Add canvas JSON import export

src/app/api/canvas/projects/[id]/export/route.ts

@@ -0,0 +1,34 @@
+import { NextResponse } from "next/server";
+import { getCanvasProjectById } from "@/lib/server/repositories/canvas-project-repository";
+import { createCanvasProjectExport } from "@/lib/server/services/canvas-project-transfer";
+
+export const runtime = "nodejs";
+
+export async function GET(
+  _request: Request,
+  context: { params: Promise<{ id: string }> },
+) {
+  const { id } = await context.params;
+  const project = getCanvasProjectById(id);
+
+  if (!project) {
+    return NextResponse.json(
+      { error: "Canvas project not found" },
+      { status: 404 },
+    );
+  }
+
+  try {
+    return NextResponse.json({
+      item: createCanvasProjectExport({
+        title: project.title,
+        data: project.data,
+      }),
+    });
+  } catch (err) {
+    return NextResponse.json(
+      { error: err instanceof Error ? err.message : "导出画布失败" },
+      { status: 400 },
+    );
+  }
+}

src/app/api/canvas/projects/[id]/route.ts

@@ -4,7 +4,10 @@ import {
   getCanvasProjectById,
   updateCanvasProject,
 } from "@/lib/server/repositories/canvas-project-repository";
-import { isCanvasProjectData } from "@/lib/canvas/types";
+import {
+  type CanvasProjectData,
+  normalizeCanvasProjectData,
+} from "@/lib/canvas/types";
 
 export const runtime = "nodejs";
 
@@ -33,19 +36,26 @@ export async function PATCH(
   const payload = await request.json().catch(() => ({}));
   const patch: {
     title?: string;
-    data?: unknown;
+    data?: CanvasProjectData;
   } = {};
 
   if (typeof payload.title === "string") {
     patch.title = payload.title;
   }
-  if (isCanvasProjectData(payload.data)) {
-    patch.data = payload.data;
+  if ("data" in payload) {
+    const data = normalizeCanvasProjectData(payload.data);
+    if (!data) {
+      return NextResponse.json(
+        { error: "画布 JSON 格式无效" },
+        { status: 400 },
+      );
+    }
+    patch.data = data;
   }
 
   const project = updateCanvasProject(id, {
     title: patch.title,
-    data: isCanvasProjectData(patch.data) ? patch.data : undefined,
+    data: patch.data,
   });
 
   if (!project) {

src/app/api/canvas/projects/import/route.ts

@@ -0,0 +1,18 @@
+import { NextResponse } from "next/server";
+import { importCanvasProjectExport } from "@/lib/server/services/canvas-project-transfer";
+
+export const runtime = "nodejs";
+
+export async function POST(request: Request) {
+  const payload = await request.json().catch(() => null);
+
+  try {
+    const project = importCanvasProjectExport(payload);
+    return NextResponse.json({ item: project }, { status: 201 });
+  } catch (err) {
+    return NextResponse.json(
+      { error: err instanceof Error ? err.message : "导入画布失败" },
+      { status: 400 },
+    );
+  }
+}

src/app/api/canvas/projects/route.ts

@@ -3,7 +3,10 @@ import {
   createCanvasProject,
   listCanvasProjects,
 } from "@/lib/server/repositories/canvas-project-repository";
-import { defaultCanvasProjectData, isCanvasProjectData } from "@/lib/canvas/types";
+import {
+  defaultCanvasProjectData,
+  normalizeCanvasProjectData,
+} from "@/lib/canvas/types";
 
 export const runtime = "nodejs";
 
@@ -17,9 +20,7 @@ export async function POST(request: Request) {
     typeof payload.title === "string" && payload.title.trim()
       ? payload.title
       : "未命名画布";
-  const data = isCanvasProjectData(payload.data)
-    ? payload.data
-    : defaultCanvasProjectData;
+  const data = normalizeCanvasProjectData(payload.data) ?? defaultCanvasProjectData;
   const project = createCanvasProject({ title, data });
 
   return NextResponse.json({ item: project }, { status: 201 });

src/components/canvas/canvas-editor-client.tsx

@@ -98,6 +98,9 @@ export function CanvasEditorClient({ projectId }: { projectId: string }) {
   const [job, setJob] = useState<ImageJobPayload | null>(null);
   const [error, setError] = useState<string | null>(null);
   const [showLibrary, setShowLibrary] = useState(false);
+  const [showImportDialog, setShowImportDialog] = useState(false);
+  const [importJson, setImportJson] = useState("");
+  const [isImporting, setIsImporting] = useState(false);
   const [selectionMode, setSelectionMode] = useState(false);
   const [historyAvailability, setHistoryAvailability] = useState({
     canUndo: false,
@@ -471,6 +474,7 @@ export function CanvasEditorClient({ projectId }: { projectId: string }) {
             ...current.data.connections,
             {
               id: crypto.randomUUID(),
+              type: inferConnectionType(current.data.nodes, fromNodeId, toNodeId),
               fromNodeId,
               toNodeId,
             },
@@ -494,6 +498,7 @@ export function CanvasEditorClient({ projectId }: { projectId: string }) {
     const node = createCanvasNode(type, position);
     const connection: CanvasConnection = {
       id: crypto.randomUUID(),
+      type: inferConnectionType(nodes, activeConnection.fromNodeId, node.id),
       fromNodeId: activeConnection.fromNodeId,
       toNodeId: node.id,
     };
@@ -543,6 +548,11 @@ export function CanvasEditorClient({ projectId }: { projectId: string }) {
               ...current.data.connections,
               {
                 id: crypto.randomUUID(),
+                type: inferConnectionType(
+                  current.data.nodes,
+                  materialConnection.fromNodeId,
+                  nextNode.id,
+                ),
                 fromNodeId: materialConnection.fromNodeId,
                 toNodeId: nextNode.id,
               },
@@ -585,6 +595,7 @@ export function CanvasEditorClient({ projectId }: { projectId: string }) {
         ...getImageNodeDimensions(naturalSize.width, naturalSize.height),
         metadata: {
           ...baseNode.metadata,
+          filePath: payload.item.filePath,
           naturalWidth: naturalSize.width,
           naturalHeight: naturalSize.height,
         },
@@ -599,6 +610,45 @@ export function CanvasEditorClient({ projectId }: { projectId: string }) {
     uploadInputRef.current?.click();
   }
 
+  async function copyCanvasJson() {
+    setError(null);
+    try {
+      const response = await fetch(`/api/canvas/projects/${projectId}/export`, {
+        cache: "no-store",
+      });
+      const payload = await response.json();
+      if (!response.ok || !payload.item) {
+        throw new Error(payload.error || "复制 JSON 失败");
+      }
+      await navigator.clipboard.writeText(JSON.stringify(payload.item, null, 2));
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "复制 JSON 失败");
+    }
+  }
+
+  async function importCanvasJson() {
+    if (!importJson.trim() || isImporting) return;
+    setError(null);
+    setIsImporting(true);
+    try {
+      const parsed = JSON.parse(importJson);
+      const response = await fetch("/api/canvas/projects/import", {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify(parsed),
+      });
+      const payload = await response.json();
+      if (!response.ok || !payload.item?.id) {
+        throw new Error(payload.error || "导入画布失败");
+      }
+      router.push(`/canvas/${payload.item.id}`);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "导入画布失败");
+    } finally {
+      setIsImporting(false);
+    }
+  }
+
   async function replaceNodeImage(nodeId: string, file: File) {
     setError(null);
     try {
@@ -856,6 +906,8 @@ export function CanvasEditorClient({ projectId }: { projectId: string }) {
         onResetView={() => updateViewport({ x: 0, y: 0, k: 1 })}
         onToggleLibrary={() => setShowLibrary((current) => !current)}
         onToggleSelectionMode={() => setSelectionMode((current) => !current)}
+        onCopyJson={() => void copyCanvasJson()}
+        onImportJson={() => setShowImportDialog(true)}
         onUndo={undoCanvasChange}
         onUploadMaterial={openUploadMaterial}
         onZoomIn={() => updateViewport({ ...viewport, k: clampScale(viewport.k * 1.18) })}
@@ -987,6 +1039,17 @@ export function CanvasEditorClient({ projectId }: { projectId: string }) {
         onReplaceNodeImage={(nodeId, file) => void replaceNodeImage(nodeId, file)}
         onUploadImage={(file) => void uploadImage(file)}
       />
+      <CanvasJsonImportDialog
+        isImporting={isImporting}
+        open={showImportDialog}
+        value={importJson}
+        onChange={setImportJson}
+        onClose={() => {
+          if (isImporting) return;
+          setShowImportDialog(false);
+        }}
+        onImport={() => void importCanvasJson()}
+      />
     </main>
   );
 }
@@ -1097,6 +1160,67 @@ function SelectionRect({ selectionBox }: { selectionBox: SelectionBox }) {
   );
 }
 
+function CanvasJsonImportDialog({
+  open,
+  value,
+  isImporting,
+  onChange,
+  onClose,
+  onImport,
+}: {
+  open: boolean;
+  value: string;
+  isImporting: boolean;
+  onChange: (value: string) => void;
+  onClose: () => void;
+  onImport: () => void;
+}) {
+  if (!open) return null;
+
+  return (
+    <div
+      className="absolute inset-0 z-[120] flex items-center justify-center bg-zinc-950/28 p-5 backdrop-blur-sm"
+      data-canvas-ui
+      onMouseDown={(event) => {
+        if (event.target === event.currentTarget) onClose();
+      }}
+    >
+      <div className="w-full max-w-2xl rounded-2xl bg-white p-5 shadow-[0_24px_80px_rgba(24,24,27,.22)] ring-1 ring-zinc-200">
+        <div className="flex items-start justify-between gap-4">
+          <div>
+            <h2 className="text-base font-semibold text-zinc-950">导入画布 JSON</h2>
+            <p className="mt-1 text-sm text-zinc-500">
+              粘贴由复制 JSON 生成的完整画布数据，导入后会创建一个新画布。
+            </p>
+          </div>
+          <button
+            type="button"
+            className="rounded-full px-3 py-1.5 text-sm text-zinc-500 transition hover:bg-zinc-100 hover:text-zinc-950"
+            disabled={isImporting}
+            onClick={onClose}
+          >
+            关闭
+          </button>
+        </div>
+        <textarea
+          className="mt-4 h-80 w-full resize-none rounded-xl border border-zinc-200 bg-zinc-50 p-3 font-mono text-xs leading-5 text-zinc-800 outline-none transition focus:border-zinc-400 focus:bg-white"
+          placeholder='{"kind":"imagegen.canvas.project","version":1,...}'
+          value={value}
+          onChange={(event) => onChange(event.target.value)}
+        />
+        <div className="mt-4 flex justify-end gap-2">
+          <Button variant="outline" disabled={isImporting} onClick={onClose}>
+            取消
+          </Button>
+          <Button disabled={isImporting || !value.trim()} onClick={onImport}>
+            {isImporting ? "导入中..." : "导入为新画布"}
+          </Button>
+        </div>
+      </div>
+    </div>
+  );
+}
+
 async function imageUrlToFile(url: string, filename: string) {
   const response = await fetch(url, { cache: "no-store" });
   if (!response.ok) {
@@ -1152,6 +1276,19 @@ function getRelatedNodeIds(
   return related;
 }
 
+function inferConnectionType(
+  nodes: CanvasNodeType[],
+  fromNodeId: string,
+  toNodeId: string,
+): CanvasConnection["type"] {
+  const from = nodes.find((node) => node.id === fromNodeId);
+  const to = nodes.find((node) => node.id === toNodeId);
+  if (to?.type === "config") return "config";
+  if (to?.type === "prompt") return from?.type === "image" ? "reference" : "prompt";
+  if (to?.type === "image") return from?.type === "config" ? "config" : "generated";
+  return undefined;
+}
+
 function wait(ms: number) {
   return new Promise((resolve) => window.setTimeout(resolve, ms));
 }

src/components/canvas/canvas-toolbar.tsx

@@ -1,6 +1,8 @@
 "use client";
 
 import {
+  ClipboardPaste,
+  Copy,
   Eraser,
   FolderOpen,
   Grid2X2,
@@ -39,6 +41,8 @@ type CanvasToolbarProps = {
   onRedo: () => void;
   onGenerate: () => void;
   onUploadMaterial: () => void;
+  onCopyJson: () => void;
+  onImportJson: () => void;
   onDeleteSelection: () => void;
   onClearCanvas: () => void;
   onBackgroundModeChange: (mode: CanvasBackgroundMode) => void;
@@ -66,6 +70,8 @@ export function CanvasToolbar({
   onRedo,
   onGenerate,
   onUploadMaterial,
+  onCopyJson,
+  onImportJson,
   onDeleteSelection,
   onClearCanvas,
   onBackgroundModeChange,
@@ -226,6 +232,17 @@ export function CanvasToolbar({
             label="素材库"
             onClick={onToggleLibrary}
           />
+          <DockDivider />
+          <DockButton
+            icon={<Copy className="size-4" />}
+            label="复制JSON"
+            onClick={onCopyJson}
+          />
+          <DockButton
+            icon={<ClipboardPaste className="size-4" />}
+            label="导入JSON"
+            onClick={onImportJson}
+          />
           {canDeleteSelection ? (
             <>
               <DockDivider />

src/lib/canvas/types.ts

@@ -13,6 +13,8 @@ export type CanvasPosition = {
 
 export type CanvasNodeType = "prompt" | "config" | "image";
 
+export const CANVAS_PROJECT_DATA_VERSION = 1;
+
 export type CanvasPromptNodeMetadata = {
   prompt: string;
 };
@@ -58,11 +60,13 @@ export type CanvasNode = {
 
 export type CanvasConnection = {
   id: string;
+  type?: "reference" | "prompt" | "config" | "generated";
   fromNodeId: string;
   toNodeId: string;
 };
 
 export type CanvasProjectData = {
+  version: typeof CANVAS_PROJECT_DATA_VERSION;
   viewport: CanvasViewport;
   backgroundMode: CanvasBackgroundMode;
   nodes: CanvasNode[];
@@ -86,6 +90,7 @@ export type CanvasProjectListItem = {
 };
 
 export const defaultCanvasProjectData: CanvasProjectData = {
+  version: CANVAS_PROJECT_DATA_VERSION,
   viewport: { x: 0, y: 0, k: 1 },
   backgroundMode: "lines",
   nodes: [],
@@ -93,15 +98,240 @@ export const defaultCanvasProjectData: CanvasProjectData = {
 };
 
 export function isCanvasProjectData(value: unknown): value is CanvasProjectData {
+  return normalizeCanvasProjectData(value) !== null;
+}
+
+export function normalizeCanvasProjectData(
+  value: unknown,
+): CanvasProjectData | null {
   if (!value || typeof value !== "object") {
-    return false;
+    return null;
   }
 
   const candidate = value as Record<string, unknown>;
+  const viewport = normalizeViewport(candidate.viewport);
+  if (!viewport || !Array.isArray(candidate.nodes) || !Array.isArray(candidate.connections)) {
+    return null;
+  }
+
+  const nodes = candidate.nodes
+    .map(normalizeCanvasNode)
+    .filter((node): node is CanvasNode => Boolean(node));
+  if (nodes.length !== candidate.nodes.length) {
+    return null;
+  }
+
+  const nodeIds = new Set(nodes.map((node) => node.id));
+  const connections = candidate.connections
+    .map((connection) => normalizeCanvasConnection(connection, nodeIds))
+    .filter((connection): connection is CanvasConnection => Boolean(connection));
+  if (connections.length !== candidate.connections.length) {
+    return null;
+  }
+
+  return {
+    version: CANVAS_PROJECT_DATA_VERSION,
+    viewport,
+    backgroundMode: normalizeBackgroundMode(candidate.backgroundMode),
+    nodes,
+    connections,
+  };
+}
+
+function normalizeViewport(value: unknown): CanvasViewport | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (
+    typeof candidate.x !== "number" ||
+    typeof candidate.y !== "number" ||
+    typeof candidate.k !== "number"
+  ) {
+    return null;
+  }
+  return { x: candidate.x, y: candidate.y, k: candidate.k };
+}
+
+function normalizeBackgroundMode(value: unknown): CanvasBackgroundMode {
+  return value === "dots" || value === "blank" || value === "lines"
+    ? value
+    : "lines";
+}
+
+function normalizeCanvasNode(value: unknown): CanvasNode | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (
+    typeof candidate.id !== "string" ||
+    typeof candidate.title !== "string" ||
+    typeof candidate.width !== "number" ||
+    typeof candidate.height !== "number"
+  ) {
+    return null;
+  }
+
+  const position = normalizePosition(candidate.position);
+  if (!position) return null;
+
+  if (candidate.type === "prompt") {
+    const metadata = normalizePromptMetadata(candidate.metadata);
+    if (!metadata) return null;
+    return {
+      id: candidate.id,
+      type: "prompt",
+      title: candidate.title,
+      position,
+      width: candidate.width,
+      height: candidate.height,
+      metadata,
+    };
+  }
+
+  if (candidate.type === "config") {
+    const metadata = normalizeConfigMetadata(candidate.metadata);
+    if (!metadata) return null;
+    return {
+      id: candidate.id,
+      type: "config",
+      title: candidate.title,
+      position,
+      width: candidate.width,
+      height: candidate.height,
+      metadata,
+    };
+  }
+
+  if (candidate.type === "image") {
+    const metadata = normalizeImageMetadata(candidate.metadata);
+    if (!metadata) return null;
+    return {
+      id: candidate.id,
+      type: "image",
+      title: candidate.title,
+      position,
+      width: candidate.width,
+      height: candidate.height,
+      metadata,
+    };
+  }
+
+  return null;
+}
+
+function normalizePosition(value: unknown): CanvasPosition | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (typeof candidate.x !== "number" || typeof candidate.y !== "number") {
+    return null;
+  }
+  return { x: candidate.x, y: candidate.y };
+}
+
+function normalizePromptMetadata(value: unknown): CanvasPromptNodeMetadata | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (typeof candidate.prompt !== "string") return null;
+  return { prompt: candidate.prompt };
+}
+
+function normalizeConfigMetadata(value: unknown): CanvasConfigNodeMetadata | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (
+    typeof candidate.model !== "string" ||
+    typeof candidate.size !== "string" ||
+    typeof candidate.quality !== "string" ||
+    typeof candidate.outputFormat !== "string"
+  ) {
+    return null;
+  }
+
+  return {
+    model: candidate.model,
+    size: candidate.size,
+    quality: candidate.quality,
+    outputFormat: candidate.outputFormat,
+    preserveIdentity:
+      typeof candidate.preserveIdentity === "boolean"
+        ? candidate.preserveIdentity
+        : true,
+  };
+}
+
+function normalizeImageMetadata(value: unknown): CanvasImageNodeMetadata | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (
+    typeof candidate.imageUrl !== "string" ||
+    (candidate.mode !== "reference" && candidate.mode !== "result")
+  ) {
+    return null;
+  }
+
+  return {
+    ...(typeof candidate.historyId === "string" ? { historyId: candidate.historyId } : {}),
+    imageUrl: candidate.imageUrl,
+    ...(typeof candidate.filePath === "string" ? { filePath: candidate.filePath } : {}),
+    mode: candidate.mode,
+    ...(typeof candidate.prompt === "string" ? { prompt: candidate.prompt } : {}),
+    ...(typeof candidate.model === "string" ? { model: candidate.model } : {}),
+    ...(typeof candidate.size === "string" ? { size: candidate.size } : {}),
+    ...(typeof candidate.quality === "string" ? { quality: candidate.quality } : {}),
+    ...(typeof candidate.outputFormat === "string"
+      ? { outputFormat: candidate.outputFormat }
+      : {}),
+    ...(isImageStatus(candidate.status) ? { status: candidate.status } : {}),
+    ...(typeof candidate.errorMessage === "string"
+      ? { errorMessage: candidate.errorMessage }
+      : {}),
+    ...(typeof candidate.naturalWidth === "number"
+      ? { naturalWidth: candidate.naturalWidth }
+      : {}),
+    ...(typeof candidate.naturalHeight === "number"
+      ? { naturalHeight: candidate.naturalHeight }
+      : {}),
+  };
+}
+
+function normalizeCanvasConnection(
+  value: unknown,
+  nodeIds: Set<string>,
+): CanvasConnection | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (
+    typeof candidate.id !== "string" ||
+    typeof candidate.fromNodeId !== "string" ||
+    typeof candidate.toNodeId !== "string" ||
+    !nodeIds.has(candidate.fromNodeId) ||
+    !nodeIds.has(candidate.toNodeId)
+  ) {
+    return null;
+  }
+
+  return {
+    id: candidate.id,
+    ...(isConnectionType(candidate.type) ? { type: candidate.type } : {}),
+    fromNodeId: candidate.fromNodeId,
+    toNodeId: candidate.toNodeId,
+  };
+}
+
+function isImageStatus(
+  value: unknown,
+): value is NonNullable<CanvasImageNodeMetadata["status"]> {
   return (
-    typeof candidate.viewport === "object" &&
-    candidate.viewport !== null &&
-    Array.isArray(candidate.nodes) &&
-    Array.isArray(candidate.connections)
+    value === "idle" ||
+    value === "loading" ||
+    value === "success" ||
+    value === "error"
+  );
+}
+
+function isConnectionType(value: unknown): value is NonNullable<CanvasConnection["type"]> {
+  return (
+    value === "reference" ||
+    value === "prompt" ||
+    value === "config" ||
+    value === "generated"
   );
 }

src/lib/server/repositories/canvas-project-repository.ts

@@ -3,7 +3,7 @@ import {
   type CanvasProjectData,
   type CanvasProjectListItem,
   type CanvasProjectRecord,
-  isCanvasProjectData,
+  normalizeCanvasProjectData,
 } from "@/lib/canvas/types";
 import { getDb } from "@/lib/server/db";
 
@@ -65,7 +65,7 @@ export function createCanvasProject(input?: {
   const now = new Date().toISOString();
   const id = crypto.randomUUID();
   const title = input?.title?.trim() || "未命名画布";
-  const data = input?.data ?? defaultCanvasProjectData;
+  const data = normalizeCanvasProjectData(input?.data) ?? defaultCanvasProjectData;
 
   getDb()
     .prepare(
@@ -88,7 +88,7 @@ export function updateCanvasProject(
   if (!current) return null;
 
   const title = patch.title?.trim() || current.title;
-  const data = patch.data ?? current.data;
+  const data = normalizeCanvasProjectData(patch.data) ?? current.data;
   const updatedAt = new Date().toISOString();
 
   getDb()
@@ -112,7 +112,7 @@ export function deleteCanvasProject(id: string) {
 function parseCanvasProjectData(raw: string): CanvasProjectData {
   try {
     const parsed = JSON.parse(raw) as unknown;
-    return isCanvasProjectData(parsed) ? parsed : defaultCanvasProjectData;
+    return normalizeCanvasProjectData(parsed) ?? defaultCanvasProjectData;
   } catch {
     return defaultCanvasProjectData;
   }

src/lib/server/services/canvas-project-transfer.ts

@@ -0,0 +1,188 @@
+import { existsSync, readFileSync } from "node:fs";
+import { extname, basename } from "node:path";
+import type { CanvasImageNodeMetadata, CanvasProjectData } from "@/lib/canvas/types";
+import { normalizeCanvasProjectData } from "@/lib/canvas/types";
+import { createCanvasProject } from "@/lib/server/repositories/canvas-project-repository";
+import {
+  getGeneratedImagePathFromUrl,
+  persistImageBuffer,
+} from "@/lib/server/storage/image-file-storage";
+
+const CANVAS_EXPORT_KIND = "imagegen.canvas.project";
+const CANVAS_EXPORT_VERSION = 1;
+
+type CanvasProjectExportAsset = {
+  nodeId: string;
+  imageUrl: string;
+  fileName: string;
+  mimeType: string;
+  dataUrl: string;
+};
+
+export type CanvasProjectExportV1 = {
+  kind: typeof CANVAS_EXPORT_KIND;
+  version: typeof CANVAS_EXPORT_VERSION;
+  exportedAt: string;
+  title: string;
+  data: CanvasProjectData;
+  assets: CanvasProjectExportAsset[];
+};
+
+export function createCanvasProjectExport(input: {
+  title: string;
+  data: CanvasProjectData;
+}): CanvasProjectExportV1 {
+  return {
+    kind: CANVAS_EXPORT_KIND,
+    version: CANVAS_EXPORT_VERSION,
+    exportedAt: new Date().toISOString(),
+    title: input.title,
+    data: input.data,
+    assets: collectExportAssets(input.data),
+  };
+}
+
+export function importCanvasProjectExport(value: unknown) {
+  const payload = normalizeCanvasProjectExport(value);
+  if (!payload) {
+    throw new Error("导入 JSON 不是有效的画布导出格式");
+  }
+
+  const assetsByNodeId = new Map(payload.assets.map((asset) => [asset.nodeId, asset]));
+  const data: CanvasProjectData = {
+    ...payload.data,
+    nodes: payload.data.nodes.map((node) => {
+      if (node.type !== "image") return node;
+      const asset = assetsByNodeId.get(node.id);
+      if (!asset) return node;
+
+      const persisted = persistDataUrl(asset.dataUrl, asset.fileName);
+      return {
+        ...node,
+        metadata: {
+          ...(node.metadata as CanvasImageNodeMetadata),
+          imageUrl: persisted.imageUrl,
+          filePath: persisted.filePath,
+        } satisfies CanvasImageNodeMetadata,
+      };
+    }),
+  };
+
+  const title = payload.title.trim()
+    ? `${payload.title.trim()} Copy`
+    : "导入画布";
+
+  return createCanvasProject({ title, data });
+}
+
+function collectExportAssets(data: CanvasProjectData) {
+  const assets: CanvasProjectExportAsset[] = [];
+
+  for (const node of data.nodes) {
+    if (node.type !== "image") continue;
+    const metadata = node.metadata as CanvasImageNodeMetadata;
+    if (!metadata.imageUrl) continue;
+
+    const filePath = metadata.filePath ?? getGeneratedImagePathFromUrl(metadata.imageUrl);
+    if (!filePath || !existsSync(filePath)) {
+      throw new Error(`图片文件不存在：${node.title || node.id}`);
+    }
+
+    const buffer = readFileSync(filePath);
+    const mimeType = getMimeType(filePath);
+    assets.push({
+      nodeId: node.id,
+      imageUrl: metadata.imageUrl,
+      fileName: basename(filePath),
+      mimeType,
+      dataUrl: `data:${mimeType};base64,${buffer.toString("base64")}`,
+    });
+  }
+
+  return assets;
+}
+
+function normalizeCanvasProjectExport(value: unknown): CanvasProjectExportV1 | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (
+    candidate.kind !== CANVAS_EXPORT_KIND ||
+    candidate.version !== CANVAS_EXPORT_VERSION ||
+    typeof candidate.title !== "string" ||
+    !Array.isArray(candidate.assets)
+  ) {
+    return null;
+  }
+
+  const data = normalizeCanvasProjectData(candidate.data);
+  if (!data) return null;
+
+  const assets = candidate.assets
+    .map(normalizeExportAsset)
+    .filter((asset): asset is CanvasProjectExportAsset => Boolean(asset));
+  if (assets.length !== candidate.assets.length) return null;
+
+  return {
+    kind: CANVAS_EXPORT_KIND,
+    version: CANVAS_EXPORT_VERSION,
+    exportedAt:
+      typeof candidate.exportedAt === "string"
+        ? candidate.exportedAt
+        : new Date().toISOString(),
+    title: candidate.title,
+    data,
+    assets,
+  };
+}
+
+function normalizeExportAsset(value: unknown): CanvasProjectExportAsset | null {
+  if (!value || typeof value !== "object") return null;
+  const candidate = value as Record<string, unknown>;
+  if (
+    typeof candidate.nodeId !== "string" ||
+    typeof candidate.imageUrl !== "string" ||
+    typeof candidate.fileName !== "string" ||
+    typeof candidate.mimeType !== "string" ||
+    typeof candidate.dataUrl !== "string" ||
+    !candidate.dataUrl.startsWith("data:")
+  ) {
+    return null;
+  }
+
+  return {
+    nodeId: candidate.nodeId,
+    imageUrl: candidate.imageUrl,
+    fileName: candidate.fileName,
+    mimeType: candidate.mimeType,
+    dataUrl: candidate.dataUrl,
+  };
+}
+
+function persistDataUrl(dataUrl: string, fileName: string) {
+  const match = /^data:([^;]+);base64,(.+)$/.exec(dataUrl);
+  if (!match) {
+    throw new Error("图片 dataUrl 格式无效");
+  }
+
+  const mimeType = match[1];
+  const extension = getExtensionFromMimeType(mimeType) ?? getExtension(fileName);
+  return persistImageBuffer(crypto.randomUUID(), extension, Buffer.from(match[2], "base64"));
+}
+
+function getMimeType(filePath: string) {
+  const extension = getExtension(filePath);
+  if (extension === "jpg" || extension === "jpeg") return "image/jpeg";
+  if (extension === "webp") return "image/webp";
+  return "image/png";
+}
+
+function getExtensionFromMimeType(mimeType: string) {
+  if (mimeType === "image/jpeg") return "jpg";
+  if (mimeType === "image/png") return "png";
+  if (mimeType === "image/webp") return "webp";
+  return null;
+}
+
+function getExtension(filePath: string) {
+  return extname(filePath).replace(".", "").toLowerCase() || "png";
+}

src/lib/server/storage/image-file-storage.ts

@@ -1,5 +1,5 @@
 import { existsSync, mkdirSync, writeFileSync } from "node:fs";
-import { join } from "node:path";
+import { basename, join } from "node:path";
 
 const imageDir = join(
   /* turbopackIgnore: true */ process.cwd(),
@@ -49,8 +49,32 @@ export function persistUploadedImageFile(
   return { fileName, filePath, imageUrl };
 }
 
+export function persistImageBuffer(
+  id: string,
+  extension: string,
+  buffer: Buffer,
+): PersistedImageFile {
+  const normalizedExtension = normalizeExtension(extension);
+  const fileName = `${id}.${normalizedExtension}`;
+  const filePath = join(getImageDir(), fileName);
+  const imageUrl = `/generated/${fileName}`;
+  writeFileSync(filePath, buffer);
+
+  return { fileName, filePath, imageUrl };
+}
+
+export function getGeneratedImagePathFromUrl(imageUrl: string) {
+  if (!imageUrl.startsWith("/generated/")) return null;
+  return join(getImageDir(), basename(imageUrl));
+}
+
 function getExtensionFromFilename(filename: string) {
   const parts = filename.split(".");
   const extension = parts.at(-1)?.toLowerCase();
-  return extension && extension.length <= 5 ? extension : "png";
+  return normalizeExtension(extension);
+}
+
+function normalizeExtension(extension: string | undefined) {
+  if (!extension || extension.length > 5) return "png";
+  return extension === "jpeg" ? "jpg" : extension;
 }