提交和编码是2回事 按正常post提交就行了

@imhered 正常提交，接口确实返回

string先转成GBK编码的buffer（可以用 https://github.com/ashtuchkin/iconv-lite），然后每个byte转成 %XX。 注意不能用 encodeURIComponent ，这个总是按照 utf8 转的（汉字3个字节）

以前写一个短信接口的时候碰到过，这是我当时写的,

'use static';
const http = require('http');
const moment = require('moment');
const iconv = require('iconv-lite');
const querystring = require('querystring');
const { logger } = require('./log');

const sms = (phone, txt) => {
  const postData = querystring.stringify({
    SpCode: '',
    LoginName: '',
    Password: '',
    MessageContent: txt,
    UserNumber: phone,
    SerialNumber: moment().format('x') + moment().format('SSS'),
    ScheduleTime: moment().format('YYYYMMDDHHmmss'),
  }, null, null, {
      encodeURIComponent: str => {
        let gbkBuffer = null;
        let tempStr = '';
        if (/[^\x00-\xff]/g.test(str)) {
          gbkBuffer = iconv.encode(str, 'gbk');
          for (let i = 0; i < gbkBuffer.length; i++) {
            tempStr += '%' + gbkBuffer[i].toString(16);
          };
          tempStr = tempStr.toUpperCase();
          return tempStr;
        } else {
          return querystring.escape(str);
        }
      }
    });
  const req = http.request({
    hostname: '',
    port: 8888,
    path: '',
    method: 'POST',
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded',
      'Content-Length': postData.length,
    },
  }, res => {
    res.on('data', chunk => {
      logger.info(phone + ': ' + iconv.decode(chunk, 'gbk'));
    });
  });
  req.on('error', e => {
    logger.info(phone + ': ' + e.message);
  });
  req.write(postData);
  req.end();
}

module.exports = sms;