Error

import traceback, poplib, smtplib from os import pathsep from types import ClassType, DictType, ListType from random import randint try: from email.message import Message except ImportError: # Python < 2.5 try: from email.Message import Message except ImportError: # Python < 2.2 Message = None from MimeWriter import MimeWriter from Common import * from MiscUtils.Funcs import dateForEmail from WebUtils.HTMLForException import HTMLForException from WebUtils.Funcs import htmlForDict, htmlEncode try: # linecache update workaround for Python < 2.4 traceback.format_exc # check version except AttributeError: # Python < 2.4 from linecache import checkcache else: # Python >= 2.4 # the linecache module updates the cache automatically def checkcache(): pass class Singleton: pass class ExceptionHandler(Object): """Exception handling. ExceptionHandler is a utility class for Application that is created to handle a particular exception. The object is a one-shot deal. After handling an exception, it should be removed. At some point, the exception handler sends `writeExceptionReport` to the transaction (if present), which in turn sends it to the other transactional objects (application, request, response, etc.) The handler is the single argument for this message. Classes may find it useful to do things like this:: exceptionReportAttrs = 'foo bar baz'.split() def writeExceptionReport(self, handler): handler.writeTitle(self.__class__.__name__) handler.writeAttrs(self, self.exceptionReportAttrs) The handler write methods that may be useful are: * write * writeTitle * writeDict * writeAttrs Derived classes must not assume that the error occured in a transaction. self._tra may be None for exceptions outside of transactions. **HOW TO CREATE A CUSTOM EXCEPTION HANDLER** In the ``__init__.py`` of your context:: from WebKit.ExceptionHandler import ExceptionHandler as _ExceptionHandler class ExceptionHandler(_ExceptionHandler): _hideValuesForFields = _ExceptionHandler._hideValuesForFields + ['foo', 'bar'] def work(self): _ExceptionHandler.work(self) # do whatever # override other methods if you like def contextInitialize(app, ctxPath): app._exceptionHandlerClass = ExceptionHandler You can also control the errors with settings in ``Application.config`` """ # keep these lower case to support case insensitivity: _hideValuesForFields = ['password', 'passwd', 'pwd', 'creditcard', 'credit card', 'cc', 'pin', 'tan'] if False: # for testing _hideValuesForFields.extend(['application', 'uri', 'http_accept', 'userid']) _hiddenString = '*** hidden ***' _addSpace = { 'PATH': pathsep, 'CLASSPATH': pathsep, 'HTTP_ACCEPT': ',', 'HTTP_ACCEPT_CHARSET': ',', 'HTTP_ACCEPT_ENCODING': ',', 'HTTP_ACCEPT_LANGUAGE': ','} _docType = ('') ## Init ## def __init__(self, application, transaction, excInfo, formatOptions=None): """Create an exception handler instance. ExceptionHandler instances are created anew for each exception. Instantiating ExceptionHandler completes the process -- the caller need not do anything else. """ Object.__init__(self) # Keep references to the objects self._app = application self._tra = transaction self._exc = excInfo if self._tra: self._req = self._tra.request() self._res = self._tra.response() else: self._req = self._res = None self._formatOptions = formatOptions # Make some repairs, if needed. We use the transaction # & response to get the error page back out # @@ 2000-05-09 ce: Maybe a fresh transaction and # response should always be made for that purpose # @@ 2003-01-10 sd: This requires a transaction which # we do not have. # Making remaining code safe for no transaction. # # if self._res is None: # self._res = HTTPResponse() # self._tra.setResponse(self._res) # Cache MaxValueLengthInExceptionReport for speed self._maxValueLength = self.setting('MaxValueLengthInExceptionReport') # exception occurance time. (overridden by response.endTime()) self._time = time.time() # Get to work self.work() ## Accessors ## def setting(self, name): """Settings are inherited from Application.""" return self._app.setting(name) def servletPathname(self): """The full filesystem path for the servlet.""" try: return self._tra.request().serverSidePath() except Exception: return None def basicServletName(self): """The base name for the servlet (sans directory).""" name = self.servletPathname() if name is None: return 'unknown' else: return os.path.basename(name) ## Exception Handling ## def work(self): """Main error handling method. Invoked by `__init__` to do the main work. This calls `logExceptionToConsole`, then checks settings to see if it should call `saveErrorPage` (to save the error to disk) and `emailException`. It also sends gives a page from `privateErrorPage` or `publicErrorPage` (which one based on ``ShowDebugInfoOnErrors``). """ if self._res: self._res.recordEndTime() self._time = self._res.endTime() checkcache() # update the linecache self.logExceptionToConsole() # Write the error page out to the response if available: if self._res and (not self._res.isCommitted() or self._res.header('Content-type', None) == 'text/html'): if not self._res.isCommitted(): self._res.reset() self._res.setStatus(500, "Servlet Error") if self.setting('ShowDebugInfoOnErrors') == 1: publicErrorPage = self.privateErrorPage() else: publicErrorPage = self.publicErrorPage() self._res.write(publicErrorPage) # Add a large block comment; this prevents IE from overriding the # page with its own generic error 500 page self._res.write('\n' * 100) privateErrorPage = None if self.setting('SaveErrorMessages'): privateErrorPage = self.privateErrorPage() filename = self.saveErrorPage(privateErrorPage) else: filename = None self.logExceptionToDisk(errorMsgFilename=filename) if self.setting('EmailErrors'): if privateErrorPage is None: privateErrorPage = self.privateErrorPage() try: self.emailException(privateErrorPage) except Exception, e: print "Could not send error email:", e def logExceptionToConsole(self, stderr=None): """Log an exception. Logs the time, servlet name and traceback to the console (typically stderr). This usually results in the information appearing in console/terminal from which AppServer was launched. """ if stderr is None: stderr = sys.stderr stderr.write('[%s] [error] WebKit: Error while executing script %s\n' % (asclocaltime(self._time), self.servletPathname())) traceback.print_exc(file=stderr) def publicErrorPage(self): """Return a public error page. Returns a brief error page telling the user that an error has occurred. Body of the message comes from ``UserErrorMessage`` setting. """ return '\n'.join((docType(), '', '', 'Error', htStyle(), '', '', htTitle('Error'), '

' % self.setting('UserErrorMessage'), '', '\n')) def privateErrorPage(self): """Return a private error page. Returns an HTML page intended for the developer with useful information such as the traceback. Most of the contents are generated in `htmlDebugInfo`. """ html = [docType(), '', '', 'Error', htStyle(), '', '', htTitle('Error'), '

' % self.setting('UserErrorMessage')] html.append(self.htmlDebugInfo()) html.extend(['', '\n']) return '\n'.join(html) def htmlDebugInfo(self): """Return the debug info. Return HTML-formatted debugging information about the current exception. Calls `writeHTML`, which uses ``self.write(...)`` to add content. """ self._html = [] self.writeHTML() html = ''.join(self._html) self._html = None return html def writeHTML(self): """Write the traceback. Writes all the parts of the traceback, invoking: * `writeTraceback` * `writeMiscInfo` * `writeTransaction` * `writeEnvironment` * `writeIds` * `writeFancyTraceback` """ self.writeTraceback() self.writeMiscInfo() self.writeTransaction() self.writeEnvironment() self.writeIds() self.writeFancyTraceback() ## Write Methods ## def write(self, s): """Output `s` to the body.""" self._html.append(str(s)) def writeln(self, s): """Output `s` plus a newline.""" self._html.append(str(s)) self._html.append('\n') def writeTitle(self, s): """Output the sub-heading to define a section.""" self.writeln(htTitle(s)) def writeDict(self, d, heading=None, encoded=None): """Output a table-formated dictionary.""" self.writeln(htmlForDict(d, addSpace=self._addSpace, filterValueCallBack=self.filterDictValue, maxValueLength=self._maxValueLength, topHeading=heading, isEncoded=encoded)) def writeAttrs(self, obj, attrNames): """Output object attributes. Writes the attributes of the object as given by attrNames. Tries ``obj._name` first, followed by ``obj.name()``. Is resilient regarding exceptions so as not to spoil the exception report. """ attrs = {} for name in attrNames: value = getattr(obj, '_' + name, Singleton) # go for data attribute try: if value is Singleton: value = getattr(obj, name, Singleton) # go for method if value is Singleton: value = '(could not find attribute or method)' else: try: if callable(value): value = value() value = self.repr(value) except Exception, e: value = '(exception during method call: %s: %s)' \ % (e.__class__.__name__, e) else: value = self.repr(value) except Exception, e: value = '(exception during value processing: %s: %s)' \ % (e.__class__.__name__, e) attrs[name] = value self.writeDict(attrs, ('Attribute', 'Value'), True) ## Traceback sections ## def writeTraceback(self): """Output the traceback. Writes the traceback, with most of the work done by `WebUtils.HTMLForException.HTMLForException`. """ self.writeTitle('Traceback') self.write('

' % self.servletPathname()) self.write(HTMLForException(self._exc, self._formatOptions)) def writeMiscInfo(self): """Output misc info. Write a couple little pieces of information about the environment. """ self.writeTitle('MiscInfo') info = { 'time': asclocaltime(self._time), 'filename': self.servletPathname(), 'os.getcwd()': os.getcwd(), 'sys.path': sys.path, 'sys.version': sys.version, } self.writeDict(info) def writeTransaction(self): """Output transaction. Lets the transaction talk about itself, using `Transaction.writeExceptionReport`. """ if self._tra: self._tra.writeExceptionReport(self) else: self.writeTitle("No current Transaction.") def writeEnvironment(self): """Output environment. Writes the environment this is being run in. This is *not* the environment that was passed in with the request (holding the CGI information) -- it's just the information from the environment that the AppServer is being executed in. """ self.writeTitle('Environment') self.writeDict(os.environ) def writeIds(self): """Output OS identification. Prints some values from the OS (like processor ID). """ self.writeTitle('OS Ids') self.writeDict(osIdDict(), ('Name', 'Value')) def writeFancyTraceback(self): """Output a fancy traceback, using cgitb.""" if self.setting('IncludeFancyTraceback'): self.writeTitle('Fancy Traceback') try: from WebUtils.ExpansiveHTMLForException \ import ExpansiveHTMLForException self.write(ExpansiveHTMLForException( context=self.setting('FancyTracebackContext'))) except Exception: self.write('

Unable to generate a fancy traceback' ' (uncaught exception)!

') try: self.write(HTMLForException(sys.exc_info())) except Exception: self.write('

Unable to even generate a normal traceback' ' of the exception in fancy traceback!

') def saveErrorPage(self, html): """Save the error page. Saves the given HTML error page for later viewing by the developer, and returns the filename used. """ filename = os.path.join(self._app._errorMessagesDir, self.errorPageFilename()) try: f = open(filename, 'w') try: f.write(html) finally: f.close() except IOError: sys.stderr.write('[%s] [error] WebKit: Cannot save error page (%s)\n' % (asclocaltime(self._time), filename)) else: return filename def errorPageFilename(self): """Create filename for error page. Construct a filename for an HTML error page, not including the ``ErrorMessagesDir`` setting (which `saveError` adds on). """ # Note: Using the timestamp and a random number is a poor technique # for filename uniqueness, but it is fast and good enough in practice. return 'Error-%s-%s-%06d.html' % (self.basicServletName(), '-'.join(map(lambda x: '%02d' % x, time.localtime(self._time)[:6])), randint(0, 999999)) def logExceptionToDisk(self, errorMsgFilename=None): """Log the exception to disk. Writes a tuple containing (date-time, filename, pathname, exception-name, exception-data,error report filename) to the errors file (typically 'Errors.csv') in CSV format. Invoked by `handleException`. """ if not self.setting('LogErrors'): return err, msg = self._exc[:2] if isinstance(err, ClassType): err, msg = err.__name__, str(msg) else: # string exception err, msg = '', str(msg or err) logline = (asclocaltime(self._time), self.basicServletName(), self.servletPathname(), err, msg, errorMsgFilename or '') def fixElement(element): element = str(element) if element.find(',') >= 0 or element.find('"') >= 0: element = element.replace('"', '""') element = '"%s"' % element return element logline = map(fixElement, logline) filename = self._app.serverSidePath(self.setting('ErrorLogFilename')) if os.path.exists(filename): f = open(filename, 'a') else: f = open(filename, 'w') f.write('time,filename,pathname,exception name,' 'exception data,error report filename\n') f.write(','.join(logline) + '\n') f.close() def emailException(self, htmlErrMsg): """Email the exception. Emails the exception, either as an attachment, or in the body of the mail. """ if Message: message = Message() else: message = StringIO() writer = MimeWriter(message) # Construct the message headers headers = self.setting('ErrorEmailHeaders').copy() headers['Date'] = dateForEmail() headers['Mime-Version'] = '1.0' headers['Subject'] = headers.get('Subject', '[WebKit Error]') \ + ' %s: %s' % sys.exc_info()[:2] add_header = Message and message.add_header or writer.addheader for h, v in headers.items(): if isinstance(v, ListType): v = ','.join(v) add_header(h, v) # Construct the message body if self.setting('EmailErrorReportAsAttachment'): # start off with a text/plain part text = ('WebKit caught an exception while processing' ' a request for "%s" at %s (timestamp: %s).' ' The plain text traceback from Python is printed below and' ' the full HTML error report from WebKit is attached.\n\n' % (self.servletPathname(), asclocaltime(self._time), self._time)) if Message: message.set_type('multipart/mixed') part = Message() part.set_type('text/plain') body = StringIO() body.write(text) traceback.print_exc(file=body) part.set_payload(body.getvalue()) body.close() message.attach(part) part = Message() add_header = part.add_header else: writer.startmultipartbody('mixed') part = writer.nextpart() body = part.startbody('text/plain') body.write(text) traceback.print_exc(file=body) part = writer.nextpart() add_header = part.addheader # now add htmlErrMsg add_header('Content-Transfer-Encoding', '7bit') add_header('Content-Description', 'HTML version of WebKit error message') if Message: add_header('Content-Disposition', 'attachment', filename='WebKitErrorMsg.html') part.set_type('text/html') part.set_payload(htmlErrMsg) message.attach(part) else: body = part.startbody('text/html; name=WebKitErrorMsg.html') body.write(htmlErrMsg) writer.lastpart() else: if Message: message.set_type('text/html') message.set_payload(htmlErrMsg, 'us-ascii') else: writer.addheader('Content-Type', 'text/html; charset=us-ascii') body = writer.startbody('text/html') body.write(htmlErrMsg) # Send the message server = self.setting('ErrorEmailServer') # This setting can be: server, server:port, server:port:user:password # or server:port:user:password:popserver:popport for "smtp after pop". parts = server.split(':', 5) server = port = user = passwd = None popserver = popssl = popport = None try: server = parts[0] try: port = int(parts[1]) except ValueError: pass user = parts[2] passwd = parts[3] popserver = parts[4] try: popport = int(parts[5]) except ValueError: popport = None if parts[6].lower() == 'ssl': popssl = True except IndexError: pass if user and passwd and popserver: # SMTP after POP if popssl is None and popport == 995: popssl = True popssl = popssl and poplib.POP3_SSL or poplib.POP3 if popport: popserver = popssl(popserver, popport) else: popserver = popssl(popserver) popserver.set_debuglevel(0) popserver.user(user) popserver.pass_(passwd) try: popserver.quit() except Exception: pass if port: server = smtplib.SMTP(server, port) else: server = smtplib.SMTP(server) server.set_debuglevel(0) if user and passwd and not popserver: # SMTP-AUTH try: server.ehlo() if server.has_extn('starttls'): server.starttls() server.ehlo() server.login(user, passwd) except AttributeError: # Python < 2.2 raise smtplib.SMTPException, \ "Python version doesn't support SMTP authentication" if Message: body = message.as_string() else: body = message.getvalue() message.close() server.sendmail(headers['From'], headers['To'], body) try: server.quit() except Exception: pass ## Filtering ## def filterDictValue(self, value, key, dict): """Filter dictionary values. Filters keys from a dict. Currently ignores the dictionary, and just filters based on the key. """ return self.filterValue(value, key) def filterValue(self, value, key): """Filter values. This is the core filter method that is used in all filtering. By default, it simply returns self._hiddenString if the key is in self._hideValuesForField (case insensitive). Subclasses could override for more elaborate filtering techniques. """ try: key = key.lower() except Exception: pass if key in self._hideValuesForFields: return self._hiddenString else: return value ## Utility ## def repr(self, value): """Get HTML encoded representation. Returns the repr() of value already HTML encoded. As a special case, dictionaries are nicely formatted in table. This is a utility method for `writeAttrs`. """ if isinstance(value, DictType): return htmlForDict(value, addSpace=self._addSpace, filterValueCallBack=self.filterDictValue, maxValueLength=self._maxValueLength) else: rep = repr(value) if self._maxValueLength and len(rep) > self._maxValueLength: rep = rep[:self._maxValueLength] + '...' return htmlEncode(rep) ## Misc functions ## def docType(): """Return the document type for the page.""" return ('') def htStyle(): """Return the page style.""" return ('''''') def htTitle(name): """Format a `name` as a section title.""" return ('

%s

' % name) def osIdDict(): """Get all OS id information. Returns a dictionary containing id information such as uid, gid, etc., all obtained from the os module. """ ids = ['egid', 'euid', 'gid', 'groups', 'pgrp', 'pid', 'ppid', 'uid'] attrs = {} for id in ids: getter = 'get' + id try: value = getattr(os, getter)() attrs[id] = value except AttributeError: pass return attrs