utoipa-swagger-ui: compilation error with rust-embed::compression feature enabled

[sergiimk]

I have a project that is already using rust-embed crate to embed some web content. The dependency is declared as:

rust-embed = { version = "8", features = [
    "interpolate-folder-path",
    "compression",
] }

When I link utoipa-swagger-ui it fails to compile:

Compiling utoipa-swagger-ui v8.0.1
error: `folder` must be a relative path under `compression` feature.
 --> /home/sergiimk/blah/.target/debug/build/utoipa-swagger-ui-1d8195b4e224114b/out/embed.rs:4:1
  |
4 | / #[folder = r"/home/sergiimk/blah/.target/debug/build/utoipa-swagger-ui-1d8195b4e224114b...
5 | | struct SwaggerUiDist;
  | |_____________________^

Disabling compression feature fixes it, but given how large Swagger UI and my other content is compression would be nice to keep.

[juhaku]

This needs some troubleshooting to see whether there is something that can be done.

[JMLX42]

IMO related to #1051

The Swagger UI is ~75% lighter when compressed. IMHO it would be a good idea to support a compressed feature in utoipa-swagger-ui.

If that's ok with you @juhaku I'll open a PR for it.

[juhaku]

@JMLX42 Yeah, it is okay for me. I guess it would be good to have it behind compressed feature flag which can be enabled by default but alternatively disabled if one choose to do so for some reason.

[JMLX42]

It turns out:

• rust-embed needs a relative path when building with the compression feature
• it's rather difficult - maybe impossible - to get that relative path right

[JMLX42]

it's rather difficult - maybe impossible - to get that relative path right

rust-embed expects the path to be relative to the location of the utoipa-swagger-ui crate itself. Which - IMO - does not make sense.

So for my test I set utoipa-swagger-ui.path in Cargo.toml:

utoipa-swagger-ui = { path = "../../../../../github.com/JMLX42/utoipa/utoipa-swagger-ui", version = "8.0.1", optional = true, features = [
    "actix-web",
    "vendored",
    "compressed",
] }

error: #[derive(RustEmbed)] folder '/home/jmlx/Projects/github.com/JMLX42/utoipa/utoipa-swagger-ui/./swagger-ui-5.17.14/dist/' does not exist. cwd: '/home/jmlx/Projects/github.com/JMLX42/utoipa/utoipa-swagger-ui'
 --> /home/jmlx/Projects/path/to/my/project/target/debug/build/utoipa-swagger-ui-0e79372353f0618e/out/embed.rs:4:1
  |
4 | / #[folder = r"./swagger-ui-5.17.14/dist/"]
5 | | struct SwaggerUiDist;
  | |_____________________^

[realradical]

i am getting a similar error when building with Bazel, cargo works fine

--> bazel-out/darwin_arm64-fastbuild/bin/external/crate_index__utoipa-swagger-ui-8.0.3/bs.out_dir/embed.rs:4:1
|
4 | / #[folder = r"/private/var/tmp/bazel_jacobshao/7e2bd1580ebb9b9ceb487e72e4c28f00/sandbox/darwin-sandbox/150/execroot/main/bazel-out/darwi...
5 | | struct SwaggerUiDist;
| |__________________^

error[E0599]: no function or associated item named get found for struct SwaggerUiDist in the current scope
--> external/crate_index__utoipa-swagger-ui-8.0.3/src/lib.rs:1358:40
|
1358 | if let Some(file) = SwaggerUiDist::get(file_path) {
| ^^^ function or associated item not found in SwaggerUiDist
|
::: bazel-out/darwin_arm64-fastbuild/bin/external/crate_index__utoipa-swagger-ui-8.0.3/_bs.out_dir/embed.rs:5:1
|
5 | struct SwaggerUiDist;
| -------------------- function or associated item get not found for this struct
|
= help: items from traits can only be used if the trait is implemented and in scope
= note: the following traits define an item get, perhaps you need to implement one of them:
candidate #1: Embed
candidate #2: `SliceIndex```