FEAT: Using Ghostscript for reduce size of big PDFs

dist/index.d.ts

@@ -11,3 +11,9 @@ export declare function rotatePDF(pdfBuffer: Buffer, direction: '90' | '180' | '
  */
 export declare function renderPDFPagesToPNG(pdfBuffer: Buffer, firstPage?: number, lastPage?: number, resolution?: number): Promise<Buffer[]>;
 export declare function isValidPDF(pdfBuffer: Buffer): Promise<boolean>;
+/**
+ * This function try, reduce size of your PDF not destroying quality
+ * @param pdfBuffer Buffer
+ * @returns Buffer
+ */
+export declare function compressPDF(pdfBuffer: Buffer | string, encoding?: BufferEncoding): Promise<Buffer>;

dist/index.js

@@ -3,7 +3,7 @@ var __importDefault = (this && this.__importDefault) || function (mod) {
     return (mod && mod.__esModule) ? mod : { "default": mod };
 };
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.isValidPDF = exports.renderPDFPagesToPNG = exports.rotatePDF = exports.extractPDFPages = exports.countPDFPages = exports.combinePDFs = void 0;
+exports.compressPDF = exports.isValidPDF = exports.renderPDFPagesToPNG = exports.rotatePDF = exports.extractPDFPages = exports.countPDFPages = exports.combinePDFs = void 0;
 const child_process_1 = __importDefault(require("child_process"));
 const fs_extra_1 = __importDefault(require("fs-extra"));
 const tempy_1 = __importDefault(require("tempy"));
@@ -166,3 +166,26 @@ async function isValidPDF(pdfBuffer) {
     }
 }
 exports.isValidPDF = isValidPDF;
+/**
+ * This function try, reduce size of your PDF not destroying quality
+ * @param pdfBuffer Buffer
+ * @returns Buffer
+ */
+async function compressPDF(pdfBuffer, encoding) {
+    try {
+        if (typeof pdfBuffer === 'string') {
+            pdfBuffer = Buffer.from(pdfBuffer, encoding !== null && encoding !== void 0 ? encoding : 'base64');
+        }
+        const compressedPdf = await useTempFilesPDFInOut(pdfBuffer, async (input, output) => {
+            await exec(`gs -q -dNOPAUSE -dBATCH -dSAFER -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dEmbedAllFonts=true -dSubsetFonts=true -dColorImageDownsampleType=/Bicubic -dColorImageResolution=144 -dGrayImageDownsampleType=/Bicubic -dGrayImageResolution=144 -dMonoImageDownsampleType=/Bicubic -dMonoImageResolution=144 -sOutputFile=${output} ${input}`);
+        });
+        if (pdfBuffer.length < compressedPdf.length) {
+            return pdfBuffer;
+        }
+        return compressedPdf;
+    }
+    catch (e) {
+        throw new Error('Failed optimize PDF: ' + e.message);
+    }
+}
+exports.compressPDF = compressPDF;

src/index.ts

@@ -201,3 +201,27 @@ export async function isValidPDF(pdfBuffer: Buffer): Promise<boolean> {
     return false;
   }
 }
+
+/**
+ * This function try, reduce size of your PDF not destroying quality
+ * @param pdfBuffer Buffer
+ * @returns Buffer
+ */
+export async function compressPDF(pdfBuffer: Buffer | string, encoding?: BufferEncoding): Promise<Buffer> {
+  try {
+    if(typeof pdfBuffer === 'string'){
+      pdfBuffer = Buffer.from(pdfBuffer, encoding ?? 'base64')
+    }
+    const compressedPdf = await useTempFilesPDFInOut(pdfBuffer, async (input, output) => {
+      await exec(
+        `gs -q -dNOPAUSE -dBATCH -dSAFER -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dEmbedAllFonts=true -dSubsetFonts=true -dColorImageDownsampleType=/Bicubic -dColorImageResolution=144 -dGrayImageDownsampleType=/Bicubic -dGrayImageResolution=144 -dMonoImageDownsampleType=/Bicubic -dMonoImageResolution=144 -sOutputFile=${output} ${input}`,
+      );
+    });
+    if (pdfBuffer.length < compressedPdf.length) {
+      return pdfBuffer;
+    }
+    return compressedPdf;
+  } catch (e: any) {
+    throw new Error('Failed optimize PDF: ' + e.message);
+  }
+}

test/index.test.ts

@@ -112,3 +112,15 @@ describe('isValidPDF', () => {
     expect(await gs.isValidPDF(Buffer.from([1, 2, 3]))).toBe(false);
   });
 });
+
+
+describe('compressPDF', () => {
+  test('returns PDF reduce size send buffer file', async () => {
+    const optimizedPDF = await gs.compressPDF(files['pdf3.pdf'])
+    expect(optimizedPDF.length).toBeLessThanOrEqual(files['pdf3.pdf'].length);
+  });
+  test('returns PDF reduce size send string encoded file', async () => {
+    const optimizedPDF = await gs.compressPDF(files['pdf3.pdf'].toString('base64'))
+    expect(optimizedPDF.length).toBeLessThanOrEqual(files['pdf3.pdf'].length);
+  });
+})