IdHeaderList

TIdHeaderList is a TIdStringList descendant that implements a collection of header names and values, and facilitates the processing of headers used in many protocols such as Gopher+, HTTP, NNTP, POP3, SMTP, and in the storage of RFC-compliant messages. 

Features include the use of a ":" instead of a comma or equal sign ("=") for separating field names from values (this can be changed with the NameValueSeparator property), and optional header folding and unfolding. 

TIdHeaderList provides facilities provide for use of RFC-compliant header names and values as the internal storage for values in the header list.

TIdMessage 

TIdHTTP 

IndySupport