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.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.thumbnailSizes[0]; 
        let thumbnailFolder = ThumbnailGeneratorMWs.getThumbnailFolder();

        if(Config.thumbnailSizes.indexOf(size) === -1){
            size = Config.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";
    }
}