systemprompt_identifiers/
client_session.rs

1//! The caller's own session identifier, carried inside `metadata.user_id`.
2//!
3//! Claude Code stamps every `/v1/messages` call with
4//! `metadata.user_id = "user_<sha256>_account_<uuid>_session_<uuid>"`, and the
5//! trailing UUID is the session id it also reports through its hook events.
6//! Parsing it lets the gateway land a request on the same context the hooks
7//! pipeline writes, without the caller having to send a dedicated header.
8//!
9//! Distinct from [`crate::SessionId`]: that is the gateway's own attested
10//! `sess_` session, minted once per credential and shared by every Claude Code
11//! run that credential drives.
12//!
13//! Copyright (c) systemprompt.io — Business Source License 1.1.
14//! See <https://systemprompt.io> for licensing details.
15
16use crate::error::IdValidationError;
17
18const SESSION_SEGMENT: &str = "_session_";
19
20fn validate(value: &str) -> Result<(), IdValidationError> {
21    let parsed = uuid::Uuid::parse_str(value)
22        .map_err(|e| IdValidationError::invalid("ClientSessionId", e.to_string()))?;
23    if parsed.hyphenated().to_string() != value {
24        return Err(IdValidationError::invalid(
25            "ClientSessionId",
26            "must be a lowercase hyphenated UUID",
27        ));
28    }
29    Ok(())
30}
31
32crate::define_id!(ClientSessionId, validated, schema, validate);
33
34impl ClientSessionId {
35    pub fn from_metadata_user_id(value: &str) -> Result<Option<Self>, IdValidationError> {
36        let value = value.trim();
37        let session = if value.starts_with('{') {
38            let metadata: serde_json::Value = serde_json::from_str(value)
39                .map_err(|e| IdValidationError::invalid("ClientSessionId", e.to_string()))?;
40            Some(
41                metadata
42                    .get("session_id")
43                    .and_then(serde_json::Value::as_str)
44                    .ok_or_else(|| {
45                        IdValidationError::invalid(
46                            "ClientSessionId",
47                            "metadata requires a string session_id",
48                        )
49                    })?
50                    .to_owned(),
51            )
52        } else {
53            value
54                .rsplit_once(SESSION_SEGMENT)
55                .map(|(_, suffix)| suffix.to_owned())
56        };
57        session
58            .map(|value| {
59                let parsed = uuid::Uuid::parse_str(value.trim())
60                    .map_err(|e| IdValidationError::invalid("ClientSessionId", e.to_string()))?;
61                Self::try_new(parsed.hyphenated().to_string())
62            })
63            .transpose()
64    }
65}
systemprompt_identifiers/client_session.rs

systemprompt_identifiers/
client_session.rs
