Where is ReducerContext?

[honeyhead]

I followed the demo at https://spacetimedb.com/docs/modules/c-sharp/quickstart and created a module using the command: spacetime init --lang csharp server.

However, following the tutorial, I couldn't find ReducerContext. I was able to create IReducerContext, but I have absolutely no idea how to implement it.

Since C# and Rust are the primary languages being offered at this stage, it would have been great to have sample projects or something similar. Is it possible that I'm just having trouble finding them?

I'm very excited to apply this to .NET MAUI, but it seems too difficult at this early stage.

By the way, the version of SpacetimeDB.Runtime I'm using is 1.0.1.

[honeyhead]

what...?
It was only missing in 1.0.1; it existed in 1.0.0. Where did it go in 1.0.1?

[honeyhead]

This fix in another issue and it might help you click

Instead of posting scam links like this, go study or do something productive

[bfops]

Hi @honeyhead! What do you mean that it's missing? This works for me:

spacetime init --lang csharp my-test-project
cd my-test-project
spacetime build

ReducerContext is generated at build time.

[dotnetCarpenter]

So every SpaceTimeDB C# project has to live with IDE errors, like "The type or namespace name 'ReducerContext' could not be found (are you missing a using directive or an assembly reference?)CS0246"?

[bfops]

So every SpaceTimeDB C# project has to live with IDE errors, like "The type or namespace name 'ReducerContext' could not be found (are you missing a using directive or an assembly reference?)CS0246"?

No, that's not expected. VSCode generally resolves the reference properly. Do you want to share your module project?

[dotnetCarpenter]

@bfops it's literally this: https://github.com/clockworklabs/com.clockworklabs.spacetimedbsdk/tree/master/examples~/quickstart-chat/server

Here is my local copy: https://github.com/dotnetCarpenter/firetime/tree/fc942e3bbcc488aa3320f12ebb01a189ca65b1dd/server

Using:

dotnet --list-sdks
8.0.408 [/usr/share/dotnet/sdk]
9.0.203 [/usr/share/dotnet/sdk]

spacetime --version
spacetime Path: /home/dotnet/.local/share/spacetime/bin/1.1.0/spacetimedb-cli
Commit: 
spacetimedb tool version 1.1.0; spacetimedb-lib version 1.1.0;

code --version
1.99.3
17baf841131aa23349f217ca7c570c76ee87b957
x64

With ms-dotnettools.csharp vscode extension
Version 2.72.34
Last Updated 2025-04-21, 14:49:03

and wasi-experimental installed.

┌──(dotnet㉿kali)-[~/projects/playground/firetime/server] (main)
└─$ dotnet workload list

Workload version: 8.0.408

Installed Workload Id      Installation Source
----------------------------------------------
wasi-experimental          SDK 8.0.400        

Use `dotnet workload search` to find additional workloads to install.

[bfops]

@dotnetCarpenter interesting.. I'm not able to reproduce it on my machine and VScode, with all the same versions. We'll have to look into it more.

Does your explorer view list SpcaetimeDB.BSATN.Codegen and SpacetimeDB.Codegen?

Can you attach a screenshot of where you're getting this error? Is it in intellisense?

[dotnetCarpenter]

@bfops strangely enough, I don't get the errors after I have restarted my system. They were showing up in the Problems pane.
Perhaps it was a language server issue.
I also don't have the same explorer view as you have made a screen shot of. Which extension are you using?

I got the following installed:
1 af4jm.vscode-m3u
2 alexcvzz.vscode-sqlite
3 astro-build.astro-vscode
4 be5invis.toml
5 bierner.markdown-mermaid
6 bradlc.vscode-tailwindcss
7 chakrounanas.turbo-console-log
8 chpl-hpe.chapel-vscode
9 devtanc.tab-hero
10 devzstudio.emoji-snippets
11 eamodio.gitlens
12 editorconfig.editorconfig
13 esbenp.prettier-vscode
14 fabiospampinato.vscode-js-beautify
15 fernandoescolar.vscode-solution-explorer
16 github.vscode-pull-request-github
17 grapecity.gc-excelviewer
18 haskell.haskell
19 jock.svg
20 justusadam.language-haskell
21 llvm-vs-code-extensions.vscode-clangd
22 mads-hartmann.bash-ide-vscode
23 modular-mojotools.vscode-mojo
24 mrmlnc.vscode-json5
25 ms-dotnettools.csharp
26 ms-dotnettools.vscode-dotnet-runtime
27 ms-python.debugpy
28 ms-python.python
29 ms-python.vscode-pylance
30 ms-toolsai.jupyter
31 ms-toolsai.jupyter-keymap
32 ms-toolsai.jupyter-renderers
33 ms-toolsai.vscode-jupyter-cell-tags
34 ms-toolsai.vscode-jupyter-slideshow
35 ms-vscode-remote.remote-wsl
36 ms-vscode.cmake-tools
37 ms-vscode.cpptools
38 ms-vscode.live-server
39 ms-vscode.makefile-tools
40 ms-vsliveshare.vsliveshare
41 nwolverson.ide-purescript
42 nwolverson.language-purescript
43 qassimfarid.ejs-language-support
44 redhat.vscode-xml
45 rpinski.shebang-snippets
46 sjhuangx.vscode-scheme
47 stkb.rewrap
48 streetsidesoftware.code-spell-checker
49 timonwong.shellcheck
50 twxs.cmake
51 tyriar.sort-lines
52 v8-torque.vscode-torque
53 wayou.vscode-todo-highlight
54 yzhang.markdown-all-in-one
55 zhuangtongfa.material-theme

[honeyhead]

Hi @honeyhead! What do you mean that it's missing? This works for me:

spacetime init --lang csharp my-test-project
cd my-test-project
spacetime build
ReducerContext is generated at build time.

At the time, I saw version 1.0.1 available via NuGet in Visual Studio 2022, so I downloaded it. However, as I mentioned in my initial question, ReducerContext was not implemented.

spacetime init --lang csharp my-test-project
cd my-test-project
spacetime build

It works if you follow the method you mentioned. However, I did not use spacetime init because I wanted to integrate it into an existing project as a module, and the packages were already available on NuGet.

Also, I misunderstood the issue. It wasn’t really a problem with versions 1.0.0 or 1.0.1. When you run spacetime init and build, the following packages are installed:

• SpacetimeDB.BSATN.Codegen
• SpacetimeDB.Codegen
• SpacetimeDB.Runtime

I think I resolved the issue by manually installing some of these packages, especially Runtime, rather than it being a version-related problem between 1.0.0 and 1.0.1.

Once you install these three packages, you’ll be able to use ReducerContext. So, if you're installing via NuGet, just make sure to include those three packages.

Since it's a module, using spacetime init is definitely the more convenient way to get started. However, there may be others like me who find the packages on NuGet and try installing them directly—only to get confused. So I think it would be helpful if the tutorial also mentioned that, in the case of installing via NuGet, those three packages need to be included.

[dotnetCarpenter]

I ran spacetime init and spacetime build, so I guess my issue was related to language server picking up everything but ReducerContext.

It would be good to add spacetime build to https://spacetimedb.com/docs/modules/c-sharp/quickstart since I did not do that until I read this issue.

[bfops]

@bfops strangely enough, I don't get the errors after I have restarted my system. They were showing up in the Problems pane. Perhaps it was a language server issue. I also don't have the same explorer view as you have made a screen shot of. Which extension are you using?

I'm glad it's working now. As far as I know, the Explorer view is built in. Do you have it under View -> Open View -> Explorer?

[bfops]

I ran spacetime init and spacetime build, so I guess my issue was related to language server picking up everything but ReducerContext.

It would be good to add spacetime build to https://spacetimedb.com/docs/modules/c-sharp/quickstart since I did not do that until I read this issue.

You shouldn't need to run spacetime build - it's run as part of spacetime publish.

[bfops]

Hi @honeyhead! What do you mean that it's missing? This works for me:
spacetime init --lang csharp my-test-project
cd my-test-project
spacetime build
ReducerContext is generated at build time.

At the time, I saw version 1.0.1 available via NuGet in Visual Studio 2022, so I downloaded it. However, as I mentioned in my initial question, ReducerContext was not implemented.

spacetime init --lang csharp my-test-project
cd my-test-project
spacetime build

It works if you follow the method you mentioned. However, I did not use spacetime init because I wanted to integrate it into an existing project as a module, and the packages were already available on NuGet.

Also, I misunderstood the issue. It wasn’t really a problem with versions 1.0.0 or 1.0.1. When you run spacetime init and build, the following packages are installed:

• SpacetimeDB.BSATN.Codegen
• SpacetimeDB.Codegen
• SpacetimeDB.Runtime

I think I resolved the issue by manually installing some of these packages, especially Runtime, rather than it being a version-related problem between 1.0.0 and 1.0.1.

Once you install these three packages, you’ll be able to use ReducerContext. So, if you're installing via NuGet, just make sure to include those three packages.

Since it's a module, using spacetime init is definitely the more convenient way to get started. However, there may be others like me who find the packages on NuGet and try installing them directly—only to get confused. So I think it would be helpful if the tutorial also mentioned that, in the case of installing via NuGet, those three packages need to be included.

Ah that makes sense. I think SpacetimeDB.Runtime is the only required one - that package should include the other ones automatically.