add a helper for serving static assets

gleam.toml

@@ -12,6 +12,7 @@ gleam_stdlib = ">= 0.34.0 and < 2.0.0"
 snag = ">= 0.3.0 and < 1.0.0"
 gleam_http = ">= 3.6.0 and < 4.0.0"
 gleam_json = ">= 1.0.0 and < 3.0.0"
+filepath = ">= 1.0.0 and < 2.0.0"
 
 [dev-dependencies]
 gleeunit = ">= 1.0.0 and < 2.0.0"

manifest.toml

@@ -2,6 +2,7 @@
 # You typically do not need to edit this file
 
 packages = [
+  { name = "filepath", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "filepath", source = "hex", outer_checksum = "EFB6FF65C98B2A16378ABC3EE2B14124168C0CE5201553DE652E2644DCFDB594" },
   { name = "gleam_http", version = "3.7.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_http", source = "hex", outer_checksum = "EA66440C2269F7CED0F6845E5BD0DB68095775D627FA709A841CA78A398D6D56" },
   { name = "gleam_json", version = "2.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_json", source = "hex", outer_checksum = "CB10B0E7BF44282FB25162F1A24C1A025F6B93E777CCF238C4017E4EEF2CDE97" },
   { name = "gleam_stdlib", version = "0.40.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "86606B75A600BBD05E539EB59FABC6E307EEEA7B1E5865AFB6D980A93BCB2181" },
@@ -10,6 +11,7 @@ packages = [
 ]
 
 [requirements]
+filepath = { version = ">= 1.0.0 and < 2.0.0" }
 gleam_http = { version = ">= 3.6.0 and < 4.0.0" }
 gleam_json = { version = ">= 1.0.0 and < 3.0.0" }
 gleam_stdlib = { version = ">= 0.34.0 and < 2.0.0" }

src/midas/task.gleam

@@ -1,3 +1,4 @@
+import filepath
 import gleam/http/request.{type Request}
 import gleam/http/response.{type Response}
 import gleam/list
@@ -175,6 +176,28 @@ pub fn serve(port, handle) {
   Serve(port, handle, result_to_effect(_, serve_error_reason))
 }
 
+pub fn serve_static(port, files) {
+  let handle = fn(request) {
+    let request.Request(path: path, ..) = request
+    let mime = case filepath.extension(path) {
+      Ok(".js") -> "application/javascript"
+      Ok(_) -> "application/octet-stream"
+      // index pages are assumed to be html
+      Error(Nil) -> "text/html"
+    }
+    case list.key_find(files, path) {
+      Ok(content) ->
+        response.new(200)
+        |> response.set_header("content-type", mime)
+        |> response.set_body(content)
+      Error(Nil) ->
+        response.new(404)
+        |> response.set_body(<<>>)
+    }
+  }
+  serve(port, handle)
+}
+
 fn serve_error_reason(message) {
   snag.new("Failed to start server: " <> message)
 }