RFC 4157

RFC 4157: The prospero URI Scheme 🎀

okay bestie, let's get into this one 💖 RFC 4157 is titled The prospero URI Scheme, written by Paul Hoffman of the VPN Consortium in August 2005 for the Network Working Group. It's in the Historic category, so it's not a standard. The header doesn't list anything it obsoletes or updates. The abstract says its real job is to keep the prospero scheme info alive on standards track after RFC 1738 gets retired 🦋

Status of This Memo ✨

This memo defines a Historic Document for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.

Copyright Notice 🌸

Copyright (C) The Internet Society (2005).

Abstract 💜

This doc specifies the prospero Uniform Resource Identifier (URI) scheme that was originally specified in RFC 1738. The whole point is to let RFC 1738 get made obsolete while keeping the info about this scheme on standards track 🫶

1. Introduction 🧚

okay so URIs were first defined in RFC 2396 [RFC2396], and then RFC 3986 [RFC3986] updated that. Both of those also explain how to define new schemes for URIs 💅

The first definitions for a bunch of URI schemes showed up in RFC 1738 [RFC1738]. That doc is now obsolete, so this one copies the prospero scheme over from it. That way the material can stay on standards track ✨

2. Scheme Definition 🍓

The prospero URL scheme is used to point at resources that are reached through the Prospero Directory Service. The Prospero protocol itself is described in the original Prospero specification [PROSP] 🔥

Historical note: The Prospero protocol was not widely implemented, and almost no Prospero servers are in use today. 💀

A prospero URL looks like this:

prospero://<host>:<port>/<hsoname>;<field>=<value>

If :<port> is left out, the port defaults to 1525. No username or password is allowed 🙈

The <hsoname> is the host-specific object name in the Prospero protocol, suitably encoded. It's opaque, which means the Prospero server is the one that interprets it 🦋 The semicolon ; is reserved, so it can't show up in the <hsoname> without quoting.

Prospero URLs get interpreted by contacting a Prospero directory server on the given host and port, so the server can work out the right access methods for a resource. Those access methods might also be represented as different URLs. External Prospero links are written as URLs of the underlying access method, not as Prospero URLs, so they never look like prospero links 👑

Heads up: a slash / can show up in the <hsoname> without quoting, and the application shouldn't assume it means anything. Slashes may hint at hierarchy on the server, but that structure isn't guaranteed 🌈 Also, a lot of <hsoname>s start with a slash. When that happens, the host or port gets followed by a double slash: the one from the URL syntax, then the initial slash from the <hsoname>. For example:

<URL:prospero://example.com//pros/name>

designates an <hsoname> of "/pros/name" ✨

After the <hsoname>, you can optionally add fields and values tied to a Prospero link. Each field/value pair is separated from the others, and from the rest of the URL, by a ; (semicolon). The field name and its value are separated by a = (equal sign). When they're there, these fields help identify the target of the URL. For instance, the OBJECT-VERSION field can be used to pick out a specific version of an object 💖

3. Security Considerations 💀

Lots of security considerations for URI schemes are covered in [RFC3986]. But [PROSP] is a big ol' red flag 🚩 It sends passwords in the clear for authentication and offers no privacy at all. Both of those are considered extremely unsafe in current practice. Be careful, bestie 😭

4. Informative References 💜

• [RFC1738]: Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform Resource Locators (URL)", RFC 1738, December 1994.
• [RFC2396]: Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998.
• [RFC3986]: Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005.
• [PROSP]: Neuman, B. and S. Augart, "The Prospero Protocol", USC/Information Sciences Institute, June 1993.

Author's Address 🎀

Paul Hoffman VPN Consortium 127 Segre Place Santa Cruz, CA 95060 US

EMail: paul.hoffman@vpnc.org

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Full Copyright Statement 🌸

Copyright (C) The Internet Society (2005).

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Acknowledgement 🌈

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