No Comments Written by Anders on April 5, 2008 – 1:31 pm

There are five groups of status codes:

1xx
Request received, processing continues.

2xx
‘Success’ (resource retrieved, put, posted etc.).

3xx
Further action needed. The 3xx codes are used for situations like a resource being temporarily or permanently moved to a new URI. The response should then include a Location header that contains this URI. Ideally, a browser will interpret this and proceed by submitting a new request to the specified location.

4xx
Client error, or request invalid. The 4xx codes are used to specify that a resource is not available, or to indicate that the client has done something wrong, like submitting a request for a non-existent byte range from a resource, or to enforce a requirement like the need to submit name and password data.

5xx
Server failure. The following example of the headers for a HTTP response message is taken from the HTTP/1.1 specification:
HTTP/1.1 206 Partial content
Date: Wed, 15 Nov 1995 06:25:24 GMT
Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
Content-Range: bytes 21010-47021/47022
Content-Length: 26012
Content-Type: image/gif
The response codes that are most common for our web applications are:

200; OK
Success response code.

401; Unauthorized
This is the challenge part of the protocol that allows the user to specify a name and password before access is granted to a controlled resource.

500; Internal Server Error
Your server-side script or program has a bug!