Updated to support base64 email attachments.

app.py

@@ -7,7 +7,7 @@ import os
 import json
 from pathlib import Path
 from datetime import datetime
-from flask import Flask, render_template, request, jsonify, send_file, session, redirect, url_for
+from flask import Flask, render_template, request, jsonify, send_file, session, redirect, url_for, make_response
 from werkzeug.security import generate_password_hash, check_password_hash
 import markdown
 import logging
@@ -238,6 +238,45 @@ def rewrite_image_paths(md_content, filepath):
     md_content = re.sub(r'!\[([^\]]*)\]\(([^\)]+)\)', replace_image_path, md_content)
     return md_content
 
+def rewrite_eml_file_links(md_content, filepath):
+    """Rewrite relative .eml file links to be served by Flask's /file/ route."""
+    # Get the directory of the current file
+    file_dir = os.path.dirname(filepath)
+    
+    # Pattern to match markdown link syntax: [text](path)
+    def replace_link_path(match):
+        link_text = match.group(1)
+        link_path = match.group(2)
+        
+        # Only process .eml files
+        if not link_path.lower().endswith('.eml'):
+            return match.group(0)
+        
+        # Skip absolute URLs
+        if link_path.startswith(('http://', 'https://', '/file/')):
+            return match.group(0)
+        
+        # Resolve relative paths
+        if link_path.startswith('/'):
+            # Absolute path from content root
+            resolved_path = link_path.lstrip('/')
+        else:
+            # Relative path - resolve it relative to the file's directory
+            if file_dir:
+                resolved_path = os.path.normpath(os.path.join(file_dir, link_path))
+            else:
+                resolved_path = link_path
+        
+        # Ensure forward slashes for URL
+        resolved_path = resolved_path.replace(os.sep, '/')
+        file_url = f"/file/{resolved_path}"
+        
+        return f"[{link_text}]({file_url})"
+    
+    # Replace all markdown link references to .eml files
+    md_content = re.sub(r'\[([^\]]+)\]\(([^\)]+\.eml)\)', replace_link_path, md_content)
+    return md_content
+
 def build_directory_tree():
     """Build a hierarchical tree of markdown files organized by directory."""
     tree = {}
@@ -370,6 +409,60 @@ def serve_image(filepath):
         logger.error(f"Error serving image {file_path}: {e}")
         return f"Error serving image: {e}", 500
 
+@app.route('/file/<path:filepath>')
+def serve_file(filepath):
+    """Serve files from content directory, with base64 decoding for .eml files if needed."""
+    # Security: prevent directory traversal
+    if '..' in filepath or filepath.startswith('/'):
+        return "Invalid path", 400
+    
+    file_path = os.path.join(CONTENT_DIR, filepath)
+    
+    # Ensure the file is within the content directory
+    try:
+        file_path = os.path.realpath(file_path)
+        content_path = os.path.realpath(CONTENT_DIR)
+        if not file_path.startswith(content_path):
+            return "Access denied", 403
+    except Exception:
+        return "Invalid path", 400
+    
+    if not os.path.exists(file_path):
+        logger.warning(f"File not found: {file_path}")
+        return "File not found", 404
+    
+    try:
+        # Check if this is an .eml file
+        if file_path.lower().endswith('.eml'):
+            with open(file_path, 'r', encoding='utf-8', errors='ignore') as f:
+                content = f.read()
+            
+            # Check if content is base64 encoded
+            # Base64 content is ASCII and contains only base64 characters
+            is_base64 = False
+            try:
+                if content.strip() and all(c in 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n\r' for c in content):
+                    decoded = base64.b64decode(content, validate=True).decode('utf-8', errors='ignore')
+                    # If it looks like an email (has headers), use decoded version
+                    if 'From:' in decoded or 'To:' in decoded or 'Subject:' in decoded:
+                        content = decoded
+                        is_base64 = True
+            except Exception:
+                # Not valid base64, use original content
+                pass
+            
+            # Return as text/plain for viewing in browser
+            response = make_response(content)
+            response.headers['Content-Type'] = 'text/plain; charset=utf-8'
+            response.headers['Content-Disposition'] = f'inline; filename="{os.path.basename(file_path)}"'
+            return response
+        else:
+            # For other file types, just serve as-is
+            return send_file(file_path)
+    except Exception as e:
+        logger.error(f"Error serving file {file_path}: {e}")
+        return f"Error serving file: {e}", 500
+
 @app.route('/api/search', methods=['GET'])
 def search():
     """Search markdown files."""
@@ -462,6 +555,9 @@ def view_file(filepath):
         # Rewrite image paths to be served by Flask
         md_content = rewrite_image_paths(md_content, filepath)
         
+        # Rewrite .eml file links to be served by Flask with base64 decoding
+        md_content = rewrite_eml_file_links(md_content, filepath)
+        
         # Normalize list indentation for proper markdown parsing
         md_content = normalize_list_indentation(md_content)