I am trying to work out an efficient way of checking that a URL returns an existing resource/page.
Performing a GET and checking the response status = 200 works but is inefficient as it requests the whole page/resource.
Using a HEAD request method and checking the status response of that would seem ideal except that my target site does not support HEAD requests (just GET and POSTaccording to an options request. (It is not my site/sites that are being checked so enabling HEAD requests is not an option.)
Requesting a known good URL with the HEAD method results in a 405 error.
By experimenting I have found that if I request non-existing pages I get a return status code of 404 and various other errors also seem to make sense. I would prefer to confirm the existence of the page, though, rather than just assume existence by checking for a non-404 status code.
Can I, therefore, safely assume that if I get a 405 error that the page/resource exists?
This seems to be a question of response status precedence/priority.
Will a 404 error always take precedence over a 405 error or is this server or server configuration dependent?
If the order of precedence is defined, is this in an RFC or something?
(This question addresses a similar situation but for another specific situation)
