Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 1 | """Handle exceptions in CGI scripts by formatting tracebacks into nice HTML. |
| 2 | |
| 3 | To enable this module, do: |
| 4 | |
| 5 | import cgitb; cgitb.enable() |
| 6 | |
| 7 | at the top of your CGI script. The optional arguments to enable() are: |
| 8 | |
| 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 Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 11 | context - number of lines of source code to show for each stack frame |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 12 | |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 13 | By default, tracebacks are displayed but not saved, and context is 5. |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 14 | |
| 15 | Alternatively, if you have caught an exception and want cgitb to display it |
Fred Drake | 4f5b49f | 2001-12-19 14:27:41 +0000 | [diff] [blame] | 16 | for you, call cgitb.handler(). The optional argument to handler() is a 3-item |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 17 | tuple (etype, evalue, etb) just like the value of sys.exc_info().""" |
| 18 | |
| 19 | __author__ = 'Ka-Ping Yee' |
| 20 | __version__ = '$Revision$' |
| 21 | |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 22 | import sys |
| 23 | |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 24 | def reset(): |
| 25 | """Return a string that resets the CGI and browser to a known state.""" |
| 26 | return '''<!--: spam |
| 27 | Content-Type: text/html |
| 28 | |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 29 | <body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> |
| 30 | <body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> --> |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 31 | </font> </font> </font> </script> </object> </blockquote> </pre> |
| 32 | </table> </table> </table> </table> </table> </font> </font> </font>''' |
| 33 | |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 34 | __UNDEF__ = [] # a special sentinel object |
| 35 | def small(text): return '<small>' + text + '</small>' |
| 36 | def strong(text): return '<strong>' + text + '</strong>' |
| 37 | def grey(text): return '<font color="#909090">' + text + '</font>' |
| 38 | |
| 39 | def lookup(name, frame, locals): |
| 40 | """Find the value for a given name in the given environment.""" |
| 41 | if name in locals: |
| 42 | return 'local', locals[name] |
| 43 | if name in frame.f_globals: |
| 44 | return 'global', frame.f_globals[name] |
Ka-Ping Yee | 711cad7 | 2002-06-26 07:10:56 +0000 | [diff] [blame] | 45 | if '__builtins__' in frame.f_globals: |
| 46 | builtins = frame.f_globals['__builtins__'] |
| 47 | if type(builtins) is type({}): |
| 48 | if name in builtins: |
| 49 | return 'builtin', builtins[name] |
| 50 | else: |
| 51 | if hasattr(builtins, name): |
| 52 | return 'builtin', getattr(builtins, name) |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 53 | return None, __UNDEF__ |
| 54 | |
| 55 | def scanvars(reader, frame, locals): |
| 56 | """Scan one logical line of Python and look up values of variables used.""" |
| 57 | import tokenize, keyword |
| 58 | vars, lasttoken, parent, prefix = [], None, None, '' |
| 59 | for ttype, token, start, end, line in tokenize.generate_tokens(reader): |
| 60 | if ttype == tokenize.NEWLINE: break |
| 61 | if ttype == tokenize.NAME and token not in keyword.kwlist: |
| 62 | if lasttoken == '.': |
| 63 | if parent is not __UNDEF__: |
| 64 | value = getattr(parent, token, __UNDEF__) |
| 65 | vars.append((prefix + token, prefix, value)) |
| 66 | else: |
| 67 | where, value = lookup(token, frame, locals) |
| 68 | vars.append((token, where, value)) |
| 69 | elif token == '.': |
| 70 | prefix += lasttoken + '.' |
| 71 | parent = value |
| 72 | else: |
| 73 | parent, prefix = None, '' |
| 74 | lasttoken = token |
| 75 | return vars |
| 76 | |
| 77 | def html((etype, evalue, etb), context=5): |
| 78 | """Return a nice HTML document describing a given traceback.""" |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 79 | import os, types, time, traceback, linecache, inspect, pydoc |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 80 | |
| 81 | if type(etype) is types.ClassType: |
| 82 | etype = etype.__name__ |
| 83 | pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable |
| 84 | date = time.ctime(time.time()) |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 85 | head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading( |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 86 | '<big><big><strong>%s</strong></big></big>' % str(etype), |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 87 | '#ffffff', '#6622aa', pyver + '<br>' + date) + ''' |
| 88 | <p>A problem occurred in a Python script. Here is the sequence of |
| 89 | function calls leading up to the error, in the order they occurred.''' |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 90 | |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 91 | indent = '<tt>' + small(' ' * 5) + ' </tt>' |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 92 | frames = [] |
| 93 | records = inspect.getinnerframes(etb, context) |
| 94 | for frame, file, lnum, func, lines, index in records: |
| 95 | file = file and os.path.abspath(file) or '?' |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 96 | link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file)) |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 97 | args, varargs, varkw, locals = inspect.getargvalues(frame) |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 98 | call = '' |
| 99 | if func != '?': |
| 100 | call = 'in ' + strong(func) + \ |
| 101 | inspect.formatargvalues(args, varargs, varkw, locals, |
| 102 | formatvalue=lambda value: '=' + pydoc.html.repr(value)) |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 103 | |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 104 | highlight = {} |
| 105 | def reader(lnum=[lnum]): |
| 106 | highlight[lnum[0]] = 1 |
| 107 | try: return linecache.getline(file, lnum[0]) |
| 108 | finally: lnum[0] += 1 |
| 109 | vars = scanvars(reader, frame, locals) |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 110 | |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 111 | rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' % |
| 112 | ('<big> </big>', link, call)] |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 113 | if index is not None: |
| 114 | i = lnum - index |
| 115 | for line in lines: |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 116 | num = small(' ' * (5-len(str(i))) + str(i)) + ' ' |
| 117 | line = '<tt>%s%s</tt>' % (num, pydoc.html.preformat(line)) |
| 118 | if i in highlight: |
| 119 | rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line) |
| 120 | else: |
| 121 | rows.append('<tr><td>%s</td></tr>' % grey(line)) |
| 122 | i += 1 |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 123 | |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 124 | done, dump = {}, [] |
| 125 | for name, where, value in vars: |
| 126 | if name in done: continue |
| 127 | done[name] = 1 |
| 128 | if value is not __UNDEF__: |
Ka-Ping Yee | 711cad7 | 2002-06-26 07:10:56 +0000 | [diff] [blame] | 129 | if where in ['global', 'builtin']: |
| 130 | name = ('<em>%s</em> ' % where) + strong(name) |
| 131 | elif where == 'local': |
| 132 | name = strong(name) |
| 133 | else: |
| 134 | name = where + strong(name.split('.')[-1]) |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 135 | dump.append('%s = %s' % (name, pydoc.html.repr(value))) |
| 136 | else: |
| 137 | dump.append(name + ' <em>undefined</em>') |
| 138 | |
| 139 | rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump)))) |
| 140 | frames.append('''<p> |
| 141 | <table width="100%%" cellspacing=0 cellpadding=0 border=0> |
| 142 | %s</table>''' % '\n'.join(rows)) |
| 143 | |
| 144 | exception = ['<p>%s: %s' % (strong(str(etype)), str(evalue))] |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 145 | if type(evalue) is types.InstanceType: |
| 146 | for name in dir(evalue): |
Ka-Ping Yee | 711cad7 | 2002-06-26 07:10:56 +0000 | [diff] [blame] | 147 | if name[:1] == '_': continue |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 148 | value = pydoc.html.repr(getattr(evalue, name)) |
| 149 | exception.append('\n<br>%s%s =\n%s' % (indent, name, value)) |
| 150 | |
| 151 | import traceback |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 152 | return head + ''.join(frames) + ''.join(exception) + ''' |
| 153 | |
| 154 | |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 155 | <!-- The above is a description of an error in a Python program, formatted |
| 156 | for a Web browser because the 'cgitb' module was enabled. In case you |
| 157 | are not reading this in a Web browser, here is the original traceback: |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 158 | |
| 159 | %s |
| 160 | --> |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 161 | ''' % ''.join(traceback.format_exception(etype, evalue, etb)) |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 162 | |
| 163 | class Hook: |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 164 | """A hook to replace sys.excepthook that shows tracebacks in HTML.""" |
| 165 | |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 166 | def __init__(self, display=1, logdir=None, context=5, file=None): |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 167 | self.display = display # send tracebacks to browser if true |
| 168 | self.logdir = logdir # log tracebacks to files if not None |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 169 | self.context = context # number of source code lines per frame |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 170 | self.file = file or sys.stdout # place to send the output |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 171 | |
| 172 | def __call__(self, etype, evalue, etb): |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 173 | self.handle((etype, evalue, etb)) |
| 174 | |
| 175 | def handle(self, info=None): |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 176 | info = info or sys.exc_info() |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 177 | self.file.write(reset()) |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 178 | |
| 179 | try: |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 180 | text, doc = 0, html(info, self.context) |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 181 | except: # just in case something goes wrong |
| 182 | import traceback |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 183 | text, doc = 1, ''.join(traceback.format_exception(*info)) |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 184 | |
| 185 | if self.display: |
| 186 | if text: |
| 187 | doc = doc.replace('&', '&').replace('<', '<') |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 188 | self.file.write('<pre>' + doc + '</pre>\n') |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 189 | else: |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 190 | self.file.write(doc + '\n') |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 191 | else: |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 192 | self.file.write('<p>A problem occurred in a Python script.\n') |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 193 | |
| 194 | if self.logdir is not None: |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 195 | import os, tempfile |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 196 | name = tempfile.mktemp(['.html', '.txt'][text]) |
| 197 | path = os.path.join(self.logdir, os.path.basename(name)) |
| 198 | try: |
| 199 | file = open(path, 'w') |
| 200 | file.write(doc) |
| 201 | file.close() |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 202 | msg = '<p> %s contains the description of this error.' % path |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 203 | except: |
Ka-Ping Yee | fa78d0f | 2001-12-04 18:45:17 +0000 | [diff] [blame] | 204 | msg = '<p> Tried to save traceback to %s, but failed.' % path |
| 205 | self.file.write(msg + '\n') |
| 206 | try: |
| 207 | self.file.flush() |
| 208 | except: pass |
Ka-Ping Yee | 6b5a48d | 2001-08-18 04:04:50 +0000 | [diff] [blame] | 209 | |
| 210 | handler = Hook().handle |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 211 | def enable(display=1, logdir=None, context=5): |
| 212 | """Install an exception handler that formats tracebacks as HTML. |
| 213 | |
| 214 | The optional argument 'display' can be set to 0 to suppress sending the |
| 215 | traceback to the browser, and 'logdir' can be set to a directory to cause |
| 216 | tracebacks to be written to files there.""" |
Ka-Ping Yee | 8320597 | 2001-08-21 06:53:01 +0000 | [diff] [blame] | 217 | sys.excepthook = Hook(display, logdir, context) |