Merge pull request #7 from arangodb/transactions

Added support for transactions

Author: fceller

README.md

@@ -137,6 +137,25 @@ Fetches all databases from the server and passes an array of new *Database* inst
 
 Deletes the database with the given *databaseName* from the server.
 
+### Transactions
+
+#### database.transaction(collections, action, [params,] [lockTimeout,] callback)
+
+Performs a server-side transaction and passes the *action*'s return value to the callback.
+
+*Parameter*
+
+* *collections*: an object with the following properties:
+ * *read*: an array of names (or a single name) of collections that will be read from during the transaction.
+ * *write*: an array of names (or a single name) of collections that will be written to or read from during the transaction.
+* *action*: a string evaluating to a JavaScript function to be executed on the server.
+* *params* (optional): parameters that will be passed to the function.
+* *lockTimeout* (optional): determines how long the database will wait while attemping to gain locks on collections used by the transaction before timing out.
+
+If *collections* is an array or string, it will be used as *collections.write*.
+
+Please note that while *action* should be a string evaluating to a well-formed JavaScript function, it's not possible to pass in a JavaScript function directly because the function needs to be evaluated on the server and will be transmitted in plain text.
+
 ### Queries
 
 #### database.query(query, [bindVars,] callback)

lib/database.js

@@ -194,6 +194,33 @@ extend(Database.prototype, {
       }
     });
   },
+  transaction: function (collections, action, params, lockTimeout, callback) {
+    if (typeof lockTimeout === 'function') {
+      callback = lockTimeout;
+      lockTimeout = undefined;
+    }
+    if (typeof params === 'function') {
+      callback = params;
+      params = undefined;
+    }
+    if (typeof params === 'number') {
+      lockTimeout = params;
+      params = undefined;
+    }
+    if (typeof collections === 'string' || Array.isArray(collections)) {
+      collections = {write: collections};
+    }
+    if (!callback) callback = noop;
+    this._api.post('transaction', {
+      collections: collections,
+      action: action,
+      params: params,
+      lockTimeout: lockTimeout
+    }, function (err, body) {
+      if (err) callback(err);
+      else callback(null, body.result);
+    });
+  },
   query: function (query, bindVars, callback) {
     if (typeof bindVars === 'function') {
       callback = bindVars;