"""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. | |
""" | |
import inspect | |
import keyword | |
import linecache | |
import os | |
import pydoc | |
import sys | |
import tempfile | |
import time | |
import tokenize | |
import traceback | |
import types | |
def reset(): | |
"""Return a string that resets the CGI and browser to a known state.""" | |
return '''<!--: spam | |
Content-Type: text/html | |
<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 | |
def small(text): | |
if text: | |
return '<small>' + text + '</small>' | |
else: | |
return '' | |
def strong(text): | |
if text: | |
return '<strong>' + text + '</strong>' | |
else: | |
return '' | |
def grey(text): | |
if text: | |
return '<font color="#909090">' + text + '</font>' | |
else: | |
return '' | |
def lookup(name, frame, locals): | |
"""Find the value for a given name in the given environment.""" | |
if name in locals: | |
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({}): | |
if name in builtins: | |
return 'builtin', builtins[name] | |
else: | |
if hasattr(builtins, name): | |
return 'builtin', getattr(builtins, name) | |
return None, __UNDEF__ | |
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 lasttoken == '.': | |
if parent is not __UNDEF__: | |
value = getattr(parent, token, __UNDEF__) | |
vars.append((prefix + token, prefix, value)) | |
else: | |
where, value = lookup(token, frame, locals) | |
vars.append((token, where, value)) | |
elif token == '.': | |
prefix += lasttoken + '.' | |
parent = value | |
else: | |
parent, prefix = None, '' | |
lasttoken = token | |
return vars | |
def html(einfo, context=5): | |
"""Return a nice HTML document describing a given traceback.""" | |
etype, evalue, etb = einfo | |
if type(etype) is types.ClassType: | |
etype = etype.__name__ | |
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>' | |
frames = [] | |
records = inspect.getinnerframes(etb, context) | |
for frame, file, lnum, func, lines, index in records: | |
if file: | |
file = os.path.abspath(file) | |
link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file)) | |
else: | |
file = link = '?' | |
args, varargs, varkw, locals = inspect.getargvalues(frame) | |
call = '' | |
if func != '?': | |
call = 'in ' + strong(func) + \ | |
inspect.formatargvalues(args, varargs, varkw, locals, | |
formatvalue=lambda value: '=' + pydoc.html.repr(value)) | |
highlight = {} | |
def reader(lnum=[lnum]): | |
highlight[lnum[0]] = 1 | |
try: return linecache.getline(file, lnum[0]) | |
finally: lnum[0] += 1 | |
vars = scanvars(reader, frame, locals) | |
rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' % | |
('<big> </big>', link, call)] | |
if index is not None: | |
i = lnum - index | |
for line in lines: | |
num = small(' ' * (5-len(str(i))) + str(i)) + ' ' | |
if i in highlight: | |
line = '<tt>=>%s%s</tt>' % (num, pydoc.html.preformat(line)) | |
rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line) | |
else: | |
line = '<tt> %s%s</tt>' % (num, pydoc.html.preformat(line)) | |
rows.append('<tr><td>%s</td></tr>' % grey(line)) | |
i += 1 | |
done, dump = {}, [] | |
for name, where, value in vars: | |
if name in done: continue | |
done[name] = 1 | |
if value is not __UNDEF__: | |
if where in ('global', 'builtin'): | |
name = ('<em>%s</em> ' % where) + strong(name) | |
elif where == 'local': | |
name = strong(name) | |
else: | |
name = where + strong(name.split('.')[-1]) | |
dump.append('%s = %s' % (name, pydoc.html.repr(value))) | |
else: | |
dump.append(name + ' <em>undefined</em>') | |
rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump)))) | |
frames.append(''' | |
<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 isinstance(evalue, BaseException): | |
for name in dir(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: | |
%s | |
--> | |
''' % pydoc.html.escape( | |
''.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 type(etype) is types.ClassType: | |
etype = etype.__name__ | |
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. | |
''' | |
frames = [] | |
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) | |
call = '' | |
if func != '?': | |
call = 'in ' + func + \ | |
inspect.formatargvalues(args, varargs, varkw, locals, | |
formatvalue=lambda value: '=' + pydoc.text.repr(value)) | |
highlight = {} | |
def reader(lnum=[lnum]): | |
highlight[lnum[0]] = 1 | |
try: return linecache.getline(file, lnum[0]) | |
finally: lnum[0] += 1 | |
vars = scanvars(reader, frame, locals) | |
rows = [' %s %s' % (file, call)] | |
if index is not None: | |
i = lnum - index | |
for line in lines: | |
num = '%5d ' % i | |
rows.append(num+line.rstrip()) | |
i += 1 | |
done, dump = {}, [] | |
for name, where, value in vars: | |
if name in done: continue | |
done[name] = 1 | |
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))) | |
else: | |
dump.append(name + ' undefined') | |
rows.append('\n'.join(dump)) | |
frames.append('\n%s\n' % '\n'.join(rows)) | |
exception = ['%s: %s' % (str(etype), str(evalue))] | |
if isinstance(evalue, BaseException): | |
for name in dir(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 | |
the original traceback: | |
%s | |
''' % ''.join(traceback.format_exception(etype, evalue, etb)) | |
class Hook: | |
"""A hook to replace sys.excepthook that shows tracebacks in HTML.""" | |
def __init__(self, display=1, logdir=None, context=5, file=None, | |
format="html"): | |
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 | |
self.format = format | |
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": | |
self.file.write(reset()) | |
formatter = (self.format=="html") and html or text | |
plain = False | |
try: | |
doc = formatter(info, self.context) | |
except: # just in case something goes wrong | |
doc = ''.join(traceback.format_exception(*info)) | |
plain = True | |
if self.display: | |
if plain: | |
doc = doc.replace('&', '&').replace('<', '<') | |
self.file.write('<pre>' + doc + '</pre>\n') | |
else: | |
self.file.write(doc + '\n') | |
else: | |
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) | |
try: | |
file = os.fdopen(fd, 'w') | |
file.write(doc) | |
file.close() | |
msg = '<p> %s contains the description of this error.' % path | |
except: | |
msg = '<p> Tried to save traceback to %s, but failed.' % path | |
self.file.write(msg + '\n') | |
try: | |
self.file.flush() | |
except: pass | |
handler = Hook().handle | |
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) |