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- """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
- 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 isinstance(etype, type):
- 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)))]
- 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 isinstance(etype, type):
- 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))]
- 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:
- with os.fdopen(fd, 'w') as file:
- file.write(doc)
- msg = '%s contains the description of this error.' % path
- except:
- msg = 'Tried to save traceback to %s, but failed.' % path
- if self.format == 'html':
- self.file.write('<p>%s</p>\n' % msg)
- else:
- 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)
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