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@5ire/api 中文文档教程

发布于 3年前 浏览 27 项目主页 更新于 3年前

@polkadot/api

Polkadot-JS API 围绕从应用程序流向节点的 JSONRPC 调用提供易于使用的包装器。 它处理所有编码和解码或参数，提供对 RPC 函数的访问，并允许查询链状态和提交交易。

API 包装器提供了一个标准接口供使用 - 提供了

  • A static .create(<optional ApiOptions>) that returns an API instance when connected, decorated and ready-to use. ApiOptions can include an optional WsProvider and optional custom type definitions { provider: <Optional WsProvider>, types: <Optional RegistryTypes> }.
  • The above is just a wrapper for new Api(<optional ApiOptions>), exposing the isReady getter
  • api.rpc.<section>.<method> provides access to actual RPC calls, be it for queries, submission or retrieving chain information
  • RPC (node interface)
  • api.query.<section>.<method> provides access to chain state queries. These are dynamically populated based on what the runtime provides
  • Storage chain state (runtime node interface)
  • api.tx.<section>.<method> provides the ability to create a transaction, like chain state, this list is populated from a runtime query
  • Extrinsics (runtime node interface)
  • api.consts.<section>.<constant> provides access to the module constants (parameter types).
  • Constants (runtime node interface)

API Selection

两种类型的 API，一种允许通过 JavaScript Promises 的标准接口，第二种使用 RxJS. 根据您的用例和熟悉程度，您可以为您的应用程序选择其中之一（甚至两者）。

  • [[ApiPromise]] All interface calls returns Promises, including the static .create(...). Additionally any subscription method uses (value) => {} callbacks, returning the value as the subscription is updated.
  • [[ApiRx]] All interface calls return RxJS Observables, including the static .create(...). In the same fashion subscription-based methods return long-running Observables that update with the latest values.

Dynamic by default

Substrate（Polkadot 建立在其上）使用链上 WASM 运行时，允许升级。 每个运行时定义实际的链外部（提交的事务和块内部）以及链状态中的可用条目。 因此，查询和交易的 API 端点是从正在运行的链中动态填充的。

由于这种动态特性，此 API 不同于仅具有固定端点的传统 API，驱动运行时可用内容的使用。 作为开始，这种通用性质有一个学习曲线，尽管提供的文档、示例和链接文档试图使这种体验尽可能无缝。

Installation & import

安装 -

npm install --save @polkadot/api

通过基于 Promise 的 API

import { ApiPromise } from '@5ire/api';

// initialise via static create
const api = await ApiPromise.create();

// make a call to retrieve the current network head
api.rpc.chain.subscribeNewHeads((header) => {
  console.log(`Chain is at #${header.number}`);
});

订阅块 - 通过基于 RxJS 的 API 订阅块 -

import { ApiRx } from '@5ire/api';

// initialise via static create
const api = await ApiRx.create().toPromise();

// make a call to retrieve the current network head
api.rpc.chain.subscribeNewHeads().subscribe((header) => {
  console.log(`Chain is at #${header.number}`);
});

Registering custom types

当创建 API 的新实例时，可以添加运行时模块使用的其他类型。 如果运行时模块使用基本 Substrate 运行时中不可用的类型，则这是必需的。

import { ApiPromise } from '@5ire/api';

// initialise via static create and register custom types
const api = await ApiPromise.create({
  types: {
    CustomTypesExample: {
      "id": "u32",
      "data": "Vec<u8>",
      "deposit": "Balance",
      "owner": "AccountId",
      "application_expiry": "Moment",
      "whitelisted": "bool",
      "challenge_id": "u32"
    }
  }
});

Users

API 的一些用户（如果您不在列表中，请告诉我们）包括 -

原文

@polkadot/api

The Polkadot-JS API provides easy-to-use wrappers around JSONRPC calls that flow from an application to a node. It handles all the encoding and decoding or parameters, provides access to RPC functions and allows for the query of chain state and the submission of transactions.

The API wrappers provide a standard interface for use -

  • A static .create(<optional ApiOptions>) that returns an API instance when connected, decorated and ready-to use. ApiOptions can include an optional WsProvider and optional custom type definitions { provider: <Optional WsProvider>, types: <Optional RegistryTypes> }.
  • The above is just a wrapper for new Api(<optional ApiOptions>), exposing the isReady getter
  • api.rpc.<section>.<method> provides access to actual RPC calls, be it for queries, submission or retrieving chain information
  • RPC (node interface)
  • api.query.<section>.<method> provides access to chain state queries. These are dynamically populated based on what the runtime provides
  • Storage chain state (runtime node interface)
  • api.tx.<section>.<method> provides the ability to create a transaction, like chain state, this list is populated from a runtime query
  • Extrinsics (runtime node interface)
  • api.consts.<section>.<constant> provides access to the module constants (parameter types).
  • Constants (runtime node interface)

API Selection

There are two flavours of the API provided, one allowing a standard interface via JavaScript Promises and the second provides an Observable wrapper using RxJS. Depending on your use-case and familiarity, you can choose either (or even both) for your application.

  • [[ApiPromise]] All interface calls returns Promises, including the static .create(...). Additionally any subscription method uses (value) => {} callbacks, returning the value as the subscription is updated.
  • [[ApiRx]] All interface calls return RxJS Observables, including the static .create(...). In the same fashion subscription-based methods return long-running Observables that update with the latest values.

Dynamic by default

Substrate (upon which Polkadot is built) uses on-chain WASM runtimes, allowing for upgradability. Each runtime defining the actual chain extrinsics (submitted transactions and block intrinsics) as well as available entries in the chain state. Due to this, the API endpoints for queries and transactions are dynamically populated from the running chain.

Due to this dynamic nature, this API departs from traditional APIs which only has fixed endpoints, driving use by what is available by the runtime. As a start, this generic nature has a learning curve, although the provided documentation, examples and linked documentation tries to make that experience as seamless as possible.

Installation & import

Installation -

npm install --save @polkadot/api

Subscribing to blocks via Promise-based API -

import { ApiPromise } from '@5ire/api';

// initialise via static create
const api = await ApiPromise.create();

// make a call to retrieve the current network head
api.rpc.chain.subscribeNewHeads((header) => {
  console.log(`Chain is at #${header.number}`);
});

Subscribing to blocks via RxJS-based API -

import { ApiRx } from '@5ire/api';

// initialise via static create
const api = await ApiRx.create().toPromise();

// make a call to retrieve the current network head
api.rpc.chain.subscribeNewHeads().subscribe((header) => {
  console.log(`Chain is at #${header.number}`);
});

Registering custom types

Additional types used by runtime modules can be added when a new instance of the API is created. This is necessary if the runtime modules use types which are not available in the base Substrate runtime.

import { ApiPromise } from '@5ire/api';

// initialise via static create and register custom types
const api = await ApiPromise.create({
  types: {
    CustomTypesExample: {
      "id": "u32",
      "data": "Vec<u8>",
      "deposit": "Balance",
      "owner": "AccountId",
      "application_expiry": "Moment",
      "whitelisted": "bool",
      "challenge_id": "u32"
    }
  }
});

Users

Some of the users of the API (let us know if you are missing from the list), include -

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