| Internet-Draft | REP purpose | October 2024 |
| Illyes | Expires 21 April 2025 | [Page] |
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.¶
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.¶
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(fill in)¶
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¶
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.¶
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.¶
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.¶
The security considerations are the same as in the parent [RFC9309].¶
The vocabulary used as purpose tokens are registered at IANA-URL.¶
# 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¶
TODO acknowledge.¶