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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 __author__ = 'Ka-Ping Yee' |
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25 |
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26 __version__ = '$Revision: 55349 $' |
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27 |
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28 import sys |
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29 |
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30 def reset(): |
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31 """Return a string that resets the CGI and browser to a known state.""" |
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32 return '''<!--: spam |
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33 Content-Type: text/html |
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34 |
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35 <body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> |
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36 <body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> --> |
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37 </font> </font> </font> </script> </object> </blockquote> </pre> |
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38 </table> </table> </table> </table> </table> </font> </font> </font>''' |
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39 |
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40 __UNDEF__ = [] # a special sentinel object |
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41 def small(text): |
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42 if text: |
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43 return '<small>' + text + '</small>' |
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44 else: |
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45 return '' |
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46 |
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47 def strong(text): |
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48 if text: |
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49 return '<strong>' + text + '</strong>' |
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50 else: |
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51 return '' |
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52 |
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53 def grey(text): |
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54 if text: |
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55 return '<font color="#909090">' + text + '</font>' |
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56 else: |
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57 return '' |
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58 |
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59 def lookup(name, frame, locals): |
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60 """Find the value for a given name in the given environment.""" |
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61 if name in locals: |
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62 return 'local', locals[name] |
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63 if name in frame.f_globals: |
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64 return 'global', frame.f_globals[name] |
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65 if '__builtins__' in frame.f_globals: |
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66 builtins = frame.f_globals['__builtins__'] |
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67 if type(builtins) is type({}): |
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68 if name in builtins: |
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69 return 'builtin', builtins[name] |
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70 else: |
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71 if hasattr(builtins, name): |
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72 return 'builtin', getattr(builtins, name) |
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73 return None, __UNDEF__ |
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74 |
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75 def scanvars(reader, frame, locals): |
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76 """Scan one logical line of Python and look up values of variables used.""" |
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77 import tokenize, keyword |
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78 vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__ |
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79 for ttype, token, start, end, line in tokenize.generate_tokens(reader): |
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80 if ttype == tokenize.NEWLINE: break |
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81 if ttype == tokenize.NAME and token not in keyword.kwlist: |
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82 if lasttoken == '.': |
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83 if parent is not __UNDEF__: |
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84 value = getattr(parent, token, __UNDEF__) |
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85 vars.append((prefix + token, prefix, value)) |
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86 else: |
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87 where, value = lookup(token, frame, locals) |
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88 vars.append((token, where, value)) |
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89 elif token == '.': |
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90 prefix += lasttoken + '.' |
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91 parent = value |
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92 else: |
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93 parent, prefix = None, '' |
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94 lasttoken = token |
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95 return vars |
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96 |
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97 def html((etype, evalue, etb), context=5): |
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98 """Return a nice HTML document describing a given traceback.""" |
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99 import os, types, time, traceback, linecache, inspect, pydoc |
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100 |
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101 if type(etype) is types.ClassType: |
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102 etype = etype.__name__ |
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103 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable |
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104 date = time.ctime(time.time()) |
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105 head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading( |
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106 '<big><big>%s</big></big>' % |
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107 strong(pydoc.html.escape(str(etype))), |
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108 '#ffffff', '#6622aa', pyver + '<br>' + date) + ''' |
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109 <p>A problem occurred in a Python script. Here is the sequence of |
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110 function calls leading up to the error, in the order they occurred.</p>''' |
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111 |
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112 indent = '<tt>' + small(' ' * 5) + ' </tt>' |
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113 frames = [] |
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114 records = inspect.getinnerframes(etb, context) |
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115 for frame, file, lnum, func, lines, index in records: |
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116 if file: |
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117 file = os.path.abspath(file) |
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118 link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file)) |
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119 else: |
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120 file = link = '?' |
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121 args, varargs, varkw, locals = inspect.getargvalues(frame) |
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122 call = '' |
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123 if func != '?': |
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124 call = 'in ' + strong(func) + \ |
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125 inspect.formatargvalues(args, varargs, varkw, locals, |
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126 formatvalue=lambda value: '=' + pydoc.html.repr(value)) |
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127 |
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128 highlight = {} |
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129 def reader(lnum=[lnum]): |
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130 highlight[lnum[0]] = 1 |
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131 try: return linecache.getline(file, lnum[0]) |
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132 finally: lnum[0] += 1 |
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133 vars = scanvars(reader, frame, locals) |
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134 |
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135 rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' % |
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136 ('<big> </big>', link, call)] |
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137 if index is not None: |
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138 i = lnum - index |
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139 for line in lines: |
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140 num = small(' ' * (5-len(str(i))) + str(i)) + ' ' |
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141 line = '<tt>%s%s</tt>' % (num, pydoc.html.preformat(line)) |
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142 if i in highlight: |
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143 rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line) |
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144 else: |
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145 rows.append('<tr><td>%s</td></tr>' % grey(line)) |
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146 i += 1 |
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147 |
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148 done, dump = {}, [] |
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149 for name, where, value in vars: |
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150 if name in done: continue |
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151 done[name] = 1 |
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152 if value is not __UNDEF__: |
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153 if where in ('global', 'builtin'): |
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154 name = ('<em>%s</em> ' % where) + strong(name) |
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155 elif where == 'local': |
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156 name = strong(name) |
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157 else: |
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158 name = where + strong(name.split('.')[-1]) |
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159 dump.append('%s = %s' % (name, pydoc.html.repr(value))) |
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160 else: |
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161 dump.append(name + ' <em>undefined</em>') |
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162 |
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163 rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump)))) |
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164 frames.append(''' |
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165 <table width="100%%" cellspacing=0 cellpadding=0 border=0> |
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166 %s</table>''' % '\n'.join(rows)) |
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167 |
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168 exception = ['<p>%s: %s' % (strong(pydoc.html.escape(str(etype))), |
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169 pydoc.html.escape(str(evalue)))] |
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170 if isinstance(evalue, BaseException): |
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171 for name in dir(evalue): |
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172 if name[:1] == '_': continue |
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173 value = pydoc.html.repr(getattr(evalue, name)) |
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174 exception.append('\n<br>%s%s =\n%s' % (indent, name, value)) |
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175 |
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176 import traceback |
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177 return head + ''.join(frames) + ''.join(exception) + ''' |
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178 |
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179 |
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180 <!-- The above is a description of an error in a Python program, formatted |
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181 for a Web browser because the 'cgitb' module was enabled. In case you |
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182 are not reading this in a Web browser, here is the original traceback: |
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183 |
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184 %s |
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185 --> |
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186 ''' % pydoc.html.escape( |
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187 ''.join(traceback.format_exception(etype, evalue, etb))) |
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188 |
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189 def text((etype, evalue, etb), context=5): |
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190 """Return a plain text document describing a given traceback.""" |
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191 import os, types, time, traceback, linecache, inspect, pydoc |
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192 |
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193 if type(etype) is types.ClassType: |
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194 etype = etype.__name__ |
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195 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable |
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196 date = time.ctime(time.time()) |
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197 head = "%s\n%s\n%s\n" % (str(etype), pyver, date) + ''' |
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198 A problem occurred in a Python script. Here is the sequence of |
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199 function calls leading up to the error, in the order they occurred. |
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200 ''' |
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201 |
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202 frames = [] |
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203 records = inspect.getinnerframes(etb, context) |
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204 for frame, file, lnum, func, lines, index in records: |
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205 file = file and os.path.abspath(file) or '?' |
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206 args, varargs, varkw, locals = inspect.getargvalues(frame) |
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207 call = '' |
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208 if func != '?': |
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209 call = 'in ' + func + \ |
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210 inspect.formatargvalues(args, varargs, varkw, locals, |
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211 formatvalue=lambda value: '=' + pydoc.text.repr(value)) |
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212 |
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213 highlight = {} |
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214 def reader(lnum=[lnum]): |
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215 highlight[lnum[0]] = 1 |
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216 try: return linecache.getline(file, lnum[0]) |
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217 finally: lnum[0] += 1 |
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218 vars = scanvars(reader, frame, locals) |
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219 |
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220 rows = [' %s %s' % (file, call)] |
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221 if index is not None: |
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222 i = lnum - index |
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223 for line in lines: |
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224 num = '%5d ' % i |
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225 rows.append(num+line.rstrip()) |
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226 i += 1 |
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227 |
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228 done, dump = {}, [] |
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229 for name, where, value in vars: |
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230 if name in done: continue |
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231 done[name] = 1 |
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232 if value is not __UNDEF__: |
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233 if where == 'global': name = 'global ' + name |
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234 elif where != 'local': name = where + name.split('.')[-1] |
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235 dump.append('%s = %s' % (name, pydoc.text.repr(value))) |
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236 else: |
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237 dump.append(name + ' undefined') |
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238 |
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239 rows.append('\n'.join(dump)) |
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240 frames.append('\n%s\n' % '\n'.join(rows)) |
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241 |
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242 exception = ['%s: %s' % (str(etype), str(evalue))] |
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243 if isinstance(evalue, BaseException): |
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244 for name in dir(evalue): |
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245 value = pydoc.text.repr(getattr(evalue, name)) |
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246 exception.append('\n%s%s = %s' % (" "*4, name, value)) |
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247 |
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248 import traceback |
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249 return head + ''.join(frames) + ''.join(exception) + ''' |
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250 |
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251 The above is a description of an error in a Python program. Here is |
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252 the original traceback: |
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253 |
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254 %s |
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255 ''' % ''.join(traceback.format_exception(etype, evalue, etb)) |
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256 |
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257 class Hook: |
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258 """A hook to replace sys.excepthook that shows tracebacks in HTML.""" |
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259 |
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260 def __init__(self, display=1, logdir=None, context=5, file=None, |
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261 format="html"): |
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262 self.display = display # send tracebacks to browser if true |
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263 self.logdir = logdir # log tracebacks to files if not None |
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264 self.context = context # number of source code lines per frame |
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265 self.file = file or sys.stdout # place to send the output |
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266 self.format = format |
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267 |
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268 def __call__(self, etype, evalue, etb): |
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269 self.handle((etype, evalue, etb)) |
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270 |
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271 def handle(self, info=None): |
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272 info = info or sys.exc_info() |
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273 if self.format == "html": |
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274 self.file.write(reset()) |
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275 |
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276 formatter = (self.format=="html") and html or text |
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277 plain = False |
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278 try: |
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279 doc = formatter(info, self.context) |
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280 except: # just in case something goes wrong |
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281 import traceback |
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282 doc = ''.join(traceback.format_exception(*info)) |
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283 plain = True |
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284 |
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285 if self.display: |
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286 if plain: |
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287 doc = doc.replace('&', '&').replace('<', '<') |
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288 self.file.write('<pre>' + doc + '</pre>\n') |
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289 else: |
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290 self.file.write(doc + '\n') |
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291 else: |
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292 self.file.write('<p>A problem occurred in a Python script.\n') |
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293 |
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294 if self.logdir is not None: |
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295 import os, tempfile |
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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 try: |
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299 file = os.fdopen(fd, 'w') |
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300 file.write(doc) |
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301 file.close() |
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302 msg = '<p> %s contains the description of this error.' % path |
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303 except: |
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304 msg = '<p> Tried to save traceback to %s, but failed.' % path |
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305 self.file.write(msg + '\n') |
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306 try: |
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307 self.file.flush() |
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308 except: pass |
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309 |
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310 handler = Hook().handle |
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311 def enable(display=1, logdir=None, context=5, format="html"): |
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312 """Install an exception handler that formats tracebacks as HTML. |
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313 |
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314 The optional argument 'display' can be set to 0 to suppress sending the |
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315 traceback to the browser, and 'logdir' can be set to a directory to cause |
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316 tracebacks to be written to files there.""" |
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317 sys.excepthook = Hook(display=display, logdir=logdir, |
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318 context=context, format=format) |