How to get the response content of an HTTP 404 response

Question

Is there an easier way of getting the content of an HTTP 404 response than directly accessing the host via tcp?

This is a sample of a 404 response with content:

HTTP/1.1 404 Object Not Found
Server: CouchDB/1.3.0 (Erlang OTP/R15B03)
Date: Wed, 24 Jul 2013 08:32:50 GMT
Content-Type: text/plain; charset=utf-8
Content-Length: 41
Cache-Control: must-revalidate

{"error":"not_found","reason":"missing"}

Answer 1

The Rebol HTTP scheme really isn't designed with this in mind, it's geared toward reading content the way you would in a browser, not services over HTTP.

In saying that, you can hack the protocol to subvert how Rebol 2 handles different response codes:

in-http-scheme: func [does [block!]][
    do bind :does bind? last body-of get in system/schemes/http/handler 'open
]

in-http-scheme [
    remove-each [code response] response-actions [find [400 403 404] code]
    append response-actions [400 success 403 success 404 success]
]

The caveat here is that the HTTP protocol has to have been initiated (any http port opened/read). response-actions can still be accessed when http has not been initiated:

select body-of get in system/schemes/http/handler 'open quote response-actions:

You can get the last response line thus:

in-http-scheme [response-line]

Alternatively you are going to need a scheme designed for services over HTTP. I have a REST protocol (two versions, one that uses cURL, and one that uses a customised HTTP scheme that works, but isn't as good). Though are for Rebol 2. I have plans for a Rebol 3 version.

Answer 2

Christopher Ross-Gill has created a REST protocol for Rebol which allows simple access to all headers and even handles OAuth. Have a look at the details here.

http://www.ross-gill.com/page/REST_Protocol

Unfortunately it is only for Rebol 2 at the moment and it depends on the use of curl for the http requests.