通过koajs的cookies方法设置cookie时，写了中文的cookie值，一直失败。代码如下:

this.cookies.set('test', '我是koajs')
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报错如下：

sent error argument value is invalid to the cloud
TypeError: argument value is invalidat new Cookie (/Users/zyy/github/fete/node_modules/cookies/lib/cookies.js:110:11)at Cookies.set (/Users/zyy/github/fete/node_modules/cookies/lib/cookies.js:73:16)at Object.<anonymous> (/Users/zyy/github/fete/app.js:54:18)at next (native)at onFulfilled (/Users/zyy/github/fete/node_modules/co/index.js:65:19)at /Users/zyy/github/fete/node_modules/co/index.js:54:5at Object.co (/Users/zyy/github/fete/node_modules/co/index.js:50:10)at converted (/Users/zyy/github/fete/node_modules/koa-convert/index.js:17:15)at dispatch (/Users/zyy/github/fete/node_modules/koa-compose/index.js:43:32)at next (/Users/zyy/github/fete/node_modules/koa-compose/index.js:44:18)at createGenerator (/Users/zyy/github/fete/node_modules/koa-convert/index.js:24:16)at next (native)at onFulfilled (/Users/zyy/github/fete/node_modules/co/index.js:65:19)at /Users/zyy/github/fete/node_modules/co/index.js:54:5at Object.co (/Users/zyy/github/fete/node_modules/co/index.js:50:10)at Object.toPromise (/Users/zyy/github/fete/node_modules/co/index.js:118:63)
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倒腾了半夜也没找到方案，其实是http协议的Header头有字符限制，下图是stackoverflow的解答，http的header字符集支持US-ASCII子集的字符集，故设置中文是'utf8'时就会报上面错误。

Paste_Image.png

问题链接如下： stackoverflow.com/questions/4… 故解决方案：

把字符串转成base64即可

this.cookies.set('test', new Buffer('我是koajs').toString('base64'))
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base64转到字符串

new Buffer(str, 'base64').toString();//str是base64编码的字符串复制代码