B.6. Infrastructure Details

Basic HTTP requests and responses aren't especially complex, even with the many options available for headers and the various versions of HTTP. A number of pieces of HTTP might be attractive for particular applications (perhaps better termed mutations) of XML-RPC. Some of these pieces are used in part by XML-RPC; others are never mentioned by the XML-RPC specification, but wouldn't be difficult to use in conjunction with XML-RPC.

B.6.1. MIME Types

As we saw earlier, both the request and response portions of HTTP 1.0 and HTTP 1.1 transactions use content-type identifiers to alert applications to the kind of information that follows the headers. These identifiers come from Multipurpose Internet Mail Extensions (MIME), showing HTTP's heritage from mail transport once again. MIME defines identifiers that can be used to describe packages within messages, allowing mail, HTTP, and other protocols to carry traffic that uses multiple formats. MIME content-type identifiers have two levels, the first of which provides a general category (text, image, application, multipart, etc.), and the second of which provides a more detailed description of the type within that category.