Serve gzipped tiles from PostGIS

mvt.js

@@ -6,6 +6,8 @@ const merc = new sm({
   size: 256
 })
 
+const zlib = require('zlib');
+
 function toBoolean(value) {
   if (!value) {
     return false;
@@ -74,6 +76,13 @@ const sql = (params, query) => {
     `
   } // TODO, use sql place holders $1, $2 etc. instead of inserting user-parameters into query
 
+let header = {
+    "Access-Control-Allow-Origin":"*",
+    "Access-Control-Allow-Headers":"Origin, X-Requested-With, Content-Type, Accept",
+    "Content-Type":"application/x-protobuf",
+    "Content-Encoding":"gzip"
+};
+
 module.exports = function(app, pool, cache) {
 
   let cacheMiddleWare = async(req, res, next) => {
@@ -91,7 +100,9 @@ module.exports = function(app, pool, cache) {
       if (mvt.length === 0) {
         res.status(204)
       }
-      res.header('Content-Type', 'application/x-protobuf').send(mvt);
+      //res.header('Content-Type', 'application/x-protobuf').send(mvt);
+      // send cached gzipped tiles with appropriate header
+      res.header(header).send(mvt);
       return;
     } else {
       res.sendResponse = res.send;
@@ -170,7 +181,11 @@ module.exports = function(app, pool, cache) {
             if (mvt.length === 0) {
                 res.status(204)
             }
-            res.header('Content-Type', 'application/x-protobuf').send(mvt);
+            //res.header('Content-Type', 'application/x-protobuf').send(mvt);
+            // gzip and send tiles
+            zlib.gzip(mvt, function(err, pbf) {
+                res.header(header).send(pbf);
+            });
         } catch(err) {
             console.log(err);
             let status = 500;

package-lock.json

@@ -6044,6 +6044,11 @@
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/yallist/-/yallist-2.1.2.tgz",
       "integrity": "sha1-HBH5IY8HYImkfdUS+TxmmaaoHVI="
+    },
+    "zlib": {
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/zlib/-/zlib-1.0.5.tgz",
+      "integrity": "sha1-bnyXL8NxxkWmr7A6sUdp3vEU/MA="
     }
   }
 }

package.json

@@ -28,6 +28,7 @@
     "morgan": "^1.9.1",
     "nodemon": "^1.19.2",
     "path": "^0.12.7",
-    "pg": "^7.12.1"
+    "pg": "^7.12.1",
+    "zlib": "^1.0.5"
   }
 }