| """Handle exceptions in CGI scripts by formatting tracebacks into nice HTML. |
| |
| To enable this module, do: |
| |
| import cgitb; cgitb.enable() |
| |
| at the top of your CGI 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 |
| |
| By default, tracebacks are displayed but not saved, and context is 5. |
| |
| 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().""" |
| |
| __author__ = 'Ka-Ping Yee' |
| __version__ = '$Revision$' |
| |
| import sys |
| |
| 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): return '<small>' + text + '</small>' |
| def strong(text): return '<strong>' + text + '</strong>' |
| def grey(text): return '<font color="#909090">' + text + '</font>' |
| |
| 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] |
| return None, __UNDEF__ |
| |
| def scanvars(reader, frame, locals): |
| """Scan one logical line of Python and look up values of variables used.""" |
| import tokenize, keyword |
| vars, lasttoken, parent, prefix = [], None, None, '' |
| 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((etype, evalue, etb), context=5): |
| """Return a nice HTML document describing a given traceback.""" |
| import os, types, time, traceback, linecache, inspect, pydoc |
| |
| 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><strong>%s</strong></big></big>' % 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.''' |
| |
| indent = '<tt>' + small(' ' * 5) + ' </tt>' |
| frames = [] |
| records = inspect.getinnerframes(etb, context) |
| for frame, file, lnum, func, lines, index in records: |
| file = file and os.path.abspath(file) or '?' |
| link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file)) |
| 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)) + ' ' |
| line = '<tt>%s%s</tt>' % (num, pydoc.html.preformat(line)) |
| if i in highlight: |
| rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line) |
| else: |
| 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 == 'global': name = '<em>global</em> ' + 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('''<p> |
| <table width="100%%" cellspacing=0 cellpadding=0 border=0> |
| %s</table>''' % '\n'.join(rows)) |
| |
| exception = ['<p>%s: %s' % (strong(str(etype)), str(evalue))] |
| if type(evalue) is types.InstanceType: |
| for name in dir(evalue): |
| value = pydoc.html.repr(getattr(evalue, name)) |
| exception.append('\n<br>%s%s =\n%s' % (indent, name, value)) |
| |
| import traceback |
| 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 |
| --> |
| ''' % ''.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): |
| 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() |
| self.file.write(reset()) |
| |
| try: |
| text, doc = 0, html(info, self.context) |
| except: # just in case something goes wrong |
| import traceback |
| text, doc = 1, ''.join(traceback.format_exception(*info)) |
| |
| if self.display: |
| if text: |
| 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: |
| import os, tempfile |
| name = tempfile.mktemp(['.html', '.txt'][text]) |
| path = os.path.join(self.logdir, os.path.basename(name)) |
| try: |
| file = open(path, '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): |
| """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, logdir, context) |