[11.x] Proper rate limiter fix with phpredis serialization/compression enabled #54372
+102
−7
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As a follow up from #54307:
As it turns out it is not safe to globally skip phpredis's serialization/compression for numeric values in EVAL script parameters. The result of my investigation (with the help of the phpredis team, see: phpredis/phpredis#2616) concludes the following: when those options are enabled, the framework must not interfere at all. The application code must disable serialization/compression on per key basis where we know that this key is used for increment/decrement or similar operations.
I have found several cases where skipping the serialization/compression for numeric values, causes the RateLimiter to still fail.
One example is when used with MSGPACK. Its a binary format and for example the rate limit counter 1 is stored as 1, but when this counter value is read, it is interpreted as 49.
Proof
For the following test I expect a fresh counter with a rate limit of 1
Redis output looks fine here
Phpunit output reveals the error when we read back the value and phpredis tries to deserialize
Solution
Because the
RateLimiter
is built on top of theCache
component, I have added this logic in all 3 places where it sets and reads the counter value. As a result the test pass with all combinations of compression/serialization settings locally.In addition a new helper method is provided in the
PacksPhpRedisValues
trait that users can use to skip phpredis serialization/compression on per key basis. This allows full control over this behavior. (fyi, we should mention in the docs that connections with those settings should ideally by only used for caching).