实现快传，完善快传和网盘的功能，实现文件的互传等一系列功能

front/src/lib/transfer.ts

@@ -0,0 +1,56 @@
+import { apiRequest } from './api';
+import type {
+  LookupTransferSessionResponse,
+  PollTransferSignalsResponse,
+  TransferSessionResponse,
+} from './types';
+
+export const DEFAULT_TRANSFER_ICE_SERVERS: RTCIceServer[] = [
+  {urls: 'stun:stun.cloudflare.com:3478'},
+  {urls: 'stun:stun.l.google.com:19302'},
+];
+
+export function toTransferFilePayload(files: File[]) {
+  return files.map((file) => ({
+    name: file.name,
+    size: file.size,
+    contentType: file.type || 'application/octet-stream',
+  }));
+}
+
+export function createTransferSession(files: File[]) {
+  return apiRequest<TransferSessionResponse>('/transfer/sessions', {
+    method: 'POST',
+    body: {
+      files: toTransferFilePayload(files),
+    },
+  });
+}
+
+export function lookupTransferSession(pickupCode: string) {
+  return apiRequest<LookupTransferSessionResponse>(
+    `/transfer/sessions/lookup?pickupCode=${encodeURIComponent(pickupCode)}`,
+  );
+}
+
+export function joinTransferSession(sessionId: string) {
+  return apiRequest<TransferSessionResponse>(`/transfer/sessions/${encodeURIComponent(sessionId)}/join`, {
+    method: 'POST',
+  });
+}
+
+export function postTransferSignal(sessionId: string, role: 'sender' | 'receiver', type: string, payload: string) {
+  return apiRequest<void>(`/transfer/sessions/${encodeURIComponent(sessionId)}/signals?role=${role}`, {
+    method: 'POST',
+    body: {
+      type,
+      payload,
+    },
+  });
+}
+
+export function pollTransferSignals(sessionId: string, role: 'sender' | 'receiver', after: number) {
+  return apiRequest<PollTransferSignalsResponse>(
+    `/transfer/sessions/${encodeURIComponent(sessionId)}/signals?role=${role}&after=${after}`,
+  );
+}