元数据和标题不更新，在Angular-v6通用项目中从后端获取数据

我设置了一个Angular CLI-v6.0.0项目，并使用此链接从服务器端渲染。我的整个项目正在从服务器端成功渲染。演示链接在这里

当我点击产品进入产品详细信息页面时，标题和元信息正在更新，当我使用静态数据时，我在源代码视图中发现了它

但问题是，当我试图通过使用http请求从后端获取数据来更新标题和元数据信息时，标题和元数据信息并没有更新

我的SEO内容更新服务：

import { Injectable, Inject } from '@angular/core';
import { Title, Meta } from '@angular/platform-browser';

@Injectable()
export class SeoContentLoaderService {

constructor(private titleService: Title, private metaService: Meta) { }

setContent(title: string, description: string, keywords: string, slug: string = '', image: string = '', update = true) {
            let tags = {
                title: title && title != '' && update ? title : "Boibazar Largest Online Book Store in Bangladesh",
                description: description && description != '' && update ? description : "Buy Books & Get Home Delivery anywhere in Bangladesh",
                keywords: keywords && keywords != '' && update ? keywords : "Books, Boibazar, Boimela, Book, Bangladesh, Largest, Big, Boro, Bishal, Online, Shop, Place",
                image: image
            }

            this.titleService.setTitle(tags.title);

            this.metaService.updateTag({ name: 'twitter:card', content: 'Product' });
            this.metaService.updateTag({ name: 'twitter:site', content: 'Boibazar.com' });
            this.metaService.updateTag({ name: 'twitter:title', content: tags.title });
            this.metaService.updateTag({ name: 'twitter:description', content: tags.description });
            this.metaService.updateTag({ name: 'twitter:image', content: `http://118.179.223.38:8081/${tags.image}` });

            this.metaService.updateTag({ property: 'og:type', content: 'Product' });
            this.metaService.updateTag({ property: 'og:site_name', content: 'Boibazar.com' });
            this.metaService.updateTag({ property: 'og:title', content: tags.title });
            this.metaService.updateTag({ property: 'og:description', content: tags.description });
            this.metaService.updateTag({ property: 'og:image', content: `http://118.179.223.38:8081/${tags.image}` });
            this.metaService.updateTag({ property: 'og:url', content: `http://118.179.223.38:8081/book/${slug}` });
        }
    }

以及产品详细信息组件：

    import { Component, ViewContainerRef } from '@angular/core';
    import { ActivatedRoute } from '@angular/router';
    import { ProductService, SeoContentLoaderService } from'../shared/services';

         @Component({
            selector: 'product-detail',
            templateUrl: './product.details.html',
            styleUrls: ['./product.details.scss'],
            encapsulation: ViewEncapsulation.None
        })

    export class ProductDetailComponent {
        public product: any = {};
        constructor(
                  private seoContentLoaderService: SeoContentLoaderService,
                  private route: ActivatedRoute,
                  public productService: ProductService){}

        ngOnInit() {
         let slug=this.route.snapshot.params['slug'];
         this.productService.get(slug).subscribe((result) => {
           this.product = result.product;
           this.seoContentLoaderService.setContent(
           this.product.name, this.product.meta_tag_description, 
           this.product.meta_tag_keywords, slug, this.product.image
           );
        })
       }

---

您使用的是什么类型的数据库？是否添加了控制台日志以确保在渲染服务器端时使用正确的值执行代码？@sugarme我在服务器端使用MongoDB，ExpressJS。@David是，当我在浏览器中检查代码时，我通过控制台获取了我的标题和元数据，我添加的标题也显示在标题栏中，但不显示在源代码视图中。您的站点收到API请求错误，您确定API在服务器端正常工作吗？