Changing the code for the default system projections?

EventStoreDB
1

Hello guys.

Quick question: is there any way for us to see and change the code for the default system projections (ex.: $by_category) on the web UI?

I’m assuming the answer is no but wanted to be sure…

Thanks.

Regards,

Luis

2

Hi Luis,

The system projections aren’t implemented in JavaScript. You can’t get the code via the web UI, but you can get it off the GitHub repository (https://github.com/EventStore/EventStore/blob/dev/src/EventStore.Projections.Core/Standard/CategorizeStreamByPath.cs
for example).

Cheers,

James

3

if i were to make my own IProjectionStateHandler how would i make use of it? Do i need to create my own build ? or is there a place where it will pick up my own assembly?
https://github.com/EventStore/EventStore/blob/f0e38e85aa473b7b4c57f1e413661da86e828e31/src/EventStore.Projections.Core/Services/Management/ProjectionStateHandlerFactory.cs

seems to suggest (if i’m looking in the correct spot) that it will.

4

You wouldn’t want to

5

+1 - it’s hard to implement properly. We don’t currently load anything from outside the projections core assembly (which gets ilmerged during build).

James