Add DVM package

packages/dvm/src/request.ts

@@ -0,0 +1,47 @@
+import {Emitter, now} from '@welshman/lib'
+import type {TrustedEvent, SignedEvent} from '@welshman/util'
+import {subscribe, publish} from '@welshman/net'
+import type {Subscription, Publish} from '@welshman/net'
+
+export enum DVMEvent {
+  Progress = "progress",
+  Result = "result",
+}
+
+export type DVMRequestOptions = {
+  event: SignedEvent
+  relays: string[]
+  timeout?: number
+  autoClose?: boolean
+  reportProgress?: boolean
+}
+
+export type DVMRequest = DVMRequestOptions & {
+  emitter: Emitter,
+  sub: Subscription
+  pub: Publish
+}
+
+export const makeDvmRequest = (request: DVMRequest) => {
+  const emitter = new Emitter()
+  const {event, relays, timeout = 30_000, autoClose = true, reportProgress = true} = request
+  const kind = event.kind + 1000
+  const kinds = reportProgress ? [kind, 7000] : [kind]
+  const filters = [{kinds, since: now() - 60, "#e": [event.id]}]
+  const sub = subscribe({relays, timeout, filters})
+  const pub = publish({event, relays, timeout})
+
+  sub.emitter.on('event', (url: string, event: TrustedEvent) => {
+    if (event.kind === 7000) {
+      emitter.emit(DVMEvent.Progress, url, event)
+    } else {
+      emitter.emit(DVMEvent.Result, url, event)
+
+      if (autoClose) {
+        sub.close()
+      }
+    }
+  })
+
+  return {request, emitter, sub, pub}
+}