1 files changed, 107 insertions, 0 deletions
diff --git a/src/server/ApiManagers/PDFManager.ts b/src/server/ApiManagers/PDFManager.ts
new file mode 100644
index 000000000..f328557b4
--- /dev/null
+++ b/src/server/ApiManagers/PDFManager.ts
@@ -0,0 +1,107 @@
+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;
+    }
+}
+\ No newline at end of file