Issue #3366: Add gamma function to math module.
[python.git] / Lib / cgitb.py
blob35f4a50d5f5729acc6153e853dec08e3757ad8fa
1 """More comprehensive traceback formatting for Python scripts.
3 To enable this module, do:
5 import cgitb; cgitb.enable()
7 at the top of your script. The optional arguments to enable() are:
9 display - if true, tracebacks are displayed in the web browser
10 logdir - if set, tracebacks are written to files in this directory
11 context - number of lines of source code to show for each stack frame
12 format - 'text' or 'html' controls the output format
14 By default, tracebacks are displayed but not saved, the context is 5 lines
15 and the output format is 'html' (for backwards compatibility with the
16 original use of this module)
18 Alternatively, if you have caught an exception and want cgitb to display it
19 for you, call cgitb.handler(). The optional argument to handler() is a
20 3-item tuple (etype, evalue, etb) just like the value of sys.exc_info().
21 The default handler displays output as HTML.
23 """
24 import inspect
25 import keyword
26 import linecache
27 import os
28 import pydoc
29 import sys
30 import tempfile
31 import time
32 import tokenize
33 import traceback
34 import types
36 def reset():
37 """Return a string that resets the CGI and browser to a known state."""
38 return '''<!--: spam
39 Content-Type: text/html
41 <body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> -->
42 <body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> -->
43 </font> </font> </font> </script> </object> </blockquote> </pre>
44 </table> </table> </table> </table> </table> </font> </font> </font>'''
46 __UNDEF__ = [] # a special sentinel object
47 def small(text):
48 if text:
49 return '<small>' + text + '</small>'
50 else:
51 return ''
53 def strong(text):
54 if text:
55 return '<strong>' + text + '</strong>'
56 else:
57 return ''
59 def grey(text):
60 if text:
61 return '<font color="#909090">' + text + '</font>'
62 else:
63 return ''
65 def lookup(name, frame, locals):
66 """Find the value for a given name in the given environment."""
67 if name in locals:
68 return 'local', locals[name]
69 if name in frame.f_globals:
70 return 'global', frame.f_globals[name]
71 if '__builtins__' in frame.f_globals:
72 builtins = frame.f_globals['__builtins__']
73 if type(builtins) is type({}):
74 if name in builtins:
75 return 'builtin', builtins[name]
76 else:
77 if hasattr(builtins, name):
78 return 'builtin', getattr(builtins, name)
79 return None, __UNDEF__
81 def scanvars(reader, frame, locals):
82 """Scan one logical line of Python and look up values of variables used."""
83 vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__
84 for ttype, token, start, end, line in tokenize.generate_tokens(reader):
85 if ttype == tokenize.NEWLINE: break
86 if ttype == tokenize.NAME and token not in keyword.kwlist:
87 if lasttoken == '.':
88 if parent is not __UNDEF__:
89 value = getattr(parent, token, __UNDEF__)
90 vars.append((prefix + token, prefix, value))
91 else:
92 where, value = lookup(token, frame, locals)
93 vars.append((token, where, value))
94 elif token == '.':
95 prefix += lasttoken + '.'
96 parent = value
97 else:
98 parent, prefix = None, ''
99 lasttoken = token
100 return vars
102 def html((etype, evalue, etb), context=5):
103 """Return a nice HTML document describing a given traceback."""
104 if type(etype) is types.ClassType:
105 etype = etype.__name__
106 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
107 date = time.ctime(time.time())
108 head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading(
109 '<big><big>%s</big></big>' %
110 strong(pydoc.html.escape(str(etype))),
111 '#ffffff', '#6622aa', pyver + '<br>' + date) + '''
112 <p>A problem occurred in a Python script. Here is the sequence of
113 function calls leading up to the error, in the order they occurred.</p>'''
115 indent = '<tt>' + small('&nbsp;' * 5) + '&nbsp;</tt>'
116 frames = []
117 records = inspect.getinnerframes(etb, context)
118 for frame, file, lnum, func, lines, index in records:
119 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 = '?'
124 args, varargs, varkw, locals = inspect.getargvalues(frame)
125 call = ''
126 if func != '?':
127 call = 'in ' + strong(func) + \
128 inspect.formatargvalues(args, varargs, varkw, locals,
129 formatvalue=lambda value: '=' + pydoc.html.repr(value))
131 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)
138 rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' %
139 ('<big>&nbsp;</big>', link, call)]
140 if index is not None:
141 i = lnum - index
142 for line in lines:
143 num = small('&nbsp;' * (5-len(str(i))) + str(i)) + '&nbsp;'
144 if i in highlight:
145 line = '<tt>=&gt;%s%s</tt>' % (num, pydoc.html.preformat(line))
146 rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line)
147 else:
148 line = '<tt>&nbsp;&nbsp;%s%s</tt>' % (num, pydoc.html.preformat(line))
149 rows.append('<tr><td>%s</td></tr>' % grey(line))
150 i += 1
152 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__:
157 if where in ('global', 'builtin'):
158 name = ('<em>%s</em> ' % where) + strong(name)
159 elif where == 'local':
160 name = strong(name)
161 else:
162 name = where + strong(name.split('.')[-1])
163 dump.append('%s&nbsp;= %s' % (name, pydoc.html.repr(value)))
164 else:
165 dump.append(name + ' <em>undefined</em>')
167 rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump))))
168 frames.append('''
169 <table width="100%%" cellspacing=0 cellpadding=0 border=0>
170 %s</table>''' % '\n'.join(rows))
172 exception = ['<p>%s: %s' % (strong(pydoc.html.escape(str(etype))),
173 pydoc.html.escape(str(evalue)))]
174 if isinstance(evalue, BaseException):
175 for name in dir(evalue):
176 if name[:1] == '_': continue
177 value = pydoc.html.repr(getattr(evalue, name))
178 exception.append('\n<br>%s%s&nbsp;=\n%s' % (indent, name, value))
180 return head + ''.join(frames) + ''.join(exception) + '''
183 <!-- The above is a description of an error in a Python program, formatted
184 for a Web browser because the 'cgitb' module was enabled. In case you
185 are not reading this in a Web browser, here is the original traceback:
189 ''' % pydoc.html.escape(
190 ''.join(traceback.format_exception(etype, evalue, etb)))
192 def text((etype, evalue, etb), context=5):
193 """Return a plain text document describing a given traceback."""
194 if type(etype) is types.ClassType:
195 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) + '''
199 A problem occurred in a Python script. Here is the sequence of
200 function calls leading up to the error, in the order they occurred.
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))
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)
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
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
235 elif where != 'local': name = where + name.split('.')[-1]
236 dump.append('%s = %s' % (name, pydoc.text.repr(value)))
237 else:
238 dump.append(name + ' undefined')
240 rows.append('\n'.join(dump))
241 frames.append('\n%s\n' % '\n'.join(rows))
243 exception = ['%s: %s' % (str(etype), str(evalue))]
244 if isinstance(evalue, BaseException):
245 for name in dir(evalue):
246 value = pydoc.text.repr(getattr(evalue, name))
247 exception.append('\n%s%s = %s' % (" "*4, name, value))
249 return head + ''.join(frames) + ''.join(exception) + '''
251 The above is a description of an error in a Python program. Here is
252 the original traceback:
255 ''' % ''.join(traceback.format_exception(etype, evalue, etb))
257 class Hook:
258 """A hook to replace sys.excepthook that shows tracebacks in HTML."""
260 def __init__(self, display=1, logdir=None, context=5, file=None,
261 format="html"):
262 self.display = display # send tracebacks to browser if true
263 self.logdir = logdir # log tracebacks to files if not None
264 self.context = context # number of source code lines per frame
265 self.file = file or sys.stdout # place to send the output
266 self.format = format
268 def __call__(self, etype, evalue, etb):
269 self.handle((etype, evalue, etb))
271 def handle(self, info=None):
272 info = info or sys.exc_info()
273 if self.format == "html":
274 self.file.write(reset())
276 formatter = (self.format=="html") and html or text
277 plain = False
278 try:
279 doc = formatter(info, self.context)
280 except: # just in case something goes wrong
281 doc = ''.join(traceback.format_exception(*info))
282 plain = True
284 if self.display:
285 if plain:
286 doc = doc.replace('&', '&amp;').replace('<', '&lt;')
287 self.file.write('<pre>' + doc + '</pre>\n')
288 else:
289 self.file.write(doc + '\n')
290 else:
291 self.file.write('<p>A problem occurred in a Python script.\n')
293 if self.logdir is not None:
294 suffix = ['.txt', '.html'][self.format=="html"]
295 (fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir)
296 try:
297 file = os.fdopen(fd, 'w')
298 file.write(doc)
299 file.close()
300 msg = '<p> %s contains the description of this error.' % path
301 except:
302 msg = '<p> Tried to save traceback to %s, but failed.' % path
303 self.file.write(msg + '\n')
304 try:
305 self.file.flush()
306 except: pass
308 handler = Hook().handle
309 def enable(display=1, logdir=None, context=5, format="html"):
310 """Install an exception handler that formats tracebacks as HTML.
312 The optional argument 'display' can be set to 0 to suppress sending the
313 traceback to the browser, and 'logdir' can be set to a directory to cause
314 tracebacks to be written to files there."""
315 sys.excepthook = Hook(display=display, logdir=logdir,
316 context=context, format=format)