init repo

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liuyuanchuang
2025-12-29 17:34:58 +08:00
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app/services/__init__.py Normal file
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"""Markdown to DOCX conversion service.
Reference implementation based on https://github.com/YogeLiu/markdown_2_docx
"""
import io
import re
from dataclasses import dataclass
from docx import Document
from docx.enum.text import WD_ALIGN_PARAGRAPH
from docx.oxml import OxmlElement
from docx.oxml.ns import qn
from docx.shared import Inches, Pt
@dataclass
class MarkdownElement:
"""Parsed markdown element."""
type: str # heading, paragraph, list_item, code_block, table, math
content: str
level: int = 0 # For headings and lists
language: str = "" # For code blocks
class DocxConverter:
"""Converts markdown content to DOCX format."""
def __init__(self):
"""Initialize the converter."""
self.heading_pattern = re.compile(r"^(#{1,6})\s+(.+)$")
self.list_pattern = re.compile(r"^(\s*)[-*+]\s+(.+)$")
self.ordered_list_pattern = re.compile(r"^(\s*)\d+\.\s+(.+)$")
self.code_block_pattern = re.compile(r"^```(\w*)$")
self.inline_code_pattern = re.compile(r"`([^`]+)`")
self.bold_pattern = re.compile(r"\*\*([^*]+)\*\*")
self.italic_pattern = re.compile(r"\*([^*]+)\*")
self.math_block_pattern = re.compile(r"\$\$(.+?)\$\$", re.DOTALL)
self.inline_math_pattern = re.compile(r"\$([^$]+)\$")
def convert(self, markdown: str) -> bytes:
"""Convert markdown content to DOCX.
Args:
markdown: Markdown content to convert.
Returns:
DOCX file as bytes.
"""
doc = Document()
elements = self._parse_markdown(markdown)
for element in elements:
self._add_element_to_doc(doc, element)
# Save to bytes
buffer = io.BytesIO()
doc.save(buffer)
buffer.seek(0)
return buffer.getvalue()
def _parse_markdown(self, markdown: str) -> list[MarkdownElement]:
"""Parse markdown into elements.
Args:
markdown: Markdown content.
Returns:
List of parsed elements.
"""
elements: list[MarkdownElement] = []
lines = markdown.split("\n")
i = 0
in_code_block = False
code_content = []
code_language = ""
while i < len(lines):
line = lines[i]
# Code block handling
code_match = self.code_block_pattern.match(line)
if code_match:
if in_code_block:
elements.append(
MarkdownElement(
type="code_block",
content="\n".join(code_content),
language=code_language,
)
)
code_content = []
in_code_block = False
else:
in_code_block = True
code_language = code_match.group(1)
i += 1
continue
if in_code_block:
code_content.append(line)
i += 1
continue
# Math block ($$...$$)
if line.strip().startswith("$$"):
math_content = []
if line.strip() == "$$":
i += 1
while i < len(lines) and lines[i].strip() != "$$":
math_content.append(lines[i])
i += 1
else:
# Single line $$...$$ or start
content = line.strip()[2:]
if content.endswith("$$"):
math_content.append(content[:-2])
else:
math_content.append(content)
i += 1
while i < len(lines):
if lines[i].strip().endswith("$$"):
math_content.append(lines[i].strip()[:-2])
break
math_content.append(lines[i])
i += 1
elements.append(
MarkdownElement(type="math", content="\n".join(math_content))
)
i += 1
continue
# Heading
heading_match = self.heading_pattern.match(line)
if heading_match:
level = len(heading_match.group(1))
content = heading_match.group(2)
elements.append(
MarkdownElement(type="heading", content=content, level=level)
)
i += 1
continue
# Unordered list
list_match = self.list_pattern.match(line)
if list_match:
indent = len(list_match.group(1))
content = list_match.group(2)
elements.append(
MarkdownElement(type="list_item", content=content, level=indent // 2)
)
i += 1
continue
# Ordered list
ordered_match = self.ordered_list_pattern.match(line)
if ordered_match:
indent = len(ordered_match.group(1))
content = ordered_match.group(2)
elements.append(
MarkdownElement(
type="ordered_list_item", content=content, level=indent // 2
)
)
i += 1
continue
# Table (simple detection)
if "|" in line and i + 1 < len(lines) and "---" in lines[i + 1]:
table_lines = [line]
i += 1
while i < len(lines) and "|" in lines[i]:
table_lines.append(lines[i])
i += 1
elements.append(
MarkdownElement(type="table", content="\n".join(table_lines))
)
continue
# Regular paragraph
if line.strip():
elements.append(MarkdownElement(type="paragraph", content=line))
i += 1
return elements
def _add_element_to_doc(self, doc: Document, element: MarkdownElement) -> None:
"""Add a markdown element to the document.
Args:
doc: Word document.
element: Parsed markdown element.
"""
if element.type == "heading":
self._add_heading(doc, element.content, element.level)
elif element.type == "paragraph":
self._add_paragraph(doc, element.content)
elif element.type == "list_item":
self._add_list_item(doc, element.content, element.level, ordered=False)
elif element.type == "ordered_list_item":
self._add_list_item(doc, element.content, element.level, ordered=True)
elif element.type == "code_block":
self._add_code_block(doc, element.content)
elif element.type == "table":
self._add_table(doc, element.content)
elif element.type == "math":
self._add_math(doc, element.content)
def _add_heading(self, doc: Document, content: str, level: int) -> None:
"""Add a heading to the document."""
# Map markdown levels to Word heading styles
heading_level = min(level, 9) # Word supports up to Heading 9
doc.add_heading(content, level=heading_level)
def _add_paragraph(self, doc: Document, content: str) -> None:
"""Add a paragraph with inline formatting."""
para = doc.add_paragraph()
self._add_formatted_text(para, content)
def _add_formatted_text(self, para, content: str) -> None:
"""Add text with inline formatting (bold, italic, code)."""
# Simple approach: process inline patterns
remaining = content
while remaining:
# Find next formatting marker
bold_match = self.bold_pattern.search(remaining)
italic_match = self.italic_pattern.search(remaining)
code_match = self.inline_code_pattern.search(remaining)
math_match = self.inline_math_pattern.search(remaining)
matches = [
(bold_match, "bold"),
(italic_match, "italic"),
(code_match, "code"),
(math_match, "math"),
]
matches = [(m, t) for m, t in matches if m]
if not matches:
para.add_run(remaining)
break
# Find earliest match
earliest = min(matches, key=lambda x: x[0].start())
match, match_type = earliest
# Add text before match
if match.start() > 0:
para.add_run(remaining[: match.start()])
# Add formatted text
run = para.add_run(match.group(1))
if match_type == "bold":
run.bold = True
elif match_type == "italic":
run.italic = True
elif match_type == "code":
run.font.name = "Courier New"
run.font.size = Pt(10)
elif match_type == "math":
run.italic = True
remaining = remaining[match.end() :]
def _add_list_item(
self, doc: Document, content: str, level: int, ordered: bool
) -> None:
"""Add a list item."""
para = doc.add_paragraph(style="List Bullet" if not ordered else "List Number")
para.paragraph_format.left_indent = Inches(0.25 * level)
self._add_formatted_text(para, content)
def _add_code_block(self, doc: Document, content: str) -> None:
"""Add a code block."""
para = doc.add_paragraph()
para.paragraph_format.left_indent = Inches(0.5)
run = para.add_run(content)
run.font.name = "Courier New"
run.font.size = Pt(9)
# Add shading
shading = OxmlElement("w:shd")
shading.set(qn("w:val"), "clear")
shading.set(qn("w:fill"), "F0F0F0")
para._p.get_or_add_pPr().append(shading)
def _add_table(self, doc: Document, content: str) -> None:
"""Add a table from markdown table format."""
lines = [l.strip() for l in content.split("\n") if l.strip()]
if len(lines) < 2:
return
# Parse header
header = [c.strip() for c in lines[0].split("|") if c.strip()]
# Skip separator line
data_lines = lines[2:] if len(lines) > 2 else []
# Create table
table = doc.add_table(rows=1, cols=len(header))
table.style = "Table Grid"
# Add header
header_cells = table.rows[0].cells
for i, text in enumerate(header):
header_cells[i].text = text
header_cells[i].paragraphs[0].runs[0].bold = True
# Add data rows
for line in data_lines:
cells = [c.strip() for c in line.split("|") if c.strip()]
row_cells = table.add_row().cells
for i, text in enumerate(cells):
if i < len(row_cells):
row_cells[i].text = text
def _add_math(self, doc: Document, content: str) -> None:
"""Add a math block.
For proper OMML rendering, this would need more complex conversion.
Currently renders as italic text with the LaTeX source.
"""
para = doc.add_paragraph()
para.alignment = WD_ALIGN_PARAGRAPH.CENTER
run = para.add_run(content)
run.italic = True
run.font.name = "Cambria Math"
run.font.size = Pt(12)

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"""Image preprocessing service using OpenCV."""
import base64
import io
from urllib.request import urlopen
import cv2
import numpy as np
from PIL import Image
from app.core.config import get_settings
settings = get_settings()
class ImageProcessor:
"""Service for image preprocessing operations."""
def __init__(self, padding_ratio: float | None = None):
"""Initialize with padding ratio.
Args:
padding_ratio: Ratio for padding on each side (default from settings).
0.15 means 15% padding on each side = 30% total expansion.
"""
self.padding_ratio = padding_ratio or settings.image_padding_ratio
def load_image_from_url(self, url: str) -> np.ndarray:
"""Load image from URL.
Args:
url: Image URL to fetch.
Returns:
Image as numpy array in BGR format.
Raises:
ValueError: If image cannot be loaded from URL.
"""
try:
with urlopen(url, timeout=30) as response:
image_data = response.read()
image = Image.open(io.BytesIO(image_data))
return cv2.cvtColor(np.array(image), cv2.COLOR_RGB2BGR)
except Exception as e:
raise ValueError(f"Failed to load image from URL: {e}") from e
def load_image_from_base64(self, base64_str: str) -> np.ndarray:
"""Load image from base64 string.
Args:
base64_str: Base64-encoded image data.
Returns:
Image as numpy array in BGR format.
Raises:
ValueError: If image cannot be decoded.
"""
try:
# Handle data URL format
if "," in base64_str:
base64_str = base64_str.split(",", 1)[1]
image_data = base64.b64decode(base64_str)
image = Image.open(io.BytesIO(image_data))
return cv2.cvtColor(np.array(image), cv2.COLOR_RGB2BGR)
except Exception as e:
raise ValueError(f"Failed to decode base64 image: {e}") from e
def add_padding(self, image: np.ndarray) -> np.ndarray:
"""Add whitespace padding around the image.
Adds padding equal to padding_ratio * max(height, width) on each side.
This expands the image by approximately 30% total (15% on each side).
Args:
image: Input image as numpy array in BGR format.
Returns:
Padded image as numpy array.
"""
height, width = image.shape[:2]
padding = int(max(height, width) * self.padding_ratio)
# Add white padding on all sides
padded_image = cv2.copyMakeBorder(
image,
top=padding,
bottom=padding,
left=padding,
right=padding,
borderType=cv2.BORDER_CONSTANT,
value=[255, 255, 255], # White
)
return padded_image
def preprocess(self, image_url: str | None, image_base64: str | None) -> np.ndarray:
"""Load and preprocess image with padding.
Args:
image_url: URL to fetch image from (optional).
image_base64: Base64-encoded image (optional).
Returns:
Preprocessed image with padding.
Raises:
ValueError: If neither input is provided or loading fails.
"""
if image_url:
image = self.load_image_from_url(image_url)
elif image_base64:
image = self.load_image_from_base64(image_base64)
else:
raise ValueError("Either image_url or image_base64 must be provided")
return self.add_padding(image)
def image_to_base64(self, image: np.ndarray, format: str = "PNG") -> str:
"""Convert numpy image to base64 string.
Args:
image: Image as numpy array in BGR format.
format: Output format (PNG, JPEG).
Returns:
Base64-encoded image string.
"""
image_rgb = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
pil_image = Image.fromarray(image_rgb)
buffer = io.BytesIO()
pil_image.save(buffer, format=format)
buffer.seek(0)
return base64.b64encode(buffer.getvalue()).decode("utf-8")

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"""DocLayout-YOLO wrapper for document layout detection."""
import numpy as np
from app.schemas.image import LayoutInfo, LayoutRegion
class LayoutDetector:
"""Wrapper for DocLayout-YOLO model."""
# Class names from DocLayout-YOLO
CLASS_NAMES = {
0: "title",
1: "plain_text",
2: "abandon",
3: "figure",
4: "figure_caption",
5: "table",
6: "table_caption",
7: "table_footnote",
8: "isolate_formula",
9: "formula_caption",
}
# Classes considered as plain text
PLAIN_TEXT_CLASSES = {"title", "plain_text", "figure_caption", "table_caption", "table_footnote"}
# Classes considered as formula
FORMULA_CLASSES = {"isolate_formula", "formula_caption"}
def __init__(self, model_path: str, confidence_threshold: float = 0.2):
"""Initialize the layout detector.
Args:
model_path: Path to the DocLayout-YOLO model weights.
confidence_threshold: Minimum confidence for detections.
"""
self.model_path = model_path
self.confidence_threshold = confidence_threshold
self.model = None
def load_model(self) -> None:
"""Load the DocLayout-YOLO model.
Raises:
RuntimeError: If model cannot be loaded.
"""
try:
from doclayout_yolo import YOLOv10
self.model = YOLOv10(self.model_path)
except Exception as e:
raise RuntimeError(f"Failed to load DocLayout-YOLO model: {e}") from e
def detect(self, image: np.ndarray, image_size: int = 1024) -> LayoutInfo:
"""Detect document layout regions.
Args:
image: Input image as numpy array in BGR format.
image_size: Image size for prediction.
Returns:
LayoutInfo with detected regions.
Raises:
RuntimeError: If model not loaded.
"""
if self.model is None:
raise RuntimeError("Model not loaded. Call load_model() first.")
# Run prediction
results = self.model.predict(
image,
imgsz=image_size,
conf=self.confidence_threshold,
device="cuda:0",
)
regions: list[LayoutRegion] = []
has_plain_text = False
has_formula = False
if results and len(results) > 0:
result = results[0]
if result.boxes is not None:
for box in result.boxes:
cls_id = int(box.cls[0].item())
confidence = float(box.conf[0].item())
bbox = box.xyxy[0].tolist()
class_name = self.CLASS_NAMES.get(cls_id, f"unknown_{cls_id}")
# Map to simplified type
if class_name in self.PLAIN_TEXT_CLASSES:
region_type = "text"
has_plain_text = True
elif class_name in self.FORMULA_CLASSES:
region_type = "formula"
has_formula = True
elif class_name in {"figure"}:
region_type = "figure"
elif class_name in {"table"}:
region_type = "table"
else:
region_type = class_name
regions.append(
LayoutRegion(
type=region_type,
bbox=bbox,
confidence=confidence,
)
)
return LayoutInfo(
regions=regions,
has_plain_text=has_plain_text,
has_formula=has_formula,
)

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app/services/ocr_service.py Normal file
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"""PaddleOCR-VL client service for text and formula recognition."""
import io
import tempfile
from pathlib import Path
import cv2
import numpy as np
from app.core.config import get_settings
from app.schemas.image import LayoutInfo
settings = get_settings()
class OCRService:
"""Service for OCR using PaddleOCR-VL."""
FORMULA_PROMPT = "Please recognize the mathematical formula in this image and output in LaTeX format."
def __init__(
self,
vl_server_url: str | None = None,
pp_doclayout_model_dir: str | None = None,
):
"""Initialize OCR service.
Args:
vl_server_url: URL of the vLLM server for PaddleOCR-VL.
pp_doclayout_model_dir: Path to PP-DocLayoutV2 model directory.
"""
self.vl_server_url = vl_server_url or settings.paddleocr_vl_url
self.pp_doclayout_model_dir = pp_doclayout_model_dir or settings.pp_doclayout_model_dir
self._pipeline = None
def _get_pipeline(self):
"""Get or create PaddleOCR-VL pipeline.
Returns:
PaddleOCRVL pipeline instance.
"""
if self._pipeline is None:
from paddleocr import PaddleOCRVL
self._pipeline = PaddleOCRVL(
vl_rec_backend="vllm-server",
vl_rec_server_url=self.vl_server_url,
layout_detection_model_name="PP-DocLayoutV2",
layout_detection_model_dir=self.pp_doclayout_model_dir,
)
return self._pipeline
def _save_temp_image(self, image: np.ndarray) -> str:
"""Save image to a temporary file.
Args:
image: Image as numpy array in BGR format.
Returns:
Path to temporary file.
"""
with tempfile.NamedTemporaryFile(suffix=".png", delete=False) as f:
cv2.imwrite(f.name, image)
return f.name
def recognize_mixed(self, image: np.ndarray) -> dict:
"""Recognize mixed content (text + formulas) using PP-DocLayoutV2.
This mode uses PaddleOCR-VL with PP-DocLayoutV2 for document-aware
recognition of mixed content.
Args:
image: Input image as numpy array in BGR format.
Returns:
Dict with 'markdown', 'latex', 'mathml' keys.
"""
try:
pipeline = self._get_pipeline()
temp_path = self._save_temp_image(image)
try:
results = list(pipeline.predict(temp_path))
markdown_content = ""
for result in results:
# PaddleOCR-VL results can be saved to markdown
md_buffer = io.StringIO()
result.save_to_markdown(save_path=md_buffer)
markdown_content += md_buffer.getvalue()
# Convert markdown to other formats
latex = self._markdown_to_latex(markdown_content)
mathml = self._extract_mathml(markdown_content)
return {
"markdown": markdown_content,
"latex": latex,
"mathml": mathml,
}
finally:
Path(temp_path).unlink(missing_ok=True)
except Exception as e:
raise RuntimeError(f"Mixed recognition failed: {e}") from e
def recognize_formula(self, image: np.ndarray) -> dict:
"""Recognize formula/math content using PaddleOCR-VL with prompt.
This mode uses PaddleOCR-VL directly with a formula recognition prompt.
Args:
image: Input image as numpy array in BGR format.
Returns:
Dict with 'latex', 'markdown', 'mathml' keys.
"""
try:
import httpx
temp_path = self._save_temp_image(image)
try:
# Use vLLM API directly for formula recognition
import base64
with open(temp_path, "rb") as f:
image_base64 = base64.b64encode(f.read()).decode("utf-8")
# Call vLLM server with formula prompt
response = httpx.post(
f"{self.vl_server_url}/chat/completions",
json={
"model": "paddleocr-vl",
"messages": [
{
"role": "user",
"content": [
{"type": "text", "text": self.FORMULA_PROMPT},
{
"type": "image_url",
"image_url": {"url": f"data:image/png;base64,{image_base64}"},
},
],
}
],
"max_tokens": 1024,
},
timeout=60.0,
)
response.raise_for_status()
result = response.json()
latex = result["choices"][0]["message"]["content"].strip()
# Convert latex to other formats
markdown = self._latex_to_markdown(latex)
mathml = self._latex_to_mathml(latex)
return {
"latex": latex,
"markdown": markdown,
"mathml": mathml,
}
finally:
Path(temp_path).unlink(missing_ok=True)
except httpx.HTTPStatusError as e:
raise RuntimeError(f"Formula recognition failed: HTTP {e.response.status_code}") from e
except Exception as e:
raise RuntimeError(f"Formula recognition failed: {e}") from e
def recognize(self, image: np.ndarray, layout_info: LayoutInfo) -> dict:
"""Recognize content based on layout detection results.
Args:
image: Input image as numpy array in BGR format.
layout_info: Layout detection results.
Returns:
Dict with recognition results including mode used.
"""
# Decision logic:
# - If plain text exists -> use mixed_recognition (PP-DocLayoutV2)
# - Otherwise -> use formula_recognition (VL with prompt)
if layout_info.has_plain_text:
result = self.recognize_mixed(image)
result["recognition_mode"] = "mixed_recognition"
else:
result = self.recognize_formula(image)
result["recognition_mode"] = "formula_recognition"
return result
def _markdown_to_latex(self, markdown: str) -> str:
"""Convert markdown to LaTeX.
Simple conversion - wraps content in LaTeX document structure.
Args:
markdown: Markdown content.
Returns:
LaTeX representation.
"""
# Basic conversion: preserve math blocks, convert structure
lines = []
in_code_block = False
for line in markdown.split("\n"):
if line.startswith("```"):
in_code_block = not in_code_block
if in_code_block:
lines.append("\\begin{verbatim}")
else:
lines.append("\\end{verbatim}")
elif in_code_block:
lines.append(line)
elif line.startswith("# "):
lines.append(f"\\section{{{line[2:]}}}")
elif line.startswith("## "):
lines.append(f"\\subsection{{{line[3:]}}}")
elif line.startswith("### "):
lines.append(f"\\subsubsection{{{line[4:]}}}")
elif line.startswith("- "):
lines.append(f"\\item {line[2:]}")
elif line.startswith("$$"):
lines.append(line.replace("$$", "\\[").replace("$$", "\\]"))
elif "$" in line:
# Keep inline math as-is
lines.append(line)
else:
lines.append(line)
return "\n".join(lines)
def _latex_to_markdown(self, latex: str) -> str:
"""Convert LaTeX to markdown.
Args:
latex: LaTeX content.
Returns:
Markdown representation.
"""
# Wrap LaTeX in markdown math block
if latex.strip():
return f"$$\n{latex}\n$$"
return ""
def _latex_to_mathml(self, latex: str) -> str:
"""Convert LaTeX to MathML.
Args:
latex: LaTeX content.
Returns:
MathML representation.
"""
# Basic LaTeX to MathML conversion
# For production, consider using latex2mathml library
if not latex.strip():
return ""
try:
# Try to use latex2mathml if available
from latex2mathml.converter import convert
return convert(latex)
except ImportError:
# Fallback: wrap in basic MathML structure
return f'<math xmlns="http://www.w3.org/1998/Math/MathML"><mtext>{latex}</mtext></math>'
except Exception:
return f'<math xmlns="http://www.w3.org/1998/Math/MathML"><mtext>{latex}</mtext></math>'
def _extract_mathml(self, markdown: str) -> str:
"""Extract and convert math from markdown to MathML.
Args:
markdown: Markdown content.
Returns:
MathML for any math content found.
"""
import re
# Find all math blocks
math_blocks = re.findall(r"\$\$(.*?)\$\$", markdown, re.DOTALL)
inline_math = re.findall(r"\$([^$]+)\$", markdown)
all_math = math_blocks + inline_math
if not all_math:
return ""
# Convert each to MathML and combine
mathml_parts = []
for latex in all_math:
mathml = self._latex_to_mathml(latex.strip())
if mathml:
mathml_parts.append(mathml)
return "\n".join(mathml_parts)