Randomize return value of /code/

Read database credentials from environmental variables, and update test
database

.gitignore

@@ -0,0 +1 @@
+.env

README.md

@@ -5,5 +5,6 @@
 - Run `npm install` on the `server` directory, then run `npm run start`
 - The website will now be available on localhost:3000.
 
-This assumes you have the database running, and properly replaced the access credentials where needed.
+This assumes you have the database running, and have a `.env` file in place of `.env.sample` with the
+needed information. `sample_database_dump.sql` is a file SQL can read that initializes a test database.
 

server/.env.sample

@@ -0,0 +1,2 @@
+DATABASE_USERNAME=username_of_db_user
+DATABASE_PASSWORD=password_of_db_user

server/app.js

@@ -1,3 +1,5 @@
+require('dotenv').config();
+
 var createError = require('http-errors');
 var express = require('express');
 var path = require('path');

server/controllers/codeSnippetController.js

@@ -1,22 +1,24 @@
-var mysql = require('mysql2');
-
-var con = mysql.createConnection({
-    host: "localhost",
-    user: "[PLACEHOLDER]",
-    password: "[PLACEHOLDER]",
-    database: "[PLACEHOLDER]"
-});
+const database = require('../utils/database');
+const random = require('../utils/random');
 
 exports.code_snippet = function (req, res) {
-    process_sql_result = function(err, result) {
+    const con = database.get_connection();
+
+    con.query("SELECT COUNT(*) FROM code_snippet;", process_count_query);
+
+    function process_count_query(err, result) {
         if (err) throw err;
-        res.send(result);
+        const code_snippet_count = result[0]["COUNT(*)"];
+        const id_to_retrieve = random.randint(0, code_snippet_count - 1);
+        con.query("SELECT * FROM code_snippet LIMIT ?, 1", [id_to_retrieve], 
+            process_query_result);
     };
 
-    con.connect(function(err) {
+
+    function process_query_result(err, result) {
         if (err) throw err;
-        con.query("SELECT * FROM code_snippet;", process_sql_result);
-    });
+        res.json(result);
+    };
 };