Add 'cache_policy' parameter. Closes #62

NEWS.md

@@ -2,6 +2,7 @@
 -----
 * Support for specifying a filename for exports (#64)
 * Support for specifying a list of fields to skip from output (#63)
+* Add 'cache_policy' parameter (#62)
 
 1.2.1 (DD/MM/YY)
 -----

app/controllers/app.js

@@ -224,9 +224,17 @@ function handleQuery(req, res) {
                 setCrossDomain(res);
 
                 // set cache headers
-                res.header('Last-Modified', new Date().toUTCString());
-                res.header('Cache-Control', 'no-cache,max-age=3600,must-revalidate,public');
                 res.header('X-Cache-Channel', generateCacheKey(database, tableCache[sql_md5], authenticated));
+                var cache_policy = req.query.cache_policy;
+                if ( cache_policy == 'persist' ) {
+                  res.header('Cache-Control', 'public,max-age=31536000'); // 1 year
+                } else {
+                  // TODO: set ttl=0 when tableCache[sql_md5].may_write is true ?
+                  var ttl = 3600;
+                  res.header('Last-Modified', new Date().toUTCString());
+                  res.header('Cache-Control', 'no-cache,max-age='+ttl+',must-revalidate,public');
+                }
+
 
                 return result;
             },

doc/API.md

@@ -27,6 +27,13 @@ Supported query string parameters:
 
   'api_key':  Needed to authenticate in order to modify the database.
 
+  'cache_policy':
+              Set to "persist" to have the server send an Cache-Control
+              header requesting caching devices to keep the response
+              cached as much as possible. This is best used with a
+              timestamp value in cache_buster for manual control of
+              updates.
+
 Response formats
 ----------------
 

test/acceptance/app.test.js

@@ -30,6 +30,7 @@ app.setMaxListeners(0);
 suite('app.test', function() {
 
 var expected_cache_control = 'no-cache,max-age=3600,must-revalidate,public';
+var expected_cache_control_persist = 'public,max-age=31536000';
 
 // use dec_sep for internationalization
 var checkDecimals = function(x, dec_sep){
@@ -67,6 +68,20 @@ test('GET /api/v1/sql with SQL parameter on SELECT only. No oAuth included ', fu
     });
 });
 
+test('cache_policy=persist', function(done){
+    assert.response(app, {
+        url: '/api/v1/sql?q=SELECT%20*%20FROM%20untitle_table_4&database=cartodb_test_user_1_db&cache_policy=persist',
+        method: 'GET'
+    },{ }, function(res) {
+        assert.equal(res.statusCode, 200, res.body);
+        // Check cache headers
+        // See https://github.com/Vizzuality/CartoDB-SQL-API/issues/43
+        assert.equal(res.headers['x-cache-channel'], 'cartodb_test_user_1_db:untitle_table_4');
+        assert.equal(res.headers['cache-control'], expected_cache_control_persist);
+        done();
+    });
+});
+
 test('GET /api/v1/sql with SQL parameter on SELECT only. no database param, just id using headers', function(done){
     assert.response(app, {
         url: '/api/v1/sql?q=SELECT%20*%20FROM%20untitle_table_4',