![](/img/trans.png)
[英]Conditional filtering of JSON before deserialisation to case class model
[英]Typescript (Angular) - JSON model Deserialisation
我想在我的 http model 中添加和填充其他字段(不是由后端服務發送的)。 問題是我無法在收到 http 響應的地方填充(映射)這些字段,因為我使用的是內部框架。
Typescript(Angular)中是否有可能以某種方式覆蓋 JSON 反序列化流/實例創建並填充提到的字段。 例如:
interface ElectricDevice {
energy_meter_start: number; // received from backend service
energy_meter_stop: number; // received from backend service
energy_spent: number; // not received by backend service, but needs to be populated as energy_meter_stop - energy_meter_start
// ...
/* I would like to somehow populate energy_spent as energy_meter_stop-energy_meter_end on instance creation (deserialisation) */
}
您需要一個HttpInterceptor ,您可以在其中操作數據。
@Injectable()
export class CustomJsonInterceptor implements HttpInterceptor {
constructor(private jsonParser: JsonParser) {}
intercept(httpRequest: HttpRequest<any>, next: HttpHandler) {
if (httpRequest.responseType === 'json') {
// If the expected response type is JSON then handle it here.
return this.handleJsonResponse(httpRequest, next);
} else {
return next.handle(httpRequest);
}
}
在教程中了解更多信息: https://angular.io/api/common/http/HttpInterceptor
我已向您詢問了您的服務的具體名稱。
但是,與此同時,我給你一個“一般”的回答你的問題。 你只需要這樣做:
this.yourService.yourGetElectriceDevices
.pipe(
map (_resp: ElectricDevice => _resp.energy_spent = _resp.energy_meter_stop - _resp.energy_meter_start
)
.subscribe( resp => { //your treatment to the response });
以上僅適用於快速測試。 如果您想做一些更“詳細”的事情,您可以將您的界面轉換為 class,並添加您的計算屬性,如下所示:
export interface ElectricDevice {
energy_meter_start: number; // received from backend service
energy_meter_stop: number; // received from backend service
}
export Class ElectricDeviceClass {
energy_meter_start: number;
energy_meter_stop: number;
energy_spent: number;
constructor (data: ElectricDevice) {
this.energy_meter_start = data.energy_meter_start;
this.energy_meter_stop= data.energy_meter_stop;
this.energy_spent = this.energy_meter_stop - this.energy_meter_start;
}
為了使用它,只需:
import { ElectricDeviceClass, ElectricDevice } from './../model/...' // There where you have yours interfaces and model classes
this.yourService.yourGetElectriceDevices
.pipe(
map (_resp: ElectricDevice => new ElectricDeviceClass(_resp)
)
.subscribe( resp => { //your treatment to the response });
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.