使用 axios 拦截器和响应时出错答案

【问题标题】：Error using axios interceptors and responses使用 axios 拦截器和响应时出错
【发布时间】：2021-10-19 19:43:23
【问题描述】：

我正在使用“axios”：“^0.23.0”，以及 ReactJs 和 Typescript。

我想拦截请求和响应并添加用户的令牌。

当我尝试使用请求拦截器时，我收到以下错误：

Object is possibly 'undefined'.  TS2532
(property) AxiosRequestConfig<any>.headers?: AxiosRequestHeaders | undefined

           (config) => {
             const user = getUserLocalStorage();
             config.headers.Authorization = user?.token;
             ^
             return config;
           },
           (error) => {

当我将 .Authorization 添加到时发生此错误

config.headers.Authorization = user?.token;

我应该怎么做才能修复这个错误？

这些是我正在使用的方法：

api.ts

import axios from "axios";
import { getUserLocalStorage } from "../context/AuthProvider/util";

export const Api = axios.create({
  baseURL: "http://localhost:8000/",
});

Api.interceptors.request.use(
  (config) => {
    const user = getUserLocalStorage();
    config.headers.Authorization = user?.token;
    return config;
  },
  (error) => {
    return Promise.reject(error);
  }
)

util.ts

import { Api } from "../../services/api";
import { IUser } from "./types";

export function setUserLocalStorage (user: IUser | null) {
  localStorage.setItem('u', JSON.stringify(user));
}

export function getUserLocalStorage () {
  const json = localStorage.getItem('u');

  if (!json) {
    return null;
  }

  const user = JSON.parse(json);

  return user ?? null;
}

export async function LoginRequest (username: string, password: string) {
  try {
    const request = await Api.post(
      'login/', 
      {username, password}
    );
    return request.data;

  } catch (error) {
    return null;
  }
}

index.tsx

import React, {createContext, useEffect, useState} from "react";
import { IAuthProvider, IContext, IUser } from "./types";
import { getUserLocalStorage, LoginRequest, setUserLocalStorage } from "./util";

export const AuthContext = createContext<IContext>({} as IContext)

export const AuthProvider = ({children}: IAuthProvider) => {
  const [user, setUser] = useState<IUser | null>()

  useEffect(() => {
    const user = getUserLocalStorage();

    if (user) {
      setUser(user);
    }
  }, [])

  async function authenticate(
    username:string, 
    password: string
  ) {
    let response: any;
    response = await LoginRequest(username, password);
    const payload = {token: response.token};

    setUser(payload);
    setUserLocalStorage(payload);
  }

  function logout () {
    setUser(null);
    setUserLocalStorage(null);
  }

  return (
    <AuthContext.Provider value={{...user, authenticate, logout}}>
      {children}
    </AuthContext.Provider>
  )
}

谢谢！

【问题讨论】：

标签： reactjs typescript axios request interceptor

【解决方案1】：

必须改变分配令牌值的方式。变化：

config.headers.Authorization = user?.token;

为：

config.headers = {
    Authorization: user?.token,
};

所以，它应该是这样的：

export const Api = axios.create({
    baseURL: "http://localhost:8000/",
});

Api.interceptors.request.use(
    (config) => {
        const user = getUserLocalStorage();

        config.headers = {
            Authorization: user?.token,
        };

        return config;
    },
    (error) => {
        return Promise.reject(error);
    }
);

【讨论】：

【解决方案2】：

实际上，你不应该在拦截器上重新定义 headers 对象。

相反，您应该在添加新的授权属性之前检查 headers 对象是否存在。

所以，不要这样：

Api.interceptors.request.use(
    (config) => {
        const user = getUserLocalStorage();

        // This might cause issues because the `headers` object is always being redefined here - previously passed headers will be discarded
        config.headers = {
            Authorization: user?.token,
        };

        return config;
    },
    (error) => {
        return Promise.reject(error);
    }
);

你应该这样做：

Api.interceptors.request.use(
    (config) => {
        const user = getUserLocalStorage();

        if(!config.headers) {
            config.headers = {};
        }

        config.headers.Authorization = user?.token;

        return config;
    },
    (error) => {
        return Promise.reject(error);
    }
);

这样可以确保您不会忽略/覆盖可能来自axios.{post/get/delete/etc}(url, config) 调用的headers 对象。

【讨论】：