How to install packages not available on CRAN?

[JosiahParry]

I'd like to use litedown with webR but running webr::install("litedown") and webr::install("yihui/litedown") both fail saying the package cannot be found.

Any tips here? I suspect the best thing i can do is to build it as part of the {rwasm} build process and mount it.

https://github.com/yihui/litedown

[georgestagg]

Yes, either build the package using {rwasm}, or create a personal r-universe repository (which builds emscripten packages for you automatically using {rwasm}).

Loading packages directly from GitHub using package references such as org/package is not currently supported, because we don't have the necessary toolchain to build the package from source available to us from inside the browser under Wasm.

[JosiahParry]

Understandable. The challenge with using r-universe is that (as far as i can tell) it doesn't give us the library.data and library.js.metadata for something locally.

[georgestagg]

It should be possible to download the .data and .js.metadata files directly from R Universe. The URLs are not exposed directly in the web UI, but the files are built as part of the Wasm cross-compilation process, and live in the same directory as the .tgz file.

e.g.

https://r-lib.r-universe.dev/bin/emscripten/contrib/4.4/cli_3.6.3.9000.data
https://r-lib.r-universe.dev/bin/emscripten/contrib/4.4/cli_3.6.3.9000.js.metadata

[yihui]

@JosiahParry FYI litedown is on both CRAN and r-universe now.

[psychemedia]

I can successfully load custom built packages using install.packages("mypackage", repos = "https://example.com/myrepo/"), but I wonder, is there an option i can set via options() to set that repos= path?

I also notice that in the JupyterLite webr kernel at least, library(newpackage) pre-emptively tries to install a missing package from the webR repo:

1. can library() take a repos= style path?
2. it would be good if we could set a repo path via options() that library() called installations could benefit from.

[georgestagg]

@psychemedia

is there an option i can set via options() to set that repos= path?

Try setting options("webr_pkg_repos").

IIRC the library() shim that preemptively installs packages should also listen to this option.