Simple Markdown Blog

Question

this is my first real website I created after learning about web development. It's amazing to me that anyone would spare their free time to code review strangers' code. So thank you in advance. I'd like a general feedback and especially on the caching I implemented. The full Code (with ejs templates and media etc) is on Github. I wrote this half a year ago and just added some more comments so, just ignore the stupid stuff :D. Here's the server code:

const ejs = require("ejs"); // not needed
const marked = require("marked");
const path = require("path");
const fs = require("fs");
const db = require("./mariadb.js");
const config = require("./config.js");
const express = require('express');
const app = express();
// used to be BodyParser.url... now deprecated
app.use(express.urlencoded({ extended: false }));
app.use(express.json());
app.use(express.static('public'))
app.set("view engine","ejs");
app.set('view cache', false);
app.set('views', path.join(__dirname, '/sites'));
app.use("*",(req, res, next) => {
 console.log("-----------------------------");
 console.log("Request:");
 console.log("\tMethod: " +req.method);
 console.log("\tOriginal URL:"+req.originalUrl);
 console.log("\tBase URL:"+req.baseUrl);
 console.log("-----------------------------");
 next();
});
app.use((error,req, res, next) => {
 console.log(error.message)
 res.status(error.code || 500);
 res.send("404 - File Not Found :(");
});
app.get("/", (req,res) => {
 if (fs.existsSync("cache/index.html")){
 fs.readFileSync("cache/index.html",(err,data) => {
 if (!err){
 res.send(data.toString());
 return;
 }
 })
 }
 res.render("index",{"cache": true}, (err,html) => {
 if (err){ throw err;}
 res.send(html)
 fs.mkdirSync("cache",{recursive: true});
 fs.writeFileSync("cache/index.html",html,(err) => {
 if (err){
 console.log(err.message)
 }
 })
 });
})
app.get("/blog/:article", (req,res) => {
 // serve cached page if possible
 if (fs.existsSync("cache"+req.baseUrl+req.path+".html")){
 fs.readFileSync("cache"+req.baseUrl+req.path+".html",(err,data) => {
 if (!err){
 res.send(data.toString());
 return;
 }
 })
 }
 // check db for wanted entry
 db.pool.query("select * from BlogEntries where url=(?);",[req.params.article],(err,rows,meta) => {
 if (err ){ //|(rows.length != 2)
 console.log(err.message | "Weird Amount of Entries from DB" ) ;
 }
 console.log(rows[0].heading);
 // render blogEntry template with queried data
 res.render("blogEntry",{heading: rows[0].heading, bloghtml: marked(rows[0].content)}, (err,html) => {
 if (err){ 
 console.log(err.message);
 res.end()
 return
 }
 // send rendered page
 res.send(html)
 // save rendered page to cache
 fs.mkdirSync(path.dirname("cache"+req.baseUrl+req.path),{recursive: true});
 fs.writeFileSync("cache"+req.baseUrl+req.path+".html",html,(err) => {
 if (err){ console.log(err.message) }
 })
 });
 });
})
app.get("/blog", (req,res) => {
 // would serve cached blogoverview, but as it's dependent on the amount on the blogentries it changes too much to be usefull
 // also: how to find if changed?
 // deleting cached on render of blog page not viable
 /* if (fs.existsSync("cache/blog.html")){
 fs.readFileSync("cache/blog.html",(err,data) => {
 if (!err){
 res.send(data.toString());
 return;
 }
 })
 } */
 db.pool.query("select url,heading,substring(content,1,200) as description from BlogEntries;",(err,rows,meta) => {
 if (err ){ 
 console.log(err.message ) ;
 }
 blogEntries = rows;
 for (let i=0; i< rows.length;i++){
 blogEntries[i].description = marked(rows[i].description)
 }
 console.log(rows[0].heading);
 res.render("blog",{blogEntries: blogEntries}, (err,html) => {
 if (err){ 
 console.log(err.message);
 res.end()
 return
 }
 res.send(html)
 // would save blog overwiev to cache
 /*
 fs.mkdirSync(path.dirname("cache"+req.baseUrl+req.path),{recursive: true});
 fs.writeFileSync("cache"+req.baseUrl+req.path+".html",html,(err) => {
 if (err){ console.log(err.message) }
 })*/
 });
 });
})
app.get("/*", (req,res) => {
 if (fs.existsSync("cache"+req.baseUrl+req.path+".html")){
 fs.readFileSync("cache"+req.baseUrl+req.path+".html",(err,data) => {
 if (!err){
 res.send(data.toString());
 return;
 }
 console.log(err.message)
 })
 }
 res.render((req.baseUrl+req.path).substr(1),{"cache": true}, (err,html) => {
 if (err){ throw err;}
 res.send(html)
 fs.mkdirSync(path.dirname("cache"+req.baseUrl+req.path),{recursive: true});
 fs.writeFileSync("cache"+req.baseUrl+req.path+".html",html,(err) => {
 if (err){
 console.log(err.message)
 }
 })
 });
})
// put data from /new form into db
app.post("/*", (req,res) =>{
 let url = req.body.heading.replace(/[;/?:@&=+,ドル ]/g ,"-")
 db.pool.query("insert into BlogEntries (heading,url,content) values ((?),(?),(?));",[req.body.heading,url,req.body.content]);
 res.status(301).redirect("/new") 
})
// no idea what this does
app.use((error,req, res, next) => {
 console.log(error.message)
 res.status(error.code || 500);
 res.send("404 - File Not Found :(");
});
// starting the server
app.listen(8080, () => console.log("Started Server on Port "+config.port));

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