"""More comprehensive traceback formatting for Python scripts.
To enable this module, do:
import cgitb; cgitb.enable()
at the top of your script. The optional arguments to enable() are:
display - if true, tracebacks are displayed in the web browser
logdir - if set, tracebacks are written to files in this directory
context - number of lines of source code to show for each stack frame
format - 'text' or 'html' controls the output format
By default, tracebacks are displayed but not saved, the context is 5 lines
and the output format is 'html' (for backwards compatibility with the
original use of this module)
Alternatively, if you have caught an exception and want cgitb to display it
for you, call cgitb.handler(). The optional argument to handler() is a
3-item tuple (etype, evalue, etb) just like the value of sys.exc_info().
The default handler displays output as HTML.
"""Return a string that resets the CGI and browser to a known state."""
<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> -->
<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> -->
</font> </font> </font> </script> </object> </blockquote> </pre>
</table> </table> </table> </table> </table> </font> </font> </font>'''
__UNDEF__ = [] # a special sentinel object
return '<small>' + text + '</small>'
return '<strong>' + text + '</strong>'
return '<font color="#909090">' + text + '</font>'
def lookup(name, frame, locals):
"""Find the value for a given name in the given environment."""
return 'local', locals[name]
if name in frame.f_globals:
return 'global', frame.f_globals[name]
if '__builtins__' in frame.f_globals:
builtins = frame.f_globals['__builtins__']
if type(builtins) is type({}):
return 'builtin', builtins[name]
if hasattr(builtins, name):
return 'builtin', getattr(builtins, name)
def scanvars(reader, frame, locals):
"""Scan one logical line of Python and look up values of variables used."""
vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__
for ttype, token, start, end, line in tokenize.generate_tokens(reader):
if ttype == tokenize.NEWLINE: break
if ttype == tokenize.NAME and token not in keyword.kwlist:
if parent is not __UNDEF__:
value = getattr(parent, token, __UNDEF__)
vars.append((prefix + token, prefix, value))
where, value = lookup(token, frame, locals)
vars.append((token, where, value))
prefix += lasttoken + '.'
parent, prefix = None, ''
def html(einfo, context=5):
"""Return a nice HTML document describing a given traceback."""
etype, evalue, etb = einfo
if isinstance(etype, type):
pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
date = time.ctime(time.time())
head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading(
'<big><big>%s</big></big>' %
strong(pydoc.html.escape(str(etype))),
'#ffffff', '#6622aa', pyver + '<br>' + date) + '''
<p>A problem occurred in a Python script. Here is the sequence of
function calls leading up to the error, in the order they occurred.</p>'''
indent = '<tt>' + small(' ' * 5) + ' </tt>'
records = inspect.getinnerframes(etb, context)
for frame, file, lnum, func, lines, index in records:
file = os.path.abspath(file)
link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file))
args, varargs, varkw, locals = inspect.getargvalues(frame)
call = 'in ' + strong(pydoc.html.escape(func)) + \
inspect.formatargvalues(args, varargs, varkw, locals,
formatvalue=lambda value: '=' + pydoc.html.repr(value))
try: return linecache.getline(file, lnum[0])
vars = scanvars(reader, frame, locals)
rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' %
('<big> </big>', link, call)]
num = small(' ' * (5-len(str(i))) + str(i)) + ' '
line = '<tt>=>%s%s</tt>' % (num, pydoc.html.preformat(line))
rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line)
line = '<tt> %s%s</tt>' % (num, pydoc.html.preformat(line))
rows.append('<tr><td>%s</td></tr>' % grey(line))
for name, where, value in vars:
if name in done: continue
if value is not __UNDEF__:
if where in ('global', 'builtin'):
name = ('<em>%s</em> ' % where) + strong(name)
name = where + strong(name.split('.')[-1])
dump.append('%s = %s' % (name, pydoc.html.repr(value)))
dump.append(name + ' <em>undefined</em>')
rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump))))
<table width="100%%" cellspacing=0 cellpadding=0 border=0>
%s</table>''' % '\n'.join(rows))
exception = ['<p>%s: %s' % (strong(pydoc.html.escape(str(etype))),
pydoc.html.escape(str(evalue)))]
if name[:1] == '_': continue
value = pydoc.html.repr(getattr(evalue, name))
exception.append('\n<br>%s%s =\n%s' % (indent, name, value))
return head + ''.join(frames) + ''.join(exception) + '''
<!-- The above is a description of an error in a Python program, formatted
for a Web browser because the 'cgitb' module was enabled. In case you
are not reading this in a Web browser, here is the original traceback:
''.join(traceback.format_exception(etype, evalue, etb)))
def text(einfo, context=5):
"""Return a plain text document describing a given traceback."""
etype, evalue, etb = einfo
if isinstance(etype, type):
pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
date = time.ctime(time.time())
head = "%s\n%s\n%s\n" % (str(etype), pyver, date) + '''
A problem occurred in a Python script. Here is the sequence of
function calls leading up to the error, in the order they occurred.
records = inspect.getinnerframes(etb, context)
for frame, file, lnum, func, lines, index in records:
file = file and os.path.abspath(file) or '?'
args, varargs, varkw, locals = inspect.getargvalues(frame)
inspect.formatargvalues(args, varargs, varkw, locals,
formatvalue=lambda value: '=' + pydoc.text.repr(value))
try: return linecache.getline(file, lnum[0])
vars = scanvars(reader, frame, locals)
rows = [' %s %s' % (file, call)]
rows.append(num+line.rstrip())
for name, where, value in vars:
if name in done: continue
if value is not __UNDEF__:
if where == 'global': name = 'global ' + name
elif where != 'local': name = where + name.split('.')[-1]
dump.append('%s = %s' % (name, pydoc.text.repr(value)))
dump.append(name + ' undefined')
rows.append('\n'.join(dump))
frames.append('\n%s\n' % '\n'.join(rows))
exception = ['%s: %s' % (str(etype), str(evalue))]
value = pydoc.text.repr(getattr(evalue, name))
exception.append('\n%s%s = %s' % (" "*4, name, value))
return head + ''.join(frames) + ''.join(exception) + '''
The above is a description of an error in a Python program. Here is
''' % ''.join(traceback.format_exception(etype, evalue, etb))
"""A hook to replace sys.excepthook that shows tracebacks in HTML."""
def __init__(self, display=1, logdir=None, context=5, file=None,
self.display = display # send tracebacks to browser if true
self.logdir = logdir # log tracebacks to files if not None
self.context = context # number of source code lines per frame
self.file = file or sys.stdout # place to send the output
def __call__(self, etype, evalue, etb):
self.handle((etype, evalue, etb))
def handle(self, info=None):
info = info or sys.exc_info()
if self.format == "html":
formatter = (self.format=="html") and html or text
doc = formatter(info, self.context)
except: # just in case something goes wrong
doc = ''.join(traceback.format_exception(*info))
doc = pydoc.html.escape(doc)
self.file.write('<pre>' + doc + '</pre>\n')
self.file.write(doc + '\n')
self.file.write('<p>A problem occurred in a Python script.\n')
if self.logdir is not None:
suffix = ['.txt', '.html'][self.format=="html"]
(fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir)
with os.fdopen(fd, 'w') as file:
msg = '%s contains the description of this error.' % path
msg = 'Tried to save traceback to %s, but failed.' % path
if self.format == 'html':
self.file.write('<p>%s</p>\n' % msg)
self.file.write(msg + '\n')
def enable(display=1, logdir=None, context=5, format="html"):
"""Install an exception handler that formats tracebacks as HTML.
The optional argument 'display' can be set to 0 to suppress sending the
traceback to the browser, and 'logdir' can be set to a directory to cause
tracebacks to be written to files there."""
sys.excepthook = Hook(display=display, logdir=logdir,
context=context, format=format)