Question

I’m developing a firefox addon which performs actions if a statuscode is a 4xx or 5xx error.
It works quite well as it is now, but it doesn’t take actions if the error code is a 408.
Firefox gives me an error but the error never reaches my extension.

My httpobserver looks like this:

observe: function(aSubject, aTopic, aData)
{       
    if (aTopic == 'http-on-examine-response') 
    {
        httpstatus = aSubject.responseStatus.toString();
        if(httpstatus.substr(0,1) in {4:1,5:1})
        {
          ...

I also tried to put an alert box after the httpstatus is set (right before the if) it alerts all codes it gets except for the 408 error.

Does anybody know how to do this? Thanks in advance!

Answer 1

What you mean is most likely not “408 Timed Out” HTTP response (that would happen e.g. if a proxy server cannot reach the server) but NS_ERROR_NET_TIMEOUT – an error generated by Gecko if it cannot reach the server. http-on-examine-response notification is only triggered if a response from server is received, for NS_ERROR_NET_TIMEOUT this is not the case.

Unfortunately, listening to such errors isn’t possible by means of observers. You can use a progress listener, whenever a load stops its onStateChange method will be called with aStateFlags including LOAD_STOP flag and aStatus being the channel status (NS_ERROR_NET_TIMEOUT in this case).