package org.ithang.tools.shiro;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.shiro.web.filter.authc.UserFilter;
import org.ithang.tools.lang.JsonUtils;
import org.ithang.tools.model.ActionResult;
import org.ithang.tools.model.ErrorInfo;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

public class ShiroUserFilter extends UserFilter{

	 /**
     * 在访问过来的时候检测是否为OPTIONS请求，如果是就直接返回true
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletResponse httpResponse = (HttpServletResponse) response;
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        if (httpRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            setHeader(httpRequest,httpResponse);
            return true;
        }
        return super.preHandle(request,response);
    }
    
    /**
     * 该方法会在验证失败后调用，这里由于是前后端分离，后台不控制页面跳转
     * 因此重写改成传输JSON数据
     */
    @Override
    protected void saveRequestAndRedirectToLogin(ServletRequest request, ServletResponse response) throws IOException {
        saveRequest(request);
        setHeader((HttpServletRequest) request,(HttpServletResponse) response);
        PrintWriter out = response.getWriter();
        ActionResult noLogin=new ActionResult(ErrorInfo.NoLoginError);
        out.println(JsonUtils.toJsonStr(noLogin));
        out.flush();
        out.close();
    }

    /**
     * 为response设置header，实现跨域
     */
    private void setHeader(HttpServletRequest request,HttpServletResponse response){
        //跨域的header设置
        response.setHeader("Access-control-Allow-Origin", request.getHeader("Origin"));
        response.setHeader("Access-Control-Allow-Methods", request.getMethod());
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("Access-Control-Allow-Headers", request.getHeader("Access-Control-Request-Headers"));
        //防止乱码，适用于传输JSON数据
        response.setHeader("Content-Type","application/json;charset=UTF-8");
        response.setStatus(HttpStatus.OK.value());
    }
	
}
