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Skip Montanaro364ca402003-06-17 12:58:31 +00001"""More comprehensive traceback formatting for Python scripts.
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +00002
3To enable this module, do:
4
5 import cgitb; cgitb.enable()
6
Skip Montanaro364ca402003-06-17 12:58:31 +00007at the top of your script. The optional arguments to enable() are:
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +00008
9 display - if true, tracebacks are displayed in the web browser
10 logdir - if set, tracebacks are written to files in this directory
Ka-Ping Yee83205972001-08-21 06:53:01 +000011 context - number of lines of source code to show for each stack frame
Tim Peters478c1052003-06-29 05:46:54 +000012 format - 'text' or 'html' controls the output format
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000013
Skip Montanaro364ca402003-06-17 12:58:31 +000014By default, tracebacks are displayed but not saved, the context is 5 lines
15and the output format is 'html' (for backwards compatibility with the
16original use of this module)
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000017
18Alternatively, if you have caught an exception and want cgitb to display it
Skip Montanaro364ca402003-06-17 12:58:31 +000019for you, call cgitb.handler(). The optional argument to handler() is a
203-item tuple (etype, evalue, etb) just like the value of sys.exc_info().
21The default handler displays output as HTML.
22"""
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000023
24__author__ = 'Ka-Ping Yee'
25__version__ = '$Revision$'
26
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +000027import sys
28
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000029def reset():
30 """Return a string that resets the CGI and browser to a known state."""
31 return '''<!--: spam
32Content-Type: text/html
33
Ka-Ping Yee83205972001-08-21 06:53:01 +000034<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> -->
35<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> -->
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000036</font> </font> </font> </script> </object> </blockquote> </pre>
37</table> </table> </table> </table> </table> </font> </font> </font>'''
38
Ka-Ping Yee83205972001-08-21 06:53:01 +000039__UNDEF__ = [] # a special sentinel object
40def small(text): return '<small>' + text + '</small>'
41def strong(text): return '<strong>' + text + '</strong>'
42def grey(text): return '<font color="#909090">' + text + '</font>'
43
44def lookup(name, frame, locals):
45 """Find the value for a given name in the given environment."""
46 if name in locals:
47 return 'local', locals[name]
48 if name in frame.f_globals:
49 return 'global', frame.f_globals[name]
Ka-Ping Yee711cad72002-06-26 07:10:56 +000050 if '__builtins__' in frame.f_globals:
51 builtins = frame.f_globals['__builtins__']
52 if type(builtins) is type({}):
53 if name in builtins:
54 return 'builtin', builtins[name]
55 else:
56 if hasattr(builtins, name):
57 return 'builtin', getattr(builtins, name)
Ka-Ping Yee83205972001-08-21 06:53:01 +000058 return None, __UNDEF__
59
60def scanvars(reader, frame, locals):
61 """Scan one logical line of Python and look up values of variables used."""
62 import tokenize, keyword
63 vars, lasttoken, parent, prefix = [], None, None, ''
64 for ttype, token, start, end, line in tokenize.generate_tokens(reader):
65 if ttype == tokenize.NEWLINE: break
66 if ttype == tokenize.NAME and token not in keyword.kwlist:
67 if lasttoken == '.':
68 if parent is not __UNDEF__:
69 value = getattr(parent, token, __UNDEF__)
70 vars.append((prefix + token, prefix, value))
71 else:
72 where, value = lookup(token, frame, locals)
73 vars.append((token, where, value))
74 elif token == '.':
75 prefix += lasttoken + '.'
76 parent = value
77 else:
78 parent, prefix = None, ''
79 lasttoken = token
80 return vars
81
82def html((etype, evalue, etb), context=5):
83 """Return a nice HTML document describing a given traceback."""
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +000084 import os, types, time, traceback, linecache, inspect, pydoc
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000085
86 if type(etype) is types.ClassType:
87 etype = etype.__name__
88 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
89 date = time.ctime(time.time())
Ka-Ping Yee83205972001-08-21 06:53:01 +000090 head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading(
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000091 '<big><big><strong>%s</strong></big></big>' % str(etype),
Ka-Ping Yee83205972001-08-21 06:53:01 +000092 '#ffffff', '#6622aa', pyver + '<br>' + date) + '''
93<p>A problem occurred in a Python script. Here is the sequence of
94function calls leading up to the error, in the order they occurred.'''
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000095
Ka-Ping Yee83205972001-08-21 06:53:01 +000096 indent = '<tt>' + small('&nbsp;' * 5) + '&nbsp;</tt>'
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000097 frames = []
98 records = inspect.getinnerframes(etb, context)
99 for frame, file, lnum, func, lines, index in records:
100 file = file and os.path.abspath(file) or '?'
Ka-Ping Yee83205972001-08-21 06:53:01 +0000101 link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file))
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000102 args, varargs, varkw, locals = inspect.getargvalues(frame)
Ka-Ping Yee83205972001-08-21 06:53:01 +0000103 call = ''
104 if func != '?':
105 call = 'in ' + strong(func) + \
106 inspect.formatargvalues(args, varargs, varkw, locals,
107 formatvalue=lambda value: '=' + pydoc.html.repr(value))
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000108
Ka-Ping Yee83205972001-08-21 06:53:01 +0000109 highlight = {}
110 def reader(lnum=[lnum]):
111 highlight[lnum[0]] = 1
112 try: return linecache.getline(file, lnum[0])
113 finally: lnum[0] += 1
114 vars = scanvars(reader, frame, locals)
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000115
Ka-Ping Yee83205972001-08-21 06:53:01 +0000116 rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' %
117 ('<big>&nbsp;</big>', link, call)]
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000118 if index is not None:
119 i = lnum - index
120 for line in lines:
Ka-Ping Yee83205972001-08-21 06:53:01 +0000121 num = small('&nbsp;' * (5-len(str(i))) + str(i)) + '&nbsp;'
122 line = '<tt>%s%s</tt>' % (num, pydoc.html.preformat(line))
123 if i in highlight:
124 rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line)
125 else:
126 rows.append('<tr><td>%s</td></tr>' % grey(line))
127 i += 1
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000128
Ka-Ping Yee83205972001-08-21 06:53:01 +0000129 done, dump = {}, []
130 for name, where, value in vars:
131 if name in done: continue
132 done[name] = 1
133 if value is not __UNDEF__:
Ka-Ping Yee711cad72002-06-26 07:10:56 +0000134 if where in ['global', 'builtin']:
135 name = ('<em>%s</em> ' % where) + strong(name)
136 elif where == 'local':
137 name = strong(name)
138 else:
139 name = where + strong(name.split('.')[-1])
Ka-Ping Yee83205972001-08-21 06:53:01 +0000140 dump.append('%s&nbsp;= %s' % (name, pydoc.html.repr(value)))
141 else:
142 dump.append(name + ' <em>undefined</em>')
143
144 rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump))))
145 frames.append('''<p>
146<table width="100%%" cellspacing=0 cellpadding=0 border=0>
147%s</table>''' % '\n'.join(rows))
148
149 exception = ['<p>%s: %s' % (strong(str(etype)), str(evalue))]
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000150 if type(evalue) is types.InstanceType:
151 for name in dir(evalue):
Ka-Ping Yee711cad72002-06-26 07:10:56 +0000152 if name[:1] == '_': continue
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000153 value = pydoc.html.repr(getattr(evalue, name))
154 exception.append('\n<br>%s%s&nbsp;=\n%s' % (indent, name, value))
155
156 import traceback
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000157 return head + ''.join(frames) + ''.join(exception) + '''
158
159
Ka-Ping Yee83205972001-08-21 06:53:01 +0000160<!-- The above is a description of an error in a Python program, formatted
161 for a Web browser because the 'cgitb' module was enabled. In case you
162 are not reading this in a Web browser, here is the original traceback:
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000163
164%s
165-->
Ka-Ping Yee83205972001-08-21 06:53:01 +0000166''' % ''.join(traceback.format_exception(etype, evalue, etb))
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000167
Skip Montanaro364ca402003-06-17 12:58:31 +0000168def text((etype, evalue, etb), context=5):
169 """Return a plain text document describing a given traceback."""
170 import os, types, time, traceback, linecache, inspect, pydoc
171
172 if type(etype) is types.ClassType:
173 etype = etype.__name__
174 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
175 date = time.ctime(time.time())
176 head = "%s\n%s\n%s\n" % (str(etype), pyver, date) + '''
177A problem occurred in a Python script. Here is the sequence of
178function calls leading up to the error, in the order they occurred.
179'''
180
181 frames = []
182 records = inspect.getinnerframes(etb, context)
183 for frame, file, lnum, func, lines, index in records:
184 file = file and os.path.abspath(file) or '?'
185 args, varargs, varkw, locals = inspect.getargvalues(frame)
186 call = ''
187 if func != '?':
188 call = 'in ' + func + \
189 inspect.formatargvalues(args, varargs, varkw, locals,
190 formatvalue=lambda value: '=' + pydoc.text.repr(value))
191
192 highlight = {}
193 def reader(lnum=[lnum]):
194 highlight[lnum[0]] = 1
195 try: return linecache.getline(file, lnum[0])
196 finally: lnum[0] += 1
197 vars = scanvars(reader, frame, locals)
198
199 rows = [' %s %s' % (file, call)]
200 if index is not None:
201 i = lnum - index
202 for line in lines:
203 num = '%5d ' % i
204 rows.append(num+line.rstrip())
205 i += 1
206
207 done, dump = {}, []
208 for name, where, value in vars:
209 if name in done: continue
210 done[name] = 1
211 if value is not __UNDEF__:
212 if where == 'global': name = 'global ' + name
213 elif where == 'local': name = name
214 else: name = where + name.split('.')[-1]
215 dump.append('%s = %s' % (name, pydoc.text.repr(value)))
216 else:
217 dump.append(name + ' undefined')
218
219 rows.append('\n'.join(dump))
220 frames.append('\n%s\n' % '\n'.join(rows))
221
222 exception = ['%s: %s' % (str(etype), str(evalue))]
223 if type(evalue) is types.InstanceType:
224 for name in dir(evalue):
225 value = pydoc.text.repr(getattr(evalue, name))
226 exception.append('\n%s%s = %s' % (" "*4, name, value))
227
228 import traceback
229 return head + ''.join(frames) + ''.join(exception) + '''
230
231The above is a description of an error in a Python program. Here is
232the original traceback:
233
234%s
235''' % ''.join(traceback.format_exception(etype, evalue, etb))
236
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000237class Hook:
Ka-Ping Yee83205972001-08-21 06:53:01 +0000238 """A hook to replace sys.excepthook that shows tracebacks in HTML."""
239
Skip Montanaro364ca402003-06-17 12:58:31 +0000240 def __init__(self, display=1, logdir=None, context=5, file=None,
241 format="html"):
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000242 self.display = display # send tracebacks to browser if true
243 self.logdir = logdir # log tracebacks to files if not None
Ka-Ping Yee83205972001-08-21 06:53:01 +0000244 self.context = context # number of source code lines per frame
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000245 self.file = file or sys.stdout # place to send the output
Skip Montanaro364ca402003-06-17 12:58:31 +0000246 self.format = format
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000247
248 def __call__(self, etype, evalue, etb):
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000249 self.handle((etype, evalue, etb))
250
251 def handle(self, info=None):
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000252 info = info or sys.exc_info()
Skip Montanaro364ca402003-06-17 12:58:31 +0000253 if self.format == "html":
254 self.file.write(reset())
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000255
Skip Montanaro364ca402003-06-17 12:58:31 +0000256 formatter = (self.format=="html") and html or text
257 plain = False
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000258 try:
Skip Montanaro364ca402003-06-17 12:58:31 +0000259 doc = formatter(info, self.context)
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000260 except: # just in case something goes wrong
261 import traceback
Skip Montanaro364ca402003-06-17 12:58:31 +0000262 doc = ''.join(traceback.format_exception(*info))
263 plain = True
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000264
265 if self.display:
Skip Montanaro364ca402003-06-17 12:58:31 +0000266 if plain:
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000267 doc = doc.replace('&', '&amp;').replace('<', '&lt;')
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000268 self.file.write('<pre>' + doc + '</pre>\n')
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000269 else:
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000270 self.file.write(doc + '\n')
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000271 else:
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000272 self.file.write('<p>A problem occurred in a Python script.\n')
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000273
274 if self.logdir is not None:
Ka-Ping Yee83205972001-08-21 06:53:01 +0000275 import os, tempfile
Skip Montanaro364ca402003-06-17 12:58:31 +0000276 suffix = ['.html', '.txt'][self.format=="html"]
277 (fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir)
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000278 try:
Guido van Rossum3b0a3292002-08-09 16:38:32 +0000279 file = os.fdopen(fd, 'w')
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000280 file.write(doc)
281 file.close()
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000282 msg = '<p> %s contains the description of this error.' % path
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000283 except:
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000284 msg = '<p> Tried to save traceback to %s, but failed.' % path
285 self.file.write(msg + '\n')
286 try:
287 self.file.flush()
288 except: pass
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000289
290handler = Hook().handle
Skip Montanaro364ca402003-06-17 12:58:31 +0000291def enable(display=1, logdir=None, context=5, format="html"):
Ka-Ping Yee83205972001-08-21 06:53:01 +0000292 """Install an exception handler that formats tracebacks as HTML.
293
294 The optional argument 'display' can be set to 0 to suppress sending the
295 traceback to the browser, and 'logdir' can be set to a directory to cause
296 tracebacks to be written to files there."""
Skip Montanaro364ca402003-06-17 12:58:31 +0000297 sys.excepthook = Hook(display=display, logdir=logdir,
298 context=context, format=format)