70 lines
2.3 KiB
Markdown
70 lines
2.3 KiB
Markdown
<!--
|
|
order: 1
|
|
-->
|
|
|
|
# Encoding
|
|
|
|
Learn about the encoding formats used on Ethermint. {synopsis}
|
|
|
|
## Pre-requisite Readings
|
|
|
|
- [Cosmos SDK Encoding](https://docs.cosmos.network/master/core/encoding.html) {prereq}
|
|
- [Ethereum RLP](https://eth.wiki/en/fundamentals/rlp) {prereq}
|
|
|
|
## Encoding Formats
|
|
|
|
### Protocol Buffers
|
|
|
|
The Cosmos [Stargate](https://stargate.cosmos.network/) release introduces
|
|
[protobuf](https://developers.google.com/protocol-buffers) as the main encoding format for both
|
|
client and state serialization. All the EVM module types that are used for state and clients
|
|
(transaction messages, genesis, query services, etc) will be implemented as protocol buffer messages.
|
|
|
|
### Amino
|
|
|
|
The Cosmos SDK also supports the legacy Amino encoding format for backwards compatibility with
|
|
previous versions, specially for client encoding and signing with Ledger devices. Ethermint does not
|
|
support Amino in the EVM module, but it is supported for all other Cosmos SDK modules that enable it.
|
|
|
|
### RLP
|
|
|
|
Recursive Length Prefix ([RLP](https://eth.wiki/en/fundamentals/rlp)), is an encoding/decoding algorithm that serializes a message and
|
|
allows for quick reconstruction of encoded data. Ethermint uses RLP to encode/decode Ethereum
|
|
messages for JSON-RPC handling to conform messages to the proper Ethereum format. This allows
|
|
messages to be encoded and decoded in the exact format as Ethereum's.
|
|
|
|
The `x/evm` transactions (`MsgEthereumTx`) encoding is performed by casting the message to a go-ethereum's `Transaction` and then marshaling the transaction data using RLP:
|
|
|
|
```go
|
|
// TxEncoder overwrites sdk.TxEncoder to support MsgEthereumTx
|
|
func (g txConfig) TxEncoder() sdk.TxEncoder {
|
|
return func(tx sdk.Tx) ([]byte, error) {
|
|
msg, ok := tx.(*evmtypes.MsgEthereumTx)
|
|
if ok {
|
|
return msg.AsTransaction().MarshalBinary()
|
|
}
|
|
return g.TxConfig.TxEncoder()(tx)
|
|
}
|
|
}
|
|
|
|
// TxDecoder overwrites sdk.TxDecoder to support MsgEthereumTx
|
|
func (g txConfig) TxDecoder() sdk.TxDecoder {
|
|
return func(txBytes []byte) (sdk.Tx, error) {
|
|
tx := ðtypes.Transaction{}
|
|
|
|
err := tx.UnmarshalBinary(txBytes)
|
|
if err == nil {
|
|
msg := &evmtypes.MsgEthereumTx{}
|
|
msg.FromEthereumTx(tx)
|
|
return msg, nil
|
|
}
|
|
|
|
return g.TxConfig.TxDecoder()(txBytes)
|
|
}
|
|
}
|
|
```
|
|
|
|
## Next {hide}
|
|
|
|
Learn how [pending state](./pending_state.md) is handled on Ethermint. {hide}
|