Angular 8 graphql.module localstorage.getItem不可用

Question

使用的版本：

Angular版本: 8.3 apollo-客户端: 2.6.0

我正在尝试将graphql与授权的jwt令牌一起使用。该令牌在登录后在本地存储中设置。

登录时，主页加载，其中执行gql查询，但是，由于graphql.module.ts在应用程序加载时导入，token在加载时不可用。有没有办法修改这个模块？参考链接为here

import { NgModule } from '@angular/core';
import { HttpClientModule } from '@angular/common/http';
import { ApolloModule, Apollo, APOLLO_OPTIONS } from 'apollo-angular';
import { HttpLinkModule, HttpLink } from 'apollo-angular-link-http';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { ApolloLink } from 'apollo-link';
import { setContext } from 'apollo-link-context';

const uri = '/graphql';

export function provideApollo(httpLink: HttpLink) {
  const basic = setContext((operation, context) => ({
    headers: {
      Accept: 'charset=utf-8'
    }
  }));

  // Get the authentication token from local storage if it exists
  const token = localStorage.getItem('token');
  const auth = setContext((operation, context) => ({
    headers: {
      Authorization: `Bearer ${token}`
    },
  }));

  const link = ApolloLink.from([basic, auth, httpLink.create({ uri })]);
  const cache = new InMemoryCache();

  return {
    link,
    cache
  }
}

@NgModule({
  exports: [
    HttpClientModule,
    ApolloModule,
    HttpLinkModule
  ],
  providers: [{
    provide: APOLLO_OPTIONS,
    useFactory: provideApollo,
    deps: [HttpLink]
  }]
})
export class GraphQLModule {}

Answer 1

下面是我对一个需要有效JWT的受保护端点进行的graphql调用的精简版本。显然，这个逻辑应该放到一个服务类中，但它至少会演示主页应该如何绑定到graphql模块类中，并让它将JWT注入到请求中。

import { Component, OnInit } from '@angular/core';
import { Apollo } from 'apollo-angular';
import gql from 'graphql-tag';

@Component({
  selector: 'app-user-profile',
  templateUrl: './user-profile.component.html',
  styleUrls: ['./user-profile.component.scss']
})
export class UserProfileComponent implements OnInit {

  constructor(
    private apollo: Apollo
  ) { }
  user: any;

  ngOnInit(): void {
    this.apollo.query<any>({
      query: gql`
        query users {
          loggedInUser {
            email,
            avatarUrl
          }
        }
      `
    }).subscribe(result => {
      this.user = result.data.loggedInUser;
      console.log(result);
    });
  }
}

这是我的graphql模块，它与你的非常相似，除了我还包含了一个刷新令牌策略。

import { NgModule } from '@angular/core';
import { HttpLinkModule, HttpLink } from 'apollo-angular-link-http';
import { AuthenticationService } from './authentication/services/authentication.service';
import { ApolloLink } from 'apollo-link';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { ApolloModule, APOLLO_OPTIONS } from 'apollo-angular';
import { onError } from 'apollo-link-error';
import { Observable } from 'apollo-link';


export function createApollo(httpLink: HttpLink, authenticationService: AuthenticationService) {

  const authLink = new ApolloLink((operation, forward) => {
    operation.setContext({
      headers: {
        Authorization: 'Bearer ' + localStorage.getItem('auth_token')
      }
    });
    return forward(operation);
  });

  const errorLink = onError(({ forward, graphQLErrors, networkError, operation }) => {
    if (graphQLErrors) {
      if (graphQLErrors.some(x => x.message.toLowerCase() === 'unauthorized')) {
        return promiseToObservable(authenticationService.refreshToken().toPromise()).flatMap(() => forward(operation));
      }
    }
  });

  return {
    link: errorLink.concat(authLink.concat(httpLink.create({ uri: '/graphql' }))),
    cache: new InMemoryCache(),
  };
}

const promiseToObservable = (promise: Promise<any>) =>
    new Observable((subscriber: any) => {
      promise.then(
        value => {
          if (subscriber.closed) {
            return;
          }
          subscriber.next(value);
          subscriber.complete();
        },
        err => subscriber.error(err)
      );
    });


@NgModule({
  exports: [ApolloModule, HttpLinkModule],
  providers: [
    {
      provide: APOLLO_OPTIONS,
      useFactory: createApollo,
      deps: [HttpLink, AuthenticationService]
    }
  ]
})
export class GraphqlModule { }