Handle an unavailable page (statusCode)

Question

I'm currently checking the status code of the current page with this code :

$.ajax({
type: 'HEAD',
url: window.location.href,
success: function() {
  console.log("Ok");
},    
error: function() {
  console.log("error");
}
});

The page exists if response's code is between 200 - 299 or not if response's codes between 400 - 499.

But for exemple a 405 error is not really an error for me, the page displays well, so no reason to be in the error state.

So I added an another test :

error: function(jqXHR, textStatus, errorThrown) {
  console.log('jqHRX : ' + JSON.stringify(jqXHR) + ' textStatus : ' + textStatus + ' errorThrown : ' + errorThrown);
  if (errorThrown != "OK") //or jqHRX.statusText
    console.log("error");
}

For exemple, if I browse to a page which returns a 405 code, I'll have this output : jqHRX : {"readyState":4,"responseText":"","status":405,"statusText":"OK"} textStatus : error errorThrown : OK

And if it's a 404 error : jqHRX : {"readyState":4,"responseText":"","status":404,"statusText":"Not Found"} textStatus : error errorThrown : Not Found error

So, are all pages with a errorThrown equals to "OK" currently available ? I found the exemple of 405 by chance so.. I don't really know if it's a isolated case or not.
Is there a better way to handle this ?

Thanks !

Alex

edit : for exemple, https://developer.chrome.com/home returns a 405 with my code but in my application there is no need to consider this like an error.

Strange thing, you can verify the statusCode with http://tools.seobook.com/server-header-checker/ : the result is 405 But if you check with http://httpstatus.io/ the result is 200

score 1 · Answer 1 · answered Nov 14 '15 at 11:17

From jQuery documentation:

"When an HTTP error occurs, errorThrown receives the textual portion of the HTTP status, such as "Not Found" or "Internal Server Error."

Relying on this is not optimal as server can provide you with whatever statusText they feel right. So I can basically send you an 500 page with errorThrown being "I know foo better than bar".

Also pages with 405 should not definetly "display well" as this error implies that used HTTP Method is not allowed on this page. Usually seen when you are trying to GET endpoints meant only for POST, PUT, PATCH.

If you have non-standard error handling (you do not consider errors like 405 as errors inside your application) use the response status code rather than anything else. You can also consider using jQuery.ajax().complete() to handle both success and error in one place.

Thanks for your time. Since your comment I investigated a little bit more this story of "methods not allowed", and I founded that the problem was my HEAD methods. With a GET I have the 200 status code I expected ! — Kureb, Nov 16 '15 at 18:14

Kureb · Accepted Answer · 2016-03-30T21:19:38.503

tl;dr : Using GET instead of HEAD will work. Get is actually the method not allowed which throwned the 405 error.

Answer : Thanks to a colleague of mine, which shows me Postman.

It allowed me to check the status code of a page via different methods like GET, PUT, POST, HEAD, LOCK, etc. And it appears that for a bunch of websites (chrome developer documentation, Amazon, etc) HEAD returned 405 while GET returned 200

According to w3.org

The HEAD method is identical to GET except that the server MUST NOT return a message-body in the response.

So in my case, sometimes I found website which did not allow HEAD request.

Solved by remplacing the code by :

$.ajax({
 type: 'GET',
 url: window.location.href,
 error: function() {
     console.log("error");
 }
});

Handle an unavailable page (statusCode)

2 Answers2