From 201f8ed17d5a07301b348d005fcf5891651b99e6 Mon Sep 17 00:00:00 2001
From: CesarPetrescu <petrescu.cesat@gmail.com>
Date: Mon, 18 Aug 2025 03:54:46 +0300
Subject: [PATCH] docs: add PDF invocation examples

---
 README.md                          | 40 +++++++++++---
 invoice-extract/Dockerfile         |  9 ++++
 invoice-extract/app/main.py        | 85 ++++++++++++++++++++++++++++++
 invoice-extract/docker-compose.yml | 11 ++++
 invoice-extract/requirements.txt   |  8 +++
 5 files changed, 147 insertions(+), 6 deletions(-)
 create mode 100644 invoice-extract/Dockerfile
 create mode 100644 invoice-extract/app/main.py
 create mode 100644 invoice-extract/docker-compose.yml
 create mode 100644 invoice-extract/requirements.txt

diff --git a/README.md b/README.md
index 8b04801..b781477 100644
--- a/README.md
+++ b/README.md
@@ -1,9 +1,37 @@
 # dots.ocr-api
 
-invoice-extract/
-  Dockerfile
-  docker-compose.yml
-  requirements.txt
-  app/
-    main.py
+This repository contains a minimal setup for extracting invoice fields with the [dots.ocr](https://huggingface.co/rednote-hilab/dots.ocr) model using a CPU-only stack.
 
+## Running the API
+
+Build and start the service with Docker Compose:
+
+```bash
+cd invoice-extract
+docker compose up -d --build
+```
+
+The API will be available at `http://localhost:8000`.
+
+## Example: extract from a PDF
+
+Send a PDF file to the `/extract` endpoint using `curl`:
+
+```bash
+curl -F "file=@/path/to/invoice.pdf" http://localhost:8000/extract
+```
+
+The response is a JSON object containing the parsed invoice fields.
+
+## Batch processing
+
+Process all PDF or image files in a folder and save the outputs:
+
+```bash
+mkdir -p out
+for f in /invoices/*.{pdf,jpg,png,jpeg}; do
+  [ -e "$f" ] || continue
+  b=$(basename "$f")
+  curl -s -F "file=@$f" http://localhost:8000/extract > "out/${b%.*}.json"
+done
+```
diff --git a/invoice-extract/Dockerfile b/invoice-extract/Dockerfile
new file mode 100644
index 0000000..2c7f5e7
--- /dev/null
+++ b/invoice-extract/Dockerfile
@@ -0,0 +1,9 @@
+FROM python:3.11-slim
+WORKDIR /app
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+COPY app /app
+ENV MODEL_ID=rednote-hilab/dots.ocr
+ENV TORCH_DTYPE=float32
+EXPOSE 8000
+CMD ["uvicorn","main:app","--host","0.0.0.0","--port","8000"]
diff --git a/invoice-extract/app/main.py b/invoice-extract/app/main.py
new file mode 100644
index 0000000..80d81bc
--- /dev/null
+++ b/invoice-extract/app/main.py
@@ -0,0 +1,85 @@
+import os, io, re, json
+from typing import List
+from fastapi import FastAPI, UploadFile, File
+from pydantic import BaseModel
+from PIL import Image
+import fitz
+import torch
+from transformers import AutoModelForCausalLM, AutoProcessor
+
+MODEL_ID = os.getenv("MODEL_ID", "rednote-hilab/dots.ocr")
+DTYPE = os.getenv("TORCH_DTYPE", "bfloat16")
+
+app = FastAPI()
+model = None
+processor = None
+device = "cpu"
+
+def load_model():
+    global model, processor, device
+    device = "cuda" if torch.cuda.is_available() else "cpu"
+    dtype = torch.bfloat16 if device == "cuda" and DTYPE.lower().startswith("bf") else torch.float32
+    model = AutoModelForCausalLM.from_pretrained(
+        MODEL_ID, trust_remote_code=True,
+        torch_dtype=dtype, device_map="auto" if device=="cuda" else None
+    )
+    processor = AutoProcessor.from_pretrained(MODEL_ID, trust_remote_code=True)
+
+@app.on_event("startup")
+def _startup():
+    load_model()
+
+def pdf_or_image_to_pils(data: bytes, filename: str) -> List[Image.Image]:
+    if filename.lower().endswith(".pdf"):
+        doc = fitz.open(stream=data, filetype="pdf")
+        imgs = []
+        for p in doc:
+            pix = p.get_pixmap(matrix=fitz.Matrix(200/72, 200/72), alpha=False)
+            imgs.append(Image.open(io.BytesIO(pix.tobytes("png"))).convert("RGB"))
+        return imgs
+    return [Image.open(io.BytesIO(data)).convert("RGB")]
+
+PROMPT = """
+Extrage câmpurile de factură și returnează UN SINGUR obiect JSON valid, fără alt text.
+
+Schema:
+{
+ "invoice_number": null,
+ "issue_date": null,
+ "due_date": null,
+ "seller": {"name": null, "vat_id": null, "iban": null, "address": null},
+ "buyer": {"name": null, "vat_id": null, "address": null},
+ "currency": null,
+ "line_items": [{"description": null, "quantity": null, "unit_price": null, "line_total": null, "tax_rate": null}],
+ "subtotal": null, "tax": null, "total": null
+}
+Reguli: păstrează limba originală a textelor; nu traduce; nu inventa; dacă lipsesc date, lasă null; numere cu punct zecimal și fără separatori de mii.
+"""
+
+def infer(images: List[Image.Image]) -> dict:
+    content = [{"type":"image","image":img} for img in images] + [{"type":"text","text":PROMPT}]
+    messages = [{"role":"user","content":content}]
+    text = processor.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
+    inputs = processor(text=[text], images=images, padding=True, return_tensors="pt")
+    if device == "cuda":
+        inputs = {k: v.to("cuda") for k, v in inputs.items()}
+    out = model.generate(**inputs, max_new_tokens=4096, temperature=0.01)
+    resp = processor.batch_decode(out[:, inputs["input_ids"].shape[1]:], skip_special_tokens=True)[0]
+    m = re.search(r"\{.*\}", resp, flags=re.S)
+    payload = m.group(0) if m else resp
+    try:
+        import json5
+        return json5.loads(payload)
+    except Exception:
+        return json.loads(payload)
+
+class ExtractResponse(BaseModel):
+    pages: int
+    data: dict
+
+@app.post("/extract", response_model=ExtractResponse)
+async def extract(file: UploadFile = File(...)):
+    blob = await file.read()
+    images = pdf_or_image_to_pils(blob, file.filename)
+    data = infer(images)
+    return {"pages": len(images), "data": data}
diff --git a/invoice-extract/docker-compose.yml b/invoice-extract/docker-compose.yml
new file mode 100644
index 0000000..77530c7
--- /dev/null
+++ b/invoice-extract/docker-compose.yml
@@ -0,0 +1,11 @@
+services:
+  api:
+    build: .
+    ports: ["8000:8000"]
+    environment:
+      - MODEL_ID=rednote-hilab/dots.ocr
+      - TORCH_DTYPE=float32
+    volumes:
+      - hf_cache:/root/.cache/huggingface
+volumes:
+  hf_cache: {}
diff --git a/invoice-extract/requirements.txt b/invoice-extract/requirements.txt
new file mode 100644
index 0000000..687f5b8
--- /dev/null
+++ b/invoice-extract/requirements.txt
@@ -0,0 +1,8 @@
+fastapi
+uvicorn[standard]
+transformers>=4.42
+accelerate
+pillow
+pymupdf
+json5
+torch