fastrag.ingestion.steps.parsing.router#

ParserRouter: dispatch each source to the parser registered for it.

Classes

ParserRouter(*[, cache, policy])

Route each source to the first matching .route parser, or .default.
class fastrag.ingestion.steps.parsing.router.ParserRouter(*, cache=None, policy=None)[source]#

Bases: RoutedStep[Document], Parser

Route each source to the first matching .route parser, or .default.

Holds no parsing logic of its own: a source matching no route with no default registered is skipped with an ItemFailed.

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

parser = (
    ParserRouter(cache=cache)
    .route(html_filter, HtmlParser())
    .default(DefaultParser())
)
Parameters:
routing_requires_content: bool = False#

Unknown routing overrides conservatively require complete inputs. Opt out only when built-in selection uses identity/metadata alone.

accepted_media_types: frozenset[str] | None = None#

None retains legacy permissiveness; MIME patterns may use type/*.

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.

config()#

No identity-affecting configuration of its own.

A routed item’s cache identity is keyed by whichever child matched it (see _dispatch_route), never by the router itself.

Return type:

Mapping[str, Any]

property config_hash: str#

Invalidate cached documents created before source-aware identities.

content_format: ContentFormat = 'text'#

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.

default(step)#

Register a fallback step for items that match no route filters.

Parameters:

step (PipelineStep[T]) – Default child step.

Returns:

Self, for fluent chaining.

Return type:

Self

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:
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.

route(filter_rule, step)#

Register a conditional branch step matching a filter predicate.

Parameters:

  • filter_rule (Filter[T]) – Filter predicate to match against incoming items.

  • step (PipelineStep[T]) – Child step to run on match.

Returns:

Self, for fluent chaining.

Return type:

Self

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]

async transform(item, context)#

Dispatch item to the first matching route, or the default.

An item matching no route with no default registered is skipped with an ItemFailed naming it — never silently dropped. A matched child that declares no explicit cache/policy of its own (cache is None) inherits this routed step’s effective cache and policy rather than the outer pipeline’s, since a routed child is conceptually scoped to its router. A child that does declare a policy has it applied to its own items, retries and timeout included — see _policy_for_item, which is where that half happens, since the retry wrap sits above this method rather than inside it.

Parameters:
Return type:

AsyncIterator[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

routes: list[tuple[Filter[T], PipelineStep[T]]]#
name: str#