feat: requires field for dependencies in HttpApiMiddleware

.changeset/slimy-points-relate.md

@@ -0,0 +1,21 @@
+---
+"@effect/platform": minor
+---
+
+Add `requires` support to `HttpApiMiddleware.Tag` to allow middlewares to depend on other middleware outputs.
+
+Details
+
+- New option: `requires?: Context.Tag | ReadonlyArray<Context.Tag>` when defining a middleware tag.
+
+Example
+
+```
+export class AdminUser extends HttpApiMiddleware.Tag<AdminUser>()("Http/Admin", {
+  failure: HttpApiError.Forbidden,
+  requires: CurrentUser // or: [CurrentUser, Session]
+}) {}
+
+// Inside the middleware implementation you can now safely use the required services
+yield* CurrentUser
+```

packages/platform/src/HttpApiBuilder.ts

@@ -708,23 +708,40 @@ const applyMiddleware = <A extends Effect.Effect<any, any, any>>(
   middleware: MiddlewareMap,
   handler: A
 ) => {
+  // Build a wrapper that threads provided services to both subsequent middleware effects and the final handler
+  let wrap = <X extends Effect.Effect<any, any, any>>(inner: X): X => inner
   for (const entry of middleware.values()) {
     const effect = HttpApiMiddleware.SecurityTypeId in entry.tag ? makeSecurityMiddleware(entry as any) : entry.effect
+    const prevWrap = wrap
     if (entry.tag.optional) {
-      const previous = handler
-      handler = Effect.matchEffect(effect, {
-        onFailure: () => previous,
-        onSuccess: entry.tag.provides !== undefined
-          ? (value) => Effect.provideService(previous, entry.tag.provides as any, value)
-          : (_) => previous
-      }) as any
+      if (entry.tag.provides !== undefined) {
+        wrap = (inner: any) => {
+          const innerWrapped = prevWrap(inner)
+          const effectWrapped = prevWrap(effect)
+          return Effect.matchEffect(effectWrapped, {
+            onFailure: () => innerWrapped,
+            onSuccess: (value) => Effect.provideService(innerWrapped, entry.tag.provides as any, value)
+          }) as any
+        }
+      } else {
+        wrap = (inner: any) => {
+          const innerWrapped = prevWrap(inner)
+          const effectWrapped = prevWrap(effect)
+          return Effect.matchEffect(effectWrapped, {
+            onFailure: () => innerWrapped,
+            onSuccess: () => innerWrapped
+          }) as any
+        }
+      }
     } else {
-      handler = entry.tag.provides !== undefined
-        ? Effect.provideServiceEffect(handler, entry.tag.provides as any, effect) as any
-        : Effect.zipRight(effect, handler) as any
+      if (entry.tag.provides !== undefined) {
+        wrap = (inner: any) => Effect.provideServiceEffect(prevWrap(inner), entry.tag.provides as any, prevWrap(effect)) as any
+      } else {
+        wrap = (inner: any) => Effect.zipRight(prevWrap(effect), prevWrap(inner)) as any
+      }
     }
   }
-  return handler
+  return wrap(handler)
 }
 
 const securityMiddlewareCache = globalValue<WeakMap<any, Effect.Effect<any, any, any>>>(

packages/platform/src/HttpApiMiddleware.ts

@@ -43,16 +43,22 @@ export const isSecurity = (u: TagClassAny): u is TagClassSecurityAny => hasPrope
  * @since 1.0.0
  * @category models
  */
-export interface HttpApiMiddleware<Provides, E> extends Effect.Effect<Provides, E, HttpRouter.HttpRouter.Provided> {}
+export interface HttpApiMiddleware<Provides, E, R = never>
+  extends Effect.Effect<Provides, E, HttpRouter.HttpRouter.Provided | R> {}
 
 /**
  * @since 1.0.0
  * @category models
  */
-export type HttpApiMiddlewareSecurity<Security extends Record<string, HttpApiSecurity.HttpApiSecurity>, Provides, E> = {
+export type HttpApiMiddlewareSecurity<
+  Security extends Record<string, HttpApiSecurity.HttpApiSecurity>,
+  Provides,
+  E,
+  R = never
+> = {
   readonly [K in keyof Security]: (
     _: HttpApiSecurity.HttpApiSecurity.Type<Security[K]>
-  ) => Effect.Effect<Provides, E, HttpRouter.HttpRouter.Provided>
+  ) => Effect.Effect<Provides, E, HttpRouter.HttpRouter.Provided | R>
 }
 
 /**
@@ -102,6 +108,12 @@ export declare namespace HttpApiMiddleware {
    */
   export type ErrorContext<A> = A extends { readonly [TypeId]: { readonly failureContext: infer R } } ? R : never
 
+  /**
+   * @since 1.0.0
+   * @category models
+   */
+  export type Requires<A> = A extends { readonly [TypeId]: { readonly requires: infer Req } } ? Req : never
+
   /**
    * @since 1.0.0
    * @category models
@@ -131,7 +143,8 @@ export type TagClass<
       HttpApiMiddlewareSecurity<
         Options["security"],
         TagClass.Service<Options>,
-        TagClass.FailureService<Options>
+        TagClass.FailureService<Options>,
+        TagClass.Requires<Options>
       >
     >,
     Options["security"]
@@ -142,7 +155,8 @@ export type TagClass<
     Options,
     HttpApiMiddleware<
       TagClass.Service<Options>,
-      TagClass.FailureService<Options>
+      TagClass.FailureService<Options>,
+      TagClass.Requires<Options>
     >
   >
 
@@ -169,6 +183,16 @@ export declare namespace TagClass {
     ? Context.Tag.Service<Options["provides"]>
     : void
 
+  /**
+   * @since 1.0.0
+   * @category models
+   */
+  export type Requires<Options> = Options extends { readonly requires: Context.Tag<any, any> }
+    ? Context.Tag.Identifier<Options["requires"]>
+    : Options extends { readonly requires: ReadonlyArray<Context.Tag<any, any>> }
+      ? Context.Tag.Identifier<Options["requires"][number]>
+      : never
+
   /**
    * @since 1.0.0
    * @category models
@@ -213,6 +237,7 @@ export declare namespace TagClass {
       & {
         readonly [TypeId]: {
           readonly provides: Provides<Options>
+          readonly requires: Requires<Options>
           readonly failure: Failure<Options>
           readonly failureContext: FailureContext<Options>
         }
@@ -222,6 +247,9 @@ export declare namespace TagClass {
     readonly failure: FailureSchema<Options>
     readonly provides: Options extends { readonly provides: Context.Tag<any, any> } ? Options["provides"]
       : undefined
+    readonly requires: Options extends { readonly requires: Context.Tag<any, any> | ReadonlyArray<Context.Tag<any, any>> }
+      ? Options["requires"]
+      : undefined
   }
 
   /**
@@ -248,6 +276,7 @@ export interface TagClassAny extends Context.Tag<any, HttpApiMiddleware.Any> {
   readonly [TypeId]: TypeId
   readonly optional: boolean
   readonly provides?: Context.Tag<any, any>
+  readonly requires?: ReadonlyArray<Context.Tag<any, any>>
   readonly failure: Schema.Schema.All
 }
 
@@ -270,6 +299,7 @@ export const Tag = <Self>(): <
     readonly optional?: boolean
     readonly failure?: Schema.Schema.All
     readonly provides?: Context.Tag<any, any>
+    readonly requires?: Context.Tag<any, any> | ReadonlyArray<Context.Tag<any, any>>
     readonly security?: Record<string, HttpApiSecurity.HttpApiSecurity>
   }
 >(
@@ -283,6 +313,7 @@ export const Tag = <Self>(): <
     readonly security?: Record<string, HttpApiSecurity.HttpApiSecurity>
     readonly failure?: Schema.Schema.All
     readonly provides?: Context.Tag<any, any>
+    readonly requires?: Context.Tag<any, any> | ReadonlyArray<Context.Tag<any, any>>
   }
 ) => {
   const Err = globalThis.Error as any
@@ -305,6 +336,9 @@ export const Tag = <Self>(): <
   if (options?.provides) {
     TagClass_.provides = options.provides
   }
+  if (options?.requires) {
+    TagClass_.requires = Array.isArray(options.requires) ? options.requires : [options.requires]
+  }
   TagClass_.optional = options?.optional ?? false
   if (options?.security) {
     if (Object.keys(options.security).length === 0) {