前端请求后台接口失败处理逻辑

前后分离项目，前端为uni-app（vue2），后台为java

后台api设置存在问题，部分公共接口为开放非登录用户访问权限

导致前台打开首页后立即跳转到登录提示页

怀疑是开了uni-app开发代理服务器，导致访问的代理服务器地址被拦截：

http://localhost:3030/api/bms/getPostPageList?page=1&limit=12&hot=1

由于不能通过单步执行，查找执行过程，只能在拦截代码中盲猜，始终未找到匹配的代码过程：

import Vue from 'vue'
import App from './App'
import store from './store'
import * as Db from './common/db.js'
import $AppEntryController from './AppEntryController.js'
import * as $apis from './apis/index.js'
import $mRouter from './common/router.js'
import $mUtils from './common/utils.js'
import $mConfig from "./config/index.config.js"
import $mAssetsPath from './config/assets.config.js'
import $mRoutesConfig from './config/routes.config.js'
import $mConstDataConfig from './config/constData.config.js'
import $modalHelper from './common/modalHelper.js'
import mPageView from "./components/m-page-view/m-page-view.vue"

Vue.component("yzb-page", mPageView)

const prePage = ()=>{
	let pages = getCurrentPages();
	let prePage = pages[pages.length - 2];
    // #ifdef H5
    return prePage;
    // #endif
	return prePage.$vm;
}
Vue.prototype.$mPage ={prePage};

Vue.config.productionTip = false;

Vue.prototype.$AppEntryController = $AppEntryController;

Vue.prototype.$store =store;

Vue.prototype.$apis = $apis;

Vue.prototype.$mRouter = $mRouter;

Vue.prototype.$mUtils = $mUtils;

Vue.prototype.$mConfig = $mConfig;

Vue.prototype.$mAssetsPath = $mAssetsPath;

Vue.prototype.$mRoutesConfig = $mRoutesConfig;

Vue.prototype.$mConstDataConfig = $mConstDataConfig;

Vue.prototype.$modalHelper = $modalHelper;

Vue.prototype.$db = Db;

import GoEasy from "./lib/goeasy-2.4.7.min.js";
const goEasy = GoEasy.getInstance({
	host:"hangzhou.goeasy.io",//应用所在的区域地址: 【hangzhou.goeasy.io |singapore.goeasy.io】
	appkey:"BC-88a9b720d97c4de88eefd2d64daf3fd0",	// common key,
    modules:["im"],
	// true表示支持通知栏提醒，false则表示不需要通知栏提醒
    allowNotification:true //仅有效于app,小程序和H5将会被自动忽略
});
Vue.prototype.GoEasy = GoEasy;
Vue.prototype.goEasy = goEasy;

$mRouter.beforeEach((navType, to) => {
	if (to.route === undefined) throw ("路由钩子函数中没有找到to.route对象，路由信息:" + JSON.stringify(to));

	console.log("进入路由过滤器")
	console.log("to=",to)
	if (to.route.path === $mRoutesConfig.login.path && store.getters.hasLogin) {
		uni.redirectTo({
			url: $mUtils.objParseUrlAndParam($mRoutesConfig.main.path, to.query)
		})
		return;
	}

	// 过滤需要权限的页面
	if (to.route.requiresAuth) {

		if (store.getters.hasLogin) {
			// 已经登录
			uni[navType]({
				url: $mUtils.objParseUrlAndParam(to.route.path, to.query)
			})
		} else {
			// 登录成功后的重定向地址和参数
			let query = {
				redirectUrl: to.route.path,
				...to.query
			}
			// 没有登录 是否强制登录?
			if (store.state.forcedLogin) {
				
				//#ifdef H5
				uni.redirectTo({
					url: $mUtils.objParseUrlAndParam($mRoutesConfig.loginPwd.path, query)
				})
				// #endif
				
				
				//#ifdef MP-WEIXIN
				uni.redirectTo({
					url: $mUtils.objParseUrlAndParam($mRoutesConfig.login.path, query)
				})
				// #endif

			} else {
				
				//#ifdef H5
				uni.redirectTo({
					url: $mUtils.objParseUrlAndParam($mRoutesConfig.loginPwd.path, query)
				})
				// #endif
				
				//#ifdef MP-WEIXIN
				uni.redirectTo({
					url: $mUtils.objParseUrlAndParam($mRoutesConfig.login.path, query)
				})
				// #endif

			}
		}
	} else {
		uni[navType]({
			url: $mUtils.objParseUrlAndParam(to.route.path, to.query)
		})
	}
})

App.mpType = 'app'

const app = new Vue({
	store,
	...App
})
app.$mount()


Vue.prototype.formatDate = function (t) {
    t = t || Date.now();
    let time = new Date(t);
    let str = time.getMonth() < 9 ? ('0' + (time.getMonth() + 1)) : (time.getMonth() + 1);
    str += '-';
    str += time.getDate() < 10 ? ('0' + time.getDate()) : time.getDate();
    str += ' ';
    str += time.getHours();
    str += ':';
    str += time.getMinutes() < 10 ? ('0' + time.getMinutes()) : time.getMinutes();
    return str;
}

// 控制全局日志开关
// console.log = (function (oriLogFunc) {
//   return function () {
//     //判断配置文件是否开启日志调试
//     if (!true) {
//       try{
//         oriLogFunc.call(console, ...arguments);
//       }catch(e){
//         console.error('console.log error', e);
//       }
//     }
//   }
// })(console.log);

重新查看uni-app发送http请求的代码段，发现在后台返回401时，代码直接跳转到登录流程：

import store from "@/store"
function HTTP(obj, config) {

	let defaultConfig = {
		isRes: false,
		loading: false
	}

	config = { ...defaultConfig,
		...config
	}


	// 如果需要显示loading,mask防止点击穿透
	config.loading && uni.showLoading({
		title: '加载中',
		mask: true
	});

	return new Promise((resolve, reject) => {

		let options = {
			url: "",
			method: "GET",
			data: {},
			dataType: "json",
			header: {
				"content-type": "application/json",
				"X-requested-With": "XMLHttpRequest",
				// 模拟用户登录
				//"X-Access-Token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE2OTQ1MjM5NDEsInVzZXJuYW1lIjoiYWRtaW4ifQ.iGxw-j0uNi-rY96KuP9B4Jgx-t-Uk2mYZxVWMb7ySbo"
			},
			success: (res) => {
				//console.log("HTTP请求结果：",res)
				//console.log("resolve：",resolve)
				uni.hideLoading();
				// 状态码为200
				if (res.statusCode == 200) {
					let data = res.data;

					//自动校验用户是否登录过期
					if (data.code == "01") {
						store.dispatch("reLogin");
						return;
					}

					//返回 { code:10000,msg:"消息",data:[] }
					if (config.isRes) {
						resolve(data)
					}
					// 返回 data:[]
					else {
						if (data.code == "200") {
							//console.log("data对象：",data)
							resolve(data.result||true)
						} else {
							wx.showToast({
								title: data.message,
								icon: "none",
								duration: 2000
							})
							reject(data.message);
						}
					}
				}else if(res.statusCode == 401) {
					store.dispatch("reLogin");
					return;
				} else {
					reject("HTTP:状态码异常！");
				}
			},
			fail: (err) => {
				uni.hideLoading();
				uni.showToast({
					title: "网络异常，请稍后再试!",
					icon: "none",
				})
				reject("网络异常，请稍后再试!");
			},
			complete: () => {}
		}

		options = { ...options,
			...obj
		};
		
		const OPENID = uni.getStorageSync("openId");
		const Token=uni.getStorageSync("token");
		// const location=uni.getStorageSync("location");
		// if(location){
		// 	//所有接口带上当前位置信息
		// 	options["data"]["latitude"] = location.latitude;
		// 	options["data"]["longitude"] = location.longitude;
		// 	options["data"]["pcitycode"] = location.pcitycode;
		// }
		console.log("Token==="+Token);
		if (OPENID) options["header"]["openId"] = OPENID;
		if (Token) options["header"]["X-Access-Token"] = Token;
		if (options.url && options.method) {
			wx.request(options);
		} else {
			wx.showToast({
				title: 'HTTP：缺失参数',
				icon: "none",
				duration: 2000
			})
		}
	})

}



export default {
	GET(url, data = {}, config) {
		return HTTP({
			url,
			data,
			method: "GET"
		}, config);
	},
	POST(url, data = {}, config) {
		return HTTP({
			url,
			data,
			method: "POST"
		}, config);
	},

	POSTformdata(url, data = {}, config) {
		return HTTP({
			url,
			data,
			method: "POST"
		}, config);
	}
}

这个过程对用户不友好，应提示用户未登录无法查看数据，让用户确认跳转还是留在原始位置。

解决办法是，使用wx.showModal（显示选择的对话框-带按钮），添加如下代码：

else if(res.statusCode == 401) {
		let res_message = res.data.message // 因为wx.showModal也有res，需要另存变量名
					wx.showModal({
					  title: '是否需要登录？',
					  content: '提示：'+res_message,
					  complete: (res) => {
						if (res.cancel) {
							reject(res_message);
						}
						if (res.confirm) {
							store.dispatch("reLogin");
						}
					  }
					})
					
					
					// 这不是正常的promise流程，添加这段代码的人不是原作者
					// store.dispatch("reLogin");
					// return;
				}