Use cgitb instead of DIY traceback

sanic/exceptions.py

@@ -77,16 +77,6 @@ TRACEBACK_WRAPPER_HTML = '''
     </html>
 '''
 
-TRACEBACK_LINE_HTML = '''
-    <div class="frame-line">
-        <p class="frame-descriptor">
-            File {0.filename}, line <i>{0.lineno}</i>,
-            in <code><b>{0.name}</b></code>
-        </p>
-        <p class="frame-code"><code>{0.line}</code></p>
-    </div>
-'''
-
 INTERNAL_SERVER_ERROR_HTML = '''
     <h1>Internal Server Error</h1>
     <p>

sanic/handlers.py

@@ -1,5 +1,7 @@
 import sys
 from traceback import format_exc, extract_tb
+import cgitb
+from io import StringIO
 
 from sanic.exceptions import (
     ContentRangeError,
@@ -7,13 +9,19 @@ from sanic.exceptions import (
     INTERNAL_SERVER_ERROR_HTML,
     InvalidRangeType,
     SanicException,
-    TRACEBACK_LINE_HTML,
     TRACEBACK_STYLE,
     TRACEBACK_WRAPPER_HTML)
 from sanic.log import log
 from sanic.response import text, html
 
 
+def format_cgitb(format, info=None):
+    s = StringIO()
+    cgitb.Hook(file=s, format=format).handle()
+    tb = s.getvalue()
+    return tb
+
+
 class ErrorHandler:
     handlers = None
 
@@ -23,17 +31,12 @@ class ErrorHandler:
 
     def _render_traceback_html(self, exception, request):
         exc_type, exc_value, tb = sys.exc_info()
-        frames = extract_tb(tb)
-
-        frame_html = []
-        for frame in frames:
-            frame_html.append(TRACEBACK_LINE_HTML.format(frame))
-
+        frame_html = format_cgitb('html')
         return TRACEBACK_WRAPPER_HTML.format(
             style=TRACEBACK_STYLE,
             exc_name=exc_type.__name__,
             exc_value=exc_value,
-            frame_html=''.join(frame_html),
+            frame_html=frame_html,
             uri=request.url)
 
     def add(self, exception, handler):