// config/plugin.js
valparams : {
  enable : true,
  package: 'egg-valparams'
},
// config/config.default.js
config.valparams = {
    locale    : 'zh-cn',
    throwError: true
};

module.exports = (option, app) => {
  return async function errorHandler(ctx, next) {
    try {
      await next();
      // 404 处理
      if (ctx.status === 404 && !ctx.body) {
        ctx.body = {
          msg: "fail",
          data: "404 错误",
        };
      }
    } catch (err) {
      // 记录一条错误日志
      app.emit("error", err, ctx);

      let status = err.status || 500;
      // 生产环境时 500 错误的详细错误内容不返回给客户端，因为可能包含敏感信息
      let error = status === 500 && app.config.env === "prod"
        ? "Internal Server Error"
        : err.message;

      // 从 error 对象上读出各个属性，设置到响应中
      ctx.body = {
        msg: "fail",
        data: error,
      };

      // 参数验证异常
      if (status === 422 && err.message === "Validation Failed") {
        if (err.errors && Array.isArray(err.errors)) {
          error = err.errors[0].err[0]
            ? err.errors[0].err[0]
            : err.errors[0].err[1];
        }
        ctx.body = {
          msg: "fail",
          data: error,
        };
      }

      ctx.status = status;
    }
  };
};

class XXXController extends app.Controller {
  // ...
  async XXX() {
    const { ctx } = this;
    ctx.validate({
      system: {
        type: "string",
        required: false,
        defValue: "account",
        desc: "系统名称",
      },
      token: { type: "string", required: true, desc: "token 验证" },
      redirect: { type: "string", required: false, desc: "登录跳转" },
    });
    // if (config.throwError === false)
    if (ctx.paramErrors) {
      // get error infos from `ctx.paramErrors`;
    }
    let params = ctx.params;
    let { query, body } = ctx.request;
    // ctx.params        = validater.ret.params;
    // ctx.request.query = validater.ret.query;
    // ctx.request.body  = validater.ret.body;
    // ...
    ctx.body = query;
  }
  // ...
}

const Valparams = require("path/to/Valparams[/index]");
Valparams.locale("zh-cn");

function list(req, res, next) {
  let validater = Valparams.setParams(req, {
    sysID: { alias: "sid", type: "int", required: true, desc: "所属系统id" },
    page: {
      type: "int",
      required: false,
      defValue: 1,
      range: { min: 0 },
      desc: "页码",
    },
    size: { type: "int", required: false, defValue: 30, desc: "页面大小" },
    offset: { type: "int", required: false, defValue: 0, desc: "位移" },
  }, {
    choices: [{ fields: ["sysID", "page"], count: 1, force: false }],
  });
  if (validater.err && validater.err.length) {
    console.log(validater.err);
  } else {
    console.log(validater);
    //{ query: { page: 1, size: 30 },
    //  body: {},
    //  params: { sysID: 2 },
    //  all: { sysID: 2, page: 1, size: 30 },
    //  err: null }
    //  raw: { query: { page: 1, size: 30 },
    //         body: {},
    //         params: { sid: 2 },
    //       }
    //}
    //do something
  }
}

Valparams.vType = {
  ALL: "all",
  STRING: "string",
  ARRAY: "array",
  DATE: "date",
  INT: "int",
  FLOAT: "float",
  LETTER: "letter",
  NUMBER: "number",
  IP: "ip",
  EMAIL: "email",
  PHONE: "phone",
  URL: "url",
  JSON: "json",
  BOOL: "bool",
  NULL: "null",
  RANGE: "range",
  DATERANGE: "dateRange",
  INTRANGE: "intRange",
  FLOATRANGE: "floatRange",
  NUMBERRANGE: "numberRange",
};