feat(api): expose service url getter on AtpAgent class

packages/api/src/agent.ts

@@ -2,9 +2,9 @@ import { AtpClient } from './client'
 import { BSKY_LABELER_DID } from './const'
 import { AtpDispatcher } from './dispatcher/atp-dispatcher'
 import {
-  ServiceDispatcher,
-  ServiceDispatcherOptions,
-} from './dispatcher/service-dispatcher'
+  StatelessDispatcher,
+  StatelessDispatcherOptions,
+} from './dispatcher/stateless-dispatcher'
 import { AtpAgentGlobalOpts, AtprotoServiceType } from './types'
 
 const MAX_LABELERS = 10
@@ -34,11 +34,11 @@ export class AtpAgent {
     return this.api.com
   }
 
-  constructor(options: AtpDispatcher | ServiceDispatcherOptions) {
+  constructor(options: AtpDispatcher | StatelessDispatcherOptions) {
     this.dispatcher =
       options instanceof AtpDispatcher
         ? options
-        : new ServiceDispatcher(options)
+        : new StatelessDispatcher(options)
 
     this.api = new AtpClient(this.dispatcher)
     this.api.setHeader('atproto-accept-labelers', () =>
@@ -70,6 +70,11 @@ export class AtpAgent {
     return inst
   }
 
+  async getServiceUrl(): Promise<URL> {
+    // Clone to prevent mutation of the original dispatcher's URL
+    return this.dispatcher.getServiceUrl()
+  }
+
   /**
    * Get the active session's repo DID
    */

packages/api/src/dispatcher/atp-dispatcher.ts

@@ -2,4 +2,5 @@ import { XrpcDispatcher } from '@atproto/xrpc'
 
 export abstract class AtpDispatcher extends XrpcDispatcher {
   abstract getRepo(): string | PromiseLike<string>
+  abstract getServiceUrl(): URL | PromiseLike<URL>
 }

packages/api/src/dispatcher/index.ts

@@ -1,3 +1,3 @@
 export * from './atp-dispatcher'
-export * from './service-dispatcher'
 export * from './session-dispatcher'
+export * from './stateless-dispatcher'

packages/api/src/dispatcher/session-dispatcher.ts

@@ -50,16 +50,20 @@ export class SessionDispatcher extends AtpDispatcher {
     // service endpoint.
     this.client = new AtpClient({
       fetch: async (request) => (0, this.fetch)(request),
-      service: () => this.serviceUrl,
+      service: () => this.getServiceUrl(),
       headers: {
         authorization: () =>
           this.session?.accessJwt && `Bearer ${this.session.accessJwt}`,
       },
     })
   }
 
-  getDispatchUri(url) {
-    return new URL(url, this.pdsUrl || this.serviceUrl)
+  getServiceUrl() {
+    return this.serviceUrl
+  }
+
+  getDispatchUrl() {
+    return this.pdsUrl || this.serviceUrl
   }
 
   /**
@@ -79,7 +83,7 @@ export class SessionDispatcher extends AtpDispatcher {
     // wait for any active session-refreshes to finish
     await this.refreshSessionPromise
 
-    const initialUri = this.getDispatchUri(url)
+    const initialUri = new URL(url, this.getDispatchUrl())
     const initialReq = new Request(initialUri, reqInit)
 
     const initialToken = this.session?.accessJwt
@@ -122,7 +126,7 @@ export class SessionDispatcher extends AtpDispatcher {
     await initialRes.body?.cancel()
 
     // We need to re-compute the URI in case the PDS endpoint has changed
-    const updatedUri = this.getDispatchUri(url)
+    const updatedUri = new URL(url, this.getDispatchUrl())
     const updatedReq = new Request(updatedUri, reqInit)
 
     updatedReq.headers.set('authorization', `Bearer ${updatedToken}`)

packages/api/src/dispatcher/stateless-dispatcher.ts

@@ -0,0 +1,19 @@
+import { AtpDispatcher } from './atp-dispatcher'
+
+export type StatelessDispatcherOptions = {
+  service: string | URL
+  headers?: { [_ in string]?: null | string }
+}
+
+export class StatelessDispatcher extends AtpDispatcher {
+  getServiceUrl: () => URL | PromiseLike<URL>
+
+  constructor({ service, headers }: StatelessDispatcherOptions) {
+    super({ service, headers })
+    this.getServiceUrl = () => new URL(service)
+  }
+
+  async getRepo(): Promise<string> {
+    throw new Error('Not logged in')
+  }
+}

packages/xrpc/src/types.ts

@@ -3,7 +3,10 @@ import { ValidationError } from '@atproto/lexicon'
 
 export type QueryParams = Record<string, any>
 export type Headers = Record<string, string>
-export type Gettable<V> = V | (() => undefined | V | PromiseLike<undefined | V>)
+export type Awaitable<V> = V | PromiseLike<V>
+export type Gettable<V, GetterFallback = undefined> =
+  | V
+  | (() => Awaitable<V | GetterFallback>)
 
 export interface CallOptions {
   encoding?: string

packages/xrpc/src/xrpc-dispatcher.ts

@@ -11,7 +11,11 @@ export type Dispatch = (
   init: RequestInit,
 ) => Promise<Response>
 
-export type XrpcDispatcherOptions = Dispatch | DispatchConfig | string | URL
+export type XrpcDispatcherOptions =
+  | Dispatch
+  | BuildDispatchOptions
+  | string
+  | URL
 
 /**
  * Default {@link FetchAgent} implementation that uses WHATWG's `fetch` API and
@@ -63,13 +67,13 @@ export class XrpcDispatcher {
   }
 }
 
-export type DispatchConfig = {
+export type BuildDispatchOptions = {
   /**
    * The service URL to make requests to. This can be a string, URL, or a
    * function that returns a string or URL. This is useful for dynamic URLs,
    * such as a service URL that changes based on authentication.
    */
-  service: Gettable<string | URL>
+  service: Gettable<string | URL, never>
 
   /**
    * Headers to be added to every request. If a function is provided, it will be