HTTP functions not supported by CICS web support
The HTTP/1.1 specification defines various roles for the parties that make use of the HTTP protocol. CICS® web support carries out many of the functions that are appropriate for an origin server, for a client, and for a user agent (although a human user might not be involved for every HTTP client request). The HTTP/1.1 specification also includes requirements that relate to proxies, gateways, tunnels and caches, and these requirements are not relevant to CICS web support and can be ignored.
- CICS does not support the HTTP TRACE method in order to avoid vulnerabilities associated with the protocol.
- CICS does not act as a proxy. You can ignore all the requirements in the HTTP/1.1 specification that relate to the behaviour of proxies.
- CICS does not act as a gateway (an intermediary for another server) or a tunnel (a relay between HTTP connections). You can ignore all the requirements in the HTTP/1.1 specification that relate to the behaviour of gateways and tunnels.
- CICS does not provide caching facilities, or provide support for user-written caching facilities. You can ignore all the requirements in the HTTP/1.1 specification that relate to the behaviour of caches. Although you may store any information you receive from a server, you should be careful that you do not deliver the stored information to a user who is making a request in the expectation of receiving current information from the server.
- CICS is not designed for use as a web browser. Through CICS as an HTTP client, user application programs can make requests for individual, known resources that are available from a server, but they would not be expected to browse the Internet generally. CICS does not provide history lists, lists of favorites or other features of a web browser, so any requirements relating to these can be ignored.