CODEWITHSUNDEEP
node.jssocketsredisnode-redis
Renan Rodrigues
Renan Rodrigues

Reputation: 306

Stacking strings with nets and nodejs

I am having problems with redis, the documentation is not being clear to me and all my efforts to try to make a simple stack has gone awry.

I use nodejs as a server andredis together with socket I need to make a list of a specific type of users the relation between them and the rooms is many to many, like this:

MEMBERS <-----> ROOMS

Several members may be in several rooms, and several rooms may have several members.

All this information was being allocated in memory, it brought a lot of unnecessary weight, hence the idea of ​​using redis to manage these types of connections.

In my code I'm doing this:

Start the service like this:

const io = require ('socket.io'). listen (http);
const redisSocket = require ('socket.io-redis');
const redis = require ("redis");

I get the connections in the socket:

io.sockets.on ('connection', (socket) => {my _functions});

And I get in a socket.on the members I need to work with

socket.on ('ioUpdateLocation', (data) => {
    // Send the location to the devices in the room
    io.sockets.to (data.room) .emit ('ioReceiveLocation', date);
    addRoom (data.room, socket.id);

    // Emits the location for line X destination Y
    io.sockets.to (data.room + data.destiny) .emit ('ioReceiveLocation', data);
    addRoom (data.room + data.destiny, socket.id);
});

And so I plan to put that socket in the room like this:

const addRoom = (room, socketId) => {
    console.log ('room% s socket% s', room, socketId);

    redisClient.lpush (room, socketId, function (err, reply) {
        console.log ('err', err); // prints 2
        console.log ('reply', reply); // prints 2
    });
  }

My idea is like this:

ROOMS | MEMBERS
123 | ['member01', 'member02', 'member03']
123A | ['member01']

So using redis I hope toadd and remove members from a room, andcheck if that member is in a room for example X.

BUSINESS RULES

  1. MEMBER can be in several rooms
  2. The room can not have 2 equal members

With the attempts was made:

1- client.set ();
2- client.hmset ();
3- client.rpush ();
4- client.sadd ();

None successfully. At first it replaced the value in the example would look like this (the same values ​​were inserted in the following order member01, member02, member03):

ROOMS | MEMBERS
123 | 'member04'
123A | 'member01'

In attempts 2,3,4 the result was an error:

{ReplyError: WRONGTYPE Operation against a key holding the wrong kind of value at new Command (/var/www/lb-api-geolocation/node_modules/redis/lib/command.js:12:22) at RedisClient.lpush (/var/www/lb-api-geolocation/node_modules/redis/lib/commands.js:58:47) at addRoom (/var/www/lb-api-geolocation/src/socket/connect.js:144:17) at Socket. (/var/www/lb-api-geolocation/src/socket/connect.js:94:9) at emitOne (events.js: 115: 13) at Socket.emit (events.js: 210: 7) at /var/www/lb-api-geolocation/node_modules/socket.io/lib/socket.js:513:12 at _combinedTickCallback (internal / process / next_tick.js: 131: 7) at process._tickDomainCallback (internal / process / next_tick.js: 218: 9) command: 'RPUSH', args: ['59c54ace9e450c004ad4c90etripA', 'E4NXUZ417M2UwUxDAAAC'], code: 'WRONGTYPE'}

How to solve this?

Upvotes: 1

Views: 226

Answers (1)

Stamos
Stamos

Reputation: 3998

you error comes directly from redis and the problem is that the key you are trying to do LPUSH already exists and has a different type.

An introduction to Redis data types and abstractions

Example why you got WRONGTYPE error:

> set foo bar
OK
> lpush foo 1 2 3
(error) WRONGTYPE Operation against a key holding the wrong kind of value
> type foo
string

I suggest that you open a redis-shell and do a FLUSHALL to clean you databases

Upvotes: 1

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