Common cross domain problems

What is cross-domain ？

Cross domain means that the browser cannot execute scripts of other websites , It can be said that it is closely related to the homology strategy of the browser , It's a strategy for browsers . Homology means agreement , domain name , port all To maintain Agreement

example ：                                http://www.a.com :8080 /stu

                                      agreement         domain name        port     route

Solution ：

• JSONP（ Rarely used ）

JSONP be based on <script> label （<script scr = " 【url+callback( Callback function name )】")></script> Conduct get Request cross domain address , To load data , Make it free from cross domain restrictions , But it can only support GET request , No other request can support .

<script src="http://aaa.com/text?callback=callbackFunction"></script>
//  To the server aaa.com Request , The query string for this request has a callback Parameters , Used to specify the name of the callback function 
//  Process the data returned by the callback function from the server 
<script>
    function callbackFunction(res){
        //  Process the data obtained 
        console.log(res.data)
    }
</script>

• nginx Reverse proxy ( The most simple )      Equivalent to conversion station

【 proxy server 】

It just needs to be modified nginx Configuration of To solve cross domain problems , Support for all browsers , Support session, You don't need to change any code , It does not affect server performance .

• Cros（ common ）

stay Springboot Configuration files in the project CorsConfig.java, After restart, cross domain access can be realized , No need for front end Then configure cross domain .

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

@Configuration
public class CorsConfig {

    //  Maximum effective duration of current cross domain request . Default here 1 God 
    private static final long MAX_AGE = 24 * 60 * 60;

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.addAllowedOrigin("*"); // 1  Set access source address （*  It can be set to allow only http://localhost:8080  visit )
        corsConfiguration.addAllowedHeader("*"); // 2  Set access source request header 
        corsConfiguration.addAllowedMethod("*"); // 3  Set access source request method 
        corsConfiguration.setMaxAge(MAX_AGE);
        source.registerCorsConfiguration("/**", corsConfiguration); // 4  Configure cross domain settings for interfaces 
        return new CorsFilter(source);
    }
}