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import ApiManager, { Registration } from "./ApiManager";
import { Method } from "../RouteManager";
import RouteSubscriber from "../RouteSubscriber";
import { exists, createReadStream, createWriteStream } from "fs";
import { filesDirectory } from "..";
import * as Pdfjs from 'pdfjs-dist';
import { createCanvas } from "canvas";
const probe = require("probe-image-size");
import * as express from "express";
import * as path from "path";
export default class PDFManager extends ApiManager {
protected initialize(register: Registration): void {
register({
method: Method.GET,
subscription: new RouteSubscriber("thumbnail").add("filename"),
onValidation: ({ req, res }) => {
let filename = req.params.filename;
let noExt = filename.substring(0, filename.length - ".png".length);
let pagenumber = parseInt(noExt.split('-')[1]);
return new Promise<void>(resolve => {
exists(filesDirectory + filename, (exists: boolean) => {
console.log(`${filesDirectory + filename} ${exists ? "exists" : "does not exist"}`);
if (exists) {
let input = createReadStream(filesDirectory + filename);
probe(input, (err: any, result: any) => {
if (err) {
console.log(err);
console.log(`error on ${filename}`);
return;
}
res.send({ path: "/files/" + filename, width: result.width, height: result.height });
});
}
else {
LoadPage(filesDirectory + filename.substring(0, filename.length - noExt.split('-')[1].length - ".PNG".length - 1) + ".pdf", pagenumber, res);
}
resolve();
});
});
}
});
function LoadPage(file: string, pageNumber: number, res: express.Response) {
console.log(file);
Pdfjs.getDocument(file).promise
.then((pdf: Pdfjs.PDFDocumentProxy) => {
let factory = new NodeCanvasFactory();
console.log(pageNumber);
pdf.getPage(pageNumber).then((page: Pdfjs.PDFPageProxy) => {
console.log("reading " + page);
let viewport = page.getViewport(1 as any);
let canvasAndContext = factory.create(viewport.width, viewport.height);
let renderContext = {
canvasContext: canvasAndContext.context,
viewport: viewport,
canvasFactory: factory
};
console.log("read " + pageNumber);
page.render(renderContext).promise
.then(() => {
console.log("saving " + pageNumber);
let stream = canvasAndContext.canvas.createPNGStream();
let pngFile = `${file.substring(0, file.length - ".pdf".length)}-${pageNumber}.PNG`;
let out = createWriteStream(pngFile);
stream.pipe(out);
out.on("finish", () => {
console.log(`Success! Saved to ${pngFile}`);
let name = path.basename(pngFile);
res.send({ path: "/files/" + name, width: viewport.width, height: viewport.height });
});
}, (reason: string) => {
console.error(reason + ` ${pageNumber}`);
});
});
});
}
}
}
class NodeCanvasFactory {
create = (width: number, height: number) => {
var canvas = createCanvas(width, height);
var context = canvas.getContext('2d');
return {
canvas,
context
};
}
reset = (canvasAndContext: any, width: number, height: number) => {
canvasAndContext.canvas.width = width;
canvasAndContext.canvas.height = height;
}
destroy = (canvasAndContext: any) => {
canvasAndContext.canvas.width = 0;
canvasAndContext.canvas.height = 0;
canvasAndContext.canvas = null;
canvasAndContext.context = null;
}
}
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