mag-file-handler

Universal document parser for any file format your product receives.

from file_handler import parse

result = parse("inbound/email.eml")
print(result.text)            # extracted plain text
print(result.format)          # "eml"
print(result.engine)          # "email"
print(result.extra)           # engine-specific provenance

Why this exists

Different document types need different tools — and getting it wrong is expensive. Born-digital PDFs should hit a free text-layer extractor; scanned newspapers should hit Tika; complex slides and textbooks need a vision LLM. This library routes each document to the right engine, automatically.

System requirements

• Python 3.10, 3.11, 3.12, or 3.13 (CPython).
• OS / arch: Linux x86-64 (glibc ≥ 2.28), macOS x86-64 (≥ 10.12), macOS ARM64 (≥ 11), Windows x86-64. Linux ARM64 (Graviton, RPi) and Windows ARM64 are not currently supported because the extractous dependency does not ship wheels for those targets.
• No JVM is required. extractous ships native binaries built with GraalVM AOT compilation, so installation and runtime are pure-native even though Apache Tika is used internally for the long tail of formats.
• Optional: a VisionClient implementation (yours or your platform's LLM gateway's) for image OCR and scanned-PDF Tier 2 routing. See Vision is pluggable.

Install

pip install mag-file-handler            # core (PDF router, Office, HTML, txt, EML)
pip install mag-file-handler[email]     # + Outlook .msg support
pip install mag-file-handler[all]       # everything optional

[vision] is a documentation-only marker extra — the library ships zero LLM SDK dependencies by design. To use vision OCR, pass a VisionClient you implement (or one your platform provides) into parse(path, vision_client=...). See below for the protocol.

Usage

Library

from file_handler import parse

result = parse("/path/to/file")
if result.ok:
    process(result.text)
else:
    log.warn("parse failed: %s", result.error)

# Engine-specific provenance lives in result.extra
if result.engine == "pdf_router":
    print(result.extra["tier_counts"])    # {"tier0_pdfium": 5, "tier1_extractous": 0, "tier2_claude": 2}
    print(result.extra["claude_usage"])   # {"input_tokens": ..., "output_tokens": ...}

CLI

file-handler parse  document.pdf            # prints extracted text
file-handler parse  document.pdf --json     # full result as JSON
file-handler detect document.pdf            # format detection only
file-handler info                           # version + which engines are available

How routing works

                     FORMAT DETECTION
                     (magic bytes + ext)
                            │
        ┌───────────────────┼───────────────────────┐
        ▼                   ▼                       ▼
       PDF              Image (jpg/png/…)       Email (eml/msg)
        │                   │                       │
        ▼                   ▼                       ▼
   PDF Router          Claude Vision         parse + recurse on
   (per-page tiers)                          each attachment
   ┌──────────────┐
   │ Tier 0  pdfium native text-layer       free, ms-fast
   │ Tier 1  Extractous (Tika)              free, ~2 s
   │ Tier 2  Claude Haiku 4.5 vision        ~$0.008, ~15 s
   └──────────────┘

   Office, HTML, MD, TXT, …  →  Extractous (Tika handles them natively)

For PDFs, the per-page decision tree picks:

If Tier 0 / Tier 1 returns near-empty text on a page that visibly has content, the engine falls back to Tier 2 automatically (conservative — only on empty output, not on questionable quality).

Returned types

@dataclass
class ParseResult:
    text: str                      # extracted plain text
    format: str                    # "pdf", "docx", "eml", …
    engine: str                    # which engine handled it
    mime: str
    detection_confidence: str      # "magic" / "ext" / "content"
    path: str
    error: str | None              # set if parsing failed
    page_count: int | None
    extra: dict                    # engine-specific provenance
    ok: bool                       # property, True if error is None

extra always carries enough to audit a parse:

Vision is pluggable — and there is no default

The library ships ZERO LLM SDK dependencies. Vision (image OCR + Tier 2 of the PDF router) requires the caller to inject a VisionClient. If none is provided, vision-needing operations return an error in result.error instead of falling back to a default provider.

class VisionClient(Protocol):
    def ocr_image(
        self,
        image_bytes: bytes,
        media_type: str,
        *,
        prompt: str | None = None,
        max_tokens: int = 16384,
    ) -> tuple[str, dict[str, Any]]:
        """Return (extracted_text, usage_metadata)."""

This is intentional — production deployments use a per-org LLM gateway (model selection, access control, cost tracking, secrets management) that the library has no business knowing about. The parse(path, vision_client=...) parameter (and recursively for email attachments) is the integration point.

Temporal integration — the canonical production pattern

In production, file_handler.parse() is not called from inside a single Temporal Activity. Instead, magoneai's workflow composes file_handler's per-tier engines as separate activities, with vision as its own activity backed by LLMGateway. This gives Temporal-native retries, observability, and rate-limiting per tier — without any asyncio.run bridging.

# magoneai/temporal/file_handler/activities.py

from pathlib import Path

from temporalio import activity

from be.core.database import get_async_session
from be.llm.gateway import LLMGateway, LoadedImage, build_vision_message

# file_handler exposes building blocks; activities orchestrate them.
import file_handler
from file_handler.engines import extractous_engine, pdfium_engine, pdf_router
from file_handler.engines._ocr_helpers import (
    render_image_file_for_ocr,
    render_pdf_page_for_ocr,
)
from file_handler.engines.page_features import extract_features


@activity.defn
async def detect_format_activity(file_uri: str) -> dict:
    fmt = file_handler.detect(file_uri)
    return {"format_id": fmt.format_id.value, "mime": fmt.mime}


@activity.defn
async def extract_via_extractous_activity(file_uri: str) -> dict:
    """Tika-based extraction for DOCX/PPTX/XLSX/HTML/MD/TXT and PDF Tier 1."""
    return extractous_engine.parse_file(Path(file_uri))


@activity.defn
async def plan_pdf_route_activity(file_uri: str) -> list[dict]:
    """Per-page tier plan, made by the workflow before dispatch."""
    import pypdfium2 as pdfium
    pdf = pdfium.PdfDocument(file_uri)
    plan = []
    for i, page in enumerate(pdf):
        f = extract_features(page, i)
        tier, reason = pdf_router._decide_tier(f)
        plan.append({"page": i, "tier": tier, "reason": reason})
    return plan


@activity.defn
async def pdfium_text_layer_activity(file_uri: str, page_idx: int) -> str:
    import pypdfium2 as pdfium
    pdf = pdfium.PdfDocument(file_uri)
    return pdfium_engine.extract_text(pdf[page_idx])


@activity.defn
async def extractous_page_activity(file_uri: str, page_idx: int) -> dict:
    return extractous_engine.parse_pdf_page(Path(file_uri), page_idx)


@activity.defn
async def vision_ocr_activity(
    file_uri: str,
    page_idx: int | None,        # None = whole-file image; int = PDF page
    project_id: str,
    llm_config_id: str,
) -> dict:
    """Vision OCR via the magoneai LLM gateway. Native async — no asyncio.run."""
    if page_idx is None:
        image_bytes, media_type, _ = render_image_file_for_ocr(Path(file_uri))
    else:
        import pypdfium2 as pdfium
        pdf = pdfium.PdfDocument(file_uri)
        image_bytes, media_type, _ = render_pdf_page_for_ocr(pdf[page_idx])

    async with get_async_session() as session:
        gateway = LLMGateway(session)
        loaded = LoadedImage(
            base64_data=__import__("base64").standard_b64encode(image_bytes).decode("ascii"),
            mime_type=media_type,
            file_id=f"file_handler-{file_uri}:{page_idx}",
            size_bytes=len(image_bytes),
        )
        response = await gateway.complete(
            project_id=project_id,
            llm_config_id=llm_config_id,
            messages=[build_vision_message(text="Transcribe this page.", images=[loaded])],
            parameters={"max_tokens": 16384},
            images=[loaded],
            source_type="file_handler",
        )
    return {
        "text": response.content,
        "input_tokens": response.usage.tokens_in,
        "output_tokens": response.usage.tokens_out,
        "request_id": response.usage.request_id,
    }

# magoneai/temporal/file_handler/workflows.py

from datetime import timedelta
from temporalio import workflow

from .activities import (
    detect_format_activity,
    extract_via_extractous_activity,
    plan_pdf_route_activity,
    pdfium_text_layer_activity,
    extractous_page_activity,
    vision_ocr_activity,
)


IMAGE_FORMATS = {"jpeg", "png", "tiff", "gif", "webp", "bmp"}


@workflow.defn
class ParseDocumentWorkflow:
    @workflow.run
    async def run(self, file_uri: str, project_id: str, llm_config_id: str) -> dict:
        fmt = await workflow.execute_activity(
            detect_format_activity, file_uri,
            start_to_close_timeout=timedelta(seconds=10),
        )

        if fmt["format_id"] == "pdf":
            return await workflow.execute_child_workflow(
                ParsePdfWorkflow.run, file_uri, project_id, llm_config_id,
            )

        if fmt["format_id"] in IMAGE_FORMATS:
            res = await workflow.execute_activity(
                vision_ocr_activity, file_uri, None, project_id, llm_config_id,
                start_to_close_timeout=timedelta(minutes=3),
            )
            return {"text": res["text"], "engine": "vision", "format": fmt["format_id"]}

        # Office, HTML, MD, TXT, EML, etc. → Tika handles them, no vision.
        res = await workflow.execute_activity(
            extract_via_extractous_activity, file_uri,
            start_to_close_timeout=timedelta(minutes=2),
        )
        return {**res, "format": fmt["format_id"]}


@workflow.defn
class ParsePdfWorkflow:
    @workflow.run
    async def run(self, file_uri: str, project_id: str, llm_config_id: str) -> dict:
        plan = await workflow.execute_activity(
            plan_pdf_route_activity, file_uri,
            start_to_close_timeout=timedelta(seconds=30),
        )

        # Fan-out: each page runs its chosen tier as an independent activity.
        async def run_tier(page_decision: dict) -> str:
            i = page_decision["page"]
            tier = page_decision["tier"]
            if tier == "tier0_pdfium":
                return await workflow.execute_activity(
                    pdfium_text_layer_activity, file_uri, i,
                    start_to_close_timeout=timedelta(seconds=30),
                )
            if tier == "tier1_extractous":
                res = await workflow.execute_activity(
                    extractous_page_activity, file_uri, i,
                    start_to_close_timeout=timedelta(minutes=2),
                )
                return res.get("text", "")
            res = await workflow.execute_activity(
                vision_ocr_activity, file_uri, i, project_id, llm_config_id,
                start_to_close_timeout=timedelta(minutes=3),
            )
            return res["text"]

        # Bounded concurrency keeps gateway rate limits in check.
        page_texts = await workflow.gather(*(run_tier(p) for p in plan))
        return {
            "text": "\n\n".join(t for t in page_texts if t),
            "engine": "pdf_router",
            "format": "pdf",
            "page_count": len(plan),
            "per_page_decisions": plan,
        }

Why this shape:

• Each tier is its own Temporal Activity. Vision-rate-limit retries don't block fast pdfium calls. Extractous subprocess crashes retry independently. Per-tier timeouts and policies live where they belong.
• The vision activity is async-native. It calls LLMGateway.complete() directly with await. No asyncio.run, no thread bridge, no nested loops.
• Routing decisions are visible in the workflow's event history. You can query "what tier did page 7 use?" directly from Temporal.
• Per-page fan-out is parallel. A 50-page PDF runs N pages concurrently (worker concurrency caps total in-flight). file_handler's sync parse() would have processed them serially.

For local dev, scripts, and the benchmark, file_handler.parse(path, vision_client=YourClient()) is still the simplest path — pass any object implementing VisionClient.

Limitations / known issues

• Legacy Office (.doc / .ppt / .xls): falls back to Tika best-effort. A libreoffice-based pre-converter is on the roadmap.
• Tables: neither Extractous nor Claude returns structured tables. pdfplumber-based table extraction is on the roadmap.
• No CJK OCR: Tika's default Tesseract is English-only. We have not invested in Chinese / Japanese / Korean OCR (out of scope).
• Dense tabloid pages: the router's column detector occasionally mis-routes a tabloid (single dominant photo + scattered text) to Tier 2. Watch this if your traffic is heavy on tabloid layouts.

Development

pip install -e ".[all,test]"
pytest