feat: 实现 DOCX 可编辑字体嵌入

2026-07-31 16:18:30 +08:00
parent f3847f3e4b
commit 10bc62cee4
32 changed files with 2195 additions and 76 deletions
@@ -0,0 +1,153 @@
+import { readFile } from "node:fs/promises";
+import { describe, expect, it } from "vitest";
+import {
+  obfuscateDocxFont,
+  prepareDocxFont,
+  prepareDocxFonts,
+  readSfntFontMetadata,
+  resolveFontEmbeddingPermission,
+  xorDocxFont
+} from "../src/font-embedding.js";
+
+const fandolFangUrl = new URL(
+  "../../../themes/_shared/official-fonts/FandolFang-Regular.woff2",
+  import.meta.url
+);
+const fandolFaces = [
+  ["FandolSong", "FandolSong-Regular.woff2", 400],
+  ["FandolSong", "FandolSong-Bold.woff2", 700],
+  ["FandolFang", "FandolFang-Regular.woff2", 400],
+  ["FandolHei", "FandolHei-Regular.woff2", 400],
+  ["FandolKai", "FandolKai-Regular.woff2", 400]
+] as const;
+
+describe("DOCX 字体嵌入", () => {
+  it("在纯 Node.js 中将 WOFF2 转为可编辑嵌入的 OpenType SFNT", async () => {
+    const content = await readFile(fandolFangUrl);
+    const prepared = await prepareDocxFont({
+      family: "Mdpdf Fandol Fang",
+      aliases: ["FangSong", "STFangsong"],
+      source:
+        "theme-shared:official-fonts/FandolFang-Regular.woff2",
+      weight: 400,
+      style: "normal",
+      license: "GPL-3.0-with-font-exception",
+      content
+    });
+
+    expect(prepared.metadata).toMatchObject({
+      family: "FandolFang",
+      subfamily: "Regular",
+      postscriptName: "FandolFang-Regular",
+      fsType: 0x0008,
+      permission: "editable",
+      noSubsetting: false,
+      signature: "OTTO"
+    });
+    expect(prepared.sfnt.byteLength).toBeGreaterThan(
+      content.byteLength
+    );
+    expect(
+      readSfntFontMetadata(prepared.sfnt)
+    ).toEqual(prepared.metadata);
+  });
+
+  it("使用稳定字体键混淆前 32 字节并可按同一算法还原", async () => {
+    const prepared = await prepareDocxFont({
+      family: "Mdpdf Fandol Fang",
+      aliases: [],
+      source:
+        "theme-shared:official-fonts/FandolFang-Regular.woff2",
+      weight: 400,
+      style: "normal",
+      license: "GPL-3.0-with-font-exception",
+      content: await readFile(fandolFangUrl)
+    });
+
+    const first = obfuscateDocxFont(prepared);
+    const second = obfuscateDocxFont(prepared);
+    expect(first.fontKey).toBe(second.fontKey);
+    expect(first.partName).toBe(second.partName);
+    expect(
+      Buffer.compare(
+        Buffer.from(first.content),
+        Buffer.from(second.content)
+      )
+    ).toBe(0);
+    expect(first.fontKey).toMatch(
+      /^\{[0-9A-F]{8}(?:-[0-9A-F]{4}){3}-[0-9A-F]{12}\}$/u
+    );
+    expect(first.partName).toMatch(/^word\/fonts\/.+\.odttf$/u);
+    expect(first.content.subarray(0, 32)).not.toEqual(
+      prepared.sfnt.subarray(0, 32)
+    );
+    expect(
+      Buffer.compare(
+        Buffer.from(
+          xorDocxFont(first.content, first.fontKey)
+        ),
+        Buffer.from(prepared.sfnt)
+      )
+    ).toBe(0);
+  });
+
+  it("串行调度底层 WASM 并安全准备多个并发 WOFF2 字形", async () => {
+    const prepared = await prepareDocxFonts(
+      await Promise.all(
+        fandolFaces.map(
+          async ([family, fileName, weight]) => ({
+            family,
+            aliases: [],
+            source: `theme-shared:official-fonts/${fileName}`,
+            weight,
+            style: "normal" as const,
+            license: "GPL-3.0-with-font-exception",
+            content: await readFile(
+              new URL(
+                `../../../themes/_shared/official-fonts/${fileName}`,
+                import.meta.url
+              )
+            )
+          })
+        )
+      )
+    );
+
+    expect(prepared).toHaveLength(5);
+    expect(
+      prepared.map((font) => font.metadata.family)
+    ).toEqual([
+      "FandolSong",
+      "FandolSong",
+      "FandolFang",
+      "FandolHei",
+      "FandolKai"
+    ]);
+    expect(
+      prepared.every((font) => font.metadata.signature === "OTTO")
+    ).toBe(true);
+  });
+
+  it("只接受可安装或可编辑嵌入权限", () => {
+    expect(resolveFontEmbeddingPermission(0)).toBe("installable");
+    expect(resolveFontEmbeddingPermission(0x0008)).toBe("editable");
+    expect(() => resolveFontEmbeddingPermission(0x0002)).toThrow(
+      "禁止嵌入"
+    );
+    expect(() => resolveFontEmbeddingPermission(0x0004)).toThrow(
+      "仅允许预览和打印"
+    );
+    expect(() => resolveFontEmbeddingPermission(0x0200)).toThrow(
+      "位图"
+    );
+    expect(() => resolveFontEmbeddingPermission(0x000c)).toThrow(
+      "组合无效"
+    );
+  });
+
+  it("拒绝损坏或非 SFNT 字体", () => {
+    expect(() =>
+      readSfntFontMetadata(new Uint8Array(64))
+    ).toThrow("TrueType 或 OpenType");
+  });
+});