I would like this exception to be caused:
// ErrBodyNotAllowed is returned by ResponseWriter.Write calls
// when the HTTP method or response code does not permit a
// body.
ErrBodyNotAllowed = errors.New("http: request method or response status code does not allow body")
When I send HEAD request with body using fiddler I get 400/504 error codes, but I don't see any error log in my application.
I assume you're talking about a go server that you control. You should see this error returned when you call writer.Write() on a HEAD request. You need to handle it in your application by checking for that error. Find where you are calling Write, and check for the error, then display it to the user. You probably need to replace:
writer.Write(data)
with something like:
_,err := writer.Write(data)
Related
In the case of a failed call to git_remote_connect(), is there any way to get the response HTTP response status code? I can use git_error_last() to get an error message of "unexpected http status code: " followed by the HTTP response status code, but I need some way to just get the status code, rather than get a string with the code embedded in it.
Looking at the libgit2 code at http.c, it seems like the status code is discarded and there is no way for the caller to retrieve it. If that is indeed the case, any instructions as to making a feature request and/or related pull would be much appreciated.
I use lua script to generate data from the parameters and bodies, and then send the data to the other server.
When i handle a GET request, nginx returns a normal response.
However, a 404 not found error occurs when handling POST requests.
However, internal operations were normal and sent the data to the other server.
Only the request method has changed.
If i explicitly pass the value to ngx.say or ngx.exit, i get 200 response normally.
Why? Is it necessary to explicitly return a response code when using a post request with a lua script?
In addition, I am using empty_gif.
I have searched for the above problem.
empty_gif can only be used to respond to GET and HEAD request methods
so I will use 204 response code
We have exposed a HTTP endpoint with POST method. To make a successful call the clients has to make the POST call with a request body and other required parameters.
When we hit the endpoint directly in the browser the response says 200 OK. Its a GET call. there is no implementation for GET.
The question is - an endpoint which supports only POST should throw an error while hitting directly on the browser with a GET ?
What should be the best error. Do we have to handle this in GET saying GET is not appropriate method on this end point?
Or is it correct to leave the GET response as 200 OK - to make the clients feel the end point is up and running?
If you're asking about what an HTTP server SHOULD do... the answer is: it has to implement GET and HEAD. See RFC 7231.
I am in reference to HttpServletResponse's sendError method:
void sendError(int sc,
java.lang.String msg)
throws java.io.IOException
... and the official documentation provided:
Sends an error response to the client using the specified status and
clears the buffer. The server defaults to creating the response to
look like an HTML-formatted server error page containing the specified
message, setting the content type to "text/html". The server will
preserve cookies and may clear or update any headers needed to serve
the error page as a valid response. If an error-page declaration has
been made for the web application corresponding to the status code
passed in, it will be served back in preference to the suggested msg
parameter and the msg parameter will be ignored.
If the response has
already been committed, this method throws an IllegalStateException.
After using this method, the response should be considered to be
committed and should not be written to.
Can anyone please explain what is meant by "clears the buffer" and "If the response has already been committed"?
what is meant by "clears the buffer"
The code will response.resetBuffer() which basically resets any written and unflushed data of response body.
and "If the response has already been committed"?
If the response headers are already sent to the client. This is a point of no return. The server cannot take back already sent data from the client and re-send a different response.
An example of the normal flow is as below:
user requests JSP
JSP writes some HTML to response body
some awkward code in midst of a JSP file throws an exception
server calls response.sendError(500) so that HTML of HTTP 500 error page will be written
user sees HTTP 500 error page
However, if between step 2 and 3 the response buffer is flushed (i.e. any so far written data gets actually sent from server to client), then the response is in a "committed" state. This cannot be resetted. The enduser basically ends up getting halfbaked HTML output representing the part until the point the exception has occurred.
That's also one of the reasons why doing business logic in a JSP file is a bad practice. See also a.o. How to avoid Java code in JSP files?
How do I handle a server error in the middle of an Http message?
Assuming I already sent the header of the message and I am streaming the
the body of the message, what do I do when I encounter an unexpected error.
I am also assuming this error was caused while generating the content and not a connection error.
(Greatly) Simplified Code:
// I can define any transfer encoding or header fields i need to.
send(header); // Sends the header to the Http client.
// Using an iterable instead of stream for code simplicity's sake.
Iterable<String> stream = getBodyStream();
Iterator<String> iterator = stream.iterator();
while (iterator.hasNext()) {
String string;
try {
string = iterator.next();
catch (Throwable error) { // Oops! an error generating the content.
// What do i do here? (In regards to the Http protocol)
}
send(string);
}
Is there a way to tell the client the server failed and should either retry or abandon the connection or am I sool?
The code is greatly simplified but I am only asking in regards to the protocol and not the exact code.
Thank You
One of the following should do it:
Close the connection (reset or normal close)
Write a malformed chunk (and close the connection) which will trigger client error
Add a http trailer telling your client that something went wrong.
Change your higher level protocol. Last piece of data you send is a hash or a length and the client knows to deal with it.
If you can generate a hash or a length (in a custom header if using http chunks) of your content before you start sending you can send it in a header so your client knows what to expect.
It depends on what you want your client to do with the data (keep it or throw it away). You may not be able to make changes on the client side so the last option will not work for example.
Here is some explanation about the different ways to close. TCP option SO_LINGER (zero) - when it's required.
I think the server should return a response code start with 5xx as per RFC 2616.
Server Error 5xx
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. Except when responding to a HEAD request, the server SHOULD include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. User agents SHOULD display any included entity to the user. These response codes are applicable to any request method.