Module idempotency 

Idempotency key validation.

The Snippe API enforces a 30-byte maximum on the Idempotency-Key header. Keys longer than 30 bytes don’t return a clear validation error — they trigger the cryptic PAY_001 (“failed to initiate payment”) error, which is hard to debug if you don’t know to look at the key length first.

This module exposes a newtype that enforces the constraint at construction time, so over-long keys can never reach the wire.

Examples

use snippe::IdempotencyKey;

let key = IdempotencyKey::new("ord-12345-att-1")?;
assert_eq!(key.as_str(), "ord-12345-att-1");

// Length is enforced — this fails before any network call:
assert!(IdempotencyKey::new("a".repeat(31)).is_err());

Picking a key

• Per request, not per resource. The retry-safe semantics work because the same key always returns the same cached response; if you reuse a key across logically distinct calls you’ll get a 422 idempotency conflict.
• Short. 30 bytes leaves room for ~15-character prefixes plus a short ID. Avoid ${userId}-${orderId}-${Date.now()} patterns — they easily overshoot.
• Stable across retries of the same logical operation. Generate the key once when you first attempt the request, and reuse it on every retry.

Structs

IdempotencyKey

A validated idempotency key — non-empty and ≤ 30 bytes.

Enums

IdempotencyKeyError

Reasons construction of an IdempotencyKey can fail.

Constants

MAX_LENGTH

Maximum byte length the Snippe API accepts on the Idempotency-Key header.