将输入字符串转换成 Redis 命令请求协议

str_to_redis_protocol.py

# coding: utf-8

def p(s):

    "将输入字符串转换成 Redis 命令请求协议"

    # 将输入字符串分割为列表，并移除其中的空白字符串
    # 比如 "SET KEY VALUE" 分为 ["SET", "KEY", "VALUE"]
    argv = s.split()

    # 获取参数个数
    argc = len(argv)

    # 协议开头的参数个数部分，例如 *5\r\n
    output = "*{0}\r\n".format(argc)

    # 协议的各个参数，例如 "$3\r\nSET\r\n"
    for arg in argv:
        output += "${len}\r\n{arg}\r\n".format(len=len(arg), arg=arg)

    return output


if __name__ == "__main__":

    # 无参数命令
    assert(
        p("PING") == "*1\r\n$4\r\nPING\r\n"
    )

    # 单参数命令
    assert(
        p("DEL KEY") == "*2\r\n$3\r\nDEL\r\n$3\r\nKEY\r\n"
    )

    # 两参数命令
    assert(
        p("SET KEY VALUE") == "*3\r\n$3\r\nSET\r\n$3\r\nKEY\r\n$5\r\nVALUE\r\n"
    )

    # 多参数命令
    assert(
        p("SADD FRUITS APPLE BANANA CHERRY") == \
        "*5\r\n" + \
        "$4\r\nSADD\r\n" +\
        "$6\r\nFRUITS\r\n" + \
        "$5\r\nAPPLE\r\n" + \
        "$6\r\nBANANA\r\n" + \
        "$6\r\nCHERRY\r\n"
    )

    # 参数带空格的命令
    assert(
        p("  SET     KEY        VALUE  ") == "*3\r\n$3\r\nSET\r\n$3\r\nKEY\r\n$5\r\nVALUE\r\n"
    )

    print("ALL TEST PASSED")