向远程监视解决方案加速器 Web UI 添加自定义服务
本文介绍如何在远程监视解决方案加速器 Web UI 中添加新服务。 本文介绍:
- 如何准备本地开发环境。
- 如何向 Web UI 添加新服务。
本文中的示例服务为网格提供数据,若要了解如何添加网格,请参阅向远程监视解决方案加速器 Web UI 添加自定义网格操作指南。
在 React 应用程序中,服务通常与后端服务交互。 远程监视解决方案加速器中的示例包括与 IoT 中心管理器和配置微服务交互的服务。
先决条件
要完成本操作指南中的步骤,需要在本地开发计算机上安装以下软件:
开始之前
应先完成向远程监视解决方案加速器 Web UI 添加自定义页面操作指南中的步骤,然后再继续操作。
添加服务
若要向 Web UI 添加服务,需要添加定义服务的源文件,然后修改部分现有文件,从而让 Web UI 识别新服务。
添加定义服务的新文件
为了帮助你入门,src/walkthrough/services 文件夹包含定义简单服务的文件:
exampleService.js
import { Observable } from 'rxjs';
import { toExampleItemModel, toExampleItemsModel } from './models';
/** Normally, you'll need to define the endpoint URL.
* See app.config.js to add a new service URL.
*
* For this example, we'll just hardcode sample data to be returned instead
* of making an actual service call. See the other service files for examples.
*/
//const ENDPOINT = Config.serviceUrls.example;
/** Contains methods for calling the example service */
export class ExampleService {
/** Returns an example item */
static getExampleItem(id) {
return Observable.of(
{ ID: id, Description: "This is an example item." },
)
.map(toExampleItemModel);
}
/** Returns a list of example items */
static getExampleItems() {
return Observable.of(
{
items: [
{ ID: "123", Description: "This is item 123." },
{ ID: "188", Description: "This is item ONE-DOUBLE-EIGHT." },
{ ID: "210", Description: "This is item TWO-TEN." },
{ ID: "277", Description: "This is item 277." },
{ ID: "413", Description: "This is item FOUR-THIRTEEN." },
{ ID: "789", Description: "This is item 789." },
]
}
).map(toExampleItemsModel);
}
/** Mimics a server call by adding a delay */
static updateExampleItems() {
return this.getExampleItems().delay(2000);
}
}
若要详细了解如何实现服务,请参阅 The introduction to Reactive Programming you've been missing(你一直错过的反应式编程简介)。
model/exampleModels.js
import { camelCaseReshape, getItems } from 'utilities';
/**
* Reshape the server side model to match what the UI wants.
*
* Left side is the name on the client side.
* Right side is the name as it comes from the server (dot notation is supported).
*/
export const toExampleItemModel = (data = {}) => camelCaseReshape(data, {
'id': 'id',
'description': 'descr'
});
export const toExampleItemsModel = (response = {}) => getItems(response)
.map(toExampleItemModel);
将 exampleService.js 复制到 src/services 文件夹,将 exampleModels.js 复制到 src/services/models 文件夹。
更新 src/services 文件夹中的 index.js 文件以导出新服务:
export * from './exampleService';
更新 src/services/models 文件夹中的 index.js 文件以导出新模型:
export * from './exampleModels';
从存储中设置对服务的调用
为了帮助你入门,src/walkthrough/store/reducers 文件夹包含一个示例化简器:
exampleReducer.js
import 'rxjs';
import { Observable } from 'rxjs';
import moment from 'moment';
import { schema, normalize } from 'normalizr';
import update from 'immutability-helper';
import { createSelector } from 'reselect';
import { ExampleService } from 'walkthrough/services';
import {
createReducerScenario,
createEpicScenario,
errorPendingInitialState,
pendingReducer,
errorReducer,
setPending,
toActionCreator,
getPending,
getError
} from 'store/utilities';
// ========================= Epics - START
const handleError = fromAction => error =>
Observable.of(redux.actions.registerError(fromAction.type, { error, fromAction }));
export const epics = createEpicScenario({
/** Loads the example items */
fetchExamples: {
type: 'EXAMPLES_FETCH',
epic: fromAction =>
ExampleService.getExampleItems()
.map(toActionCreator(redux.actions.updateExamples, fromAction))
.catch(handleError(fromAction))
}
});
// ========================= Epics - END
// ========================= Schemas - START
const itemSchema = new schema.Entity('examples');
const itemListSchema = new schema.Array(itemSchema);
// ========================= Schemas - END
// ========================= Reducers - START
const initialState = { ...errorPendingInitialState, entities: {}, items: [], lastUpdated: '' };
const updateExamplesReducer = (state, { payload, fromAction }) => {
const { entities: { examples }, result } = normalize(payload, itemListSchema);
return update(state, {
entities: { $set: examples },
items: { $set: result },
lastUpdated: { $set: moment() },
...setPending(fromAction.type, false)
});
};
/* Action types that cause a pending flag */
const fetchableTypes = [
epics.actionTypes.fetchExamples
];
export const redux = createReducerScenario({
updateExamples: { type: 'EXAMPLES_UPDATE', reducer: updateExamplesReducer },
registerError: { type: 'EXAMPLE_REDUCER_ERROR', reducer: errorReducer },
isFetching: { multiType: fetchableTypes, reducer: pendingReducer }
});
export const reducer = { examples: redux.getReducer(initialState) };
// ========================= Reducers - END
// ========================= Selectors - START
export const getExamplesReducer = state => state.examples;
export const getEntities = state => getExamplesReducer(state).entities || {};
export const getItems = state => getExamplesReducer(state).items || [];
export const getExamplesLastUpdated = state => getExamplesReducer(state).lastUpdated;
export const getExamplesError = state =>
getError(getExamplesReducer(state), epics.actionTypes.fetchExamples);
export const getExamplesPendingStatus = state =>
getPending(getExamplesReducer(state), epics.actionTypes.fetchExamples);
export const getExamples = createSelector(
getEntities, getItems,
(entities, items) => items.map(id => entities[id])
);
// ========================= Selectors - END
将 exampleReducer.js 复制到 src/store/reducers 文件夹。
若要详细了解化简器和 Epics,请参阅 redux-observable。
配置中间件
若要配置中间件,请将化简器添加到 src/store 文件夹中的 rootReducer.js 文件:
import { reducer as exampleReducer } from './reducers/exampleReducer';
const rootReducer = combineReducers({
...appReducer,
...devicesReducer,
...rulesReducer,
...simulationReducer,
...exampleReducer
});
将 epics 添加到 src/store 文件夹中的 rootEpics.js 文件:
import { epics as exampleEpics } from './reducers/exampleReducer';
// Extract the epic function from each property object
const epics = [
...appEpics.getEpics(),
...devicesEpics.getEpics(),
...rulesEpics.getEpics(),
...simulationEpics.getEpics(),
...exampleEpics.getEpics()
];
后续步骤
本文介绍了可以帮助你在远程监视解决方案加速器 Web UI 中添加或自定义服务的资源。
现在已定义了服务,下一步是向远程监视解决方案加速器 Web UI 添加自定义网格,该网格将显示服务返回的数据。
有关远程监视解决方案加速器的更多概念信息,请参阅 远程监视体系结构。