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Diffstat (limited to 'paste/exceptions/errormiddleware.py')
| -rw-r--r-- | paste/exceptions/errormiddleware.py | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/paste/exceptions/errormiddleware.py b/paste/exceptions/errormiddleware.py new file mode 100644 index 0000000..95c1261 --- /dev/null +++ b/paste/exceptions/errormiddleware.py @@ -0,0 +1,466 @@ +# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org) +# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php + +""" +Error handler middleware +""" +import sys +import traceback +import cgi +from six.moves import cStringIO as StringIO +from paste.exceptions import formatter, collector, reporter +from paste import wsgilib +from paste import request +import six + +__all__ = ['ErrorMiddleware', 'handle_exception'] + +class _NoDefault(object): + def __repr__(self): + return '<NoDefault>' +NoDefault = _NoDefault() + +class ErrorMiddleware(object): + + """ + Error handling middleware + + Usage:: + + error_catching_wsgi_app = ErrorMiddleware(wsgi_app) + + Settings: + + ``debug``: + If true, then tracebacks will be shown in the browser. + + ``error_email``: + an email address (or list of addresses) to send exception + reports to + + ``error_log``: + a filename to append tracebacks to + + ``show_exceptions_in_wsgi_errors``: + If true, then errors will be printed to ``wsgi.errors`` + (frequently a server error log, or stderr). + + ``from_address``, ``smtp_server``, ``error_subject_prefix``, ``smtp_username``, ``smtp_password``, ``smtp_use_tls``: + variables to control the emailed exception reports + + ``error_message``: + When debug mode is off, the error message to show to users. + + ``xmlhttp_key``: + When this key (default ``_``) is in the request GET variables + (not POST!), expect that this is an XMLHttpRequest, and the + response should be more minimal; it should not be a complete + HTML page. + + Environment Configuration: + + ``paste.throw_errors``: + If this setting in the request environment is true, then this + middleware is disabled. This can be useful in a testing situation + where you don't want errors to be caught and transformed. + + ``paste.expected_exceptions``: + When this middleware encounters an exception listed in this + environment variable and when the ``start_response`` has not + yet occurred, the exception will be re-raised instead of being + caught. This should generally be set by middleware that may + (but probably shouldn't be) installed above this middleware, + and wants to get certain exceptions. Exceptions raised after + ``start_response`` have been called are always caught since + by definition they are no longer expected. + + """ + + def __init__(self, application, global_conf=None, + debug=NoDefault, + error_email=None, + error_log=None, + show_exceptions_in_wsgi_errors=NoDefault, + from_address=None, + smtp_server=None, + smtp_username=None, + smtp_password=None, + smtp_use_tls=False, + error_subject_prefix=None, + error_message=None, + xmlhttp_key=None): + from paste.util import converters + self.application = application + # @@: global_conf should be handled elsewhere in a separate + # function for the entry point + if global_conf is None: + global_conf = {} + if debug is NoDefault: + debug = converters.asbool(global_conf.get('debug')) + if show_exceptions_in_wsgi_errors is NoDefault: + show_exceptions_in_wsgi_errors = converters.asbool(global_conf.get('show_exceptions_in_wsgi_errors')) + self.debug_mode = converters.asbool(debug) + if error_email is None: + error_email = (global_conf.get('error_email') + or global_conf.get('admin_email') + or global_conf.get('webmaster_email') + or global_conf.get('sysadmin_email')) + self.error_email = converters.aslist(error_email) + self.error_log = error_log + self.show_exceptions_in_wsgi_errors = show_exceptions_in_wsgi_errors + if from_address is None: + from_address = global_conf.get('error_from_address', 'errors@localhost') + self.from_address = from_address + if smtp_server is None: + smtp_server = global_conf.get('smtp_server', 'localhost') + self.smtp_server = smtp_server + self.smtp_username = smtp_username or global_conf.get('smtp_username') + self.smtp_password = smtp_password or global_conf.get('smtp_password') + self.smtp_use_tls = smtp_use_tls or converters.asbool(global_conf.get('smtp_use_tls')) + self.error_subject_prefix = error_subject_prefix or '' + if error_message is None: + error_message = global_conf.get('error_message') + self.error_message = error_message + if xmlhttp_key is None: + xmlhttp_key = global_conf.get('xmlhttp_key', '_') + self.xmlhttp_key = xmlhttp_key + + def __call__(self, environ, start_response): + """ + The WSGI application interface. + """ + # We want to be careful about not sending headers twice, + # and the content type that the app has committed to (if there + # is an exception in the iterator body of the response) + if environ.get('paste.throw_errors'): + return self.application(environ, start_response) + environ['paste.throw_errors'] = True + + try: + __traceback_supplement__ = Supplement, self, environ + sr_checker = ResponseStartChecker(start_response) + app_iter = self.application(environ, sr_checker) + return self.make_catching_iter(app_iter, environ, sr_checker) + except: + exc_info = sys.exc_info() + try: + for expect in environ.get('paste.expected_exceptions', []): + if isinstance(exc_info[1], expect): + raise + start_response('500 Internal Server Error', + [('content-type', 'text/html')], + exc_info) + # @@: it would be nice to deal with bad content types here + response = self.exception_handler(exc_info, environ) + if six.PY3: + response = response.encode('utf8') + return [response] + finally: + # clean up locals... + exc_info = None + + def make_catching_iter(self, app_iter, environ, sr_checker): + if isinstance(app_iter, (list, tuple)): + # These don't raise + return app_iter + return CatchingIter(app_iter, environ, sr_checker, self) + + def exception_handler(self, exc_info, environ): + simple_html_error = False + if self.xmlhttp_key: + get_vars = request.parse_querystring(environ) + if dict(get_vars).get(self.xmlhttp_key): + simple_html_error = True + return handle_exception( + exc_info, environ['wsgi.errors'], + html=True, + debug_mode=self.debug_mode, + error_email=self.error_email, + error_log=self.error_log, + show_exceptions_in_wsgi_errors=self.show_exceptions_in_wsgi_errors, + error_email_from=self.from_address, + smtp_server=self.smtp_server, + smtp_username=self.smtp_username, + smtp_password=self.smtp_password, + smtp_use_tls=self.smtp_use_tls, + error_subject_prefix=self.error_subject_prefix, + error_message=self.error_message, + simple_html_error=simple_html_error) + +class ResponseStartChecker(object): + def __init__(self, start_response): + self.start_response = start_response + self.response_started = False + + def __call__(self, *args): + self.response_started = True + self.start_response(*args) + +class CatchingIter(object): + + """ + A wrapper around the application iterator that will catch + exceptions raised by the a generator, or by the close method, and + display or report as necessary. + """ + + def __init__(self, app_iter, environ, start_checker, error_middleware): + self.app_iterable = app_iter + self.app_iterator = iter(app_iter) + self.environ = environ + self.start_checker = start_checker + self.error_middleware = error_middleware + self.closed = False + + def __iter__(self): + return self + + def next(self): + __traceback_supplement__ = ( + Supplement, self.error_middleware, self.environ) + if self.closed: + raise StopIteration + try: + return self.app_iterator.next() + except StopIteration: + self.closed = True + close_response = self._close() + if close_response is not None: + return close_response + else: + raise StopIteration + except: + self.closed = True + close_response = self._close() + exc_info = sys.exc_info() + response = self.error_middleware.exception_handler( + exc_info, self.environ) + if close_response is not None: + response += ( + '<hr noshade>Error in .close():<br>%s' + % close_response) + + if not self.start_checker.response_started: + self.start_checker('500 Internal Server Error', + [('content-type', 'text/html')], + exc_info) + + if six.PY3: + response = response.encode('utf8') + return response + __next__ = next + + def close(self): + # This should at least print something to stderr if the + # close method fails at this point + if not self.closed: + self._close() + + def _close(self): + """Close and return any error message""" + if not hasattr(self.app_iterable, 'close'): + return None + try: + self.app_iterable.close() + return None + except: + close_response = self.error_middleware.exception_handler( + sys.exc_info(), self.environ) + return close_response + + +class Supplement(object): + + """ + This is a supplement used to display standard WSGI information in + the traceback. + """ + + def __init__(self, middleware, environ): + self.middleware = middleware + self.environ = environ + self.source_url = request.construct_url(environ) + + def extraData(self): + data = {} + cgi_vars = data[('extra', 'CGI Variables')] = {} + wsgi_vars = data[('extra', 'WSGI Variables')] = {} + hide_vars = ['paste.config', 'wsgi.errors', 'wsgi.input', + 'wsgi.multithread', 'wsgi.multiprocess', + 'wsgi.run_once', 'wsgi.version', + 'wsgi.url_scheme'] + for name, value in self.environ.items(): + if name.upper() == name: + if value: + cgi_vars[name] = value + elif name not in hide_vars: + wsgi_vars[name] = value + if self.environ['wsgi.version'] != (1, 0): + wsgi_vars['wsgi.version'] = self.environ['wsgi.version'] + proc_desc = tuple([int(bool(self.environ[key])) + for key in ('wsgi.multiprocess', + 'wsgi.multithread', + 'wsgi.run_once')]) + wsgi_vars['wsgi process'] = self.process_combos[proc_desc] + wsgi_vars['application'] = self.middleware.application + if 'paste.config' in self.environ: + data[('extra', 'Configuration')] = dict(self.environ['paste.config']) + return data + + process_combos = { + # multiprocess, multithread, run_once + (0, 0, 0): 'Non-concurrent server', + (0, 1, 0): 'Multithreaded', + (1, 0, 0): 'Multiprocess', + (1, 1, 0): 'Multi process AND threads (?)', + (0, 0, 1): 'Non-concurrent CGI', + (0, 1, 1): 'Multithread CGI (?)', + (1, 0, 1): 'CGI', + (1, 1, 1): 'Multi thread/process CGI (?)', + } + +def handle_exception(exc_info, error_stream, html=True, + debug_mode=False, + error_email=None, + error_log=None, + show_exceptions_in_wsgi_errors=False, + error_email_from='errors@localhost', + smtp_server='localhost', + smtp_username=None, + smtp_password=None, + smtp_use_tls=False, + error_subject_prefix='', + error_message=None, + simple_html_error=False, + ): + """ + For exception handling outside of a web context + + Use like:: + + import sys + from paste.exceptions.errormiddleware import handle_exception + try: + do stuff + except: + handle_exception( + sys.exc_info(), sys.stderr, html=False, ...other config...) + + If you want to report, but not fully catch the exception, call + ``raise`` after ``handle_exception``, which (when given no argument) + will reraise the exception. + """ + reported = False + exc_data = collector.collect_exception(*exc_info) + extra_data = '' + if error_email: + rep = reporter.EmailReporter( + to_addresses=error_email, + from_address=error_email_from, + smtp_server=smtp_server, + smtp_username=smtp_username, + smtp_password=smtp_password, + smtp_use_tls=smtp_use_tls, + subject_prefix=error_subject_prefix) + rep_err = send_report(rep, exc_data, html=html) + if rep_err: + extra_data += rep_err + else: + reported = True + if error_log: + rep = reporter.LogReporter( + filename=error_log) + rep_err = send_report(rep, exc_data, html=html) + if rep_err: + extra_data += rep_err + else: + reported = True + if show_exceptions_in_wsgi_errors: + rep = reporter.FileReporter( + file=error_stream) + rep_err = send_report(rep, exc_data, html=html) + if rep_err: + extra_data += rep_err + else: + reported = True + else: + line = ('Error - %s: %s\n' + % (exc_data.exception_type, exc_data.exception_value)) + if six.PY3: + line = line.encode('utf8') + error_stream.write(line) + if html: + if debug_mode and simple_html_error: + return_error = formatter.format_html( + exc_data, include_hidden_frames=False, + include_reusable=False, show_extra_data=False) + reported = True + elif debug_mode and not simple_html_error: + error_html = formatter.format_html( + exc_data, + include_hidden_frames=True, + include_reusable=False) + head_html = formatter.error_css + formatter.hide_display_js + return_error = error_template( + head_html, error_html, extra_data) + extra_data = '' + reported = True + else: + msg = error_message or ''' + An error occurred. See the error logs for more information. + (Turn debug on to display exception reports here) + ''' + return_error = error_template('', msg, '') + else: + return_error = None + if not reported and error_stream: + err_report = formatter.format_text(exc_data, show_hidden_frames=True) + err_report += '\n' + '-'*60 + '\n' + error_stream.write(err_report) + if extra_data: + error_stream.write(extra_data) + return return_error + +def send_report(rep, exc_data, html=True): + try: + rep.report(exc_data) + except: + output = StringIO() + traceback.print_exc(file=output) + if html: + return """ + <p>Additionally an error occurred while sending the %s report: + + <pre>%s</pre> + </p>""" % ( + cgi.escape(str(rep)), output.getvalue()) + else: + return ( + "Additionally an error occurred while sending the " + "%s report:\n%s" % (str(rep), output.getvalue())) + else: + return '' + +def error_template(head_html, exception, extra): + return ''' + <html> + <head> + <title>Server Error</title> + %s + </head> + <body> + <h1>Server Error</h1> + %s + %s + </body> + </html>''' % (head_html, exception, extra) + +def make_error_middleware(app, global_conf, **kw): + return ErrorMiddleware(app, global_conf=global_conf, **kw) + +doc_lines = ErrorMiddleware.__doc__.splitlines(True) +for i in range(len(doc_lines)): + if doc_lines[i].strip().startswith('Settings'): + make_error_middleware.__doc__ = ''.join(doc_lines[i:]) + break +del i, doc_lines |