.net Angular 通用在渲染前不等待API/http请求

i2byvkas  于 2022-12-05  发布在  .NET
关注(0)|答案(3)|浏览(150)

我有一个全新的Angular 通用项目，似乎伪装所有的HTML（这是好的）。然而，我试图使一个API调用我的.NET服务器，这是一个标准的API构建与天气预报API。
API调用，它工作得很好，但它只发生在我的Web应用程序从预渲染切换到csr之后。请参见示例1。

示例1

如果我禁用页面上的javascript，这就是我得到的

这是HTML代码

<div style="padding: 5rem">
    <h1>TEST</h1>
    <h2>{{ this.SampleMessage }}</h2>
    <div *ngFor="let product of weather$ | async">
      <p>{{ this.product.summary }}</p>
    </div>
  </div>

应用程序.组件.ts

import { AppService } from './app.service';
import { Component, OnInit } from '@angular/core';
import { Observable } from 'rxjs';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent implements OnInit {
  title = 'ModernaMediaAngular';
  text:string = "test"

  weather$: Observable<any>;
  SampleMessage="Example of Angular Async Pipe";    
  
  constructor(private as: AppService, ) {}

  async ngOnInit() {
    await this.getWeatherAsyncPipe();
    //non async
    this.as.getWeather().subscribe( res =>
      {
        this.text = res[0].date;
        console.log("got resolution");
        console.log(res);
        console.log(this.text);
      }
    );

  }
  public async getWeatherAsyncPipe() {    
        this.SampleMessage="Example of Angular Async Pipe";    
        this.weather$ = await this.as.getWeatherAsync();    
        console.log(this.weather$);
      }    
}

应用程序.服务.ts

import { environment } from './../environments/environment';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class AppService {
  public waeatherUrl = environment.url + '/api/weatherForecast/get'
  constructor(private http: HttpClient) { }

  getWeather() : Observable<object> {
    const headers = new HttpHeaders(
      {'Content-Type': 'application/json',
      'Access-Control-Allow-Origin' : 'http://localhost:4200'
    }
      );
    var x = this.http.get(this.waeatherUrl, {headers: headers}).pipe();
    console.log(x);
    return x;
  }

  public getWeatherAsync():Observable<any> {
    return this.http.get<any[]>(this.waeatherUrl);    
  }
}

应用程序模块.ts

import { BrowserStateInterceptor } from './interceptors/browserstate.interceptor';
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { HttpClientModule } from '@angular/common/http';

import { TransferHttpCacheModule } from '@nguniversal/common'

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule.withServerTransition({ appId: 'serverApp' }),
    TransferHttpCacheModule,
    AppRoutingModule,
    HttpClientModule,
  ],
  bootstrap: [AppComponent]
})
export class AppModule {}

应用服务器模块

import { NgModule } from '@angular/core';
import { ServerModule, ServerTransferStateModule } from '@angular/platform-server';
import { AppModule } from './app.module';
import { AppComponent } from './app.component';

@NgModule({
  imports: [
    AppModule,
    ServerModule,
    ServerTransferStateModule
  ],
  bootstrap: [AppComponent],
})
export class AppServerModule {}

主文件.ts

import { enableProdMode } from '@angular/core';
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';

import { AppModule } from './app/app.module';
import { environment } from './environments/environment';

if (environment.production) {
  enableProdMode();
}

document.addEventListener('DOMContentLoaded', () => {
  platformBrowserDynamic().bootstrapModule(AppModule)
  .catch(err => console.error(err));
  console.log("DOMCONTENTLOADED");
});

每当预渲染试图从API中获取时，我也会收到我认为是cors错误的消息。

chunk {main} main.js, main.js.map (main) 66.3 kB [initial] [rendered]
chunk {polyfills} polyfills.js, polyfills.js.map (polyfills) 141 kB [initial] [rendered]
chunk {runtime} runtime.js, runtime.js.map (runtime) 6.15 kB [entry] [rendered]
chunk {styles} styles.css, styles.css.map (styles) 118 bytes [initial] [rendered]
chunk {vendor} vendor.js, vendor.js.map (vendor) 2.8 MB [initial] [rendered]
Date: 2021-03-15T14:26:38.903Z - Hash: a20337e49cf8941fcbf6 - Time: 12492ms
Hash: af451acd21594faf190e
Time: 19059ms
Built at: 2021-03-15 15:26:41
      Asset      Size  Chunks                          Chunk Names
    main.js  6.44 MiB    main  [emitted]        [big]  main
main.js.map  6.99 MiB    main  [emitted] [dev]         main
Entrypoint main [big] = main.js main.js.map
chunk {main} main.js, main.js.map (main) 6.08 MiB [entry] [rendered]

Compiled successfully.
** Angular Universal Live Development Server is listening on http://localhost:4200, open your browser on http://localhost:4200 **
Observable {
  _isScalar: false,
  source: Observable {
    _isScalar: false,
    source: Observable {
      _isScalar: false,
      source: [Observable],
      operator: [MergeMapOperator]
    },
    operator: FilterOperator { predicate: [Function], thisArg: undefined }
  },
  operator: MapOperator { project: [Function], thisArg: undefined }
}

Observable {
  _isScalar: false,
  source: Observable {
    _isScalar: false,
    source: Observable {
      _isScalar: false,
      source: [Observable],
      operator: [MergeMapOperator]
    },
    operator: FilterOperator { predicate: [Function], thisArg: undefined }
  },
  operator: MapOperator { project: [Function], thisArg: undefined }
}

ERROR HttpErrorResponse {
  headers: HttpHeaders {
    normalizedNames: Map {},
    lazyUpdate: null,
    headers: Map {}
  },
  status: 0,
  statusText: 'Unknown Error',
  url: 'https://localhost:5001/api/weatherForecast/get',
  ok: false,
  name: 'HttpErrorResponse',
  message: 'Http failure response for https://localhost:5001/api/weatherForecast/get: 0 Unknown Error',
  error: ProgressEvent {
    type: 'error',
    target: XMLHttpRequest {
      onloadstart: null,
      onprogress: null,
      onabort: null,
      onerror: null,
      onload: null,
      ontimeout: null,
      onloadend: null,
      _listeners: [Object],
      onreadystatechange: null,
      _anonymous: undefined,
      readyState: 4,
      response: null,
      responseText: '',
      responseType: 'text',
      responseURL: '',
      status: 0,
      statusText: '',
      timeout: 0,
      upload: [XMLHttpRequestUpload],
      _method: 'GET',
      _url: [Url],
      _sync: false,
      _headers: [Object],
      _loweredHeaders: [Object],
      _mimeOverride: null,
      _request: null,
      _response: null,
      _responseParts: null,
      _responseHeaders: null,
      _aborting: null,
      _error: null,
      _loadedBytes: 0,
      _totalBytes: 0,
      _lengthComputable: false
    },
    currentTarget: XMLHttpRequest {
      onloadstart: null,
      onprogress: null,
      onabort: null,
      onerror: null,
      onload: null,
      ontimeout: null,
      onloadend: null,
      _listeners: [Object],
      onreadystatechange: null,
      _anonymous: undefined,
      readyState: 4,
      response: null,
      responseText: '',
      responseType: 'text',
      responseURL: '',
      status: 0,
      statusText: '',
      timeout: 0,
      upload: [XMLHttpRequestUpload],
      _method: 'GET',
      _url: [Url],
      _sync: false,
      _headers: [Object],
      _loweredHeaders: [Object],
      _mimeOverride: null,
      _request: null,
      _response: null,
      _responseParts: null,
      _responseHeaders: null,
      _aborting: null,
      _error: null,
      _loadedBytes: 0,
      _totalBytes: 0,
      _lengthComputable: false
    },
    lengthComputable: false,
    loaded: 0,
    total: 0
  }
}

ERROR HttpErrorResponse {
  headers: HttpHeaders {
    normalizedNames: Map {},
    lazyUpdate: null,
    headers: Map {}
  },
  status: 0,
  statusText: 'Unknown Error',
  url: 'https://localhost:5001/api/weatherForecast/get',
  ok: false,
  name: 'HttpErrorResponse',
  message: 'Http failure response for https://localhost:5001/api/weatherForecast/get: 0 Unknown Error',
  error: ProgressEvent {
    type: 'error',
    target: XMLHttpRequest {
      onloadstart: null,
      onprogress: null,
      onabort: null,
      onerror: null,
      onload: null,
      ontimeout: null,
      onloadend: null,
      _listeners: [Object],
      onreadystatechange: null,
      _anonymous: undefined,
      readyState: 4,
      response: null,
      responseText: '',
      responseType: 'text',
      responseURL: '',
      status: 0,
      statusText: '',
      timeout: 0,
      upload: [XMLHttpRequestUpload],
      _method: 'GET',
      _url: [Url],
      _sync: false,
      _headers: [Object],
      _loweredHeaders: [Object],
      _mimeOverride: null,
      _request: null,
      _response: null,
      _responseParts: null,
      _responseHeaders: null,
      _aborting: null,
      _error: null,
      _loadedBytes: 0,
      _totalBytes: 0,
      _lengthComputable: false
    },
    currentTarget: XMLHttpRequest {
      onloadstart: null,
      onprogress: null,
      onabort: null,
      onerror: null,
      onload: null,
      ontimeout: null,
      onloadend: null,
      _listeners: [Object],
      onreadystatechange: null,
      _anonymous: undefined,
      readyState: 4,
      response: null,
      responseText: '',
      responseType: 'text',
      responseURL: '',
      status: 0,
      statusText: '',
      timeout: 0,
      upload: [XMLHttpRequestUpload],
      _method: 'GET',
      _url: [Url],
      _sync: false,
      _headers: [Object],
      _loweredHeaders: [Object],
      _mimeOverride: null,
      _request: null,
      _response: null,
      _responseParts: null,
      _responseHeaders: null,
      _aborting: null,
      _error: null,
      _loadedBytes: 0,
      _totalBytes: 0,
      _lengthComputable: false
    },
    lengthComputable: false,
    loaded: 0,
    total: 0
  }
}

但控制台中没有错误：

在我的.NET 5项目的startup.cs中，我配置了cors：

public void ConfigureServices(IServiceCollection services) {
    services.AddControllers();
    services.AddSwaggerGen(c => {
        c.SwaggerDoc("v1", new OpenApiInfo { Title = "ModernaMediaDotNet", Version = "v1" });
        });
    services.AddCors();
}

并在公共void中配置（IApplicationBuilder应用程序、IWebHostEnvironment环境）

app.UseRouting();
app.UseCors(x => x
            .AllowAnyOrigin()
            .AllowAnyMethod()
            .AllowAnyHeader()
            .SetIsOriginAllowed(origin => true) // allow any origin
            );
.net

3条答案

按热度按时间
ffscu2ro

ffscu2ro1#

我曾经在我们的测试环境中遇到过同样的问题，这是由于我们使用了自签名证书，而节点不喜欢这个证书。
我们最终在server.ts中添加了下面的行，以便节点禁用TLS验证。

process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';

注意这是不安全的（文档），不应在生产中使用（在生产中应具有有效证书）。

另一个选择是只在服务器端进行http调用，可以使用HttpInterceptor

赞(0）分享  回复(0）举报  2022-12-05
c6ubokkw

c6ubokkw2#

您的应用可能需要将API调用 Package 在区域宏任务中。

  1. npm安装@bespunky/angular-zen
    1.导入RouterXModule（.forRoot()或.forChild()取决于您的模块）。
    1.让您的组件/服务扩展RouteAware类。
    1.在对this.resolveInMacroTask()的调用中 Package 您的可观察性。
    您可以手动执行此操作，但RouteAware可以处理所有事务***并且***为您提供额外的优势。
    更多
    Docs (See the Angular Universal section)
    Live example using RouteAware
赞(0）分享  回复(0）举报  2022-12-05
vxqlmq5t

vxqlmq5t3#

我也面临着同样的问题，在你的路由模块中使用一个解析器，这将解决它，快乐编码！

constructor(
    private activatedRoute: ActivatedRoute,
  ) {
    this.activatedRoute.data.subscribe(({ animes }) => {
      this.animeList = animes;
    });
  }
赞(0）分享  回复(0）举报  2022-12-05
我来回答

相关问题

    查看更多

    热门标签

    更多
    JavaquerypythonNode开发语言requestUtil数据库Table后端算法LoggerMessageElementParser

    最新问答

    更多
    • 蜀ICP备13028337号-1 大数据知识库 https://www.saoniuhuo.com © All rights reserved
    • 本站内容来源互联网,如果侵犯您的权益请联系我们删除, 联系方式：448109455@qq.com