These are both timeout errors, but who is timing out in a 408 vs. a 504?
From w3, 408 is defined as:
The client did not produce a request within the time that the server was prepared to wait. The client MAY repeat the request without modifications at any later time.
...And 504 is:
The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the URI (e.g. HTTP, FTP, LDAP) or some other auxiliary server (e.g. DNS) it needed to access in attempting to complete the request.
So who is the 'client' in the 408 if not an intermediary server? If it's an actual end user, how does a server know to wait for their request before they have made it?
The client is the browser or client application. The server knows to wait for a request because it has accepted a connection, or already read part of the request, say a header or two.
Amazon documentation tells: http://docs.aws.amazon.com/en_en/elasticloadbalancing/latest/classic/ts-elb-error-message.html#ts-elb-errorcodes-http408
Indicates that the client cancelled the request or failed to send a full request
Mozilla documentation tells: https://developer.mozilla.org/en/docs/Web/HTTP/Status/408
The HTTP 408 Request Timeout response status code means that the server would like to shut down this unused connection. It is sent on an idle connection by some servers, even without any previous request by the client
Related
I’m writing small http server and try to understand timeout issues.
RFC7230 don’t give an answer for the question what are conditions that forces server to send timeout (408 Request timeout). Should it be sent when client sends request too long? Or if nothing was sent in opened connection for some time? What the logic should be? Is there any standard or behavioral model?
The whole process would be
server wait for a request -> read request header -> read request body -> prepare response header -> prepare response body
So if the request take to long Ex: 30 seconds, then server will return a response header with code 408 Request timeout
The next case is when server can read whole request header and body and try to process that request but can not complete in an amount of time then it will return 504 Gateway Timeout or 503 Service Unavailable.
It will depend of each situation. But the rule is always use 4xx for request errors and 5xx for server errors
The short explaination for thoose http code is listed here: HTTP response status codes
I am using calculate route API to calculate distance and time from origin to destination. Wanted to validate some error codes that I have observed in error code documentation.
One of which is 500 Internal error.
Description for this says "There is a server configuration issue" can I get a clear reason for cause of this error! What does server configuration Issue mean?!
Response status codes beginning with the digit "5" indicate cases in which the server is aware that it has erred or is incapable of performing the request.
500 Internal Server Error
The server encountered an unexpected condition which prevented it from fulfilling the request.
501 Not Implemented
The server does not support the functionality required to fulfill the request. This is the appropriate response when the server does not recognize the request method and is not capable of supporting it for any resource.
502 Bad Gateway
The server, while acting as a gateway or proxy, received an invalid response from the upstream server it accessed in attempting to fulfill the request.
503 Service Unavailable
The server is currently unable to handle the request due to a temporary overloading or maintenance of the server. The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the delay MAY be indicated in a Retry-After header. If no Retry-After is given, the client SHOULD handle the response as it would for a 500 response.
504 Gateway Timeout
The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the URI (e.g. HTTP, FTP, LDAP) or some other auxiliary server (e.g. DNS) it needed to access in attempting to complete the request.
505 HTTP Version Not Supported
The server does not support, or refuses to support, the HTTP protocol version that was used in the request message. The server is indicating that it is unable or unwilling to complete the request using the same major version as the client, as described in section 3.1, other than with this error message. The response SHOULD contain an entity describing why that version is not supported and what other protocols are supported by that server.
I was playing around my redis server and tried to hit with the browser. Redis detected it as a Cross Protocol Scripting attack and returned an error in the response's payload. However, when I checked the window's console, it turned out that the request was returned without a status code. So, in such cases what status code should a client assume?
There is no such thing as a response without a status code. Every HTTP response has one, and if you didn't get one it means:
You weren't talking to a HTTP server.
The HTTP server did something it shouldn't.
In each case I would expect your HTTP client to throw some kind of exception but not return a Http Response object.
I'm trying to diagnose a web service that sits behind some load balancers and proxies. Under load, one of the servers along the way starts to return HTTP 504 errors, which indicates a gateway timeout. With that background out of the way, here is my question:
When a proxy makes a request to the destination server, and the destination server receives the request but doesn't respond in time (thus exceeding the timeout), resulting in a 504, what happens when the destination server does eventually respond? Does it know somehow that the requestor is no longer interested in a response? Does it happily send a response with no idea that the gateway already sent HTTP error response back to the client? Any insight would be much appreciated.
It's implementation-dependent, but any proxy that conforms to RFC 2616 section 8.1.2.1 should include Connection: close on the 504 and close the connection back to the client so it can no longer be associated with anything coming back from the defunct server connection, which should also be closed. Under load there is the potential for race conditions in this scenario so you could be looking at a bug in your proxy.
If the client then wants to make further requests it'll create a new connection to the proxy which will result in a new connection to the backend.
I am creating a Netty Client which sends HTTP request to POST data to server.To increase the performance what i did was using Keep alive Http request(i know that in HTTP 1.1 all requests are keep alive by default, so i am making sure that Connection header is not set to close while sending the Http request) so that it uses the same channel to send the Http Request. Now when i send the Http request to the correct URL,i.e. if i get HttpResponse Status OK in return from server, i am able to send the next Http Request properly but when i send the Http Request for which i get BAD REQUEST or SERVICE UNAVAILABLE or something other than OK then i am unable to send the next request that is the channel future f.success() returned after calling channel.write(request) is false. I am unable to understand why it happens. I have followed the same model of coding as done in HttpSnoopClient example given in netty,
except i have removed the connection:close header & even the client handler is the same as that given in snoop client, also i have am instantiating the bootstrap only once at the starting
I tried getting channelFuture f.cause().getMessage() but it was null it seems