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Diffstat (limited to 'cherrypy/_cperror.py')
| -rw-r--r-- | cherrypy/_cperror.py | 609 |
1 files changed, 0 insertions, 609 deletions
diff --git a/cherrypy/_cperror.py b/cherrypy/_cperror.py deleted file mode 100644 index 6256595b..00000000 --- a/cherrypy/_cperror.py +++ /dev/null @@ -1,609 +0,0 @@ -"""Exception classes for CherryPy. - -CherryPy provides (and uses) exceptions for declaring that the HTTP response -should be a status other than the default "200 OK". You can ``raise`` them like -normal Python exceptions. You can also call them and they will raise -themselves; this means you can set an -:class:`HTTPError<cherrypy._cperror.HTTPError>` -or :class:`HTTPRedirect<cherrypy._cperror.HTTPRedirect>` as the -:attr:`request.handler<cherrypy._cprequest.Request.handler>`. - -.. _redirectingpost: - -Redirecting POST -================ - -When you GET a resource and are redirected by the server to another Location, -there's generally no problem since GET is both a "safe method" (there should -be no side-effects) and an "idempotent method" (multiple calls are no different -than a single call). - -POST, however, is neither safe nor idempotent--if you -charge a credit card, you don't want to be charged twice by a redirect! - -For this reason, *none* of the 3xx responses permit a user-agent (browser) to -resubmit a POST on redirection without first confirming the action with the -user: - -===== ================================= =========== -300 Multiple Choices Confirm with the user -301 Moved Permanently Confirm with the user -302 Found (Object moved temporarily) Confirm with the user -303 See Other GET the new URI--no confirmation -304 Not modified (for conditional GET only--POST should not raise this error) -305 Use Proxy Confirm with the user -307 Temporary Redirect Confirm with the user -===== ================================= =========== - -However, browsers have historically implemented these restrictions poorly; -in particular, many browsers do not force the user to confirm 301, 302 -or 307 when redirecting POST. For this reason, CherryPy defaults to 303, -which most user-agents appear to have implemented correctly. Therefore, if -you raise HTTPRedirect for a POST request, the user-agent will most likely -attempt to GET the new URI (without asking for confirmation from the user). -We realize this is confusing for developers, but it's the safest thing we -could do. You are of course free to raise ``HTTPRedirect(uri, status=302)`` -or any other 3xx status if you know what you're doing, but given the -environment, we couldn't let any of those be the default. - -Custom Error Handling -===================== - -.. image:: /refman/cperrors.gif - -Anticipated HTTP responses --------------------------- - -The 'error_page' config namespace can be used to provide custom HTML output for -expected responses (like 404 Not Found). Supply a filename from which the -output will be read. The contents will be interpolated with the values -%(status)s, %(message)s, %(traceback)s, and %(version)s using plain old Python -`string formatting <http://docs.python.org/2/library/stdtypes.html#string-formatting-operations>`_. - -:: - - _cp_config = { - 'error_page.404': os.path.join(localDir, "static/index.html") - } - - -Beginning in version 3.1, you may also provide a function or other callable as -an error_page entry. It will be passed the same status, message, traceback and -version arguments that are interpolated into templates:: - - def error_page_402(status, message, traceback, version): - return "Error %s - Well, I'm very sorry but you haven't paid!" % status - cherrypy.config.update({'error_page.402': error_page_402}) - -Also in 3.1, in addition to the numbered error codes, you may also supply -"error_page.default" to handle all codes which do not have their own error_page -entry. - - - -Unanticipated errors --------------------- - -CherryPy also has a generic error handling mechanism: whenever an unanticipated -error occurs in your code, it will call -:func:`Request.error_response<cherrypy._cprequest.Request.error_response>` to -set the response status, headers, and body. By default, this is the same -output as -:class:`HTTPError(500) <cherrypy._cperror.HTTPError>`. If you want to provide -some other behavior, you generally replace "request.error_response". - -Here is some sample code that shows how to display a custom error message and -send an e-mail containing the error:: - - from cherrypy import _cperror - - def handle_error(): - cherrypy.response.status = 500 - cherrypy.response.body = [ - "<html><body>Sorry, an error occured</body></html>" - ] - sendMail('error@domain.com', - 'Error in your web app', - _cperror.format_exc()) - - class Root: - _cp_config = {'request.error_response': handle_error} - - -Note that you have to explicitly set -:attr:`response.body <cherrypy._cprequest.Response.body>` -and not simply return an error message as a result. -""" - -from cgi import escape as _escape -from sys import exc_info as _exc_info -from traceback import format_exception as _format_exception -from cherrypy._cpcompat import basestring, bytestr, iteritems, ntob -from cherrypy._cpcompat import tonative, urljoin as _urljoin -from cherrypy.lib import httputil as _httputil - - -class CherryPyException(Exception): - - """A base class for CherryPy exceptions.""" - pass - - -class TimeoutError(CherryPyException): - - """Exception raised when Response.timed_out is detected.""" - pass - - -class InternalRedirect(CherryPyException): - - """Exception raised to switch to the handler for a different URL. - - This exception will redirect processing to another path within the site - (without informing the client). Provide the new path as an argument when - raising the exception. Provide any params in the querystring for the new - URL. - """ - - def __init__(self, path, query_string=""): - import cherrypy - self.request = cherrypy.serving.request - - self.query_string = query_string - if "?" in path: - # Separate any params included in the path - path, self.query_string = path.split("?", 1) - - # Note that urljoin will "do the right thing" whether url is: - # 1. a URL relative to root (e.g. "/dummy") - # 2. a URL relative to the current path - # Note that any query string will be discarded. - path = _urljoin(self.request.path_info, path) - - # Set a 'path' member attribute so that code which traps this - # error can have access to it. - self.path = path - - CherryPyException.__init__(self, path, self.query_string) - - -class HTTPRedirect(CherryPyException): - - """Exception raised when the request should be redirected. - - This exception will force a HTTP redirect to the URL or URL's you give it. - The new URL must be passed as the first argument to the Exception, - e.g., HTTPRedirect(newUrl). Multiple URLs are allowed in a list. - If a URL is absolute, it will be used as-is. If it is relative, it is - assumed to be relative to the current cherrypy.request.path_info. - - If one of the provided URL is a unicode object, it will be encoded - using the default encoding or the one passed in parameter. - - There are multiple types of redirect, from which you can select via the - ``status`` argument. If you do not provide a ``status`` arg, it defaults to - 303 (or 302 if responding with HTTP/1.0). - - Examples:: - - raise cherrypy.HTTPRedirect("") - raise cherrypy.HTTPRedirect("/abs/path", 307) - raise cherrypy.HTTPRedirect(["path1", "path2?a=1&b=2"], 301) - - See :ref:`redirectingpost` for additional caveats. - """ - - status = None - """The integer HTTP status code to emit.""" - - urls = None - """The list of URL's to emit.""" - - encoding = 'utf-8' - """The encoding when passed urls are not native strings""" - - def __init__(self, urls, status=None, encoding=None): - import cherrypy - request = cherrypy.serving.request - - if isinstance(urls, basestring): - urls = [urls] - - abs_urls = [] - for url in urls: - url = tonative(url, encoding or self.encoding) - - # Note that urljoin will "do the right thing" whether url is: - # 1. a complete URL with host (e.g. "http://www.example.com/test") - # 2. a URL relative to root (e.g. "/dummy") - # 3. a URL relative to the current path - # Note that any query string in cherrypy.request is discarded. - url = _urljoin(cherrypy.url(), url) - abs_urls.append(url) - self.urls = abs_urls - - # RFC 2616 indicates a 301 response code fits our goal; however, - # browser support for 301 is quite messy. Do 302/303 instead. See - # http://www.alanflavell.org.uk/www/post-redirect.html - if status is None: - if request.protocol >= (1, 1): - status = 303 - else: - status = 302 - else: - status = int(status) - if status < 300 or status > 399: - raise ValueError("status must be between 300 and 399.") - - self.status = status - CherryPyException.__init__(self, abs_urls, status) - - def set_response(self): - """Modify cherrypy.response status, headers, and body to represent - self. - - CherryPy uses this internally, but you can also use it to create an - HTTPRedirect object and set its output without *raising* the exception. - """ - import cherrypy - response = cherrypy.serving.response - response.status = status = self.status - - if status in (300, 301, 302, 303, 307): - response.headers['Content-Type'] = "text/html;charset=utf-8" - # "The ... URI SHOULD be given by the Location field - # in the response." - response.headers['Location'] = self.urls[0] - - # "Unless the request method was HEAD, the entity of the response - # SHOULD contain a short hypertext note with a hyperlink to the - # new URI(s)." - msg = { - 300: "This resource can be found at ", - 301: "This resource has permanently moved to ", - 302: "This resource resides temporarily at ", - 303: "This resource can be found at ", - 307: "This resource has moved temporarily to ", - }[status] - msg += '<a href=%s>%s</a>.' - from xml.sax import saxutils - msgs = [msg % (saxutils.quoteattr(u), u) for u in self.urls] - response.body = ntob("<br />\n".join(msgs), 'utf-8') - # Previous code may have set C-L, so we have to reset it - # (allow finalize to set it). - response.headers.pop('Content-Length', None) - elif status == 304: - # Not Modified. - # "The response MUST include the following header fields: - # Date, unless its omission is required by section 14.18.1" - # The "Date" header should have been set in Response.__init__ - - # "...the response SHOULD NOT include other entity-headers." - for key in ('Allow', 'Content-Encoding', 'Content-Language', - 'Content-Length', 'Content-Location', 'Content-MD5', - 'Content-Range', 'Content-Type', 'Expires', - 'Last-Modified'): - if key in response.headers: - del response.headers[key] - - # "The 304 response MUST NOT contain a message-body." - response.body = None - # Previous code may have set C-L, so we have to reset it. - response.headers.pop('Content-Length', None) - elif status == 305: - # Use Proxy. - # self.urls[0] should be the URI of the proxy. - response.headers['Location'] = self.urls[0] - response.body = None - # Previous code may have set C-L, so we have to reset it. - response.headers.pop('Content-Length', None) - else: - raise ValueError("The %s status code is unknown." % status) - - def __call__(self): - """Use this exception as a request.handler (raise self).""" - raise self - - -def clean_headers(status): - """Remove any headers which should not apply to an error response.""" - import cherrypy - - response = cherrypy.serving.response - - # Remove headers which applied to the original content, - # but do not apply to the error page. - respheaders = response.headers - for key in ["Accept-Ranges", "Age", "ETag", "Location", "Retry-After", - "Vary", "Content-Encoding", "Content-Length", "Expires", - "Content-Location", "Content-MD5", "Last-Modified"]: - if key in respheaders: - del respheaders[key] - - if status != 416: - # A server sending a response with status code 416 (Requested - # range not satisfiable) SHOULD include a Content-Range field - # with a byte-range-resp-spec of "*". The instance-length - # specifies the current length of the selected resource. - # A response with status code 206 (Partial Content) MUST NOT - # include a Content-Range field with a byte-range- resp-spec of "*". - if "Content-Range" in respheaders: - del respheaders["Content-Range"] - - -class HTTPError(CherryPyException): - - """Exception used to return an HTTP error code (4xx-5xx) to the client. - - This exception can be used to automatically send a response using a - http status code, with an appropriate error page. It takes an optional - ``status`` argument (which must be between 400 and 599); it defaults to 500 - ("Internal Server Error"). It also takes an optional ``message`` argument, - which will be returned in the response body. See - `RFC2616 <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4>`_ - for a complete list of available error codes and when to use them. - - Examples:: - - raise cherrypy.HTTPError(403) - raise cherrypy.HTTPError( - "403 Forbidden", "You are not allowed to access this resource.") - """ - - status = None - """The HTTP status code. May be of type int or str (with a Reason-Phrase). - """ - - code = None - """The integer HTTP status code.""" - - reason = None - """The HTTP Reason-Phrase string.""" - - def __init__(self, status=500, message=None): - self.status = status - try: - self.code, self.reason, defaultmsg = _httputil.valid_status(status) - except ValueError: - raise self.__class__(500, _exc_info()[1].args[0]) - - if self.code < 400 or self.code > 599: - raise ValueError("status must be between 400 and 599.") - - # See http://www.python.org/dev/peps/pep-0352/ - # self.message = message - self._message = message or defaultmsg - CherryPyException.__init__(self, status, message) - - def set_response(self): - """Modify cherrypy.response status, headers, and body to represent - self. - - CherryPy uses this internally, but you can also use it to create an - HTTPError object and set its output without *raising* the exception. - """ - import cherrypy - - response = cherrypy.serving.response - - clean_headers(self.code) - - # In all cases, finalize will be called after this method, - # so don't bother cleaning up response values here. - response.status = self.status - tb = None - if cherrypy.serving.request.show_tracebacks: - tb = format_exc() - - response.headers.pop('Content-Length', None) - - content = self.get_error_page(self.status, traceback=tb, - message=self._message) - response.body = content - - _be_ie_unfriendly(self.code) - - def get_error_page(self, *args, **kwargs): - return get_error_page(*args, **kwargs) - - def __call__(self): - """Use this exception as a request.handler (raise self).""" - raise self - - -class NotFound(HTTPError): - - """Exception raised when a URL could not be mapped to any handler (404). - - This is equivalent to raising - :class:`HTTPError("404 Not Found") <cherrypy._cperror.HTTPError>`. - """ - - def __init__(self, path=None): - if path is None: - import cherrypy - request = cherrypy.serving.request - path = request.script_name + request.path_info - self.args = (path,) - HTTPError.__init__(self, 404, "The path '%s' was not found." % path) - - -_HTTPErrorTemplate = '''<!DOCTYPE html PUBLIC -"-//W3C//DTD XHTML 1.0 Transitional//EN" -"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> -<html> -<head> - <meta http-equiv="Content-Type" content="text/html; charset=utf-8"></meta> - <title>%(status)s</title> - <style type="text/css"> - #powered_by { - margin-top: 20px; - border-top: 2px solid black; - font-style: italic; - } - - #traceback { - color: red; - } - </style> -</head> - <body> - <h2>%(status)s</h2> - <p>%(message)s</p> - <pre id="traceback">%(traceback)s</pre> - <div id="powered_by"> - <span> - Powered by <a href="http://www.cherrypy.org">CherryPy %(version)s</a> - </span> - </div> - </body> -</html> -''' - - -def get_error_page(status, **kwargs): - """Return an HTML page, containing a pretty error response. - - status should be an int or a str. - kwargs will be interpolated into the page template. - """ - import cherrypy - - try: - code, reason, message = _httputil.valid_status(status) - except ValueError: - raise cherrypy.HTTPError(500, _exc_info()[1].args[0]) - - # We can't use setdefault here, because some - # callers send None for kwarg values. - if kwargs.get('status') is None: - kwargs['status'] = "%s %s" % (code, reason) - if kwargs.get('message') is None: - kwargs['message'] = message - if kwargs.get('traceback') is None: - kwargs['traceback'] = '' - if kwargs.get('version') is None: - kwargs['version'] = cherrypy.__version__ - - for k, v in iteritems(kwargs): - if v is None: - kwargs[k] = "" - else: - kwargs[k] = _escape(kwargs[k]) - - # Use a custom template or callable for the error page? - pages = cherrypy.serving.request.error_page - error_page = pages.get(code) or pages.get('default') - - # Default template, can be overridden below. - template = _HTTPErrorTemplate - if error_page: - try: - if hasattr(error_page, '__call__'): - # The caller function may be setting headers manually, - # so we delegate to it completely. We may be returning - # an iterator as well as a string here. - # - # We *must* make sure any content is not unicode. - result = error_page(**kwargs) - if cherrypy.lib.is_iterator(result): - from cherrypy.lib.encoding import UTF8StreamEncoder - return UTF8StreamEncoder(result) - elif isinstance(result, cherrypy._cpcompat.unicodestr): - return result.encode('utf-8') - else: - if not isinstance(result, cherrypy._cpcompat.bytestr): - raise ValueError('error page function did not ' - 'return a bytestring, unicodestring or an ' - 'iterator - returned object of type %s.' - % (type(result).__name__)) - return result - else: - # Load the template from this path. - template = tonative(open(error_page, 'rb').read()) - except: - e = _format_exception(*_exc_info())[-1] - m = kwargs['message'] - if m: - m += "<br />" - m += "In addition, the custom error page failed:\n<br />%s" % e - kwargs['message'] = m - - response = cherrypy.serving.response - response.headers['Content-Type'] = "text/html;charset=utf-8" - result = template % kwargs - return result.encode('utf-8') - - - -_ie_friendly_error_sizes = { - 400: 512, 403: 256, 404: 512, 405: 256, - 406: 512, 408: 512, 409: 512, 410: 256, - 500: 512, 501: 512, 505: 512, -} - - -def _be_ie_unfriendly(status): - import cherrypy - response = cherrypy.serving.response - - # For some statuses, Internet Explorer 5+ shows "friendly error - # messages" instead of our response.body if the body is smaller - # than a given size. Fix this by returning a body over that size - # (by adding whitespace). - # See http://support.microsoft.com/kb/q218155/ - s = _ie_friendly_error_sizes.get(status, 0) - if s: - s += 1 - # Since we are issuing an HTTP error status, we assume that - # the entity is short, and we should just collapse it. - content = response.collapse_body() - l = len(content) - if l and l < s: - # IN ADDITION: the response must be written to IE - # in one chunk or it will still get replaced! Bah. - content = content + (ntob(" ") * (s - l)) - response.body = content - response.headers['Content-Length'] = str(len(content)) - - -def format_exc(exc=None): - """Return exc (or sys.exc_info if None), formatted.""" - try: - if exc is None: - exc = _exc_info() - if exc == (None, None, None): - return "" - import traceback - return "".join(traceback.format_exception(*exc)) - finally: - del exc - - -def bare_error(extrabody=None): - """Produce status, headers, body for a critical error. - - Returns a triple without calling any other questionable functions, - so it should be as error-free as possible. Call it from an HTTP server - if you get errors outside of the request. - - If extrabody is None, a friendly but rather unhelpful error message - is set in the body. If extrabody is a string, it will be appended - as-is to the body. - """ - - # The whole point of this function is to be a last line-of-defense - # in handling errors. That is, it must not raise any errors itself; - # it cannot be allowed to fail. Therefore, don't add to it! - # In particular, don't call any other CP functions. - - body = ntob("Unrecoverable error in the server.") - if extrabody is not None: - if not isinstance(extrabody, bytestr): - extrabody = extrabody.encode('utf-8') - body += ntob("\n") + extrabody - - return (ntob("500 Internal Server Error"), - [(ntob('Content-Type'), ntob('text/plain')), - (ntob('Content-Length'), ntob(str(len(body)), 'ISO-8859-1'))], - [body]) |