mechanisms/evm/exact/server

ConvertFromTokenAmount converts from token smallest unit to decimal

ConvertToTokenAmount converts a decimal amount to token smallest unit

EnhancePaymentRequirements adds scheme-specific enhancements to V2 payment requirements

GetAssetDecimals implements AssetDecimalsProvider. Returns the decimal precision for the given asset on the given network, falling back to 6 if the asset is not recognized.

GetDisplayAmount formats an amount for display

GetSupportedNetworks returns the list of supported networks

ParsePrice parses a price string and converts it to an asset amount (V2) If price is already an AssetAmount, returns it directly. If price is Money (string | number), parses to decimal and tries custom parsers. Falls back to default conversion if all custom parsers return nil.

Args:

price: The price to parse (can be string, number, or AssetAmount map)
network: The network identifier

Returns:

AssetAmount with amount, asset, and optional extra fields

RegisterMoneyParser registers a custom money parser in the parser chain. Multiple parsers can be registered - they will be tried in registration order. Each parser receives a decimal amount (e.g., 1.50 for $1.50). If a parser returns nil, the next parser in the chain will be tried. The default parser is always the final fallback.

Args:

parser: Custom function to convert amount to AssetAmount (or nil to skip)

Returns:

The server instance for chaining

Example:

evmServer.RegisterMoneyParser(func(amount float64, network x402.Network) (*x402.AssetAmount, error) {
    // Use DAI for large amounts
    if amount > 100 {
        return &x402.AssetAmount{
            Amount: fmt.Sprintf("%.0f", amount * 1e18),
            Asset:  "0x6B175474E89094C44Da98b954EedeAC495271d0F", // DAI
            Extra:  map[string]interface{}{"token": "DAI"},
        }, nil
    }
    return nil, nil // Use next parser
})

Scheme returns the scheme identifier

ValidatePaymentRequirements validates that requirements are valid for this scheme. All EVM networks are supported - this validates required fields only.