Overview

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概述

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简介

了解 09-localhost 轻客户端模块。 09-localhost 轻客户端模块实现了一个无状态的 localhost 环回客户端，能够在同一个状态机内发送和接收 IBC 数据包。

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背景

在多链环境中，应用开发者通常会通过 IBC 开发跨链应用。从他们的视角来看，无论交互对象是同一条链上的多个模块，还是不同链上的模块，都不应有差别。localhost 客户端模块通过开发者熟悉的 IBC 应用层语义，为单链上的不同应用交互提供了统一接口。

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实现

存在一个 localhost 轻客户端模块，可通过客户端标识符 09-localhost 调用。该轻客户端是无状态的，因此 ClientState 会在需要时按需构造。 作为补充，一个哨兵 ConnectionEnd 会存储在 core IBC 状态中，其连接标识符为 connection-localhost。这使得 IBC 应用可以直接在这个哨兵连接之上创建通道，从而利用 09-localhost 的环回能力。 在握手过程中或处理数据包时，对通道状态进行的状态验证复杂度会降低，因为 09-localhost 客户端只需比较标准化键路径下存储的字节即可。

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Localhost 与_常规_客户端的区别

localhost 客户端的目标，是像 IBC 应用层支持跨链交互那样，为单链上的应用交互提供一种统一方式。不过，为了实现这一统一接口，其底层实现与“常规” IBC 客户端存在一些差异（不包括 06-solomachine 和 09-localhost 本身）。 下表列出了一些重要差异：

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Overview

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Synopsis

Learn about the 09-localhost light client module. The 09-localhost light client module implements a stateless localhost loopback client with the ability to send and receive IBC packets to and from the same state machine.

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Context

In a multichain environment, application developers will be used to developing cross-chain applications through IBC. From their point of view, whether or not they are interacting with multiple modules on the same chain or on different chains should not matter. The localhost client module enables a unified interface to interact with different applications on a single chain, using the familiar IBC application layer semantics.

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Implementation

There exists a localhost light client module which can be invoked with the client identifier 09-localhost. The light client is stateless, so the ClientState is constructed on demand when required. To supplement this, a sentinel ConnectionEnd is stored in core IBC state with the connection identifier connection-localhost. This enables IBC applications to create channels directly on top of the sentinel connection which leverage the 09-localhost loopback functionality. State verification for channel state in handshakes or processing packets is reduced in complexity, the 09-localhost client can simply compare bytes stored under the standardized key paths.

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Localhost vs regular client

The localhost client aims to provide a unified approach to interacting with applications on a single chain, as the IBC application layer provides for cross-chain interactions. To achieve this unified interface though, there are a number of differences under the hood compared to a ‘regular’ IBC client (excluding 06-solomachine and 09-localhost itself). The table below lists some important differences: