浏览跨域请求

以前没注意到还Ajax跨域发两次请求, 一次Option, 一次真实的请求
Option请求发到Server端, Server端检查是不是自己人的请求, Header不能多也不能少必须按照服务配置传才能进行下次真实请求…

Ajax跨域发两次请求

const request = {
	method: 'GET',
	headers: {
		'Accept': 'application/json',
 		'Content-Type': 'application/json',
 		'Platform': 'wechat'
 	}
};
fetch(url, request);

服务端

response.setHeader("Access-Control-Allow-Headers", "Platform,Origin,Content-Type");
response.setHeader("Access-Control-Allow-Origin",  req.getHeader("Origin"));
response.setHeader("Access-Control-Allow-Methods", "POST,GET,OPTIONS");
response.setHeader("Access-Control-Allow-Credentials", "true"); response.setHeader("P3P","CP=CAO PSA OUR"); // 解决ie跨域不能使用cookie

第一次Options探测请求, 判断服务端是否支付跨域

Request URL:http://localhost:8080/opened/allCats
Request Method:OPTIONS
Status Code:200 OK
Remote Address:[::1]:8080

Response Headers
Access-Control-Allow-Credentials:true
Access-Control-Allow-Headers:Platform,Origin,Content-Type
Access-Control-Allow-Methods:*
Access-Control-Allow-Origin:*
Access-Control-Max-Age:86400
Allow:GET, HEAD, POST, PUT, DELETE, TRACE, OPTIONS, PATCH
Connection:keep-alive
Content-Length:0
Date:Thu, 14 Jul 2016 06:56:28 GMT
Keep-Alive:timeout=2, max=100
P3P:CP=CAO PSA OUR
Server:Apache-Coyote/1.1
X-Application-Context:application

Request Headers
Accept:*/*
Accept-Encoding:gzip, deflate, sdch
Accept-Language:en-US,en;q=0.8,zh-CN;q=0.6,zh;q=0.4
Access-Control-Request-Headers:accept, content-type, platform
Access-Control-Request-Method:GET
Cache-Control:no-cache
Connection:keep-alive
Host:localhost:8080
Origin:http://localhost:3000
Pragma:no-cache
Referer:http://localhost:3000/
User-Agent:Mozilla/5.0 (Linux; Android 5.0; SM-G900P Build/LRX21T) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.23 Mobile Safari/537.36

第二次真证请求

Request URL:http://localhost:8080/opened/allCats
Request Method:GET
Status Code:200 OK
Remote Address:[::1]:8080

Response Headers
Access-Control-Allow-Credentials:true
Access-Control-Allow-Headers:Platform,Origin,Content-Type
Access-Control-Allow-Methods:*
Access-Control-Allow-Origin:*
Access-Control-Max-Age:86400
Connection:keep-alive
Content-Length:6568
Content-Type:application/json;charset=UTF-8
Date:Thu, 14 Jul 2016 06:56:28 GMT
Keep-Alive:timeout=2, max=100
P3P:CP=CAO PSA OUR
Server:Apache-Coyote/1.1
X-Application-Context:application

Request Headers
accept:application/json
Accept-Encoding:gzip, deflate, sdch
Accept-Language:en-US,en;q=0.8,zh-CN;q=0.6,zh;q=0.4
Cache-Control:no-cache
Connection:keep-alive
content-type:application/json
Host:localhost:8080
Origin:http://localhost:3000
platform:wechat
Pragma:no-cache
Referer:http://localhost:3000/
User-Agent:Mozilla/5.0 (Linux; Android 5.0; SM-G900P Build/LRX21T) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.23 Mobile Safari/537.36