Update md files under docs folder

api/http/nodejs/example.js

@@ -0,0 +1,11 @@
+const GStoreClient = require("./index.js");
+const client = new GStoreClient(
+	"root",
+	"123456",
+	"http://127.0.0.1:9001"
+);
+
+(async function() {
+	const result = await client.query("small","select * where {?s ?p ?o}");
+	console.log(JSON.stringify(result,","));
+})();

docs/API.md

@@ -77,6 +77,18 @@ The HTTP API of gStore is placed in api/http directory in the root directory of
 
             - GstoreConnector.py
 
+    - nodejs/ (the Nodejs API)
+
+        - index.js (source code of Nodejs API)
+
+        - LICENSE
+
+        - package.json
+
+        - README.md
+
+        - example.js (small example to show the basic idea of using the Nodejs API)			
+			
     - php/ (the Php API)
 
         - example/
@@ -239,6 +251,47 @@ def fquery(self, username, password, db_name, sparql, filename):
 
 - - -
 
+## Nodejs API
+
+#### Interface
+
+Before using Nodejs API, type `npm install request` and `npm install request-promise` under the nodejs folder to add the required module.
+
+To use Nodejs API, please see gStore/api/http/nodejs/index.js. Functions should be called like following:
+
+```
+# start a gc with given IP and Port
+gc =  new GStoreClient(username, password, "http://127.0.0.1:9000")
+
+# build database with a RDF graph
+ret = gc.build("test", "data/lubm/lubm.nt")
+
+# load the database
+ret = gc.load("test")
+
+# query
+print (gc.query("test", sparql))
+
+# unload the database
+ret = gc.unload("test")
+```
+The original declaration of these functions are as below:
+
+```
+class GStoreClient
+
+async build(db = '', dataPath = '')
+
+async load(db = '')
+
+async unload(db = '')
+
+async query(db = '', sparql = '')
+
+```
+
+- - -
+
 ## Php API
 
 #### Interface

docs/DEMAND.md

@@ -16,6 +16,7 @@ readline-devel | need to be installed
 openjdk | needed if using Java api
 openjdk-devel | needed if using Java api
 requests | needed if using Python http api
+node | needed if using Nodejs http api and version >= 10.9.0
 pthreads | needed if using php http api 
 curl-devel | needed if using php http api
 realpath | needed if using gconsole
@@ -78,19 +79,27 @@ We will run make clear just to be sure that no other crashed build will mess our
 # make
 # make install
 
-8- Copy configuration file of PHP and add local lib to include path
+8- install node
+# wget https://npm.taobao.org/mirrors/node/v10.9.0/node-v10.9.0.tar.gz
+# tar -xvf node-v10.9.0.tar.gz
+# cd node-v10.9.0
+# ./configure
+# make
+# sudo make install
+
+9- Copy configuration file of PHP and add local lib to include path
 # cp php.ini-development /etc/php.ini
 
 Edit php.ini and set Include_path to be like this:
 
 Include_path = "/usr/local/lib/php"
 
-9- Check Modules
+10- Check Modules
 # php -m (check pthread loaded)
 
 You have to see pthreads listed
 
-10- If pthread is not listed, update php.ini
+11- If pthread is not listed, update php.ini
 # echo "extension=pthreads.so" >> /etc/php.ini
 
 ```

docs/USAGE.md

@@ -95,18 +95,26 @@ type:
 
 `bin/ghttp db_name serverPort` or `bin/ghttp serverPort db_name` to start server with serverPort and load database named db_name initially.
 
-Attention: the argument serverPort can be left out
+Attention: the argument serverPort or db_name can be left out
 
 if you leave out the argument serverPort in the commond, then the corresponding value will be set to default as 9000.
 
+if you leave out the argument db_name in the commond, then the server will start with no database loaded.
 
-operation: build, load, unload, query, monitor, show, checkpoint, user
+
+operation: build, load, unload, query, monitor, show, checkpoint, checkall, user, drop
 
 ```
 // build a new database by a RDF file.
 gc.build("test", "data/lubm/LUBM_10.n3", "root", "123456");
 
-// load databse
+// drop a database already built but leave a backup.
+gc.drop("test", "root", "123456");
+
+// drop a database already built completely.
+gc.drop_r("test", "root", "123456");
+
+// load database
 gc.load("test", "root", "123456");
 
 // then you can execute SPARQL query on this database.
@@ -115,10 +123,16 @@ answer = gc.query("root", "123456", "test", sparql);
 // output information of a database
 cout << answer << std::endl;
 
-// unload this databse
+// unload this database
 gc.unload("lubm", "root", "123456");
 
-//add a user(with username: Jack, passwor: 2)
+// show all databases already built and if they are loaded
+gc.show();
+
+// show statistical information of a loaded database  
+gc.monitor("lubm");
+
+//add a user(with username: Jack, password: 2)
 answer = gc.user("add_user", "root", "123456", "Jack", "2");
 
 //add privilege to user Jack(add_query, add_load, add_unload)
@@ -292,10 +306,16 @@ After starting ghttp, type `bin/gshow ip port` to check loaded database.
     null--->[HTTP/1.1 200 OK]
     Content-Length--->[4]
     database: lubm
+
+- - -
+
+#### 11. shutdown
+
+After starting ghttp, type `bin/shutdown port` to stop the server.
     
 ---
 
-#### 11. test utilities
+#### 12. test utilities
 
 A series of test program are placed in the scripts/ folder, and we will introduce the two useful ones: gtest.cpp and full_test.sh