last_fix
Reputation: 379
Convert pdf to html files using node.js and pdf.js
I want to convert pdf to html pages using pdf.js. Pdf.js does that in a browser but is it possible to get those html pages rendered by browser in backend thus converting a pdf of n pages to n number of html files. I am using node.js as backend. I have tried pdf2html and other similar npm modules, they don't work great and have issues with some pdfs. Thank you for suggestions.
Upvotes: 7
Views: 13711
Answers (1)
Jan
Reputation: 2247
Maybe I found something similar - I am working with local PDF file and browser. I made small changes in ready made viewer.js / PDF.js, it should be possible to process using both Node.js & browser.
This script include's PDF specified by argument to viewer.js Webpack and start browser.
const fs = require('fs');
const path = require('path');
const pdf = require('process').argv[2];
const chp = require('child_process');
const datauri = require(path.join(process.env.APPDATA, 'npm/node_modules', 'datauri'));
datauri(pdf, (err, content, meta) => {
if (err) {
throw err;
}
const viewerJSpath = path.join(__dirname, './viewer.js');
let wp = fs.readFileSync(viewerJSpath, 'utf-8');
const pdfName = 'compressed.tracemonkey-pldi-09.pdf';
const srcPos = [wp.indexOf(pdfName)];
srcPos.push(srcPos[0] + pdfName.length);
let HOSTED_VIEWER_ORIGINS = wp.indexOf('HOSTED_VIEWER_ORIGINS');
HOSTED_VIEWER_ORIGINS = wp.indexOf(']', HOSTED_VIEWER_ORIGINS);
wp = wp.substr(0, srcPos[0]) + content +
wp.substr(srcPos[1], HOSTED_VIEWER_ORIGINS - srcPos[1]) + ', "file://"' +
wp.substr(HOSTED_VIEWER_ORIGINS);
fs.writeFileSync(viewerJSpath, wp, 'utf-8');
const c = path.join(__dirname, 'viewer.html');
chp.execSync(c);
});
Then tried to add original width as next style parameter to renderTextLayer's appendText method and elements sort by position to TextLayerBuilder's render method next2 this.textLayerDiv.appendChild(textLayerFrag);.
All mentioned PDF.js changes on my Github it seems only web and build folders are required (except npm i -g datauri fox example).
Readability improvements ? #12512 PR
Using puppeteer and slightly modified PDF.js it is possible to convert directly (works both head/less, but element sizes slightly differ)
const fs = require('fs');
const path = require('path');
const pdf = require('process').argv[2];
const datauri = require(path.join(process.env.APPDATA, 'npm/node_modules', 'datauri'));
const puppeteer = require(path.join(process.env.APPDATA, 'npm/node_modules', 'puppeteer'));
datauri(pdf, (err, content, meta) => {
if (err) {
throw err;
}
const viewerJSpath = path.join(__dirname, './viewer');
let wp = fs.readFileSync(viewerJSpath + 'Src.js', 'utf-8');
const pdfName = 'compressed.tracemonkey-pldi-09.pdf';
const srcPos = [wp.indexOf(pdfName)];
srcPos.push(srcPos[0] + pdfName.length);
let HOSTED_VIEWER_ORIGINS = wp.indexOf('HOSTED_VIEWER_ORIGINS');
HOSTED_VIEWER_ORIGINS = wp.indexOf(']', HOSTED_VIEWER_ORIGINS);
wp = wp.substr(0, srcPos[0]) + content +
wp.substr(srcPos[1], HOSTED_VIEWER_ORIGINS - srcPos[1]) + ', "file://"' +
wp.substr(HOSTED_VIEWER_ORIGINS);
fs.writeFileSync(viewerJSpath + '.js', wp, 'utf-8');
(async () => {
const browser = await puppeteer.launch({
// headless: false
});
const page = await browser.pages();
const c = path.join(__dirname, 'viewer.html');
await page[0].goto('file:///' + c);
page[0].exposeFunction('reader', (elLists) => {
fs.writeFileSync(path.join(__dirname, 'PDFtexts.txt'), JSON.stringify(elLists, null, 4));
setTimeout(() => { browser.close(); }, 100);
});
})();
});
Fixes required for puppeteer/chromium:
const message = exception?.message; // => exception.message
page: this.pageLabel ?? this.id // => this.pageLabel || this.id
viewer.js => viewerSrc.js basic additions:
function webViewerPageRendered({
...
if (pageNumber < PDFViewerApplication.pagesCount) {
arguments[0].source.eventBus.dispatch("pagenumberchanged", {
value: pageNumber + 1
}); // generate all remaining pages
}
}
class BaseViewer {
constructor(options) {
this.pageNo = []; // rendered pages array
...
_setCurrentPageNumber(val, resetCurrentPageView = false) {
...
if (this.pageNo.indexOf(val) < 0) {
this.pageNo.push(val);
}
if (this.pagesCount - 1 <= this.pageNo.length) {
window.reader(elLists); // sent result back 2 node.js
}
And result looks like {PageNo:{ElNo:{data}, ...}, ...} and could be simply translated to web page or further processed.
{
"1": {
"0": {
"x": 99.9871,
"y": 98.0496,
"w": 557.695,
"h": 22,
"text": "Trace-based Just-in-Time Type Specialization for Dynamic",
"ff": "sans-serif",
"fs": "22.2695px",
"cssText": "left: 99.9871px; top: 98.0496px; width: 557.695px; font-size: 22.2695px; font-family: sans-serif; transform: scaleX(0.970163);"
},
"1": {
"x": 327.478,
"y": 122.793,
"w": 102.707,
"h": 22,
"text": "Languages",
"ff": "sans-serif",
"fs": "22.2695px",
"cssText": "left: 327.478px; top: 122.793px; width: 102.707px; font-size: 22.2695px; font-family: sans-serif; transform: scaleX(0.932262);"
},
...
"2": {
"0": {
"x": 393.677,
"y": 90.3408,
"w": 192.909,
"h": 11,
"text": "1 for (var i = 2; i < 100; ++i) {",
"ff": "monospace",
"fs": "11.1347px",
"cssText": "left: 393.677px; top: 90.3408px; width: 192.909px; font-size: 11.1347px; font-family: monospace; transform: scaleX(0.875232);"
},
"1": {
"x": 67.0588,
"y": 91.7599,
"w": 173.346,
"h": 11,
"text": "Hence, recording and compiling a trace",
"ff": "sans-serif",
"fs": "11.1347px",
"cssText": "left: 67.0588px; top: 91.7599px; width: 173.346px; font-size: 11.1347px; font-family: sans-serif; transform: scaleX(0.895175);"
},
Summary of changes (in original gh-pages branch):
- changes in PDF.js
function appendText(task, geom, styles) {
...
let left, top;
+++ , width;
...
if (angle === 0) {
left = tx[4];
top = tx[5] - fontAscent;
} else {
left = tx[4] + fontAscent * Math.sin(angle);
top = tx[5] - fontAscent * Math.cos(angle);
}
+++ width = geom.width * task._viewport.transform[0];
textDiv.style.left = `${left}px`;
textDiv.style.top = `${top}px`;
+++ textDiv.style.width = `${width}px`;
- new nodeView.js
const fs = require('fs');
const path = require('path');
const pdf = require('process').argv[2];
const chp = require('child_process');
const datauri = require(path.join(process.env.APPDATA, 'npm/node_modules', 'datauri'));
const viewerJSpath = path.join(__dirname, './viewer');
const content = datauri(pdf);
let wp = fs.readFileSync(viewerJSpath, 'utf-8');
const pdfName = 'compressed.tracemonkey-pldi-09.pdf';
const srcPos = [wp.indexOf(pdfName)];
srcPos.push(srcPos[0] + pdfName.length);
let HOSTED_VIEWER_ORIGINS = wp.indexOf('HOSTED_VIEWER_ORIGINS');
HOSTED_VIEWER_ORIGINS = wp.indexOf(']', HOSTED_VIEWER_ORIGINS);
wp = wp.substr(0, srcPos[0]) + content +
wp.substr(srcPos[1], HOSTED_VIEWER_ORIGINS - srcPos[1]) + ', "file://"' +
wp.substr(HOSTED_VIEWER_ORIGINS);
fs.writeFileSync(viewerJSpath + '.js', wp, 'utf-8');
const c = path.join(__dirname, 'viewer.ff');
chp.execSync(c);
- new openFF.bat: start node nodeView.js %1
- new pdf2sortedMergedTexts.js
const fs = require('fs');
const path = require('path');
const pdf = require('process').argv[2];
const datauri = require(path.join(process.env.APPDATA, 'npm/node_modules', 'datauri'));
const puppeteer = require(path.join(process.env.APPDATA, 'npm/node_modules', 'puppeteer'));
datauri(pdf, (err, content, meta) => {
if (err) {
throw err;
}
const viewerJSpath = path.join(__dirname, './viewer');
let wp = fs.readFileSync(viewerJSpath + 'Src.js', 'utf-8');
const pdfName = 'compressed.tracemonkey-pldi-09.pdf';
const srcPos = [wp.indexOf(pdfName)];
srcPos.push(srcPos[0] + pdfName.length);
let HOSTED_VIEWER_ORIGINS = wp.indexOf('HOSTED_VIEWER_ORIGINS');
HOSTED_VIEWER_ORIGINS = wp.indexOf(']', HOSTED_VIEWER_ORIGINS);
wp = wp.substr(0, srcPos[0]) + content +
wp.substr(srcPos[1], HOSTED_VIEWER_ORIGINS - srcPos[1]) + ', "file://"' +
wp.substr(HOSTED_VIEWER_ORIGINS);
fs.writeFileSync(viewerJSpath + '.js', wp, 'utf-8');
(async () => {
const browser = await puppeteer.launch({
// headless: false
});
const page = await browser.pages();
const c = path.join(__dirname, 'viewer.html');
await page[0].goto('file:///' + c);
page[0].exposeFunction('reader', (elLists) => {
fs.writeFileSync(path.join(__dirname, 'PDFtexts.txt'), JSON.stringify(elLists, null, 4));
setTimeout(() => { browser.close(); }, 100);
});
})();
});
- changed viewer.js -> viewerSrc.js
function webViewerPageRendered({
... +++
if (pageNumber < PDFViewerApplication.pagesCount) {
arguments[0].source.eventBus.dispatch("pagenumberchanged", {
value: pageNumber + 1
});
}
}
...
class BaseViewer {
constructor(options) {
+++ this.pageNo = [];
...
_setCurrentPageNumber(val, resetCurrentPageView = false) {
...
+++ if (this.pageNo.indexOf(val) < 0) {
+++ this.pageNo.push(val);
+++ console.log(this.pageNo);
+++ }
+++ if (this.pagesCount - 1 <= this.pageNo.length) {
+++ window.reader(elLists);
+++ }
this._currentPageNumber = val;
render(timeout = 0) {
...
this.textLayerRenderTask.promise.then(() => {
this.textLayerDiv.appendChild(textLayerFrag);
+++ this.reorder(this.textLayerDiv);
... new
reorder(_src) {
const src = _src.children;
let els = [];
const elDest = [];
for (let j = 0; j < src.length; j++) {
const i = src[j];
if (i.className === 'endOfContent') continue;
els.push({ x: parseFloat(i.style.left), y: parseFloat(i.style.top), w: parseFloat(i.style.width), h: i.offsetHeight, text: i.innerText, ff: i.style.fontFamily, fs: i.style.fontSize, cssText: i.style.cssText });
}
els.sort((a, b) => {
if (Math.abs(a.y - b.y) <= 1) {
if (Math.abs(a.x - b.x) <= 1) return 0;
else return a.x - b.x;
} else return a.y - b.y;
});
let elMin = els[0];
for (let i = 1; i < els.length; i++) {
if (elMin.x + elMin.w + 1 >= els[i].x &&
Math.abs(elMin.y - els[i].y) < 1 &&
elMin.h === els[i].h &&
elMin.ff === els[i].ff &&
elMin.fs === els[i].fs) {
elMin.text += els[i].text;
elMin.w = els[i].x + els[i].w - elMin.x;
if (elDest[elDest.length - 1] !== elMin) elDest.push(elMin);
continue;
}
if (elDest[elDest.length - 1] !== elMin) elDest.push(elMin);
elMin = els[i];
}
if (elDest[elDest.length - 1] !== elMin) elDest.push(elMin);
els = _src;
while (els.lastChild) els.removeChild(els.lastChild);
const elList = [];
if (window.elLists === undefined) window.elLists = {};
const uqIdx = { x: [], y: [] };
for (let i = 0; i < elDest.length; i++) {
const o = document.createElement('DIV');
o.innerHTML = elDest[i].text;
o.setAttribute('style', elDest[i].cssText + 'width:' + elDest[i].w + 'px;position:absolute;');
els.appendChild(o);
elList.push([elDest[i].x, elDest[i].x + elDest[i].w, o, elDest[i].y, elDest[i].y + elDest[i].h, elDest[i].text]);
if (uqIdx.x.indexOf(elDest[i].x) < 0) uqIdx.x.push(elDest[i].x);
if (uqIdx.y.indexOf(elDest[i].y) < 0) uqIdx.y.push(elDest[i].y);
}
elLists[_src.parentElement.getAttribute("data-page-Number")] = Object.assign({}, elDest);
}
- changed viewer.css
+++ input{padding:0px;border:1px solid #e0e0e0;}input:focus{background-color:red;}
Upvotes: 3
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