From 7114311b75f2cdc2e83b480f671352bdeb6e8470 Mon Sep 17 00:00:00 2001
From: Raul Ochoa <rochoaf@gmail.com>
Date: Tue, 21 Jun 2016 15:05:44 +0200
Subject: [PATCH] Split turbo-carto adapter substitutions tokens query

---
 NEWS.md                                       |   3 +
 .../mapconfig/adapter/turbo-carto-adapter.js  | 106 +++++++++++-------
 2 files changed, 66 insertions(+), 43 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 1e18e2fc..c9ce3cbd 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -4,6 +4,9 @@
 
 Released 2016-mm-dd
 
+Enhancements:
+ - Split turbo-carto adapter substitutions tokens query.
+
 
 ## 2.50.0
 
diff --git a/lib/cartodb/models/mapconfig/adapter/turbo-carto-adapter.js b/lib/cartodb/models/mapconfig/adapter/turbo-carto-adapter.js
index 43a3ffaa..8efaf5a6 100644
--- a/lib/cartodb/models/mapconfig/adapter/turbo-carto-adapter.js
+++ b/lib/cartodb/models/mapconfig/adapter/turbo-carto-adapter.js
@@ -40,56 +40,38 @@ TurboCartoAdapter.prototype.getMapConfig = function (user, requestMapConfig, par
     });
 };
 
-var bboxTemplate = dot.template('(select ST_SetSRID(st_extent(the_geom_webmercator), 3857) from ({{=it._sql}}) __c)');
-var zoomTemplate = dot.template([
-    'GREATEST(',
-    'ceil(log(40075017000 / 256 / GREATEST(',
-    '  st_xmax({{=it._bbox}}) - st_xmin({{=it._bbox}}),',
-    '  st_ymax({{=it._bbox}}) - st_ymin({{=it._bbox}})',
-    '))/log(2)),',
-    '0',
-    ')'
+var tokensQueryTpl = dot.template([
+    'WITH input_query AS (',
+    '  {{=it._sql}}',
+    '),',
+    'bbox_query AS (',
+    '  SELECT ST_SetSRID(ST_Extent(the_geom_webmercator), 3857) as bbox from input_query',
+    '),',
+    'zoom_query as (',
+    '  SELECT GREATEST(',
+    '  ceil(log(40075017000 / 256 / GREATEST(ST_XMax(bbox) - ST_XMin(bbox), ST_YMax(bbox) - ST_YMin(bbox)))/log(2)),',
+    '  0) as zoom',
+    '  FROM bbox_query',
+    '),',
+    'pixel_size_query as (',
+    '  SELECT 40075017 * cos(radians(ST_Y(ST_Transform(ST_Centroid(bbox), 4326)))) / 2 ^ ((zoom) + 8) as pixel_size',
+    '  FROM bbox_query, zoom_query',
+    '),',
+    'scale_denominator_query as (',
+    '  SELECT (pixel_size / 0.00028)::numeric as scale_denominator',
+    '  FROM pixel_size_query',
+    ')',
+    'select ST_AsText(bbox) bbox, pixel_size, scale_denominator, zoom',
+    'from bbox_query, pixel_size_query, scale_denominator_query, zoom_query'
 ].join('\n'));
-// http://wiki.openstreetmap.org/wiki/Zoom_levels
-var pixelSizeTemplate = dot.template(
-    '40075017 * cos(radians(ST_Y(ST_Transform(ST_Centroid({{=it._bbox}}), 4326)))) / (2 ^ ({{=it._zoom}} + 8))'
-);
-var scaleDenominatorTemplate = dot.template('({{=it._pixelSize}} / 0.00028)::numeric');
-
 
 TurboCartoAdapter.prototype._parseCartoCss = function (username, params, layer, index, callback) {
     if (!shouldParseLayerCartocss(layer)) {
         return callback(null, layer);
     }
 
-    var tokens = {
-        bbox: 'ST_MakeEnvelope(-20037508.34,-20037508.34,20037508.34,20037508.34,3857)',
-        scale_denominator: '500000001',
-        pixel_width: '156412',
-        pixel_height: '156412'
-    };
-
-    var layerSql = layer.options.sql;
-    var layerRawSql = layer.options.sql_raw;
-    if (SubstitutionTokens.hasTokens(layerSql) && layerRawSql) {
-        var bbox = bboxTemplate({ _sql: layerRawSql });
-        var zoom = zoomTemplate({ _bbox: bbox });
-        var pixelSize = pixelSizeTemplate({ _bbox: bbox, _zoom: zoom });
-        var scaleDenominator = scaleDenominatorTemplate({ _pixelSize: pixelSize });
-
-        tokens = {
-            bbox: bbox,
-            scale_denominator: scaleDenominator,
-            pixel_width: pixelSize,
-            pixel_height: pixelSize
-        };
-    }
-
-    var sql = SubstitutionTokens.replace(layerSql, tokens);
-
     var pg = new PSQL(dbParamsFromReqParams(params));
-
-    this.process(pg, layer.options.cartocss, sql, function (err, cartocss) {
+    function processCallback(err, cartocss) {
         // Only return turbo-carto errors
         if (err && err.name === 'TurboCartoError') {
             var error = new Error('turbo-carto: ' + err.message);
@@ -109,7 +91,45 @@ TurboCartoAdapter.prototype._parseCartoCss = function (username, params, layer,
             layer.options.cartocss = cartocss;
         }
         return callback(null, layer);
-    });
+    }
+
+    var layerSql = layer.options.sql;
+    var layerRawSql = layer.options.sql_raw;
+    if (SubstitutionTokens.hasTokens(layerSql) && layerRawSql) {
+        var self = this;
+        var tokensQuery = tokensQueryTpl({_sql: layerRawSql});
+        return pg.query(tokensQuery, function(err, resultSet) {
+            if (err) {
+                var error = new Error('turbo-carto: ' + err.message);
+                error.type = 'turbo-carto';
+                return callback(error);
+            }
+
+            resultSet = resultSet || {};
+            var rows = resultSet.rows || [];
+            var result = rows[0] || {};
+
+            var tokens = {
+                bbox: 'ST_SetSRID(ST_GeomFromText(\'' + result.bbox + '\'), 3857)',
+                scale_denominator: result.scale_denominator,
+                pixel_width: result.pixel_size,
+                pixel_height: result.pixel_size
+            };
+
+            var sql = SubstitutionTokens.replace(layerSql, tokens);
+            self.process(pg, layer.options.cartocss, sql, processCallback);
+        }, true); // use read-only transaction
+    }
+
+    var tokens = {
+        bbox: 'ST_MakeEnvelope(-20037508.34,-20037508.34,20037508.34,20037508.34,3857)',
+        scale_denominator: '500000001',
+        pixel_width: '156412',
+        pixel_height: '156412'
+    };
+
+    var sql = SubstitutionTokens.replace(layerSql, tokens);
+    this.process(pg, layer.options.cartocss, sql, processCallback);
 };
 
 TurboCartoAdapter.prototype.process = function (psql, cartocss, sql, callback) {