Storing nested javascript objects in redis - NodeJS

Question

I recently switched from memcached to redis in nodejs. The thing I liked in node-memcached was that I can save the whole javascript object in the memory. Sadly I couldn't do this in redis. For example, I got the following object:

var obj = {
    name: "Hello world!",
    author: "admin",
    user: {
        "yolololo" : {
             "id": "352asdsafaseww",
             "server": 5,
             "data" : {
                  x: 1, 
                  y: 1,
                  z: 50
             }
        },
        "yolol" : {
             "id": "358dsa",
             "server": 7
        }
    }
}

with the 3rd-Eden/node-memcached I could just do:

memcached.set("obj", obj, 12345, function(err) { });

and then

memcached.get("obj", function(err, data) {
    console.log(data);
});

And I'll get the object I saved, just the way it is.

The problem with redis is that if I save the object like this:

redisclient.set("obj", obj, redis.print);

When I get the value with

redisclient.get("obj", function(err, data) {
    console.log(data);
});

The output is just string containing [object Object].

Yeah I understand redis is text-based protocol and it's trying to do obj.toString(), but seems memcached take care of objects and redis don't. I thought I could just do:

redisClient.set("obj", JSON.stringify(obj));

but I'm not sure if this will be good, because there will be insane high I/O and I'm not sure if the JSON obj->string will be bottleneck ( 10k+ request/second ).

Both Memcached and Redis store the data as string, but does redis have built-in feature for converting objects?

I think memcached stores data as string. node-memcached does (de)serialization process automatically. — fardjad
– fardjad, Commented Sep 22, 2013 at 9:09
@fardjad Yeah, you're right, but does Redis have such build-in process or I need to convert it manually? — Deepsy
– Deepsy, Commented Sep 22, 2013 at 9:11

fardjad · Accepted Answer · 2013-09-22 09:37:22Z

First of all redis only supports the following data types:

String
List
Set
Hash
Sorted set

You'll need to store objects as string in both redis and memcached.

node-memcached parses/stringifies the data automatically. But node-redis doesn't.

However, you can implement your own serialization/deserialization functions for your app.

The way node-memcached stringifies an object is as follows:

if (Buffer.isBuffer(value)) {
    flag = FLAG_BINARY;
    value = value.toString('binary');
} else if (valuetype === 'number') {
    flag = FLAG_NUMERIC;
    value = value.toString();
} else if (valuetype !== 'string') {
    flag = FLAG_JSON;
    value = JSON.stringify(value);
}

It also parses the retrieved text this way:

switch (flag) {
    case FLAG_JSON:
        dataSet = JSON.parse(dataSet);
        break;
    case FLAG_NUMERIC:
        dataSet = +dataSet;
        break;
    case FLAG_BINARY:
        tmp = new Buffer(dataSet.length);
        tmp.write(dataSet, 0, 'binary');
        dataSet = tmp;
        break;
}

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