redis_image_server.js

const express = require('express');
const urlJoin = require('url-join');
const path    = require('path');

// you can uncomment those two lines, and create a .env file to store following configs in.
//const readConfig = require('@oufok/env-reader').readEnv;
//let configDir = path.join(__dirname, './config');

const REDIS_HOST="localhost";
const REDIS_IMAGE_SERVICE_HOST="http://localhost";
const REDIS_IMAGE_SERVICE_PORT=8008;
const REDIS_PORT=6379;

const app = express();
const redis = require('redis');
const redisClient = redis.createClient(REDIS_PORT, REDIS_HOST);
const type = "image/jpeg";
const PORT = REDIS_IMAGE_SERVICE_PORT;

app.get('/get/:imageId', (req, res) => {
    let imageId = "" + req.params.imageId;
    redisClient.get(imageId + "_content", (error, imgData) => {
        if(error) res.status(500);

        if (imgData === null) {
            // Try to find if this image has a redirect ( this can be written by symfony-message-handler when moving the content of the img to permanent storage)
            redisClient.get(imageId + "_redirect", (error, redirectPath) => {
                if(error) res.status(500);
                else{
                    res.redirect(301, isAbsoluteUrl(redirectPath)? redirectPath : urlJoin(WEBSITE_ROOT_URL, redirectPath));
                    console.log("Got redirect path " + redirectPath);
                }
            });

        } else {
            try {
                var buff = Buffer.from(imgData, 'base64');
                let imgContent = buff.toString('binary');
                res.set('Content-Type', type);
                res.header('Cache-Control', 'max-age=2592000000');
                res.end(imgContent, 'binary');
            } catch (e) {
                res.status(500);
                res.send();
            }

        }
    });
});

app.listen(PORT, () => {
    console.log('Redis image server is running on port ' + PORT);
});

function isAbsoluteUrl(urlString) {
    const pat = /^https?:\/\//i;
    return pat.test(urlString);
}