Remove dependency on raw mongo from SchemaRouter.delete.

src/Adapters/Storage/Mongo/MongoStorageAdapter.js

@@ -30,6 +30,13 @@ export class MongoStorageAdapter {
     });
   }
 
+  dropCollection(name: string) {
+    return this.connect.then(() => this.collection(name).then(collection => collection.drop()));
+  }
+
+  dropCollection(name: string) {
+    return this.collection(name).then(collection => collection.drop());
+  }
   // Used for testing only right now.
   collectionsContaining(match: string) {
     return this.connect().then(() => {

src/Controllers/DatabaseController.js

@@ -42,6 +42,10 @@ DatabaseController.prototype.rawCollection = function(className) {
   return this.adapter.collection(this.collectionPrefix + className);
 };
 
+DatabaseController.prototype.dropCollection = function(className) {
+  return this.adapter.dropCollection(this.collectionPrefix + className);
+};
+
 function returnsTrue() {
   return true;
 }

src/Routers/SchemasRouter.js

@@ -184,20 +184,12 @@ function modifySchema(req) {
 }
 
 // A helper function that removes all join tables for a schema. Returns a promise.
-var removeJoinTables = (database, prefix, mongoSchema) => {
+var removeJoinTables = (database, mongoSchema) => {
   return Promise.all(Object.keys(mongoSchema)
     .filter(field => mongoSchema[field].startsWith('relation<'))
     .map(field => {
-      var joinCollectionName = prefix + '_Join:' + field + ':' + mongoSchema._id;
-      return new Promise((resolve, reject) => {
-        database.dropCollection(joinCollectionName, (err, results) => {
-          if (err) {
-            reject(err);
-          } else {
-            resolve();
-          }
-        })
-      });
+      let collectionName = `_Join:${field}:${mongoSchema._id}`;
+      return database.dropCollection(collectionName);
     })
   );
 };
@@ -208,63 +200,43 @@ function deleteSchema(req) {
   }
 
   if (!Schema.classNameIsValid(req.params.className)) {
-    return Promise.resolve({
-      status: 400,
-      response: {
-        code: Parse.Error.INVALID_CLASS_NAME,
-        error: Schema.invalidClassNameMessage(req.params.className),
-      }
-    });
+    throw new Parse.Error(Parse.Error.INVALID_CLASS_NAME, Schema.invalidClassNameMessage(req.params.className));
   }
 
   return req.config.database.collection(req.params.className)
-  .then(coll => new Promise((resolve, reject) => {
-    coll.count((err, count) => {
-      if (err) {
-        reject(err);
-      } else if (count > 0) {
-        resolve({
-          status: 400,
-          response: {
-            code: 255,
-            error: 'class ' + req.params.className + ' not empty, contains ' + count + ' objects, cannot drop schema',
+    .then(collection => {
+      return collection.count()
+        .then(count => {
+          if (count > 0) {
+            throw new Parse.Error(255, `Class ${req.params.className} is not empty, contains ${count} objects, cannot drop schema.`);
           }
-        });
-      } else {
-        coll.drop((err, reply) => {
-          if (err) {
-            reject(err);
-          } else {
-            // We've dropped the collection now, so delete the item from _SCHEMA
-            // and clear the _Join collections
-            req.config.database.collection('_SCHEMA')
-            .then(coll => new Promise((resolve, reject) => {
-              coll.findAndRemove({ _id: req.params.className }, [], (err, doc) => {
-                if (err) {
-                  reject(err);
-                } else if (doc.value === null) {
-                  //tried to delete non-existant class
-                  resolve({ response: {}});
-                } else {
-                  removeJoinTables(req.config.database.adapter.database, req.config.database.collectionPrefix, doc.value)
-                  .then(resolve, reject);
-                }
-              });
-            }))
-            .then(resolve.bind(undefined, {response: {}}), reject);
-          }
-        });
+          return collection.drop();
+        })
+        .then(() => {
+          // We've dropped the collection now, so delete the item from _SCHEMA
+          // and clear the _Join collections
+          return req.config.database.collection('_SCHEMA')
+            .then(coll => coll.findAndRemove({_id: req.params.className}, []))
+            .then(doc => {
+              if (doc.value === null) {
+                //tried to delete non-existent class
+                return Promise.resolve();
+              }
+              return removeJoinTables(req.config.database, doc.value);
+            });
+        })
+    })
+    .then(() => {
+      // Success
+      return { response: {} };
+    }, error => {
+      if (error.message == 'ns not found') {
+        // If they try to delete a non-existent class, that's fine, just let them.
+        return { response: {} };
       }
+
+      return Promise.reject(error);
     });
-  }))
-  .catch( (error) => {
-    if (error.message == 'ns not found') {
-      // If they try to delete a non-existant class, thats fine, just let them.
-      return Promise.resolve({ response: {} });
-    } 
-    
-    return Promise.reject(error);
-  });
 }
 
 export class SchemasRouter extends PromiseRouter {