how to get all keys and values in redis in javascript?

Question

I am creating a node API using javascript. I have used redis as my key value store. I created a redis-client in my app and am able to get values for perticular key.

I want to retrieve all keys along with their values. So Far I have done this :

app.get('/jobs', function (req, res) {
    var jobs = [];
    client.keys('*', function (err, keys) {
        if (err) return console.log(err);
        if(keys){
            for(var i=0;i<keys.length;i++){
                client.get(keys[i], function (error, value) {
                    if (err) return console.log(err);
                    var job = {};
                    job['jobId']=keys[i];
                    job['data']=value;
                    jobs.push(job);
                });  
            }
            console.log(jobs);
            res.json({data:jobs});
        }
    });
});

but I always get blank array in response.

is there any way to do this in javascript?

Thanks

Cmon, @Bhushan -- with 3K points you'd know better than to make a question without any code... — MoshMage, Mar 21 '17 at 12:23
Possible duplicate of [Redis command to get all available keys?](http://stackoverflow.com/questions/5252099/redis-command-to-get-all-available-keys) — MoshMage, Mar 21 '17 at 12:24
This question is about returning values from async functions, so it's duplicate of http://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call — ponury-kostek, Mar 28 '17 at 13:02

score 26 · Accepted Answer · answered Mar 28 '17 at 01:43

First of all, the issue in your question is that, inside the for loop, client.get is invoked with an asynchronous callback where the synchronous for loop will not wait for the asynchronous callback and hence the next line res.json({data:jobs}); is getting called immediately after the for loop before the asynchronous callbacks. At the time of the line res.json({data:jobs}); is getting invoked, the array jobs is still empty [] and getting returned with the response.

To mitigate this, you should use any promise modules like async, bluebird, ES6 Promise etc.

Modified code using async module,

app.get('/jobs', function (req, res) {
    var jobs = [];
    client.keys('*', function (err, keys) {
        if (err) return console.log(err);
        if(keys){
            async.map(keys, function(key, cb) {
               client.get(key, function (error, value) {
                    if (error) return cb(error);
                    var job = {};
                    job['jobId']=key;
                    job['data']=value;
                    cb(null, job);
                }); 
            }, function (error, results) {
               if (error) return console.log(error);
               console.log(results);
               res.json({data:results});
            });
        }
    });
});

But from the Redis documentation, it is observed that usage of Keys are intended for debugging and special operations, such as changing your keyspace layout and not advisable to production environments.

Hence, I would suggest using another module called redisscan as below which uses SCAN instead of KEYS as suggested in the Redis documentation.

Something like,

var redisScan = require('redisscan');
var redis     = require('redis').createClient();


redisScan({
        redis: redis,
        each_callback: function (type, key, subkey, value, cb) {
            console.log(type, key, subkey, value);
            cb();
        },
        done_callback: function (err) {
            console.log("-=-=-=-=-=--=-=-=-");
            redis.quit();
        }
    });

score 9 · Answer 2 · answered Oct 04 '17 at 14:53

9

Combination of 2 requests:

import * as ioredis from 'ioredis';

const redis = new ioredis({
    port: redisPort,
    host: redisServer,
    password: '',
    db: 0
  });

const keys = await redis.collection.keys('*');
const values = await redis.collection.mget(keys);

Order will be the same for both arrays.

answered Oct 04 '17 at 14:53

Iurii Perevertailo

2,515
2
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12

this is not working. there is no keys property – rakesht Jan 26 '21 at 12:08
what i really wanted to know is how to limit keys – nanquim Aug 24 '21 at 15:09
@rakesht - looks like it is there https://github.com/luin/ioredis/issues/828#issuecomment-476716136 – Iurii Perevertailo Oct 25 '21 at 22:31
if you want to limit then use scan method to get keys, its fast and reliable and non blocking.. – Adnan Nov 15 '21 at 15:14

rsp · Answer 3 · 2017-03-21T12:32:27.833

4

This will get all keys but with no values:

const redis = require('redis');
const client = redis.createClient();

client.keys('*', (err, keys) => {
  // ...
});

Now you need to get the values for those keys in a usual way. For example:

Promise.all(keys.map(key => client.getAsync(key))).then(values => {
  // ...
});

or with async module or in any way you like.

edited Mar 21 '17 at 12:32

answered Mar 21 '17 at 12:28

rsp

107,747
29
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177

1

Worth to mention that the documentation explicitly states that this command should not be used to do that – baao Mar 21 '17 at 12:30
1

@baao Yeah. I would argue that getting all keys and all values is a need that demonstrates that Redis is used in a strange way here. Unfortunately the question is about a solution, not a bout a problem, so it's hard to recommend anything else. – rsp Mar 21 '17 at 12:35
_that Redis is used in a strange way here_ That's true. :D – baao Mar 21 '17 at 12:37
1

Despite the question, a better solution would be to use `SCAN` instead of `KEYS`. – Itamar Haber Mar 21 '17 at 12:44

Adam Eri · Answer 4 · 2018-10-12T10:41:36.953

You should never do this. First off, it is not recommended to use KEYS * in production. Second, this does not scale (cluster).

You can organise your cached entries into SETs and query for the items within the SET, then retrieve the references keys. This also makes invalidation easier.

Have a look at some data storage best practices.

https://redis.io/topics/data-types-intro how to get all keys and values in redis in javascript?

score 0 · Answer 5 · answered Mar 31 '17 at 08:56

0

You may find something useful in this link

https://github.com/NodeRedis/node_redis/tree/master/examples

answered Mar 31 '17 at 08:56

Dhiraj

1,430
11
21

how to get all keys and values in redis in javascript?

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