The method of prohibiting Multi-end Login based on Redis unordered set

This article is about how to implement the function of prohibiting multi-side login based on Redis unordered collection. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

Preface

A collection type can store up to 2 ^ 32-1 strings

Collection types are implemented inside redis using a hash table (hash table) with empty values, so the time complexity of adding or deleting elements in the collection is O (1).

The collection has element uniqueness.

Application background

The names of multiple applications are assumed to be An and B, which prohibit users from logging in from A / B at the same time.

Realization idea

Set two unordered sets a_set, b_set

A / b executes when logging in

$redis- > sAdd ('ajar setter sRem); / A log in to $redis- > sRem (' bouncy setter dagger camera UserID); / / kick Blockrediss-> sAdd ('bouncy setter requlibility UserID); / B Log in to $redis- > sRem (' aholysetter reflexive UserID); / / kick A

Before api acquires data, determine whether the id of this end is online (the api of the two sides of the AB is separate)

If ($redis- > sIsmember) {/ / true} else {/ / false}

B judgment

If ($redis- > sIsmember ('baked setbacks grammatical user ID)) {/ / true} else {/ / false}

The method used

Sadd key_set value setting value to set

The sismember key_set value judgment value is stored in the key_set.

Srem key_set value removes the specified value

Smembers key_set gets all the value

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