| 1 | """More comprehensive traceback formatting for Python scripts.
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| 2 |
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| 3 | To enable this module, do:
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| 4 |
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| 5 | import cgitb; cgitb.enable()
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| 6 |
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| 7 | at the top of your script. The optional arguments to enable() are:
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| 8 |
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| 9 | display - if true, tracebacks are displayed in the web browser
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| 10 | logdir - if set, tracebacks are written to files in this directory
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| 11 | context - number of lines of source code to show for each stack frame
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| 12 | format - 'text' or 'html' controls the output format
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| 13 |
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| 14 | By default, tracebacks are displayed but not saved, the context is 5 lines
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| 15 | and the output format is 'html' (for backwards compatibility with the
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| 16 | original use of this module)
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| 17 |
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| 18 | Alternatively, if you have caught an exception and want cgitb to display it
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| 19 | for you, call cgitb.handler(). The optional argument to handler() is a
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| 20 | 3-item tuple (etype, evalue, etb) just like the value of sys.exc_info().
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| 21 | The default handler displays output as HTML.
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| 22 |
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| 23 | """
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| 24 | import inspect
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| 25 | import keyword
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| 26 | import linecache
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| 27 | import os
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| 28 | import pydoc
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| 29 | import sys
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| 30 | import tempfile
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| 31 | import time
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| 32 | import tokenize
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| 33 | import traceback
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| 34 | import types
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| 35 |
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| 36 | def reset():
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| 37 | """Return a string that resets the CGI and browser to a known state."""
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| 38 | return '''<!--: spam
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| 39 | Content-Type: text/html
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| 40 |
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| 41 | <body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> -->
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| 42 | <body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> -->
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| 43 | </font> </font> </font> </script> </object> </blockquote> </pre>
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| 44 | </table> </table> </table> </table> </table> </font> </font> </font>'''
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| 45 |
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| 46 | __UNDEF__ = [] # a special sentinel object
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| 47 | def small(text):
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| 48 | if text:
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| 49 | return '<small>' + text + '</small>'
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| 50 | else:
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| 51 | return ''
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| 52 |
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| 53 | def strong(text):
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| 54 | if text:
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| 55 | return '<strong>' + text + '</strong>'
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| 56 | else:
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| 57 | return ''
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| 58 |
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| 59 | def grey(text):
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| 60 | if text:
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| 61 | return '<font color="#909090">' + text + '</font>'
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| 62 | else:
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| 63 | return ''
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| 64 |
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| 65 | def lookup(name, frame, locals):
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| 66 | """Find the value for a given name in the given environment."""
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| 67 | if name in locals:
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| 68 | return 'local', locals[name]
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| 69 | if name in frame.f_globals:
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| 70 | return 'global', frame.f_globals[name]
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| 71 | if '__builtins__' in frame.f_globals:
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| 72 | builtins = frame.f_globals['__builtins__']
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| 73 | if type(builtins) is type({}):
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| 74 | if name in builtins:
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| 75 | return 'builtin', builtins[name]
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| 76 | else:
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| 77 | if hasattr(builtins, name):
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| 78 | return 'builtin', getattr(builtins, name)
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| 79 | return None, __UNDEF__
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| 80 |
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| 81 | def scanvars(reader, frame, locals):
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| 82 | """Scan one logical line of Python and look up values of variables used."""
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| 83 | vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__
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| 84 | for ttype, token, start, end, line in tokenize.generate_tokens(reader):
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| 85 | if ttype == tokenize.NEWLINE: break
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| 86 | if ttype == tokenize.NAME and token not in keyword.kwlist:
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| 87 | if lasttoken == '.':
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| 88 | if parent is not __UNDEF__:
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| 89 | value = getattr(parent, token, __UNDEF__)
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| 90 | vars.append((prefix + token, prefix, value))
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| 91 | else:
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| 92 | where, value = lookup(token, frame, locals)
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| 93 | vars.append((token, where, value))
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| 94 | elif token == '.':
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| 95 | prefix += lasttoken + '.'
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| 96 | parent = value
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| 97 | else:
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| 98 | parent, prefix = None, ''
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| 99 | lasttoken = token
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| 100 | return vars
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| 101 |
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| 102 | def html(einfo, context=5):
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| 103 | """Return a nice HTML document describing a given traceback."""
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| 104 | etype, evalue, etb = einfo
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| 105 | if type(etype) is types.ClassType:
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| 106 | etype = etype.__name__
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| 107 | pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
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| 108 | date = time.ctime(time.time())
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| 109 | head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading(
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| 110 | '<big><big>%s</big></big>' %
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| 111 | strong(pydoc.html.escape(str(etype))),
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| 112 | '#ffffff', '#6622aa', pyver + '<br>' + date) + '''
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| 113 | <p>A problem occurred in a Python script. Here is the sequence of
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| 114 | function calls leading up to the error, in the order they occurred.</p>'''
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| 115 |
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| 116 | indent = '<tt>' + small(' ' * 5) + ' </tt>'
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| 117 | frames = []
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| 118 | records = inspect.getinnerframes(etb, context)
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| 119 | for frame, file, lnum, func, lines, index in records:
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| 120 | if file:
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| 121 | file = os.path.abspath(file)
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| 122 | link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file))
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| 123 | else:
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| 124 | file = link = '?'
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| 125 | args, varargs, varkw, locals = inspect.getargvalues(frame)
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| 126 | call = ''
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| 127 | if func != '?':
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| 128 | call = 'in ' + strong(func) + \
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| 129 | inspect.formatargvalues(args, varargs, varkw, locals,
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| 130 | formatvalue=lambda value: '=' + pydoc.html.repr(value))
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| 131 |
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| 132 | highlight = {}
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| 133 | def reader(lnum=[lnum]):
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| 134 | highlight[lnum[0]] = 1
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| 135 | try: return linecache.getline(file, lnum[0])
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| 136 | finally: lnum[0] += 1
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| 137 | vars = scanvars(reader, frame, locals)
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| 138 |
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| 139 | rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' %
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| 140 | ('<big> </big>', link, call)]
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| 141 | if index is not None:
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| 142 | i = lnum - index
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| 143 | for line in lines:
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| 144 | num = small(' ' * (5-len(str(i))) + str(i)) + ' '
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| 145 | if i in highlight:
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| 146 | line = '<tt>=>%s%s</tt>' % (num, pydoc.html.preformat(line))
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| 147 | rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line)
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| 148 | else:
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| 149 | line = '<tt> %s%s</tt>' % (num, pydoc.html.preformat(line))
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| 150 | rows.append('<tr><td>%s</td></tr>' % grey(line))
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| 151 | i += 1
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| 152 |
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| 153 | done, dump = {}, []
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| 154 | for name, where, value in vars:
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| 155 | if name in done: continue
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| 156 | done[name] = 1
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| 157 | if value is not __UNDEF__:
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| 158 | if where in ('global', 'builtin'):
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| 159 | name = ('<em>%s</em> ' % where) + strong(name)
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| 160 | elif where == 'local':
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| 161 | name = strong(name)
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| 162 | else:
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| 163 | name = where + strong(name.split('.')[-1])
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| 164 | dump.append('%s = %s' % (name, pydoc.html.repr(value)))
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| 165 | else:
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| 166 | dump.append(name + ' <em>undefined</em>')
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| 167 |
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| 168 | rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump))))
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| 169 | frames.append('''
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| 170 | <table width="100%%" cellspacing=0 cellpadding=0 border=0>
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| 171 | %s</table>''' % '\n'.join(rows))
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| 172 |
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| 173 | exception = ['<p>%s: %s' % (strong(pydoc.html.escape(str(etype))),
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| 174 | pydoc.html.escape(str(evalue)))]
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| 175 | if isinstance(evalue, BaseException):
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| 176 | for name in dir(evalue):
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| 177 | if name[:1] == '_': continue
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| 178 | value = pydoc.html.repr(getattr(evalue, name))
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| 179 | exception.append('\n<br>%s%s =\n%s' % (indent, name, value))
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| 180 |
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| 181 | return head + ''.join(frames) + ''.join(exception) + '''
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| 182 |
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| 183 |
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| 184 | <!-- The above is a description of an error in a Python program, formatted
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| 185 | for a Web browser because the 'cgitb' module was enabled. In case you
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| 186 | are not reading this in a Web browser, here is the original traceback:
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| 187 |
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| 188 | %s
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| 189 | -->
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| 190 | ''' % pydoc.html.escape(
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| 191 | ''.join(traceback.format_exception(etype, evalue, etb)))
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| 192 |
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| 193 | def text(einfo, context=5):
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| 194 | """Return a plain text document describing a given traceback."""
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| 195 | etype, evalue, etb = einfo
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| 196 | if type(etype) is types.ClassType:
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| 197 | etype = etype.__name__
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| 198 | pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
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| 199 | date = time.ctime(time.time())
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| 200 | head = "%s\n%s\n%s\n" % (str(etype), pyver, date) + '''
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| 201 | A problem occurred in a Python script. Here is the sequence of
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| 202 | function calls leading up to the error, in the order they occurred.
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| 203 | '''
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| 204 |
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| 205 | frames = []
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| 206 | records = inspect.getinnerframes(etb, context)
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| 207 | for frame, file, lnum, func, lines, index in records:
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| 208 | file = file and os.path.abspath(file) or '?'
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| 209 | args, varargs, varkw, locals = inspect.getargvalues(frame)
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| 210 | call = ''
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| 211 | if func != '?':
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| 212 | call = 'in ' + func + \
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| 213 | inspect.formatargvalues(args, varargs, varkw, locals,
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| 214 | formatvalue=lambda value: '=' + pydoc.text.repr(value))
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| 215 |
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| 216 | highlight = {}
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| 217 | def reader(lnum=[lnum]):
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| 218 | highlight[lnum[0]] = 1
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| 219 | try: return linecache.getline(file, lnum[0])
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| 220 | finally: lnum[0] += 1
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| 221 | vars = scanvars(reader, frame, locals)
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| 222 |
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| 223 | rows = [' %s %s' % (file, call)]
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| 224 | if index is not None:
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| 225 | i = lnum - index
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| 226 | for line in lines:
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| 227 | num = '%5d ' % i
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| 228 | rows.append(num+line.rstrip())
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| 229 | i += 1
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| 230 |
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| 231 | done, dump = {}, []
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| 232 | for name, where, value in vars:
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| 233 | if name in done: continue
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| 234 | done[name] = 1
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| 235 | if value is not __UNDEF__:
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| 236 | if where == 'global': name = 'global ' + name
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| 237 | elif where != 'local': name = where + name.split('.')[-1]
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| 238 | dump.append('%s = %s' % (name, pydoc.text.repr(value)))
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| 239 | else:
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| 240 | dump.append(name + ' undefined')
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| 241 |
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| 242 | rows.append('\n'.join(dump))
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| 243 | frames.append('\n%s\n' % '\n'.join(rows))
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| 244 |
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| 245 | exception = ['%s: %s' % (str(etype), str(evalue))]
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| 246 | if isinstance(evalue, BaseException):
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| 247 | for name in dir(evalue):
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| 248 | value = pydoc.text.repr(getattr(evalue, name))
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| 249 | exception.append('\n%s%s = %s' % (" "*4, name, value))
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| 250 |
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| 251 | return head + ''.join(frames) + ''.join(exception) + '''
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| 252 |
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| 253 | The above is a description of an error in a Python program. Here is
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| 254 | the original traceback:
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| 255 |
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| 256 | %s
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| 257 | ''' % ''.join(traceback.format_exception(etype, evalue, etb))
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| 258 |
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| 259 | class Hook:
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| 260 | """A hook to replace sys.excepthook that shows tracebacks in HTML."""
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| 261 |
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| 262 | def __init__(self, display=1, logdir=None, context=5, file=None,
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| 263 | format="html"):
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| 264 | self.display = display # send tracebacks to browser if true
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| 265 | self.logdir = logdir # log tracebacks to files if not None
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| 266 | self.context = context # number of source code lines per frame
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| 267 | self.file = file or sys.stdout # place to send the output
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| 268 | self.format = format
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| 269 |
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| 270 | def __call__(self, etype, evalue, etb):
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| 271 | self.handle((etype, evalue, etb))
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| 272 |
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| 273 | def handle(self, info=None):
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| 274 | info = info or sys.exc_info()
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| 275 | if self.format == "html":
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| 276 | self.file.write(reset())
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| 277 |
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| 278 | formatter = (self.format=="html") and html or text
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| 279 | plain = False
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| 280 | try:
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| 281 | doc = formatter(info, self.context)
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| 282 | except: # just in case something goes wrong
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| 283 | doc = ''.join(traceback.format_exception(*info))
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| 284 | plain = True
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| 285 |
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| 286 | if self.display:
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| 287 | if plain:
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| 288 | doc = doc.replace('&', '&').replace('<', '<')
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| 289 | self.file.write('<pre>' + doc + '</pre>\n')
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| 290 | else:
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| 291 | self.file.write(doc + '\n')
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| 292 | else:
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| 293 | self.file.write('<p>A problem occurred in a Python script.\n')
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| 294 |
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| 295 | if self.logdir is not None:
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| 296 | suffix = ['.txt', '.html'][self.format=="html"]
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| 297 | (fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir)
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| 298 |
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| 299 | try:
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| 300 | file = os.fdopen(fd, 'w')
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| 301 | file.write(doc)
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| 302 | file.close()
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| 303 | msg = '%s contains the description of this error.' % path
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| 304 | except:
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| 305 | msg = 'Tried to save traceback to %s, but failed.' % path
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| 306 |
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| 307 | if self.format == 'html':
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| 308 | self.file.write('<p>%s</p>\n' % msg)
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| 309 | else:
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| 310 | self.file.write(msg + '\n')
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| 311 | try:
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| 312 | self.file.flush()
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| 313 | except: pass
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| 314 |
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| 315 | handler = Hook().handle
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| 316 | def enable(display=1, logdir=None, context=5, format="html"):
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| 317 | """Install an exception handler that formats tracebacks as HTML.
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| 318 |
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| 319 | The optional argument 'display' can be set to 0 to suppress sending the
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| 320 | traceback to the browser, and 'logdir' can be set to a directory to cause
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| 321 | tracebacks to be written to files there."""
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| 322 | sys.excepthook = Hook(display=display, logdir=logdir,
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| 323 | context=context, format=format)
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