Network Working Group G. Illyes Internet-Draft Google LLC. Intended status: Informational 18 October 2024 Expires: 21 April 2025 Robots Exclusion Protocol User Agent Purpose Extension draft-illyes-rep-purpose-00 Abstract The Robots Exclusion Protocol defined in [RFC9309] specifies the user-agent rule for targeting automatic clients either by prefix matching their self-defined product token or by a global rule * that matches all clients. This document extends [RFC9309] by defining a new rule for targeting automatic clients based on the clients' purpose for accessing the service. About This Document This note is to be removed before publishing as an RFC. The latest revision of this draft can be found at https://garyillyes.github.io/ietf-rep-purpose/draft-illyes-rep- purpose.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-illyes-rep-purpose/. Source for this draft and an issue tracker can be found at https://github.com/garyillyes/ietf-rep-purpose. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 21 April 2025. Illyes Expires 21 April 2025 [Page 1] Internet-Draft REP purpose October 2024 Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Specification . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1. user-agent-purpose . . . . . . . . . . . . . . . . . . . 3 2.2. user-agent-purpose tokens . . . . . . . . . . . . . . . . 3 3. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 3 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 3 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.2. Informative References . . . . . . . . . . . . . . . . . 4 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction (fill in) 2. Specification We define user-agent-purpose as the new rule with a predefined set of values. The values are registered with IANA at ... Below is an Augmented Backus-Naur Form (ABNF) description, as described in [RFC5234]. purpose = *WS "user-agent-purpose" *WS ":" *WS purpose-token NL purpose-token = "EXAMPLE-PURPOSE-1" /"EXAMPLE-PURPOSE-2" / "EXAMPLE-PURPOSE-3" ; but check IANA for full list NL = %x0D / %x0A / %x0D.0A WS = %x20 / %x09 Illyes Expires 21 April 2025 [Page 2] Internet-Draft REP purpose October 2024 2.1. user-agent-purpose The user-agent-purpose rule is semantically equivalent to the user- agent rule defined in Section 2.2.1. of [RFC9309]. As the user-agent rule, user-agent-purpose acts as a starter of rule groups. 2.2. user-agent-purpose tokens The user-agent-purpose token MUST be a substring of the identification string that the automatic client sends to the service. For example, in the case of HTTP [RFC9110], the purpose token MUST be a substring in the User-Agent header, along with the product token. Here's an example of a User-Agent HTTP request header with the purpose token by the product token: User-Agent: Mozilla/5.0 (compatible; ExampleBot/0.1; ExamplePurpose; https://www.example.com/bot.html) The purpose token MUST be one of the tokens registered with IANA. Unrecognized tokens MAY be discarded by parsers. Crawlers MUST use case-insensitive matching to find the group that matches the purpose token and obey the rules of the group. If there's a group that matches the product token of the automatic client, the client SHOULD obey that group. If no matching group exists, crawlers MUST obey the group with a user-agent line with the "*" value, if present. If there is more than one group matching the user-agent-purpose, the matching groups' rules MUST be combined into one group and parsed according to Section X. 3. Conventions and Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 4. Security Considerations The security considerations are the same as in the parent [RFC9309]. 5. IANA Considerations The vocabulary used as purpose tokens are registered at IANA-URL. 6. Examples Illyes Expires 21 April 2025 [Page 3] Internet-Draft REP purpose October 2024 # robots.txt with purpose # FooBot and all bots that are crawling for EXAMPLE-PURPOSE-1 are disallowed. User-Agent: FooBot User-Agent-Purpose: EXAMPLE-PURPOSE-1 Disallow: / # EXAMPLE-PURPOSE-2 crawlers are allowed. User-Agent-Purpose: EXAMPLE-PURPOSE-2 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP Semantics", STD 97, RFC 9110, DOI 10.17487/RFC9110, June 2022, . [RFC9309] Koster, M., Illyes, G., Zeller, H., and L. Sassman, "Robots Exclusion Protocol", RFC 9309, DOI 10.17487/RFC9309, September 2022, . 7.2. Informative References [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/RFC5234, January 2008, . Acknowledgments TODO acknowledge. Author's Address Gary Illyes Google LLC. Email: garyillyes@google.com Illyes Expires 21 April 2025 [Page 4]