Implement LZMA query param inflating as middleware

The req2params method is doing too many things,
this is an initial step to do fewer things in that method.

lib/cartodb/controllers/base.js

@@ -4,9 +4,6 @@ var _ = require('underscore');
 var step = require('step');
 var debug = require('debug')('windshaft:cartodb');
 
-var LZMA = require('lzma').LZMA;
-var lzmaWorker = new LZMA();
-
 // Whitelist query parameters and attach format
 var REQUEST_QUERY_PARAMS_WHITELIST = [
     'config',
@@ -28,7 +25,7 @@ function BaseController(authApi, pgConnection) {
 
 module.exports = BaseController;
 
-// jshint maxcomplexity:10
+// jshint maxcomplexity:8
 /**
  * Whitelist input and get database name & default geometry type from
  * subdomain/user metadata held in CartoDB Redis
@@ -38,35 +35,6 @@ module.exports = BaseController;
 BaseController.prototype.req2params = function(req, callback){
     var self = this;
 
-    if ( req.query.lzma ) {
-
-        // Decode (from base64)
-        var lzma = new Buffer(req.query.lzma, 'base64')
-            .toString('binary')
-            .split('')
-            .map(function(c) {
-                return c.charCodeAt(0) - 128;
-            });
-
-
-        // Decompress
-        lzmaWorker.decompress(
-            lzma,
-            function(result) {
-                req.profiler.done('lzma');
-                try {
-                    delete req.query.lzma;
-                    _.extend(req.query, JSON.parse(result));
-                    self.req2params(req, callback);
-                } catch (err) {
-                    req.profiler.done('req2params');
-                    callback(new Error('Error parsing lzma as JSON: ' + err));
-                }
-            }
-        );
-        return;
-    }
-
     var allowedQueryParams = REQUEST_QUERY_PARAMS_WHITELIST;
     if (Array.isArray(req.context.allowedQueryParams)) {
         allowedQueryParams = allowedQueryParams.concat(req.context.allowedQueryParams);

lib/cartodb/middleware/lzma.js

@@ -0,0 +1,30 @@
+'use strict';
+
+var LZMA = require('lzma').LZMA;
+
+var lzmaWorker = new LZMA();
+
+module.exports = function lzmaMiddleware(req, res, next) {
+    if (!req.query.hasOwnProperty('lzma')) {
+        return next();
+    }
+
+    // Decode (from base64)
+    var lzma = new Buffer(req.query.lzma, 'base64')
+        .toString('binary')
+        .split('')
+        .map(function(c) {
+            return c.charCodeAt(0) - 128;
+        });
+
+    // Decompress
+    lzmaWorker.decompress(lzma, function(result) {
+        try {
+            delete req.query.lzma;
+            Object.assign(req.query, JSON.parse(result));
+            next();
+        } catch (err) {
+            next(new Error('Error parsing lzma as JSON: ' + err));
+        }
+    });
+};

lib/cartodb/server.js

@@ -4,6 +4,8 @@ var RedisPool = require('redis-mpool');
 var cartodbRedis = require('cartodb-redis');
 var _ = require('underscore');
 
+var lzmaMiddleware = require('./middleware/lzma');
+
 var controller = require('./controllers');
 
 var SurrogateKeysCache = require('./cache/surrogate_keys_cache');
@@ -345,6 +347,8 @@ function bootstrap(opts) {
         next();
     });
 
+    app.use(lzmaMiddleware);
+
     // temporary measure until we upgrade to newer version expressjs so we can check err.status
     app.use(function(err, req, res, next) {
         if (err) {

test/unit/cartodb/lzmaMiddleware.test.js

@@ -0,0 +1,36 @@
+var assert = require('assert');
+var testHelper = require('../../support/test_helper');
+
+var lzmaMiddleware = require('../../../lib/cartodb/middleware/lzma');
+
+describe('lzma-middleware', function() {
+
+    it('it should extend params with decoded lzma', function(done) {
+        var qo = {
+            config: {
+                version: '1.3.0'
+            }
+        };
+        testHelper.lzma_compress_to_base64(JSON.stringify(qo), 1, function(err, data) {
+            var req = {
+                headers: {
+                    host:'localhost'
+                },
+                query: {
+                    api_key: 'test',
+                    lzma: data
+                }
+            };
+            lzmaMiddleware(req, {}, function(err) {
+                if ( err ) {
+                    return done(err);
+                }
+                var query = req.query;
+                assert.deepEqual(qo.config, query.config);
+                assert.equal('test', query.api_key);
+                done();
+            });
+        });
+    });
+
+});

test/unit/cartodb/req2params.test.js

@@ -1,6 +1,6 @@
 var assert = require('assert');
 var _ = require('underscore');
-var test_helper = require('../../support/test_helper');
+require('../../support/test_helper');
 
 var RedisPool = require('redis-mpool');
 var cartodbRedis = require('cartodb-redis');
@@ -98,13 +98,10 @@ describe('req2params', function() {
       });
     });
 
-    it('it should extend params with decoded lzma', function(done) {
-        var qo = {
-            config: {
+    it('it should remove invalid params', function(done) {
+        var config = {
             version: '1.3.0'
-            }
         };
-        test_helper.lzma_compress_to_base64(JSON.stringify(qo), 1, function(err, data) {
         var req = {
             headers: {
                 host:'localhost'
@@ -113,7 +110,7 @@ describe('req2params', function() {
                 non_included: 'toberemoved',
                 api_key: 'test',
                 style: 'override',
-                    lzma: data
+                config: config
             }
         };
         baseController.req2params(prepareRequest(req), function(err, req) {
@@ -121,12 +118,12 @@ describe('req2params', function() {
                 return done(err);
             }
             var query = req.params;
-                assert.deepEqual(qo.config, query.config);
+            assert.deepEqual(config, query.config);
             assert.equal('test', query.api_key);
             assert.equal(undefined, query.non_included);
+            assert.equal(undefined, query.style);
             done();
         });
     });
-    });
 
 });