用Erlang写一个操作redis的代码

下面是一个用Erlang操作Redis的示例代码：

-module(redis_test).
-export([start/0]).

start() ->
    %% 连接Redis
    {ok, Socket} = gen_tcp:connect("127.0.0.1", 6379, []),
    ok = gen_tcp:send(Socket, "PING\r\n"),

    %% 读取响应
    {ok, Response} = read_response(Socket),
    io:format("Response from Redis: ~p~n", [Response]),

    %% 设置键值对
    ok = set_key(Socket, "mykey", "myvalue"),

    %% 获取键值对
    {ok, Value} = get_key(Socket, "mykey"),
    io:format("Value of mykey: ~p~n", [Value]),

    %% 关闭连接
    ok = gen_tcp:close(Socket).

%% 设置键值对
set_key(Socket, Key, Value) ->
    Command = ["SET", Key, Value],
    ok = execute_command(Socket, Command).

%% 获取键值对
get_key(Socket, Key) ->
    Command = ["GET", Key],
    execute_command(Socket, Command).

%% 执行Redis命令
execute_command(Socket, Command) ->
    %% 构造命令字符串
    CommandStr = build_command_str(Command),
    %% 发送命令
    ok = gen_tcp:send(Socket, CommandStr),
    %% 读取响应
    {ok, Response} = read_response(Socket),
    %% 解析响应
    parse_response(Response).

%% 构造命令字符串
build_command_str(Command) ->
    %% 将命令列表转换为字符串
    CommandStr = lists:flatten(io_lib:format("~w\r\n", [Command])),
    %% 计算命令字符串的长度
    Len = length(CommandStr),
    %% 在命令字符串前加上长度信息
    lists:flatten(io_lib:format("$~w\r\n~s", [Len, CommandStr])).

%% 读取响应
read_response(Socket) ->
    %% 读取第一行响应
    {ok, [Line]} = gen_tcp:recv(Socket, 0),
    %% 解析响应类型
    case Line of
        "+OK\r\n" -> {ok, ok};
        "-ERR" ++ _ -> {error, string:substr(Line, 5)};
        ":" ++ Value ++ "\r\n" -> {ok, list_to_integer(Value)};
        "$" ++ ValueLen ++ "\r\n" ++ Value ++ "\r\n" -> {ok, Value};
        _ -> {error, "Unknown response"}
    end.

%% 解析响应
parse_response(Response) ->
    case Response of
        {error, Reason} -> {error, Reason};
        Value -> {ok, Value}
    end.

这个示例代码实现了连接Redis、发送命令、读取响应、设置键值对和获取键值对等功能。你可以根据需要修改和扩展该代码，以满足你的实际需求。