added new request handlers

code/server/incoming_request_handlers.js

@@ -0,0 +1,70 @@
+/**
+ *
+ * @param {Request} request The incoming request
+ * @param {Response} response The response to send back
+ * @param {Express} app Express app instance
+ * @param {Pool} pool MariaDB pool instance
+ */
+function handleIncoming(request, response, app, pool)
+{
+
+    let query = 'SELECT * FROM Exercise WHERE ExerciseID = ?';
+    let parameters = [];
+
+    if (!request.hasOwnProperty('uid') || typeof request.uid !== 'number')
+    {
+        query = 'SELECT * FROM Exercise ORDER BY RAND() LIMIT 1';
+    } else parameters.push(request.uid);
+
+    // Acquire database connection
+    pool.getConnection()
+        .then(conn => {
+            conn.query(query, parameters)
+                .then(rows => {
+                    if (rows.length === 0)
+                    {
+                        response
+                            .status(404)
+                            .send(JSON.stringify({error: 'Exercise not found'}));
+                    }
+                    else
+                    {
+                        // Send back the data in the right format
+                        let converted = rows.map(row => {
+                            return {
+                                name: row.Name,
+                                description: row.Description,
+                                muscleGroup: row.MuscleGroup,
+                                imageUrl: row.ImageURL,
+                                videoUrl: row.VideoURL
+                            };
+                        });
+
+                        response
+                            .status(200)
+                            .send(JSON.stringify(converted));
+                    }
+                })
+                .catch(error => {
+                    console.log(error);
+                    response
+                        .status(500)
+                        .send(JSON.stringify({error: 'Internal server error (Querying)'}));
+                })
+                .finally(() => {
+                    conn.end();
+                });
+        })
+        .catch(error => {
+            console.log(error);
+            response
+                .status(500)
+                .send(JSON.stringify({error: 'Internal server error (Connection)'}));
+        });
+
+}
+
+// Export the function that registers the incoming request handlers
+module.exports = function(app, pool) {
+    app.post('/', (req, res) => handleIncoming(req, res, app, pool));
+};