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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.
Brett Cannonf47e84c2009-04-01 16:06:01 +000022
Skip Montanaro364ca402003-06-17 12:58:31 +000023"""
Brett Cannonf47e84c2009-04-01 16:06:01 +000024import inspect
25import keyword
26import linecache
27import os
28import pydoc
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +000029import sys
Brett Cannonf47e84c2009-04-01 16:06:01 +000030import tempfile
31import time
32import tokenize
33import traceback
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +000034
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000035def reset():
36 """Return a string that resets the CGI and browser to a known state."""
37 return '''<!--: spam
38Content-Type: text/html
39
Ka-Ping Yee83205972001-08-21 06:53:01 +000040<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> -->
41<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> -->
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +000042</font> </font> </font> </script> </object> </blockquote> </pre>
43</table> </table> </table> </table> </table> </font> </font> </font>'''
44
Ka-Ping Yee83205972001-08-21 06:53:01 +000045__UNDEF__ = [] # a special sentinel object
Andrew M. Kuchling5fcefdb2004-07-10 14:14:51 +000046def small(text):
47 if text:
48 return '<small>' + text + '</small>'
49 else:
50 return ''
Tim Peters182b5ac2004-07-18 06:16:08 +000051
Andrew M. Kuchling5fcefdb2004-07-10 14:14:51 +000052def strong(text):
53 if text:
54 return '<strong>' + text + '</strong>'
55 else:
56 return ''
Tim Peters182b5ac2004-07-18 06:16:08 +000057
Andrew M. Kuchling5fcefdb2004-07-10 14:14:51 +000058def grey(text):
59 if text:
60 return '<font color="#909090">' + text + '</font>'
61 else:
62 return ''
Ka-Ping Yee83205972001-08-21 06:53:01 +000063
64def lookup(name, frame, locals):
65 """Find the value for a given name in the given environment."""
66 if name in locals:
67 return 'local', locals[name]
68 if name in frame.f_globals:
69 return 'global', frame.f_globals[name]
Ka-Ping Yee711cad72002-06-26 07:10:56 +000070 if '__builtins__' in frame.f_globals:
71 builtins = frame.f_globals['__builtins__']
72 if type(builtins) is type({}):
73 if name in builtins:
74 return 'builtin', builtins[name]
75 else:
76 if hasattr(builtins, name):
77 return 'builtin', getattr(builtins, name)
Ka-Ping Yee83205972001-08-21 06:53:01 +000078 return None, __UNDEF__
79
80def scanvars(reader, frame, locals):
81 """Scan one logical line of Python and look up values of variables used."""
Andrew M. Kuchling26f6bdf2004-06-05 19:15:34 +000082 vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__
Ka-Ping Yee83205972001-08-21 06:53:01 +000083 for ttype, token, start, end, line in tokenize.generate_tokens(reader):
84 if ttype == tokenize.NEWLINE: break
85 if ttype == tokenize.NAME and token not in keyword.kwlist:
86 if lasttoken == '.':
87 if parent is not __UNDEF__:
88 value = getattr(parent, token, __UNDEF__)
89 vars.append((prefix + token, prefix, value))
90 else:
91 where, value = lookup(token, frame, locals)
92 vars.append((token, where, value))
93 elif token == '.':
94 prefix += lasttoken + '.'
95 parent = value
96 else:
97 parent, prefix = None, ''
98 lasttoken = token
99 return vars
100
Guido van Rossum1bc535d2007-05-15 18:46:22 +0000101def html(einfo, context=5):
Ka-Ping Yee83205972001-08-21 06:53:01 +0000102 """Return a nice HTML document describing a given traceback."""
Guido van Rossum1bc535d2007-05-15 18:46:22 +0000103 etype, evalue, etb = einfo
Guido van Rossum13257902007-06-07 23:15:56 +0000104 if isinstance(etype, type):
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000105 etype = etype.__name__
106 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
107 date = time.ctime(time.time())
Ka-Ping Yee83205972001-08-21 06:53:01 +0000108 head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading(
Andrew M. Kuchling5fcefdb2004-07-10 14:14:51 +0000109 '<big><big>%s</big></big>' %
110 strong(pydoc.html.escape(str(etype))),
Ka-Ping Yee83205972001-08-21 06:53:01 +0000111 '#ffffff', '#6622aa', pyver + '<br>' + date) + '''
112<p>A problem occurred in a Python script. Here is the sequence of
Andrew M. Kuchling5fcefdb2004-07-10 14:14:51 +0000113function calls leading up to the error, in the order they occurred.</p>'''
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000114
Ka-Ping Yee83205972001-08-21 06:53:01 +0000115 indent = '<tt>' + small('&nbsp;' * 5) + '&nbsp;</tt>'
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000116 frames = []
117 records = inspect.getinnerframes(etb, context)
118 for frame, file, lnum, func, lines, index in records:
Georg Brandl07c81d92005-06-26 21:57:55 +0000119 if file:
120 file = os.path.abspath(file)
121 link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file))
122 else:
123 file = link = '?'
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000124 args, varargs, varkw, locals = inspect.getargvalues(frame)
Ka-Ping Yee83205972001-08-21 06:53:01 +0000125 call = ''
126 if func != '?':
127 call = 'in ' + strong(func) + \
128 inspect.formatargvalues(args, varargs, varkw, locals,
129 formatvalue=lambda value: '=' + pydoc.html.repr(value))
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000130
Ka-Ping Yee83205972001-08-21 06:53:01 +0000131 highlight = {}
132 def reader(lnum=[lnum]):
133 highlight[lnum[0]] = 1
134 try: return linecache.getline(file, lnum[0])
135 finally: lnum[0] += 1
136 vars = scanvars(reader, frame, locals)
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000137
Ka-Ping Yee83205972001-08-21 06:53:01 +0000138 rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' %
139 ('<big>&nbsp;</big>', link, call)]
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000140 if index is not None:
141 i = lnum - index
142 for line in lines:
Ka-Ping Yee83205972001-08-21 06:53:01 +0000143 num = small('&nbsp;' * (5-len(str(i))) + str(i)) + '&nbsp;'
Ka-Ping Yee83205972001-08-21 06:53:01 +0000144 if i in highlight:
Benjamin Petersonef3e4c22009-04-11 19:48:14 +0000145 line = '<tt>=&gt;%s%s</tt>' % (num, pydoc.html.preformat(line))
Ka-Ping Yee83205972001-08-21 06:53:01 +0000146 rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line)
147 else:
Benjamin Petersonef3e4c22009-04-11 19:48:14 +0000148 line = '<tt>&nbsp;&nbsp;%s%s</tt>' % (num, pydoc.html.preformat(line))
Ka-Ping Yee83205972001-08-21 06:53:01 +0000149 rows.append('<tr><td>%s</td></tr>' % grey(line))
150 i += 1
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000151
Ka-Ping Yee83205972001-08-21 06:53:01 +0000152 done, dump = {}, []
153 for name, where, value in vars:
154 if name in done: continue
155 done[name] = 1
156 if value is not __UNDEF__:
Raymond Hettingerdbecd932005-02-06 06:57:08 +0000157 if where in ('global', 'builtin'):
Ka-Ping Yee711cad72002-06-26 07:10:56 +0000158 name = ('<em>%s</em> ' % where) + strong(name)
159 elif where == 'local':
160 name = strong(name)
161 else:
162 name = where + strong(name.split('.')[-1])
Ka-Ping Yee83205972001-08-21 06:53:01 +0000163 dump.append('%s&nbsp;= %s' % (name, pydoc.html.repr(value)))
164 else:
165 dump.append(name + ' <em>undefined</em>')
166
167 rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump))))
Andrew M. Kuchling5fcefdb2004-07-10 14:14:51 +0000168 frames.append('''
Ka-Ping Yee83205972001-08-21 06:53:01 +0000169<table width="100%%" cellspacing=0 cellpadding=0 border=0>
170%s</table>''' % '\n'.join(rows))
171
Andrew M. Kuchlingb67c9432004-03-31 20:17:56 +0000172 exception = ['<p>%s: %s' % (strong(pydoc.html.escape(str(etype))),
173 pydoc.html.escape(str(evalue)))]
Georg Brandl57b39e02007-04-11 19:24:50 +0000174 for name in dir(evalue):
175 if name[:1] == '_': continue
176 value = pydoc.html.repr(getattr(evalue, name))
177 exception.append('\n<br>%s%s&nbsp;=\n%s' % (indent, name, value))
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000178
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000179 return head + ''.join(frames) + ''.join(exception) + '''
180
181
Ka-Ping Yee83205972001-08-21 06:53:01 +0000182<!-- The above is a description of an error in a Python program, formatted
183 for a Web browser because the 'cgitb' module was enabled. In case you
184 are not reading this in a Web browser, here is the original traceback:
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000185
186%s
187-->
Guido van Rossumd59da4b2007-05-22 18:11:13 +0000188''' % pydoc.html.escape(
189 ''.join(traceback.format_exception(etype, evalue, etb)))
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000190
Guido van Rossum1bc535d2007-05-15 18:46:22 +0000191def text(einfo, context=5):
Skip Montanaro364ca402003-06-17 12:58:31 +0000192 """Return a plain text document describing a given traceback."""
Guido van Rossum1bc535d2007-05-15 18:46:22 +0000193 etype, evalue, etb = einfo
Guido van Rossum13257902007-06-07 23:15:56 +0000194 if isinstance(etype, type):
Skip Montanaro364ca402003-06-17 12:58:31 +0000195 etype = etype.__name__
196 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
197 date = time.ctime(time.time())
198 head = "%s\n%s\n%s\n" % (str(etype), pyver, date) + '''
199A problem occurred in a Python script. Here is the sequence of
200function calls leading up to the error, in the order they occurred.
201'''
202
203 frames = []
204 records = inspect.getinnerframes(etb, context)
205 for frame, file, lnum, func, lines, index in records:
206 file = file and os.path.abspath(file) or '?'
207 args, varargs, varkw, locals = inspect.getargvalues(frame)
208 call = ''
209 if func != '?':
210 call = 'in ' + func + \
211 inspect.formatargvalues(args, varargs, varkw, locals,
212 formatvalue=lambda value: '=' + pydoc.text.repr(value))
213
214 highlight = {}
215 def reader(lnum=[lnum]):
216 highlight[lnum[0]] = 1
217 try: return linecache.getline(file, lnum[0])
218 finally: lnum[0] += 1
219 vars = scanvars(reader, frame, locals)
220
221 rows = [' %s %s' % (file, call)]
222 if index is not None:
223 i = lnum - index
224 for line in lines:
225 num = '%5d ' % i
226 rows.append(num+line.rstrip())
227 i += 1
228
229 done, dump = {}, []
230 for name, where, value in vars:
231 if name in done: continue
232 done[name] = 1
233 if value is not __UNDEF__:
234 if where == 'global': name = 'global ' + name
Skip Montanaro1c0228a2004-06-07 11:20:40 +0000235 elif where != 'local': name = where + name.split('.')[-1]
Skip Montanaro364ca402003-06-17 12:58:31 +0000236 dump.append('%s = %s' % (name, pydoc.text.repr(value)))
237 else:
238 dump.append(name + ' undefined')
239
240 rows.append('\n'.join(dump))
241 frames.append('\n%s\n' % '\n'.join(rows))
242
243 exception = ['%s: %s' % (str(etype), str(evalue))]
Georg Brandl57b39e02007-04-11 19:24:50 +0000244 for name in dir(evalue):
245 value = pydoc.text.repr(getattr(evalue, name))
246 exception.append('\n%s%s = %s' % (" "*4, name, value))
Skip Montanaro364ca402003-06-17 12:58:31 +0000247
Skip Montanaro364ca402003-06-17 12:58:31 +0000248 return head + ''.join(frames) + ''.join(exception) + '''
249
250The above is a description of an error in a Python program. Here is
251the original traceback:
252
253%s
254''' % ''.join(traceback.format_exception(etype, evalue, etb))
255
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000256class Hook:
Ka-Ping Yee83205972001-08-21 06:53:01 +0000257 """A hook to replace sys.excepthook that shows tracebacks in HTML."""
258
Skip Montanaro364ca402003-06-17 12:58:31 +0000259 def __init__(self, display=1, logdir=None, context=5, file=None,
260 format="html"):
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000261 self.display = display # send tracebacks to browser if true
262 self.logdir = logdir # log tracebacks to files if not None
Ka-Ping Yee83205972001-08-21 06:53:01 +0000263 self.context = context # number of source code lines per frame
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000264 self.file = file or sys.stdout # place to send the output
Skip Montanaro364ca402003-06-17 12:58:31 +0000265 self.format = format
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000266
267 def __call__(self, etype, evalue, etb):
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000268 self.handle((etype, evalue, etb))
269
270 def handle(self, info=None):
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000271 info = info or sys.exc_info()
Skip Montanaro364ca402003-06-17 12:58:31 +0000272 if self.format == "html":
273 self.file.write(reset())
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000274
Skip Montanaro364ca402003-06-17 12:58:31 +0000275 formatter = (self.format=="html") and html or text
276 plain = False
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000277 try:
Skip Montanaro364ca402003-06-17 12:58:31 +0000278 doc = formatter(info, self.context)
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000279 except: # just in case something goes wrong
Skip Montanaro364ca402003-06-17 12:58:31 +0000280 doc = ''.join(traceback.format_exception(*info))
281 plain = True
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000282
283 if self.display:
Skip Montanaro364ca402003-06-17 12:58:31 +0000284 if plain:
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000285 doc = doc.replace('&', '&amp;').replace('<', '&lt;')
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000286 self.file.write('<pre>' + doc + '</pre>\n')
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000287 else:
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000288 self.file.write(doc + '\n')
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000289 else:
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000290 self.file.write('<p>A problem occurred in a Python script.\n')
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000291
292 if self.logdir is not None:
Andrew M. Kuchling30633c92004-05-06 13:13:44 +0000293 suffix = ['.txt', '.html'][self.format=="html"]
Skip Montanaro364ca402003-06-17 12:58:31 +0000294 (fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir)
R David Murray252cd0e2012-10-27 14:42:47 -0400295
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000296 try:
Guido van Rossum3b0a3292002-08-09 16:38:32 +0000297 file = os.fdopen(fd, 'w')
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000298 file.write(doc)
299 file.close()
R David Murray252cd0e2012-10-27 14:42:47 -0400300 msg = '%s contains the description of this error.' % path
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000301 except:
R David Murray252cd0e2012-10-27 14:42:47 -0400302 msg = 'Tried to save traceback to %s, but failed.' % path
303
304 if self.format == 'html':
305 self.file.write('<p>%s</p>\n' % msg)
306 else:
307 self.file.write(msg + '\n')
Ka-Ping Yeefa78d0f2001-12-04 18:45:17 +0000308 try:
309 self.file.flush()
310 except: pass
Ka-Ping Yee6b5a48d2001-08-18 04:04:50 +0000311
312handler = Hook().handle
Skip Montanaro364ca402003-06-17 12:58:31 +0000313def enable(display=1, logdir=None, context=5, format="html"):
Ka-Ping Yee83205972001-08-21 06:53:01 +0000314 """Install an exception handler that formats tracebacks as HTML.
315
316 The optional argument 'display' can be set to 0 to suppress sending the
317 traceback to the browser, and 'logdir' can be set to a directory to cause
318 tracebacks to be written to files there."""
Skip Montanaro364ca402003-06-17 12:58:31 +0000319 sys.excepthook = Hook(display=display, logdir=logdir,
320 context=context, format=format)