, metadata=None, *, content_format=None)#

Build one document from source’s parsed content.

Sets id (a hash of the source identity and parsed content), source_id, step_config_hash (this parser’s own config_hash), and the reserved metadata keys every parser gets right without writing them itself: source_uri, content_type (source’s own, as declared or guessed upstream), and content_format (what kind of string content is — content_format unless overridden for this one call). The site_name/favicon_url a fetcher found on source are carried over too, unless metadata sets its own.

Parameters:

source (Source) – The source content was parsed from.
content (str) – The parsed text.
metadata (dict[str, Any] | None) – Extra metadata to carry, e.g. an HTML page’s title.
content_format (ContentFormat | None) – Overrides content_format for this one document, for a parser whose output format depends on its own configuration rather than being fixed per class.

Return type:

Document

property cache: CacheStore | Literal[False] | None#: Return the cache explicitly configured for this step.

property config_hash: str#: Invalidate cached documents created before source-aware identities.

effective_policy(context)#

Resolve this step’s policy over the one inherited from context.

The step’s own explicitly-set fields take priority; everything else falls through to the pipeline (or enclosing router/aggregator) policy.

Parameters:: context (ExecutionContext)
Return type:: Policy

async evaluate(context)#

Emit DocumentParsed per document.

Wraps DocumentStep’s concrete evaluate (which already resolved, per item, whether the document came from cache or a fresh transform() call — document.cached is trustworthy either way) rather than emitting inside a concrete parser’s own transform(), so the event fires the same way for a cache hit as for a fresh parse, and exactly once regardless of how many layers of routing (e.g. ParserRouter) produced the document.

Parameters:: context (ExecutionContext)
Return type:: AsyncIterator[Document]

async evaluate_items(items, context)#

Transform a bounded cache window independently of worker concurrency.

Parameters:

items (AsyncIterator[Any])
context (ExecutionContext)

Return type:

AsyncIterator[Document]

event_name: str = 'Parsing'#

The stage this step’s work belongs to, e.g. "Chunking".

Declared as a plain class attribute by a family base class, and inherited by every concrete step in that family:

class Chunker(DocumentStep, ABC):
    event_name = "Chunking"


class ChunkerRouter(RoutedStep[Document], Chunker):
    ...  # -> "Chunking", inherited from `Chunker`

A concrete step overrides it to opt out of its family’s label:

class ChunkerRouter(RoutedStep[Document], Chunker):
    event_name = "ChunkerRouter"  # -> "ChunkerRouter"

Resolution walks the MRO for the first class that declares it in its own class body (so a mixin listed first, e.g. RoutedStep, contributes nothing unless it declares one itself), and falls back to the class’s own name when nothing in the MRO does — a step family that never declares an event_name still labels each of its steps distinctly rather than collapsing them under one blank heading. That fallback is computed per instance rather than assigned onto the class: assigning it would make it look “declared” to every subclass, which would then inherit their base’s name instead of getting their own.

property policy: Policy | None#: Return the policy explicitly configured for this step.

replay_needs_content: bool = False#: Set by a step whose cached replay reads the full documents anyway (e.g. to re-validate them): its cache reads then skip the header-only projection rather than fetching every entry twice.

async run()#

Execute this step independently and collect every item.

Builds a default ExecutionContext when none is installed (this step’s own policy, or a fresh Policy). Intended primarily for testing and standalone use — pipeline-wide event observation is Pipeline’s job.

Return type:: list[T]

property upstream: PipelineStep[Any] | None#

Return the upstream step bound via __call__, or None.

Read-only counterpart to __call__’s self._upstream assignment — lets external code (e.g. Pipeline, walking a graph from its root to classify each step by position) introspect composition without reaching into a private attribute.

validate_input(item)#

Validate declared source capabilities before work and cache replay.

Parameters:: item (Source)
Return type:: None

name: str#