1 files changed, 39 insertions, 35 deletions

diff --git a/src/server/ApiManagers/PDFManager.ts b/src/server/ApiManagers/PDFManager.ts
index a190ab0cb..0136b758e 100644
--- a/src/server/ApiManagers/PDFManager.ts
+++ b/src/server/ApiManagers/PDFManager.ts
@@ -1,7 +1,7 @@
 import ApiManager, { Registration } from "./ApiManager";
 import { Method } from "../RouteManager";
 import RouteSubscriber from "../RouteSubscriber";
-import { exists, createReadStream, createWriteStream } from "fs";
+import { existsSync, createReadStream, createWriteStream } from "fs";
 import * as Pdfjs from 'pdfjs-dist';
 import { createCanvas } from "canvas";
 const imageSize = require("probe-image-size");
@@ -17,42 +17,37 @@ export default class PDFManager extends ApiManager {
         register({
             method: Method.GET,
             subscription: new RouteSubscriber("thumbnail").add("filename"),
-            onValidation: ({ req, res }) => getOrCreateThumbnail(req.params.filename, res)
+            secureHandler: ({ req, res }) => getOrCreateThumbnail(req.params.filename, res)
         });
 
     }
 
 }
 
-function getOrCreateThumbnail(thumbnailName: string, res: express.Response) {
+async function getOrCreateThumbnail(thumbnailName: string, res: express.Response): Promise<void> {
     const noExtension = thumbnailName.substring(0, thumbnailName.length - ".png".length);
     const pageString = noExtension.split('-')[1];
     const pageNumber = parseInt(pageString);
-    return new Promise<void>(resolve => {
+    return new Promise<void>(async resolve => {
         const path = serverPathToFile(Directory.pdf_thumbnails, thumbnailName);
-        exists(path, (exists: boolean) => {
-            if (exists) {
-                const existingThumbnail = createReadStream(path);
-                imageSize(existingThumbnail, (err: any, { width, height }: any) => {
-                    if (err) {
-                        console.log(red(`In PDF thumbnail response, unable to determine dimensions of ${thumbnailName}:`));
-                        console.log(err);
-                        return;
-                    }
-                    res.send({
-                        path: clientPathToFile(Directory.pdf_thumbnails, thumbnailName),
-                        width,
-                        height
-                    });
-                });
-            } else {
-                const offset = thumbnailName.length - pageString.length - 5;
-                const name = thumbnailName.substring(0, offset) + ".pdf";
-                const path = serverPathToFile(Directory.pdfs, name);
-                CreateThumbnail(path, pageNumber, res);
+        if (existsSync(path)) {
+            const existingThumbnail = createReadStream(path);
+            const { err, viewport } = await new Promise<any>(resolve => {
+                imageSize(existingThumbnail, (err: any, viewport: any) => resolve({ err, viewport }));
+            });
+            if (err) {
+                console.log(red(`In PDF thumbnail response, unable to determine dimensions of ${thumbnailName}:`));
+                console.log(err);
+                return;
             }
-            resolve();
-        });
+            dispatchThumbnail(res, viewport, thumbnailName);
+        } else {
+            const offset = thumbnailName.length - pageString.length - 5;
+            const name = thumbnailName.substring(0, offset) + ".pdf";
+            const path = serverPathToFile(Directory.pdfs, name);
+            await CreateThumbnail(path, pageNumber, res);
+        }
+        resolve();
     });
 }
 
@@ -70,19 +65,28 @@ async function CreateThumbnail(file: string, pageNumber: number, res: express.Re
     await page.render(renderContext).promise;
     const pngStream = canvas.createPNGStream();
     const filenames = path.basename(file).split(".");
-    const pngFile = serverPathToFile(Directory.pdf_thumbnails, `${filenames[0]}-${pageNumber}.png`);
+    const thumbnailName = `${filenames[0]}-${pageNumber}.png`;
+    const pngFile = serverPathToFile(Directory.pdf_thumbnails, thumbnailName);
     const out = createWriteStream(pngFile);
     pngStream.pipe(out);
-    out.on("finish", () => {
-        res.send({
-            path: pngFile,
-            width: viewport.width,
-            height: viewport.height
+    return new Promise<void>((resolve, reject) => {
+        out.on("finish", () => {
+            dispatchThumbnail(res, viewport, thumbnailName);
+            resolve();
+        });
+        out.on("error", error => {
+            console.log(red(`In PDF thumbnail creation, encountered the following error when piping ${pngFile}:`));
+            console.log(error);
+            reject();
         });
     });
-    out.on("error", error => {
-        console.log(red(`In PDF thumbnail creation, encountered the following error when piping ${pngFile}:`));
-        console.log(error);
+}
+
+function dispatchThumbnail(res: express.Response, { width, height }: Pdfjs.PDFPageViewport, thumbnailName: string) {
+    res.send({
+        path: clientPathToFile(Directory.pdf_thumbnails, thumbnailName),
+        width,
+        height
     });
 }