c5d4ddaab0
- Tilføjer 'get_long_path' for at understøtte Windows-stier over 260 tegn - Implementerer dual-mode hashing: Bruger 'quickxorhash' C-bibliotek hvis muligt, ellers manual Python fallback - Opdaterer requirements.txt med quickxorhash - Opdaterer README.md og GEMINI.md med de seneste funktioner og tekniske specifikationer
47 lines
3.2 KiB
Markdown
47 lines
3.2 KiB
Markdown
# SharePoint Download Tool - Technical Documentation
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A production-ready Python utility for robust synchronization of SharePoint Online folders using Microsoft Graph API.
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## Project Overview
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* **Purpose:** Enterprise-grade synchronization tool for local mirroring of SharePoint content.
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* **Technologies:**
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* **Microsoft Graph API:** Advanced REST API for SharePoint data.
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* **MSAL:** Secure authentication using Azure AD Client Credentials.
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* **Requests:** High-performance HTTP client with streaming and Range header support.
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* **ThreadPoolExecutor:** Parallel file processing for optimized throughput.
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## Core Features (Production Ready)
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1. **Windows Long Path Support:** Automatically handles Windows path limitations by using `get_long_path` and `\\?\` absolute path prefixing.
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2. **High-Performance Integrity:** Uses the `quickxorhash` C-library if available for fast validation of large files. Includes a manual 160-bit circular XOR fallback implementation.
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3. **Timestamp Synchronization:** Compares SharePoint `lastModifiedDateTime` with local file `mtime`. Only downloads if the remote source is newer, significantly reducing sync time.
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4. **Optimized Integrity Validation:** Includes a configurable threshold (default 30MB) and a global toggle to balance security and performance for large assets.
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5. **Resumable Downloads:** Implements HTTP `Range` headers to resume partially downloaded files, critical for multi-gigabyte assets.
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6. **Reliability:** Includes a custom `retry_request` decorator for Exponential Backoff, handling throttling (429) and transient network errors.
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7. **Robust Library Discovery:** Automatic resolution of document library IDs with built-in fallbacks for localized names.
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8. **Self-Healing Sessions:** Automatically refreshes expiring Microsoft Graph Download URLs and MSAL Access Tokens mid-process.
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9. **Concurrency:** Multi-threaded architecture (5 workers) for simultaneous scanning and downloading.
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10. **Pagination:** Full support for OData pagination, ensuring complete folder traversal.
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## Building and Running
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### Setup
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1. **Dependencies:** `pip install -r requirements.txt` (Installing `quickxorhash` via C-compiler is recommended for best performance).
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2. **Configuration:** Settings are managed via `connection_info.txt` or the GUI.
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* `ENABLE_HASH_VALIDATION`: (True/False)
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* `HASH_THRESHOLD_MB`: (Size limit for hashing)
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### Execution
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* **GUI:** `python sharepoint_gui.py`
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* **CLI:** `python download_sharepoint.py`
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## Development Conventions
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* **QuickXorHash:** When implementing/updating hashing, ensure the file length is XORed into the **last 64 bits** (bits 96-159) of the 160-bit state per MS spec.
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* **Long Paths:** Always use `get_long_path()` when interacting with local file system (open, os.path.exists, etc.).
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* **Timezone Handling:** Always use UTC (ISO8601) when comparing timestamps with SharePoint.
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* **Error Handling:** Always use the `safe_get` (retry-wrapped) method for Graph API calls. For item-specific operations, use `get_fresh_download_url`.
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* **Authentication:** Use `get_headers(app, force_refresh=True)` when a 401 error is encountered.
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* **Logging:** Prefer `logger.info()` or `logger.error()` over `print()`.
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