👷 implementing baseURL to allow usage behind load balancers

docs/config.rst

@@ -66,6 +66,16 @@ The value of ``root`` is used as prefix for all data types.
 
 You can use this to optionally specify on what domains the rendered tiles are accessible. This can be used for basic load-balancing or to bypass browser's limit for the number of connections per domain.
 
+``baseURL``
+-----------
+
+When you run the tile server server behind a load-balancer, the automatic URL generators wont't have the required information to build URLs which point to the correct LB endpoint.
+
+Also, if your load balancer is forwarding a HTTPS connection to the non-HTTPS ``tileserver-gl``, setting the ``baseURL`` is indispensable.
+
+Not compatible with the ``domains`` option.
+
+
 ``formatQuality``
 -----------------
 

src/serve_data.js

@@ -14,7 +14,8 @@ module.exports = function(options, repo, params, id) {
 
   var mbtilesFile = path.resolve(options.paths.mbtiles, params.mbtiles);
   var tileJSON = {
-    'tiles': params.domains || options.domains
+    'tiles': params.domains || options.domains,
+    'baseURL': options.baseURL
   };
 
   repo[id] = tileJSON;

src/serve_rendered.js

@@ -539,7 +539,7 @@ module.exports = function(options, repo, params, id, dataResolver) {
   app.get('/rendered.json', function(req, res, next) {
     var info = clone(tileJSON);
     info.tiles = utils.getTileUrls(req, info.tiles,
-                                   'styles/' + id + '/rendered', info.format);
+                                   'styles/' + id + '/rendered', info.format, info.baseURL);
     return res.send(info);
   });
 

src/serve_style.js

@@ -12,6 +12,8 @@ module.exports = function(options, repo, params, id, reportTiles, reportFont) {
 
   var styleFile = path.join(options.paths.styles, params.style);
 
+  var baseURL = options.baseURL;
+
   var styleJSON = clone(require(styleFile));
   Object.keys(styleJSON.sources).forEach(function(name) {
     var source = styleJSON.sources[name];
@@ -57,8 +59,9 @@ module.exports = function(options, repo, params, id, reportTiles, reportFont) {
       if (!opt_nokey && req.query.key) {
         query = '?key=' + req.query.key;
       }
+      var url = baseURL ? baseURL : req.protocol + '://' + req.headers.host;
       return url.replace(
-          'local://', req.protocol + '://' + req.headers.host + '/') + query;
+          'local://', url + '/') + query;
     };
 
     var styleJSON_ = clone(styleJSON);

src/server.js

@@ -69,6 +69,8 @@ module.exports = function(opts, callback) {
   }
 
   var options = config.options || {};
+  var baseURL = config.baseURL;
+
   var paths = options.paths || {};
   options.paths = paths;
   paths.root = path.resolve(
@@ -165,7 +167,7 @@ module.exports = function(opts, callback) {
         version: styleJSON.version,
         name: styleJSON.name,
         id: id,
-        url: req.protocol + '://' + req.headers.host +
+        url: (baseURL ? baseURL : req.protocol + '://' + req.headers.host) +
              '/styles/' + id + '.json' + query
       });
     });
@@ -176,7 +178,7 @@ module.exports = function(opts, callback) {
     Object.keys(serving[type]).forEach(function(id) {
       var info = clone(serving[type][id]);
       info.tiles = utils.getTileUrls(req, info.tiles,
-                                     type + '/' + id, info.format);
+                                     type + '/' + id, info.format, baseURL);
       arr.push(info);
     });
     return arr;
@@ -224,6 +226,7 @@ module.exports = function(opts, callback) {
 
   serveTemplate('/$', 'index', function(req) {
     var styles = clone(config.styles || {});
+
     Object.keys(styles).forEach(function(id) {
       var style = styles[id];
       style.name = (serving.styles[id] || serving.rendered[id] || {}).name;
@@ -247,9 +250,10 @@ module.exports = function(opts, callback) {
           base64url('http://' + req.headers.host +
             '/styles/' + id + '/rendered.json' + query) + '/wmts';
 
+
         var tiles = utils.getTileUrls(
             req, style.serving_rendered.tiles,
-            'styles/' + id + '/rendered', style.serving_rendered.format);
+            'styles/' + id + '/rendered', style.serving_rendered.format, baseURL);
         style.xyz_link = tiles[0];
       }
     });
@@ -277,7 +281,7 @@ module.exports = function(opts, callback) {
             '/data/' + id + '.json' + query) + '/wmts';
 
         var tiles = utils.getTileUrls(
-            req, data_.tiles, 'data/' + id, data_.format);
+            req, data_.tiles, 'data/' + id, data_.format, baseURL);
         data_.xyz_link = tiles[0];
       }
       if (data_.filesize) {

src/utils.js

@@ -6,20 +6,24 @@ var async = require('async'),
 
 var glyphCompose = require('glyph-pbf-composite');
 
-module.exports.getTileUrls = function(req, domains, path, format) {
+module.exports.getTileUrls = function(req, domains, path, format, baseURL) {
+  var key = req.query.key;
+  var query = (key && key.length > 0) ? ('?key=' + key) : '';
+
+  if (baseURL) {
+    return [baseURL + path + '/{z}/{x}/{y}.' + format + query]
+  }
 
   if (domains) {
     if (domains.constructor === String && domains.length > 0) {
       domains = domains.split(',');
     }
+
   }
   if (!domains || domains.length == 0) {
     domains = [req.headers.host];
   }
 
-  var key = req.query.key;
-  var query = (key && key.length > 0) ? ('?key=' + key) : '';
-
   var uris = [];
   domains.forEach(function(domain) {
     uris.push(req.protocol + '://' + domain + '/' + path +