如何使用Node.js在Redis缓存中创建LIKE运算符搜索？

Question

I have a question, is it possible to create a LIKE operator search in Redis? Similar to relational (mysql/oracle) database.

I have complex json:

   {"_id" : ObjectId("581c8b8854fdcd1ff8c944e0"),
"Objectcode" : "xxxxx",
"Objecttype" : "xxxx",
"docid" : "581c8b8554fdcd1ff8c93d10",
"description" : "Tags based search .... ",
"metaTags" : [ 
    "tag1", 
    "tag2", 
    "tag3", 
    "tag5", 
    "tag6", 
    "tag7", 
    "tag8", 
    "tag9", 
    "tag10"
],
"__v" : 0

}

and i want to search on array of metaTags how can i do it?

Thanks

Answer 1

You can use Redis *SCAN commands http://redis.io/commands/scan , depending of your type of data to filter by a pattern:

• SCAN iterates the set of keys in the currently selected Redis database.
• SSCAN iterates elements of Sets types.
• HSCAN iterates fields of Hash types and their associated values.
• ZSCAN iterates elements of Sorted Set types and their associated scores.

Never use KEYS in app code, because it may ruin performance.

The two major nodejs redis client libraries node_redis and ioredis support it, with some syntax sugar:

const keys = [];
const redis = new Redis(); // ioredis
redis.mset('foo1', 1, 'foo2', 1, 'foo3', 1, 'foo4', 1, 'foo10', 1, () => {
  const stream = redis.scanStream();
  stream.on('data', data => {
    keys = keys.concat(data);
  });
  stream.on('end', () => {
    assert.equal(keys.sort(), ['foo1', 'foo10', 'foo2', 'foo3', 'foo4']);
  });
});

Answer 2

You can use MATCH commands to search data.

Eg: scan 0 MATCH *11*

Refer: http://redis.io/commands/scan