simplify

cli/package.json

@@ -1,14 +1,18 @@
 {
   "name": "cli",
   "private": true,
-  "devDependencies": {
-    "@types/node": "^18.11.11"
+  "scripts": {
+    "dev": "tsx --watch"
   },
   "dependencies": {
     "@effect/cli": "^0.12.0",
     "@effect/platform": "^0.16.1",
     "@effect/platform-node": "^0.17.0",
     "@effect/schema": "^0.36.5",
     "effect": "2.0.0-next.34"
+  },
+  "devDependencies": {
+    "@types/node": "^18.11.11",
+    "tsx": "^3.12.10"
   }
 }

cli/src/wttr.ts

@@ -1,8 +1,13 @@
-import { Effect, Data, Context, Layer, Option } from 'effect'
-import * as Http from '@effect/platform/HttpClient'
+import { Effect, Option, Cause } from 'effect'
+import * as Http from '@effect/platform-node/HttpClient'
+import * as Node from '@effect/platform-node/Runtime'
+import * as Command from '@effect/cli/Command'
+import * as Cli from '@effect/cli/CliApp'
+import * as Options from '@effect/cli/Options'
+import * as Args from '@effect/cli/Args'
+import * as Console from '@effect/cli/Console'
 import * as Schema from '@effect/schema/Schema'
 
-type WttrWeather = Schema.Schema.To<typeof WttrWeatherSchema>
 const WttrWeatherSchema = Schema.struct({
   date: Schema.dateFromString(Schema.string),
   avgtempC: Schema.numberFromString(Schema.string),
@@ -19,33 +24,47 @@ const WttrResponseSchema = Schema.struct({
   weather: Schema.array(WttrWeatherSchema)
 })
 
-class WttrError extends Data.TaggedClass('WttrError')<{
-  cause: unknown
-}> {}
+const cli = Cli.make({
+  name: 'Weather',
+  version: '1.2.3',
+  command: Command.make('weather', {
+    // Accept 0 or 1 arguments for the location and convert it to a `Option<string>`.
+    args: Args.between(Args.text({ name: 'location' }), 0, 1).pipe(Args.map(Option.fromIterable)),
+    options: Options.all({
+      url: Options.withDefault(Options.text('url'), 'https://wttr.in'),
+    }),
+  })
+})
 
-export const Wttr = Context.Tag<Wttr>()
-export interface Wttr {
-  readonly getWeather: (location: Option.Option<string>) => Effect.Effect<never, WttrError, ReadonlyArray<WttrWeather>>
-}
+Node.runMain(Effect.sync(() => process.argv.slice(2)).pipe(
+  Effect.flatMap((args) =>
+    Cli.run(cli, args, ({ options: { url }, args: location }) => {
+      const program = Effect.gen(function* ($) {
+        const defaultClient = yield* $(Http.client.Client)
+        const wttrClient = defaultClient.pipe(
+          // Always prepend the service url to all requests. This makes it more convenient to use the client.
+          Http.client.mapRequest(Http.request.prependUrl(url)),
+          // Tell the wttr.in service to return json.
+          Http.client.mapRequest(Http.request.appendUrlParam('format', 'j1')),
+          // Only accept status responses with a `2xx` status code. Fail otherwise.
+          Http.client.filterStatusOk,
+          // Decode all responses using the `WttrResponseSchema` schema.
+          Http.client.mapEffect(Http.response.schemaBodyJson(WttrResponseSchema)),
+        );
 
-export const makeLayer = (url: string) => Layer.effect(Wttr, Effect.gen(function* ($) {
-  const defaultClient = yield* $(Http.client.Client)
-  const wttrClient = defaultClient.pipe(
-    Http.client.mapRequest(Http.request.prependUrl(url)),
-    Http.client.mapRequest(Http.request.appendUrlParam('format', 'j1')),
-    Http.client.filterStatusOk,
-    Http.client.mapEffect(Http.response.schemaBodyJson(WttrResponseSchema)),
-    Http.client.catchTags({
-      'RequestError': (cause) => Effect.fail(new WttrError({ cause })),
-      'ResponseError': (cause) => Effect.fail(new WttrError({ cause })),
-      'ParseError': (cause) => Effect.fail(new WttrError({ cause })),
-    }),
-  )
+        // Request the weather for the provided location or the current location if none was provided.
+        const wttrResponse = yield* $(Option.match(location, {
+          onNone: () => Http.request.get('/'),
+          onSome: (_) => Http.request.get(`/${encodeURIComponent(_)}`),
+        }).pipe(wttrClient, Effect.map(_ => _.weather)));
 
-  return Wttr.of({
-    getWeather: (location) => Option.match(location, {
-      onNone: () => Http.request.get('/'),
-      onSome: (_) => Http.request.get(`/${encodeURIComponent(_)}`),
-    }).pipe(wttrClient, Effect.map(_ => _.weather)),
-  })
-}))
+        // TODO: Pretty print the weather.
+        yield* $(Effect.log(wttrResponse));
+      });
+
+      return Effect.provideLayer(program, Http.client.layer)
+    })
+  ),
+  Effect.provideLayer(Console.layer),
+  Effect.tapErrorCause((_) => Effect.logError(Cause.pretty(_)))
+))