pigallery2/backend/middlewares/ThumbnailGeneratorMWs.ts

///<reference path="jimp.d.ts"/>


import * as path from "path";
import * as Jimp from "jimp";
import * as crypto from "crypto";
import * as fs from "fs";
import {NextFunction, Request, Response} from "express";
import {Error, ErrorCodes} from "../../common/entities/Error";
import {Config} from "../config/Config";


export class ThumbnailGeneratorMWs {

    private static getThumbnailFolder() {
        return path.join(__dirname, "/../../", Config.Server.thumbnailFolder);
    }

    public static generateThumbnail(req:Request, res:Response, next:NextFunction) {
        if (!req.resultPipe)
            return next();

        let imagePath = req.resultPipe;
        let size:number = parseInt(req.params.size) || Config.Server.thumbnailSizes[0];
        let thumbnailFolder = ThumbnailGeneratorMWs.getThumbnailFolder();

        if (Config.Server.thumbnailSizes.indexOf(size) === -1) {
            size = Config.Server.thumbnailSizes[0];
        }

        let thPath = path.join(thumbnailFolder, ThumbnailGeneratorMWs.generateThumbnailName(imagePath, size));


        req.resultPipe = thPath;

        if (fs.existsSync(thPath) === true) {
            return next();
        }

        if (!fs.existsSync(thumbnailFolder)) {
            fs.mkdirSync(thumbnailFolder);
        }

        Jimp.read(imagePath).then((image) => {
            if (image.bitmap.with < image.bitmap.height) {
                image.resize(size, Jimp.AUTO);   // resize
            } else {
                image.resize(Jimp.AUTO, size);   // resize
            }

            image.quality(60);        // set JPEG quality
            image.write(thPath, () => { // save
                return next();
            });
        }).catch(function (err) {
            return next(new Error(ErrorCodes.GENERAL_ERROR));
        });
    }

    private static generateThumbnailName(imagePath:string, size:number):string {
        return crypto.createHash('md5').update(imagePath).digest('hex') + "_" + size + ".jpg";
    }
}