[Python] Deal with Chinese in Cookie

前言

在 Flask 中設定 cookie 時，若其值含有中文，會被轉換為 8 進位 (Ex. \344\270\255\346\226\207\346\270\254\350\251\246 )，在前端顯示時就無法正確顯示，這一篇文章來記錄一下解決方式。

Solution

目前有以下兩個解法:

• Solution 1: 前端將 8 進位轉為 16 進位，再將 16 進位轉成 UTF-8 字串
• Solution 2: 後端將其值做 Base64 encode, 前端再做 Base64 decode

Solution 1

前端將 8 進位轉為 16 進位，再將 16 進位轉成 UTF-8 字串:

/**
 * Convert hex to string
 * @param {string} hexStr Hex string
 * @returns UTF-8 string 
 */
const convertHexToStr = (hexStr) => {
    let content = '';

    for(let i = 0; i < hexStr.length; i += 2) {
        content += String.fromCharCode(parseInt(hexStr.substr(i, 2), 16));
    }

    return decodeURI(escape(content));
}

/**
 * Convert octal to string
 * @param {string} octStr Octal string
 * @returns UTF-8 string 
 */
const convertOctToStr = (octStr) => {
    let octalList = octStr.split('\\');
    let octalGroup = [];
    
    for(let i = 1; i < octalList.length; i += 3) {
        octalGroup.push(octalList.slice(i, i+3));
    }

    let result = '';
    octalGroup.forEach((group) => {
        let word = '';

        group.forEach((item) => {
            let hexStr = parseInt(item, 8).toString(16);
            word += hexStr;
        });

        result += convertHexToStr(word);
    });

    return result;
}

const user = convertOctToStr(cookies.get('user'));

Solution 2

後端將 cookie 值做 Base64 encode:

# In app.py
import base64
from flask import Flask, jsonify


app = Flask(__name__)

@app.route('/login', methods=['POST'])
def login():
    # User authentication

    # Set cookie
    response = jsonify(status='success')
    response.set_cookie(
        key='user', 
        value=base64.b64encode('中文名稱'.encode('utf-8'))
    )

    return response

if __name__ == '__main__':
  app.run()

前端再做 Base64 decode:

decodeURI(escape(atob(cookies.get('user'))))