/Lib/cgitb.py
Python | 318 lines | 307 code | 0 blank | 11 comment | 3 complexity | 5649cc63c8b3919b72a18bdbc4c47036 MD5 | raw file
1"""More comprehensive traceback formatting for Python scripts. 2 3To enable this module, do: 4 5 import cgitb; cgitb.enable() 6 7at the top of your 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 11 context - number of lines of source code to show for each stack frame 12 format - 'text' or 'html' controls the output format 13 14By 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) 17 18Alternatively, if you have caught an exception and want cgitb to display it 19for 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. 22""" 23 24__author__ = 'Ka-Ping Yee' 25 26__version__ = '$Revision: 55348 $' 27 28import sys 29 30def reset(): 31 """Return a string that resets the CGI and browser to a known state.""" 32 return '''<!--: spam 33Content-Type: text/html 34 35<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> 36<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> --> 37</font> </font> </font> </script> </object> </blockquote> </pre> 38</table> </table> </table> </table> </table> </font> </font> </font>''' 39 40__UNDEF__ = [] # a special sentinel object 41def small(text): 42 if text: 43 return '<small>' + text + '</small>' 44 else: 45 return '' 46 47def strong(text): 48 if text: 49 return '<strong>' + text + '</strong>' 50 else: 51 return '' 52 53def grey(text): 54 if text: 55 return '<font color="#909090">' + text + '</font>' 56 else: 57 return '' 58 59def lookup(name, frame, locals): 60 """Find the value for a given name in the given environment.""" 61 if name in locals: 62 return 'local', locals[name] 63 if name in frame.f_globals: 64 return 'global', frame.f_globals[name] 65 if '__builtins__' in frame.f_globals: 66 builtins = frame.f_globals['__builtins__'] 67 if type(builtins) is type({}): 68 if name in builtins: 69 return 'builtin', builtins[name] 70 else: 71 if hasattr(builtins, name): 72 return 'builtin', getattr(builtins, name) 73 return None, __UNDEF__ 74 75def scanvars(reader, frame, locals): 76 """Scan one logical line of Python and look up values of variables used.""" 77 import tokenize, keyword 78 vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__ 79 for ttype, token, start, end, line in tokenize.generate_tokens(reader): 80 if ttype == tokenize.NEWLINE: break 81 if ttype == tokenize.NAME and token not in keyword.kwlist: 82 if lasttoken == '.': 83 if parent is not __UNDEF__: 84 value = getattr(parent, token, __UNDEF__) 85 vars.append((prefix + token, prefix, value)) 86 else: 87 where, value = lookup(token, frame, locals) 88 vars.append((token, where, value)) 89 elif token == '.': 90 prefix += lasttoken + '.' 91 parent = value 92 else: 93 parent, prefix = None, '' 94 lasttoken = token 95 return vars 96 97def html((etype, evalue, etb), context=5): 98 """Return a nice HTML document describing a given traceback.""" 99 import os, types, time, traceback, linecache, inspect, pydoc 100 101 if type(etype) is types.ClassType: 102 etype = etype.__name__ 103 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable 104 date = time.ctime(time.time()) 105 head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading( 106 '<big><big>%s</big></big>' % 107 strong(pydoc.html.escape(str(etype))), 108 '#ffffff', '#6622aa', pyver + '<br>' + date) + ''' 109<p>A problem occurred in a Python script. Here is the sequence of 110function calls leading up to the error, in the order they occurred.</p>''' 111 112 indent = '<tt>' + small(' ' * 5) + ' </tt>' 113 frames = [] 114 records = inspect.getinnerframes(etb, context) 115 for frame, file, lnum, func, lines, index in records: 116 if file: 117 file = os.path.abspath(file) 118 link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file)) 119 else: 120 file = link = '?' 121 args, varargs, varkw, locals = inspect.getargvalues(frame) 122 call = '' 123 if func != '?': 124 call = 'in ' + strong(func) + \ 125 inspect.formatargvalues(args, varargs, varkw, locals, 126 formatvalue=lambda value: '=' + pydoc.html.repr(value)) 127 128 highlight = {} 129 def reader(lnum=[lnum]): 130 highlight[lnum[0]] = 1 131 try: return linecache.getline(file, lnum[0]) 132 finally: lnum[0] += 1 133 vars = scanvars(reader, frame, locals) 134 135 rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' % 136 ('<big> </big>', link, call)] 137 if index is not None: 138 i = lnum - index 139 for line in lines: 140 num = small(' ' * (5-len(str(i))) + str(i)) + ' ' 141 line = '<tt>%s%s</tt>' % (num, pydoc.html.preformat(line)) 142 if i in highlight: 143 rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line) 144 else: 145 rows.append('<tr><td>%s</td></tr>' % grey(line)) 146 i += 1 147 148 done, dump = {}, [] 149 for name, where, value in vars: 150 if name in done: continue 151 done[name] = 1 152 if value is not __UNDEF__: 153 if where in ('global', 'builtin'): 154 name = ('<em>%s</em> ' % where) + strong(name) 155 elif where == 'local': 156 name = strong(name) 157 else: 158 name = where + strong(name.split('.')[-1]) 159 dump.append('%s = %s' % (name, pydoc.html.repr(value))) 160 else: 161 dump.append(name + ' <em>undefined</em>') 162 163 rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump)))) 164 frames.append(''' 165<table width="100%%" cellspacing=0 cellpadding=0 border=0> 166%s</table>''' % '\n'.join(rows)) 167 168 exception = ['<p>%s: %s' % (strong(pydoc.html.escape(str(etype))), 169 pydoc.html.escape(str(evalue)))] 170 if isinstance(evalue, BaseException): 171 for name in dir(evalue): 172 if name[:1] == '_': continue 173 value = pydoc.html.repr(getattr(evalue, name)) 174 exception.append('\n<br>%s%s =\n%s' % (indent, name, value)) 175 176 import traceback 177 return head + ''.join(frames) + ''.join(exception) + ''' 178 179 180<!-- The above is a description of an error in a Python program, formatted 181 for a Web browser because the 'cgitb' module was enabled. In case you 182 are not reading this in a Web browser, here is the original traceback: 183 184%s 185--> 186''' % pydoc.html.escape( 187 ''.join(traceback.format_exception(etype, evalue, etb))) 188 189def text((etype, evalue, etb), context=5): 190 """Return a plain text document describing a given traceback.""" 191 import os, types, time, traceback, linecache, inspect, pydoc 192 193 if type(etype) is types.ClassType: 194 etype = etype.__name__ 195 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable 196 date = time.ctime(time.time()) 197 head = "%s\n%s\n%s\n" % (str(etype), pyver, date) + ''' 198A problem occurred in a Python script. Here is the sequence of 199function calls leading up to the error, in the order they occurred. 200''' 201 202 frames = [] 203 records = inspect.getinnerframes(etb, context) 204 for frame, file, lnum, func, lines, index in records: 205 file = file and os.path.abspath(file) or '?' 206 args, varargs, varkw, locals = inspect.getargvalues(frame) 207 call = '' 208 if func != '?': 209 call = 'in ' + func + \ 210 inspect.formatargvalues(args, varargs, varkw, locals, 211 formatvalue=lambda value: '=' + pydoc.text.repr(value)) 212 213 highlight = {} 214 def reader(lnum=[lnum]): 215 highlight[lnum[0]] = 1 216 try: return linecache.getline(file, lnum[0]) 217 finally: lnum[0] += 1 218 vars = scanvars(reader, frame, locals) 219 220 rows = [' %s %s' % (file, call)] 221 if index is not None: 222 i = lnum - index 223 for line in lines: 224 num = '%5d ' % i 225 rows.append(num+line.rstrip()) 226 i += 1 227 228 done, dump = {}, [] 229 for name, where, value in vars: 230 if name in done: continue 231 done[name] = 1 232 if value is not __UNDEF__: 233 if where == 'global': name = 'global ' + name 234 elif where != 'local': name = where + name.split('.')[-1] 235 dump.append('%s = %s' % (name, pydoc.text.repr(value))) 236 else: 237 dump.append(name + ' undefined') 238 239 rows.append('\n'.join(dump)) 240 frames.append('\n%s\n' % '\n'.join(rows)) 241 242 exception = ['%s: %s' % (str(etype), str(evalue))] 243 if isinstance(evalue, BaseException): 244 for name in dir(evalue): 245 value = pydoc.text.repr(getattr(evalue, name)) 246 exception.append('\n%s%s = %s' % (" "*4, name, value)) 247 248 import traceback 249 return head + ''.join(frames) + ''.join(exception) + ''' 250 251The above is a description of an error in a Python program. Here is 252the original traceback: 253 254%s 255''' % ''.join(traceback.format_exception(etype, evalue, etb)) 256 257class Hook: 258 """A hook to replace sys.excepthook that shows tracebacks in HTML.""" 259 260 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 267 268 def __call__(self, etype, evalue, etb): 269 self.handle((etype, evalue, etb)) 270 271 def handle(self, info=None): 272 info = info or sys.exc_info() 273 if self.format == "html": 274 self.file.write(reset()) 275 276 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 import traceback 282 doc = ''.join(traceback.format_exception(*info)) 283 plain = True 284 285 if self.display: 286 if plain: 287 doc = doc.replace('&', '&').replace('<', '<') 288 self.file.write('<pre>' + doc + '</pre>\n') 289 else: 290 self.file.write(doc + '\n') 291 else: 292 self.file.write('<p>A problem occurred in a Python script.\n') 293 294 if self.logdir is not None: 295 import os, tempfile 296 suffix = ['.txt', '.html'][self.format=="html"] 297 (fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir) 298 try: 299 file = os.fdopen(fd, 'w') 300 file.write(doc) 301 file.close() 302 msg = '<p> %s contains the description of this error.' % path 303 except: 304 msg = '<p> Tried to save traceback to %s, but failed.' % path 305 self.file.write(msg + '\n') 306 try: 307 self.file.flush() 308 except: pass 309 310handler = Hook().handle 311def enable(display=1, logdir=None, context=5, format="html"): 312 """Install an exception handler that formats tracebacks as HTML. 313 314 The optional argument 'display' can be set to 0 to suppress sending the 315 traceback to the browser, and 'logdir' can be set to a directory to cause 316 tracebacks to be written to files there.""" 317 sys.excepthook = Hook(display=display, logdir=logdir, 318 context=context, format=format)