feat(satori): support async iterator bridge

adapters/satori/src/bot.ts

@@ -5,13 +5,41 @@ function createInternal(bot: SatoriBot, prefix = '') {
     apply(target, thisArg, args) {
       const key = prefix.slice(1)
       bot.logger.debug('[request.internal]', key, args)
-      const form = new FormData()
-      args = JsonForm.dump(args, '$', form)
-      if (![...form.entries()].length) {
-        return bot.http.post('/v1/' + bot.getInternalUrl(`/_api/${key}`, {}, true), args)
+
+      const impl = async () => {
+        const request = await JsonForm.encode(args)
+        const response = await bot.http('/v1/' + bot.getInternalUrl(`/_api/${key}`, {}, true), {
+          method: 'POST',
+          headers: Object.fromEntries(request.headers.entries()),
+          data: request.body,
+          responseType: 'arraybuffer',
+        })
+        return await JsonForm.decode({ body: response.data, headers: response.headers })
+      }
+
+      let promise: Promise<any> | undefined
+      const result = {}
+      for (const key of ['then', 'catch', 'finally']) {
+        result[key] = (...args: any[]) => {
+          return (promise ??= impl())[key](...args)
+        }
       }
-      form.append('$', JSON.stringify(args))
-      return bot.http.post('/v1/' + bot.getInternalUrl(`/_api/${key}`, {}, true), form)
+      let response: any
+      result['next'] = async function () {
+        response ??= await (promise ??= impl())
+        const pagination = response?.pagination
+        if (!pagination) throw new Error('Missing pagination')
+        if (pagination.data.length) return { done: false, value: pagination.data.shift() }
+        if (!pagination.next) return { done: true, value: undefined }
+        args = pagination.next
+        response = await impl()
+        return this.next()
+      }
+      result[Symbol.asyncIterator] = function () {
+        return this
+      }
+
+      return result
     },
     get(target, key, receiver) {
       if (typeof key === 'symbol' || key in target) {

packages/core/src/index.ts

@@ -202,31 +202,15 @@ export class Satori<C extends Context = Context> extends Service<unknown, C> {
 
     this.defineInternalRoute('/_api/:name', async ({ bot, headers, params, method, body }) => {
       if (method !== 'POST') return { status: 405 }
-      const type = headers['content-type']
-      let args: any
-      if (type?.startsWith('multipart/form-data')) {
-        const response = new globalThis.Response(body, { headers })
-        const form = await response.formData()
-        const rawData = form.get('$') as string
-        try {
-          args = JSON.parse(rawData)
-        } catch {
-          return { status: 400 }
-        }
-        args = JsonForm.load(args, '$', form)
-      } else {
-        args = JSON.parse(new TextDecoder().decode(body))
-      }
+      const args = await JsonForm.decode({ body, headers: new Headers(headers) })
+      if (!args) return { status: 400 }
       try {
         const result = await bot.internal[params.name](...args)
-        const body = new TextEncoder().encode(JSON.stringify(result))
-        const headers = new Headers()
-        if (body.byteLength) {
-          headers.set('content-type', 'application/json')
-        }
-        return { body, headers, status: 200 }
+        const payload = { result, pagination: result[Symbol.for('satori.pagination')] }
+        return { ...await JsonForm.encode(payload), status: 200 }
       } catch (error) {
         if (!ctx.http.isError(error) || !error.response) throw error
+        // FIXME: missing response body
         return error.response
       }
     })

packages/core/src/internal.ts

@@ -132,4 +132,43 @@ export namespace JsonForm {
       return dump(value, `${path}.${key}`, form)
     })
   }
+
+  export interface Body {
+    body: ArrayBuffer
+    headers: Headers
+  }
+
+  export async function decode(body: Body) {
+    const type = body.headers.get('content-type')
+    if (type.startsWith('multipart/form-data')) {
+      const response = new globalThis.Response(body.body, { headers: body.headers })
+      const form = await response.formData()
+      const json = form.get('$') as string
+      return load(JSON.parse(json), '$', form)
+    } else if (type.startsWith('application/json')) {
+      return JSON.parse(new TextDecoder().decode(body.body))
+    }
+  }
+
+  export async function encode(data: any): Promise<Body> {
+    const form = new FormData()
+    const json = JSON.stringify(JsonForm.dump(data, '$', form))
+    if ([...form.entries()].length) {
+      form.append('$', json)
+      const request = new Request('stub:', {
+        method: 'POST',
+        body: form,
+      })
+      return {
+        body: await request.arrayBuffer(),
+        headers: request.headers,
+      }
+    } else {
+      const body = new TextEncoder().encode(json)
+      const headers = new Headers({
+        'content-type': 'application/json',
+      })
+      return { body, headers }
+    }
+  }
 }