fix(preview): improve file content handling

Refined how file content is displayed in the preview, distinguishing and safely handling text, Markdown, and image files. Introduced proper escaping for non-Markdown text files to prevent potential security issues.

src/gitcloak/app.py

@@ -5,6 +5,7 @@ import logging
 import os
 import base64
 import mimetypes
+import html
 from pathlib import Path
 
 logger = logging.getLogger(__name__)
@@ -164,9 +165,15 @@ def preview_file(owner: str, repo: str, file_path: str):
         file_content = git.get_file_content(file_path)
 
         content_type, _ = mimetypes.guess_type(file_path)
-        is_text = content_type and content_type.startswith("text")
+
+        try:
+            file_content.decode("utf-8")
+            is_text = True
+        except UnicodeDecodeError:
+            is_text = False
+
         is_image = content_type and content_type.startswith("image")
-        is_safe = False
+        is_raw = True
 
         if content_type == "text/markdown":
             base_url = f"/{owner}/{repo}/raw/main/{'/'.join(file_path.split('/')[:-1])}".rstrip(
@@ -175,7 +182,11 @@ def preview_file(owner: str, repo: str, file_path: str):
             file_content = RelativeURLRewriter(base_url).convert(
                 file_content.decode("utf-8")
             )
-            is_safe = True
+            is_raw = False
+
+        elif is_text:
+            file_content = file_content.decode("utf-8")
+            file_content = html.escape(file_content)
 
         if is_image:
             file_content = base64.b64encode(file_content).decode("utf-8")
@@ -188,7 +199,7 @@ def preview_file(owner: str, repo: str, file_path: str):
             file_content=file_content,
             is_text=is_text,
             is_image=is_image,
-            is_safe=is_safe,
+            is_raw=is_raw,
         )
     except Exception as e:
         logger.error(f"Error previewing file {file_path} in {owner}/{repo}: {e}")

src/gitcloak/templates/preview.html

@@ -14,10 +14,10 @@
         <div class="card">
             <div class="card-body">
                 {% if is_text %}
-                    {% if is_safe %}
-                        <div>{{ file_content | safe }}</div>
+                    {% if is_raw %}
+                        <pre>{{ file_content | safe }}</pre>
                     {% else %}
-                        <pre>{{ file_content }}</pre>
+                        <div>{{ file_content | safe }}</div>
                     {% endif %}
                 {% elif is_image %}
                     <img src="data:image/png;base64,{{ file_content }}" class="img-fluid" alt="{{ file_path }}">