我正在开发一个Ionic 4应用程序，该应用程序从wordpress API中提取帖子。我正在使用mergeMap和forkjoin获取特色图片，以在主帖子页面上获取帖子特色图片。
当有特征图像要获取时，以下代码可以正常工作，但是如果没有特征图像，那么我只是从throwError中得到一个错误。我似乎无法记录错误。
%h – Remote hostname (or IP address if the resolveHosts attribute is set to false; by default the value is false).
%l – Remote logical user name; this is always a hyphen (-).
%u – Remote user that has been authenticated. In the example, “admin” and a hyphen (-). If there is none, it’s a hyphen (-).
%t – Date and time in common log file format.
%r – The first line of the request. In the example, “GET / HTTP/1.1” (note that this is configured to be shown within quotes (“”)).
%s – The HTTP status code of the response. In the example 200 is the OK status.
%b – Bytes sent count, excluding HTTP headers, and shows a hyphen (-) if zero.
这是我的home.page.ts文件
dumpbin /EXPORTS bcryptcpp.lib
这是我使用wordpress api的服务文件
ERROR Something went wrong ;)
我检查一下是否import { Component } from '@angular/core';
import { Router } from '@angular/router';
import { LoadingController } from '@ionic/angular';
import { WordpressRestapiService, Post } from '../services/wordpress-restapi.service';
@Component({
selector: 'app-home',
templateUrl: 'home.page.html',
styleUrls: ['home.page.scss'],
})
export class HomePage {
categoryId: number;
private posts : Post[] = [];
constructor(
public loadingController: LoadingController,
private router: Router,
private wordpressService: WordpressRestapiService) { }
async ngOnInit() {
const loading = await this.loadingController.create();
await loading.present();
this.loadPosts().subscribe((posts: Post[]) => {
this.posts = posts;
loading.dismiss();
});
}
loadPosts() {
return this.wordpressService.getRecentPosts(this.categoryId);
}
openPost(postId) {
this.router.navigateByUrl('/post/' + postId);
}
}
才返回帖子，否则请进行api调用以获取精选图片，但这似乎永远不会返回帖子。 import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable, forkJoin, throwError, empty } from 'rxjs';
import { catchError, map, mergeMap } from 'rxjs/operators';
@Injectable({
providedIn: 'root'
})
export class WordpressRestapiService {
baseRestApiUrl: string = 'http://example.com/wp-json/wp/v2/';
constructor(private httpClient: HttpClient) { }
getRecentPosts(categoryId: number, page: number = 1): Observable<any[]> {
// Get posts by a category if a category id is passed
let category_url = categoryId ? ("&categories=" + categoryId) : "";
return this.httpClient.get(this.baseRestApiUrl + "posts?page=" + page + category_url).pipe(
map((res: any) => res),
mergeMap((posts: any[]) => {
if (posts.length > 0) {
return forkJoin(
posts.map((post: any) => {
if (post.featured_media === 0) {
console.log('fired');
post.media = {};
return new Post(post);
}
else {
return this.httpClient.get(this.baseRestApiUrl + "media/" + post.featured_media).pipe(
map((res: any) => {
let media: any = res;
post.media = new Media(media);
return new Post(post);
}),
catchError(error => {
return throwError('Something went wrong ;)');
})
);
}
})
);
}
return empty();
}),
catchError(error => {
return throwError('Something went wrong ;)');
})
);
}
}
export class Post {
author: number;
categories: number[];
comment_status: string;
content: object;
date: string;
date_gmt: string;
excerpt: object;
featured_media: number;
format: string;
guid: object;
id: number;
link: string;
media: object;
meta: object;
modified: string;
modified_gmt: string;
ping_status: string;
slug: string;
status: string;
sticky: boolean;
tags: number[];
template: string;
title: object;
type: string;
_links: object;
constructor(values: Object = {}) {
Object.assign(this, values);
}
}
export class Media {
date: string;
date_gmt: string;
guid: object;
id: number;
link: string;
modified: string;
modified_gmt: string;
slug: string;
status: string;
type: string;
title: object;
author: number;
comment_status: string;
ping_status: string;
meta: object;
template: string;
alt_text: string;
caption: object;
description: object;
media_type: string;
mime_type: string;
media_details: object;
post: number;
source_url: string;
constructor(values: Object = {}) {
Object.assign(this, values);
}
}
被调用，但是loadingCtrl永远不会关闭，帖子也不会显示。
如果没有特色图片但返回所有帖子，我如何只为post.media返回一个空对象？
更新：基于David所说的，我使用以下内容更新了WordpresRestapiService中的getRecentPosts（）函数。这给了我想要的结果。
post.featured_media === 0}
答案 0 :(得分：1)
我认为问题在于，您正在向要传递给forkJoin的数组添加一个Post，而不是一个Observable of Post。
您可以尝试
import { Observable, forkJoin, throwError, empty, of } from 'rxjs';
...
if (post.featured_media === 0) {
console.log('fired');
post.media = {};
return of(new Post(post));
}
在旁注中，我会避免像那样使用catchError。本质上，它正在吞噬任何JavaScript错误（以及不成功的HTTP响应）。这就是为什么在这种情况下看不到有用的错误的原因。
参考： （这些不是官方文档，但我发现它们更具可读性） 堆栈溢出认为这些链接是代码...
https://www.learnrxjs.io/operators/combination/forkjoin.html
https://www.learnrxjs.io/operators/creation/of.html
https://www.learnrxjs.io/operators/error_handling/catch.html