Nodejs将json写入文件

I just started learning nodejs. I am currently working with sockets and made chat program.

我刚开始学nodejs。我目前正在使用socket和做聊天程序。

I want to save entire chat to a json file. Currently my code is this :

我想把整个聊天保存到一个json文件。目前我的代码是:

  socket.on('chat', function  (data) {
    message = {user : data.message.user, message : data.message.message};
    chat_room.sockets.emit('chat', {message: message});

    jsonString = JSON.stringify(message);

    fs.appendFile("public/chat.json", jsonString, function(err) {
        if(err) {
            console.log(err);
        } else {
            console.log("The file was saved!");
        }
    }); 

  });

This is currently working perfect, but the json which is written in file is wrong.

这目前运行良好，但是在文件中写入的json是错误的。

This gave me a wrong json

这给了我一个错误的json

{"user":"niraj","message":"hw r u?"}{"user":"ntechi","message":"hello"}{"user":"ntechi","message":"hw r u?"}

{“用户”:“niraj”、“消息”:“hw r u ?”} {“用户”:“ntechi”、“消息”:“你好”} {“用户”:“ntechi”、“消息”:“hw r u ?”}

The above code is called when message is triggered. I want json in this format

当消息被触发时，将调用上面的代码。我想要json格式

{"user":"awd","message":"hw r u?","user":"ntechi","message":"hello","user":"ntechi","message":"hw r u?"}

{“用户”:“awd”、“消息”:“hw r u ?”“用户”:“ntechi”、“信息”:“你好”,“用户”:“ntechi”、“消息”:“hw r u ?”}

Can anyone help me in this? Thanks in advance

有人能帮我吗?谢谢提前

1 个解决方案

#1

The first set of wrong JSON is created because you are appending a piece of JSON to a file each time you get a message.

第一个错误的JSON集被创建，因为每次收到消息时，您都要向文件中添加一块JSON。

The second set of JSON is also wrong - each property name has to be unique.

第二组JSON也是错误的——每个属性名都必须是唯一的。

Presumably you want something like:

大概你想要的是:

[
{"user":"niraj","message":"hw r u?"},
{"user":"ntechi","message":"hello"},
{"user":"ntechi","message":"hw r u?"}
]

In which case the logic you need to use is:

在这种情况下，您需要使用的逻辑是:

Read data from file
从文件读取数据
Parse data as JSON and assign to a variable
将数据解析为JSON并分配给变量
In the event of an error, assign an empty array to that variable
在发生错误时，为该变量分配一个空数组
push the message object onto the end of the array
将消息对象推到数组的末尾。
stringify the array
stringify数组
Overwrite the file with the new string
用新字符串覆盖文件

#1