Support for EVALSHA seems to be missing

[tw-bert]

We use Redis' server-side Lua scripting a lot, but we have split the responsibilities. Clients aren't allowed to inject Lua code into Redis. Instead, Lua code is automatically injected into Redis instances by a (custom) Lua script manager, after commits / pushes to a DVCS repository. How we use this client-side: see this diagram for a gist (the Lua scripts return SHA1 checksums themselves).

Therefore we need to call EVALSHA directly, supplying only the SHA1 checksum and the parameters.

Is this possible in StackExchange.Redis? Sidenote: we have no problems using this Lua setup in redis-py (python) from various AIX/Linux servers.

Kind regards, TW

[mgravell]

Ah, I see. That isn't a scenario I had considered. At the moment, the client manages that all internally, using the SCRIPT methods to prepare things as-needed. I will add an overload that accepts a byte[] instead of a string, and treats that as the hash for EVALSHA - that work?

[mgravell]

I have pushed fixes for this; you can now use SHA1 hashes by either:

• passing the hex string to the existing method (i.e. a script that is exactly 40 hex characters will automatically be assumed to be a SHA1 hash)
• passing the length-20 byte[] to a new overload

Note that ScriptLoad has also been corrected to provide the 20-byte answer, not the 40-byte ascii

[tw-bert]

Hi Marc, yes, that will be great. You might want to consider using a different name instead of an overload, for example StackExchange.Redis.IDatabase.ScriptEvaluateByHash() or LoadedScriptEvaluate().

As a sidenote, StackExchange.Redis.IDatabase.ScriptLoad() + IsScriptLoaded() are missing as well, but I don't need them at the moment (since I can rely on Python for loading the scripts in my scenario).

Thanks, top stuff.

Edit: Our posts crossed eachother ;) Thanks, I'll pull the changes

[mgravell]

No need for a different method; there is no scenario where "2BAB3B661081DB58BD2341920E0BA7CF5DC77B25" is a valid Lua script, so we can just detect that scenario automatically.

[mgravell]

ScriptLoad and ScriptExists are there; they are on IServer; basically, the same as these: https://github.com/StackExchange/StackExchange.Redis/blob/master/Docs/KeysScan.md

[tw-bert]

Ah yes, missed that. Thanks. + agreed on overload.

[mgravell]

now deployed to nuget too

[tw-bert]

Fast :) thx!