Merge pull request #57 from MapQuest/tilejson_array

Use arrays for center and bounds in tilejson

src/tilejson.cpp

@@ -13,6 +13,8 @@
 #include <mapnik/feature_layer_desc.hpp>
 #include <mapnik/datasource.hpp>
 
+#include <unordered_set>
+
 namespace bpt = boost::property_tree;
 namespace bal = boost::algorithm;
 
@@ -177,6 +179,7 @@ mapnik::parameters make_default_parameters() {
 std::string make_tilejson(const mapnik::Map &map,
                           const std::string &base_url) {
   static const mapnik::parameters defaults = make_default_parameters();
+  static const std::unordered_set<std::string> array_keys = {"center", "bounds"};
 
   // TODO: remove super-hacky hard-coded 'JSON' serialiser and use
   // a proper one.
@@ -216,7 +219,11 @@ std::string make_tilejson(const mapnik::Map &map,
 
   for (auto const &row : params) {
     out << "\"" << row.first << "\":";
-    mapnik::util::apply_visitor(json_converter(out), row.second);
+    if (array_keys.count(row.first) > 0) {
+      out << "[" << row.second << "]";
+    } else {
+      mapnik::util::apply_visitor(json_converter(out), row.second);
+    }
     out << ",";
   }
 

test/tilejson.cpp

@@ -92,6 +92,22 @@ void test_tilejson_generate_numeric() {
         }
       }
 
+      // Some params need to be arrays of integers
+      for (auto &param : {"center", "bounds"}) {
+        // The same check as above for presense
+        sregex is_present = as_xpr('"') >> param >> '"' >> *space >> as_xpr(':');
+        if (regex_search(json.begin(), json.end(), is_present)) {
+          sregex is_array = as_xpr('"') >> param >> '"' >> *space >> as_xpr(':')
+                                        >> *space >> as_xpr('[');
+
+          if (!regex_search(json.begin(), json.end(), is_array)) {
+            throw std::runtime_error(
+              (boost::format("Parameter \"%1%\" should be an array of numbers, but is not "
+                             "in TileJSON: %2%") % param % json).str());
+          }
+        }
+      }
+
     } catch (const std::exception &e) {
       std::throw_with_nested(
         std::runtime_error(

test/tilejson_params.xml

@@ -2,7 +2,8 @@
      srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs +over">
   <Parameters>
     <Parameter name="metatile">1</Parameter>
-    <Parameter name="center">-75.6038,40.0799,11</Parameter>
+    <Parameter name="center">-75,40,11</Parameter>
+    <Parameter name="bounds">-180,-85,180,85</Parameter>
     <Parameter name="maxzoom">16</Parameter>
     <Parameter name="minzoom">0</Parameter>
     <Parameter name="name"><![CDATA[MQ Carto Vector]]></Parameter>