History of XML-RPC/WebServices

August 14, 2008 7:11 AM

Can anyone provide me with information about the earliest forms of RPC over http? I'm looking for predecessor systems or papers that describe the desire or implementation of moving RPC (or any other remote object access) to the Web, or even to the Internet generally. I don't necessarily need text-based implementations like XML-RPC, but that seems like one area of possible information.
posted by jwmelvin to computers & internet (3 comments total)

I don't have an answer for you but I can help future answerers by saying that HTTP 1.0 was released in May 1996 and that XML-RPC was developed in 1998. Chances are that something (at least in academia) had to occur between those two dates. It should also be noted that there was a HTTP 0.9 protocol that wasn't widely used before the 1.0 implementation.
posted by mmascolino at 7:30 AM on August 14, 2008

Prior art search, perchance?
posted by bz at 9:05 AM on August 14, 2008

HTTP itself refers to the verbs GET, PUT, HEAD, etc., as methods, and the item being referred to by the URI as an object. So HTTP itself is arguably viewed as an object oriented RPC mechanism.

XMLRPC is the first widespread standardized generic RPC over HTTP implementation I encountered (it having the advantage, or disadvantage, that since it ran over port 80 it was invisible to firewalls); I'm sure there were many earlier ad-hoc implementations, probably mostly based around the form-submission syntax. Tunneling RPCs over arbitrary protocols was not a new idea at all.

If you're interested in "the Internet generally", of course, things go back 'way farther than HTTP; SunRPC (whatever it's called now) dates to the mid-80s, and is still in common use. The X window system protocol is extremely RPC-like, though I don't know if the early design was explicitly based on that concept. Xerox PARC presumably did all this decades earlier anyway and had to wait for the rest of us to catch up.
posted by hattifattener at 9:19 AM on August 14, 2008