1a72622b06
* add truffle guide, update broken links * cleanup * update guide Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com> Co-authored-by: Federico Kunze <federico.kunze94@gmail.com>
74 lines
3.4 KiB
Markdown
74 lines
3.4 KiB
Markdown
<!--
|
|
order: 1
|
|
-->
|
|
|
|
# Encoding
|
|
|
|
The `codec` is used everywhere in the Cosmos SDK to encode and decode structs and interfaces. The specific codec used in the Cosmos SDK is called `go-amino`. {synopsis}
|
|
|
|
## Pre-requisite Readings
|
|
|
|
- [Cosmos SDK Encoding](https://docs.cosmos.network/master/core/encoding.html) {prereq}
|
|
|
|
## Encoding Formats
|
|
|
|
The Cosmos SDK utilizes two binary wire encoding protocols, [Amino](https://github.com/tendermint/go-amino/)
|
|
and [Protocol Buffers](https://developers.google.com/protocol-buffers), where Amino
|
|
is an object encoding specification. It is a subset of Proto3 with an extension for
|
|
interface support. See the [Proto3 spec](https://developers.google.com/protocol-buffers/docs/proto3)
|
|
for more information on Proto3, which Amino is largely compatible with (but not with Proto2).
|
|
|
|
Due to Amino having significant performance drawbacks, being reflection-based, and
|
|
not having any meaningful cross-language/client support, Protocol Buffers, specifically
|
|
[gogoprotobuf](https://github.com/gogo/protobuf/), is being used in place of Amino.
|
|
Note, this process of using Protocol Buffers over Amino is still an ongoing process.
|
|
|
|
Binary wire encoding of types in the Cosmos SDK can be broken down into two main
|
|
categories, client encoding and store encoding. Client encoding mainly revolves
|
|
around transaction processing and signing, whereas store encoding revolves around
|
|
types used in state-machine transitions and what is ultimately stored in the Merkle
|
|
tree.
|
|
|
|
For store encoding, protobuf definitions can exist for any type and will typically
|
|
have an Amino-based "intermediary" type. Specifically, the protobuf-based type
|
|
definition is used for serialization and persistence, whereas the Amino-based type
|
|
is used for business logic in the state-machine where they may converted back-n-forth.
|
|
Note, the Amino-based types may slowly be phased-out in the future so developers
|
|
should take note to use the protobuf message definitions where possible.
|
|
|
|
In the `codec` package, there exists two core interfaces, `Marshaler` and `ProtoMarshaler`,
|
|
where the former encapsulates the current Amino interface except it operates on
|
|
types implementing the latter instead of generic `interface{}` types.
|
|
|
|
In addition, there exists three implementations of `Marshaler`. The first being
|
|
`AminoCodec`, where both binary and JSON serialization is handled via Amino. The
|
|
second being `ProtoCodec`, where both binary and JSON serialization is handled
|
|
via Protobuf. Finally, `HybridCodec`, a codec that utilizes Protobuf for binary
|
|
serialization and Amino for JSON serialization. The `HybridCodec` is typically
|
|
the codec that used in majority in situations as it's easier to use for client
|
|
and state serialization.
|
|
|
|
This means that modules may use Amino or Protobuf encoding but the types must
|
|
implement `ProtoMarshaler`. If modules wish to avoid implementing this interface
|
|
for their types, they may use an Amino codec directly.
|
|
|
|
### Amino
|
|
|
|
Every module uses an Amino codec to serialize types and interfaces. This codec typically
|
|
has types and interfaces registered in that module's domain only (e.g. messages),
|
|
but there are exceptions like `x/gov`. Each module exposes a `RegisterCodec` function
|
|
that allows a user to provide a codec and have all the types registered. An application
|
|
will call this method for each necessary module.
|
|
|
|
### Protobuf
|
|
|
|
<!-- TODO: -->
|
|
|
|
## RLP
|
|
|
|
<!-- TODO: -->
|
|
|
|
## Next {hide}
|
|
|
|
Learn how to deploy a Solidity smart contract on Ethermint using [Truffle](./../guides/truffle.md) {hide}
|