tile map server added

tms/index.js

@@ -0,0 +1,39 @@
+// this is a simple tile map server implementation, built with Express, serves tiles indentified by combination of zoom_level, row_id and column_id
+const express = require('express');
+const app = express(); // express app's instance gets created here
+const join = require('path').join;
+const exists = require('fs').exists; // only importing `exists` method
+let tile_path = '/home/anjan/Documents/my_programs/still_working/python_codes/mapZ/tiles/';
+app.get('/tile/:zoom/:row/:col.png', (req, res) => {
+    // this is the path we're listening to
+    // where zoom, request param, gives us zoom level for that tile requested
+    // row, gives row number of tile to be served
+    // col, gives column number of tile to be served
+    console.log(`\t[+]Incoming request from --- ${req.ip}`);
+    var target_path = join(tile_path, `${req.params.zoom
+        }_${req.params.row}_${req.params.col}.png`); // this is requested tile
+    exists(target_path, (e) => {
+        if (e) {
+            res.status(200).type('png').sendFile(target_path, {
+                headers: {
+                    'x-timestamp': Date.now(),
+                    'x-sent': true
+                },
+                dotfiles: 'deny' // setting header
+            }, (err) => {
+                if (err)
+                    console.log(`\t\t[!]${err}`); // denotes error
+            });
+            // sets status code
+            // sets Content-Type field in Header
+            // sends tile
+        }
+        else {
+            res.status(404).json({ err: 'Illegal tile requested' }); // if requested tile is not available
+        }
+    });
+});
+app.listen(8000, '0.0.0.0', () => {
+    // tms listens at 0.0.0.0:8000, so that it can be accessed via both localhost and devices present in local network
+    console.log('[+]Tile Map Server listening at - `0.0.0.0: 8000`\n');
+});