Added conversion for custom field names and coordinate systems

config.sample.js

@@ -1,7 +1,11 @@
 module.exports = {
-  host: 'localhost',
-  user: 'yourusername',
-  password: 'yourpassword',
-  port: 5432,
-  database: 'yourdatabase'
-}
+  database: {
+    host: 'localhost',
+    user: 'yourusername',
+    password: 'yourpassword',
+    port: 5432,
+    database: 'yourdatabase'
+  },
+  dataCoordinateSystem: 26915,
+  geomFieldNames: ['pt_geom', 'the_geom']
+}

server.js

@@ -11,14 +11,44 @@ var express = require('express'),
 var app = express(),
   port = process.env.PORT || 3000,
   config = require('./config.js'),
-  db = pgp(config);
+  db = pgp(config['database']);
 
 //use express static to serve up the frontend
 app.use(express.static(__dirname + '/public'));
 
 //expose sql endpoint, grab query as URL parameter and send it to the database
 app.get('/sql', function(req, res){
   var sql = req.query.q;
+
+  // Check for custom fields or ST_Transform in SELECT [...] FROM
+  sqlSplit=sql.split('FROM');
+  sql=sqlSplit[0]
+
+  // Apply ST_Transform and replace custom geom field names as necessary
+  if(config['dataCoordinateSystem'] != 4326){
+    if(config['geomFieldNames'].length > 0){
+      config['geomFieldNames'].forEach(function(v){
+          sql=sql.replace(v, 'ST_Transform('+v+', 4326) as $geom'); //Custom geom name and coordinate system
+      });
+    }
+    else{
+      sql=sql.replace('geom', 'ST_Transform(geom, 4326)'); //Custom coordinate system only
+    }
+  }
+  else{
+    // Custom geom field name only
+    if(config['geomFieldNames'].length > 0){
+      config['geomFieldNames'].forEach(function(v){
+          sql=sql.replace(v, v+' as $geom');
+      });
+    }
+  }
+
+  // Merge sql into one string
+  sqlSplit.shift(); //Remove first part of query
+  sql=sql+' FROM '+sqlSplit.join(); //Append remaining from original sql
+  sql=sql.replace('$geom', 'geom'); //Replace $geom - needed due to potential SELECT (ST_Transform(geom, 4326) as geom) issues
+
   console.log('Executing SQL: ' + sql);
 
   //query using pg-promise