SpringBoot+Vue跨域配置(CORS)問(wèn)題得解決過(guò)程

更新時(shí)間：2024年08月14日 08:57:33 作者：繁依Fanyi

在使用 Spring Boot 和 Vue 開(kāi)發(fā)前后端分離的項(xiàng)目時(shí),跨域資源共享（CORS）問(wèn)題是一個(gè)常見(jiàn)的挑戰(zhàn),接下來(lái),我將分享我是如何一步步解決這個(gè)問(wèn)題的,包括中間的一些試錯(cuò)過(guò)程,希望能夠幫助到正在經(jīng)歷類似問(wèn)題的你

1. 問(wèn)題描述

在我們開(kāi)發(fā)的過(guò)程中，Vue 前端需要與 Spring Boot 后端通信。如果后端沒(méi)有正確配置 CORS，瀏覽器會(huì)進(jìn)行跨域檢查并阻止請(qǐng)求，報(bào)錯(cuò)信息如下：

Access to XMLHttpRequest at 'http://localhost:8789/auth/register' from origin 'http://localhost:8081' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

2. 解決方案概述

為了解決這個(gè)問(wèn)題，我們需要在 Spring Boot 應(yīng)用中配置 CORS。這個(gè)過(guò)程包括創(chuàng)建一個(gè) CORS 配置類，并在 Spring Security 配置類中應(yīng)用這個(gè)配置。

3. 試錯(cuò)過(guò)程

3.1 初步嘗試：簡(jiǎn)單的 CORS 配置

我首先嘗試在 Spring Boot 中添加一個(gè)簡(jiǎn)單的 CORS 配置類：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.CorsConfigurationSource;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;

@Configuration
public class CorsConfig {

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        CorsConfiguration configuration = new CorsConfiguration();
        configuration.addAllowedOrigin("*");
        configuration.addAllowedMethod("*");
        configuration.addAllowedHeader("*");
        configuration.setAllowCredentials(true);
        configuration.setMaxAge(3600L);

        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", configuration);
        return source;
    }
}

然后，在 WebSecurityConfig 中應(yīng)用這個(gè)配置：

http.cors().configurationSource(corsConfigurationSource());

結(jié)果，前端依舊報(bào)錯(cuò)，沒(méi)有任何變化。

3.2 細(xì)化 Security 配置

我接著嘗試在 WebSecurityConfig 中進(jìn)一步細(xì)化 CORS 配置：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.CorsConfigurationSource;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;

@Configuration
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.cors().configurationSource(corsConfigurationSource())
            .and().csrf().disable();
    }

    @Bean
    CorsConfigurationSource corsConfigurationSource() {
        CorsConfiguration configuration = new CorsConfiguration();
        configuration.addAllowedOrigin("*");
        configuration.addAllowedMethod("*");
        configuration.addAllowedHeader("*");
        configuration.setAllowCredentials(true);
        configuration.setMaxAge(3600L);

        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", configuration);
        return source;
    }
}

然而，前端還是無(wú)法正常發(fā)起跨域請(qǐng)求，這讓我非常困惑。

3.3 嘗試代理配置

為了確保開(kāi)發(fā)過(guò)程中跨域請(qǐng)求能正確代理到后端，我在 Vue 項(xiàng)目中添加了代理配置：

首先，確保項(xiàng)目使用 vue-cli 創(chuàng)建，并確保有 vue.config.js 文件。然后添加如下代理配置：

let proxyObj = {};
proxyObj['/'] = {
    target: 'http://localhost:8789/',
    changeOrigin: true,
    pathRewrite: {
        '^/': ''
    }
}

module.exports = {
    devServer: {
        open: true,
        host: 'localhost',
        port: 8081,
        proxy: proxyObj,
    },
}

這種配置可以使前端的跨域請(qǐng)求通過(guò)代理轉(zhuǎn)發(fā)到后端。不過(guò)，這只是開(kāi)發(fā)環(huán)境下的解決方案，并沒(méi)有真正解決后端的 CORS 配置問(wèn)題。

3.4 最終解決方案：完善的 CORS 和 Security 配置

經(jīng)過(guò)幾次嘗試和查閱資料后，我最終找到了一個(gè)有效的解決方案，結(jié)合之前的經(jīng)驗(yàn)，創(chuàng)建了一個(gè)完善的 CORS 和 Security 配置。

CorsConfig.java

package cn.techfanyi.fanyi.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.CorsConfigurationSource;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;

@Configuration
public class CorsConfig {

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        CorsConfiguration corsConfig = new CorsConfiguration();
        corsConfig.addAllowedOriginPattern("*"); // 允許任何源
        corsConfig.addAllowedMethod("*"); // 允許任何HTTP方法
        corsConfig.addAllowedHeader("*"); // 允許任何HTTP頭
        corsConfig.setAllowCredentials(true); // 允許證書(shū)（cookies）
        corsConfig.setMaxAge(3600L); // 預(yù)檢請(qǐng)求的緩存時(shí)間（秒）

        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", corsConfig); // 對(duì)所有路徑應(yīng)用這個(gè)配置
        return source;
    }
}

WebSecurityConfig.java

package cn.techfanyi.fanyi.config;

import cn.techfanyi.fanyi.filter.JwtRequestFilter;
import cn.techfanyi.fanyi.security.CustomAccessDeniedHandler;
import cn.techfanyi.fanyi.security.CustomAuthenticationEntryPoint;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.annotation.authentication.configuration.AuthenticationConfiguration;
import org.springframework.security.config.annotation.method.configuration.EnableGlobalMethodSecurity;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.http.SessionCreationPolicy;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class WebSecurityConfig {

    private final JwtRequestFilter jwtRequestFilter;
    private final CustomAuthenticationEntryPoint customAuthenticationEntryPoint;
    private final CustomAccessDeniedHandler customAccessDeniedHandler;

    public WebSecurityConfig(JwtRequestFilter jwtRequestFilter,
                          CustomAuthenticationEntryPoint customAuthenticationEntryPoint,
                          CustomAccessDeniedHandler customAccessDeniedHandler) {
        this.jwtRequestFilter = jwtRequestFilter;
        this.customAuthenticationEntryPoint = customAuthenticationEntryPoint;
        this.customAccessDeniedHandler = customAccessDeniedHandler;
    }

    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws  Exception {
        http.csrf().disable()
                .cors(cors -> cors.configurationSource(corsConfigurationSource()))
                .authorizeRequests(authorizedRequests ->
                        authorizedRequests.requestMatchers("/**").permitAll()
                                .anyRequest().authenticated())
                .exceptionHandling(exceptionHandling ->
                        exceptionHandling.authenticationEntryPoint(customAuthenticationEntryPoint)
                                .accessDeniedHandler(customAccessDeniedHandler))
                .sessionManagement(sessionManagement ->
                        sessionManagement.sessionCreationPolicy(SessionCreationPolicy.STATELESS))
                .addFilterBefore(jwtRequestFilter, UsernamePasswordAuthenticationFilter.class);

        return http.build();
    }

    @Bean
    public BCryptPasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Bean
    public AuthenticationManager authenticationManager(AuthenticationConfiguration authenticationConfiguration) throws Exception {
        return authenticationConfiguration.getAuthenticationManager();
    }

    private CorsConfigurationSource corsConfigurationSource() {
        return new CorsConfig().corsConfigurationSource();
    }
}

但是又出現(xiàn)以下錯(cuò)誤：

java.lang.IllegalArgumentException: When allowCredentials is true, allowedOrigins cannot contain the special value "*" since that cannot be set on the "Access-Control-Allow-Origin" response header. To allow credentials to a set of origins, list them explicitly or consider using "allowedOriginPatterns" instead.

這個(gè)錯(cuò)誤信息表明，在 Spring Boot 的 CORS 配置中，當(dāng) allowCredentials 設(shè)置為 true 時(shí)，allowedOrigins 不能包含特殊值 "*", 因?yàn)闉g覽器不允許在 Access-Control-Allow-Origin 響應(yīng)頭中設(shè)置 "*", 同時(shí)還允許憑證（如 cookies）。此時(shí)應(yīng)該使用 allowedOriginPatterns 來(lái)代替 allowedOrigins。

具體的錯(cuò)誤原因如下：

java.lang.IllegalArgumentException: When allowCredentials is true, allowedOrigins cannot contain the special value "*" since that cannot be set on the "Access-Control-Allow-Origin" response header. To allow credentials to a set of origins, list them explicitly or consider using "allowedOriginPatterns" instead.

這意味著當(dāng) allowCredentials 設(shè)置為 true 時(shí)，不能將 allowedOrigins 設(shè)置為 "*", 因?yàn)樗荒茉陧憫?yīng)頭中設(shè)置 Access-Control-Allow-Origin 為 "*", 同時(shí)還允許憑證。為了解決這個(gè)問(wèn)題，您需要將 allowedOrigins 改為使用 allowedOriginPatterns。

修改 CorsConfigurationSource 如下：

 @Bean
 public CorsConfigurationSource corsConfigurationSource() {
     CorsConfiguration corsConfig = new CorsConfiguration();
     corsConfig.addAllowedOriginPattern("*"); // 使用 allowedOriginPatterns 代替 allowedOrigins
     corsConfig.addAllowedMethod("*"); 
     corsConfig.addAllowedHeader("*");
     corsConfig.setAllowCredentials(true);
     corsConfig.setMaxAge(3600L);

     UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
     source.registerCorsConfiguration("/**", corsConfig);
     return source;
 }

通過(guò)以上配置，可以解決 allowCredentials 和 allowedOrigins 中 "*" 沖突的問(wèn)題，使得您的 Spring Boot 應(yīng)用可以正確處理跨域請(qǐng)求。

通過(guò)以上配置，前端請(qǐng)求終于可以成功與后端通信，CORS 問(wèn)題不再出現(xiàn)。

4. 為什么要這樣修改

在 Spring Security 6 中，安全配置的方式有所變化。與之前版本相比，Spring Security 6 更加靈活和模塊化。為了使 CORS 配置生效，我們需要：

明確指定 CORS 配置源：在 securityFilterChain 方法中，通過(guò) http.cors(cors -> cors.configurationSource(corsConfigurationSource())) 明確指定使用我們自定義的 CorsConfigurationSource。
禁用默認(rèn)的 CSRF 保護(hù)：對(duì)于大多數(shù) API 項(xiàng)目，特別是無(wú)狀態(tài)的 RESTful 服務(wù)，禁用 CSRF 是常見(jiàn)的做法。通過(guò) http.csrf().disable() 來(lái)實(shí)現(xiàn)。
配置異常處理和會(huì)話管理：確保我們的應(yīng)用是無(wú)狀態(tài)的，并且正確處理認(rèn)證和授權(quán)異常。