176 lines
4.1 KiB
Markdown
176 lines
4.1 KiB
Markdown
# Technical Design
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## Architecture Overview
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```
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User Upload (DOC/DOCX/PPT/PPTX)
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↓
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File Validation & Storage
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↓
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Format Detection
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↓
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Office Document Converter
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↓
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PDF Generation
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↓
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PDF to Images (existing)
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↓
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PaddleOCR Processing (existing)
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↓
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Results & Export
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```
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## Component Design
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### 1. Office Document Converter Service
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```python
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# app/services/office_converter.py
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class OfficeConverter:
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"""Convert Office documents to PDF for OCR processing"""
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def convert_to_pdf(self, file_path: Path) -> Path:
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"""Main conversion dispatcher"""
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def convert_docx_to_pdf(self, docx_path: Path) -> Path:
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"""Convert DOCX to PDF using python-docx and pypandoc"""
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def convert_doc_to_pdf(self, doc_path: Path) -> Path:
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"""Convert legacy DOC to PDF"""
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def convert_pptx_to_pdf(self, pptx_path: Path) -> Path:
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"""Convert PPTX to PDF using python-pptx"""
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def convert_ppt_to_pdf(self, ppt_path: Path) -> Path:
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"""Convert legacy PPT to PDF"""
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```
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### 2. OCR Service Integration
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```python
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# Extend app/services/ocr_service.py
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def process_image(self, image_path: Path, ...):
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# Check file type
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if is_office_document(image_path):
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# Convert to PDF first
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pdf_path = self.office_converter.convert_to_pdf(image_path)
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# Use existing PDF processing
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return self.process_pdf(pdf_path, ...)
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elif is_pdf:
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# Existing PDF processing
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...
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else:
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# Existing image processing
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...
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```
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### 3. File Format Detection
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```python
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OFFICE_FORMATS = {
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'.doc': 'application/msword',
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'.docx': 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
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'.ppt': 'application/vnd.ms-powerpoint',
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'.pptx': 'application/vnd.openxmlformats-officedocument.presentationml.presentation'
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}
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def is_office_document(file_path: Path) -> bool:
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return file_path.suffix.lower() in OFFICE_FORMATS
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```
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## Library Selection
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### For Word Documents
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- **python-docx**: Read/write DOCX files
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- **doc2pdf**: Simple conversion (requires LibreOffice)
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- Alternative: **pypandoc** with pandoc backend
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### For PowerPoint Documents
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- **python-pptx**: Read/write PPTX files
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- **unoconv**: Universal Office Converter (requires LibreOffice)
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### Recommended Approach
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Use **LibreOffice** headless mode for universal conversion:
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```bash
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libreoffice --headless --convert-to pdf input.docx
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```
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This provides:
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- Support for all Office formats
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- High fidelity conversion
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- Maintained by active community
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## Configuration Changes
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### Token Expiration
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```python
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# app/core/config.py
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class Settings(BaseSettings):
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# Change from 30 to 1440 (24 hours)
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access_token_expire_minutes: int = 1440
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```
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### File Upload Limits
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```python
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# Consider Office files can be larger
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max_file_size: int = 100 * 1024 * 1024 # 100MB
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allowed_extensions: Set[str] = {
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'.png', '.jpg', '.jpeg', '.pdf',
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'.doc', '.docx', '.ppt', '.pptx'
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}
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```
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## Error Handling
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1. **Conversion Failures**
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- Corrupted Office files
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- Unsupported Office features
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- LibreOffice not installed
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2. **Performance Considerations**
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- Office conversion is CPU intensive
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- Consider queuing for large files
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- Add conversion timeout (60 seconds)
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3. **Security**
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- Validate Office files before processing
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- Scan for macros/embedded objects
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- Sandbox conversion process
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## Dependencies
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### System Requirements
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```bash
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# macOS
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brew install libreoffice
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# Linux
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apt-get install libreoffice
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# Python packages
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pip install python-docx python-pptx pypandoc
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```
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### Alternative: Docker Container
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Use a Docker container with LibreOffice pre-installed for consistent conversion across environments.
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## Testing Strategy
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1. **Unit Tests**
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- Test each conversion method
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- Mock LibreOffice calls
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- Test error handling
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2. **Integration Tests**
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- End-to-end Office → OCR pipeline
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- Test with various Office versions
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- Performance benchmarks
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3. **Sample Documents**
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- Simple text documents
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- Documents with tables
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- Documents with images
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- Presentations with multiple slides
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- Legacy formats (DOC, PPT) |