buds 4 and 6 implemented

IMPLEMENTATION.md

@@ -88,15 +88,43 @@ This document tracks the implementation status of ginxsom, a high-performance Fa
 
 ## BUD-03: Server List (User Server Lists) ⚪ **FOR CLIENTS, NOT SERVERS**
 
-## BUD-04: Blob Mirroring ⚪ **PARTIAL** 
+## BUD-04: Blob Mirroring ✅ **COMPLETE**
 
-### Current Status
+### HTTP Client Implementation
+- [x] CURL library integration and HTTP client functions
+- [x] `write_callback()` - Download response data with dynamic buffering
+- [x] `header_callback()` - Extract Content-Type headers
+- [x] `download_blob_from_url()` - Complete HTTP download with security controls
+- [x] Memory management and error handling
+
+### PUT /mirror Endpoint
 - [x] nginx endpoint configured (`PUT /mirror`)
-- [x] FastCGI routing established
-- [ ] URL downloading implementation
-- [ ] Hash verification after download
-- [ ] Authorization handling for mirroring
-- [ ] Inter-server mirroring testing
+- [x] FastCGI routing and request handling
+- [x] JSON request body parsing (extract `url` field)
+- [x] URL validation and security checks (HTTPS-only, SSRF protection)
+- [x] Remote blob downloading with CURL
+- [x] SHA-256 hash calculation and verification
+- [x] Content-Type detection (headers, URL extension, file signature)
+- [x] File storage with proper extensions (.png, .jpg, etc.)
+- [x] Database metadata storage
+- [x] Blob descriptor JSON response
+
+### Security Features
+- [x] HTTPS-only URL validation (no HTTP allowed)
+- [x] SSRF protection (blocks localhost, private IPs: 127.x, 192.168.x, 10.x, 172.16-31.x)
+- [x] File size limits (100MB maximum)
+- [x] Request timeouts (30s total, 10s connect)
+- [x] SSL certificate verification
+- [x] Authorization hash verification (when provided)
+
+### Testing Status
+- [x] Mirror request with valid HTTPS URL (HTTP 200)
+- [x] Hash verification against downloaded content
+- [x] Content-Type detection from PNG file
+- [x] File accessibility after mirroring
+- [x] HEAD request metadata retrieval
+- [x] Error handling for invalid URLs
+- [x] Security validation (private IP blocking)
 
 ---
 
@@ -112,24 +140,24 @@ This document tracks the implementation status of ginxsom, a high-performance Fa
 
 ---
 
-## BUD-06: Upload Requirements ⚪ **NOT IMPLEMENTED**
+## BUD-06: Upload Requirements ✅ **COMPLETE**
 
 ### HEAD /upload Pre-flight Validation
-- [ ] `HEAD /upload` endpoint implementation
-- [ ] Client header parsing (X-SHA-256, X-Content-Length, X-Content-Type)
-- [ ] Pre-flight validation without file transfer:
-  - [ ] SHA-256 format validation
-  - [ ] File size limit checking
-  - [ ] MIME type restrictions
-  - [ ] Authentication validation
-  - [ ] Duplicate detection
-  - [ ] Banned hash checking
-- [ ] Proper HTTP status codes (200, 400, 401, 403, 411, 413, 415)
-- [ ] X-Reason headers for error messages
+- [x] `HEAD /upload` endpoint implementation
+- [x] Client header parsing (X-SHA-256, X-Content-Length, X-Content-Type)
+- [x] Pre-flight validation without file transfer:
+  - [x] SHA-256 format validation
+  - [x] File size limit checking (100MB default)
+  - [ ] MIME type restrictions (policy 415 not enforced yet)
+  - [x] Authentication validation (optional via rules system)
+  - [x] Duplicate detection (policy configurable)
+  - [x] Banned hash checking (via rules engine)
+- [x] Proper HTTP status codes (200, 400, 401, 409, 411, 413; 415 reserved for future MIME policy)
+- [x] X-Reason headers for error messages
 
 ### Upload Policy Configuration
 - [ ] Server configuration system
-- [ ] Maximum file size limits
+- [ ] Maximum file size limits (currently hard limit in code; move to config)
 - [ ] Allowed MIME type restrictions
 - [ ] Rate limiting implementation
 - [ ] DOS protection benefits