4.6.7 first pr (#726)

packages/web/common/file/read/pdf.ts

@@ -0,0 +1,64 @@
+/* read file to txt */
+import * as pdfjsLib from 'pdfjs-dist';
+
+type TokenType = {
+  str: string;
+  dir: string;
+  width: number;
+  height: number;
+  transform: number[];
+  fontName: string;
+  hasEOL: boolean;
+};
+
+export const readPdfFile = async ({ pdf }: { pdf: ArrayBuffer }) => {
+  pdfjsLib.GlobalWorkerOptions.workerSrc = '/js/pdf.worker.js';
+
+  const readPDFPage = async (doc: any, pageNo: number) => {
+    const page = await doc.getPage(pageNo);
+    const tokenizedText = await page.getTextContent();
+
+    const viewport = page.getViewport({ scale: 1 });
+    const pageHeight = viewport.height;
+    const headerThreshold = pageHeight * 0.95;
+    const footerThreshold = pageHeight * 0.05;
+
+    const pageTexts: TokenType[] = tokenizedText.items.filter((token: TokenType) => {
+      return (
+        !token.transform ||
+        (token.transform[5] < headerThreshold && token.transform[5] > footerThreshold)
+      );
+    });
+
+    // concat empty string 'hasEOL'
+    for (let i = 0; i < pageTexts.length; i++) {
+      const item = pageTexts[i];
+      if (item.str === '' && pageTexts[i - 1]) {
+        pageTexts[i - 1].hasEOL = item.hasEOL;
+        pageTexts.splice(i, 1);
+        i--;
+      }
+    }
+
+    page.cleanup();
+
+    return pageTexts
+      .map((token) => {
+        const paragraphEnd = token.hasEOL && /([。？！.?!\n\r]|(\r\n))$/.test(token.str);
+
+        return paragraphEnd ? `${token.str}\n` : token.str;
+      })
+      .join('');
+  };
+
+  const doc = await pdfjsLib.getDocument(pdf).promise;
+  const pageTextPromises = [];
+  for (let pageNo = 1; pageNo <= doc.numPages; pageNo++) {
+    pageTextPromises.push(readPDFPage(doc, pageNo));
+  }
+  const pageTexts = await Promise.all(pageTextPromises);
+
+  return {
+    rawText: pageTexts.join('')
+  };
+};