r402-evm 0.15.0

EIP-155 (EVM) chain support for the x402 payment protocol.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45

//! Server-side price tag generation for the EIP-155 exact scheme.
//!
//! This module provides functionality for servers to create price tags
//! that clients can use to generate payment authorizations.

use alloy_primitives::U256;
use r402_core::chain::{ChainId, DeployedTokenAmount};
use r402_core::wire;

use crate::chain::{ChecksummedAddress, Eip155TokenDeployment};
use crate::exact::{AssetTransferMethod, Eip155Exact, ExactScheme, PaymentRequirementsExtra};

impl Eip155Exact {
    /// Creates a price tag for an EVM exact payment.
    ///
    /// Generates a [`wire::PriceTag`] that specifies the payment requirements for a
    /// resource. Uses CAIP-2 chain IDs (e.g., `eip155:8453`) and embeds the
    /// requirements directly in the price tag.
    ///
    /// # Transfer method
    ///
    /// - `None` or `Some(Eip3009)` — EIP-3009 `transferWithAuthorization` (default)
    /// - `Some(Permit2)` — Uniswap Permit2 via `x402Permit2Proxy`
    pub fn price_tag<A: Into<ChecksummedAddress>>(
        pay_to: A,
        asset: DeployedTokenAmount<U256, Eip155TokenDeployment>,
        transfer_method: Option<AssetTransferMethod>,
    ) -> wire::PriceTag {
        let chain_id: ChainId = asset.token.chain_reference.into();
        let extra = PaymentRequirementsExtra::from_deployment(asset.token.eip712, transfer_method);
        let requirements = wire::PaymentRequirements::new(
            ExactScheme.to_string().into(),
            chain_id,
            asset.amount.to_string().into(),
            pay_to.into().to_string().into(),
            asset.token.address.to_string().into(),
            300,
        )
        .with_optional_extra(extra);
        wire::PriceTag {
            requirements,
            enricher: None,
        }
    }
}