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| − | ==Module Information==
| + | [[Media:Exploration_of_the_Darts_dataset_using_statistics.pdf]] |
| − | | |
| − | ===Module Objectives===
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| − | | |
| − | *How to implement a cloud based storage solution for a company's big data needs
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| − | *The knowledge needed to integrate desktop and web applications to utilize web services and stored data.
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| − | *How cloud based DNS solutions can help to optimize a company's IT infrastructure
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| − | *How cloud based servers and service implementations can be easily deployed for rapid utilisation
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| − | *The steps involved in data exchange between web services and cloud based applications
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| − | | |
| − | ===Resources - References===
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| − | | |
| − | *Programming Amazon EC2, Juirg van Vliet 1st 2011 O’Reilly
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| − | *Google Compute Engine, Marc Cohen 1st 2011 O’Reilly
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| − | *Python for Google App Engine, Massimiliano Pippi 1st 2015 Packet
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| − | *Big Data Fundamentals Concepts, Drivers & Techniques, Thomas Erl, Wajid Khattak, and Paul Buhler, Prentice Hall
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| − | | |
| − | | |
| − | ==Service-Oriented Architecture (SOA)==
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| − | | |
| − | *A service-oriented architecture (SOA) is a style of software design where services are provided to the other components by application components, through a communication protocol over a network.
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| − | | |
| − | *A service is a discrete unit of functionality that can be accessed remotely and acted upon and updated independently, such as retrieving a credit card statement online.
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| − | | |
| − | *SOA provides access to reusable Web services over a TCP/IP network,
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| − | | |
| − | ==XML==
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| − | | |
| − | ==Web service==
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| − | | |
| − | *A software component stored on one computer that can be accessed via method calls by an application (or other software component) on another computer over a network
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| − | | |
| − | *Web services communicate using such technologies as:
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| − | **XML, JSON and HTTP
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| − | **'''Simple Object Access Protocol (SOAP):''' An XML-based protocol that allows web services and clients to communicate in a platform-independent manner
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| − | | |
| − | | |
| − | '''Basic concepts:'''
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| − | | |
| − | *'''Remote machine or server:''' The computer on which a web service resides
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| − | *'''A client application''' that accesses a web service sends a method call over a network to the remote machine, which processes the call and returns a response over the network to the application
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| − | *'''Publishing (deploying) a web service:''' Making a web service available to receive client requests.
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| − | *'''Consuming a web service:''' Using a web service from a client application.
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| − | *In Java, a web service is implemented as a class that resides on a server.
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| − | | |
| − | | |
| − | '''An application that consumes a web service (client) needs:'''
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| − | | |
| − | *An object of a '''''proxy class''''' for interacting with the web service.
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| − | *The ''proxy object'' handles the details of communicating with the web service on the client's behalf
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| − | | |
| − | [[File:Interaction_between_a_web_service_client_and_a_web_service.png|709x709px|thumb|center]]
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| − | | |
| − | | |
| − | '''JAX-WS:'''
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| − | | |
| − | *The Java API for XML Web Services (JAX-WS) is a Java programming language API for creating web services, particularly SOAP services. JAX-WS is one of the Java XML programming APIs. It is part of the Java EE platform.
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| − | **Requests to and responses from web services are typically transmitted via SOAP.
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| − | **Any client capable of generating and processing SOAP messages can interact with a web service, regardless of the language in which the web service is written.
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| − | | |
| − | | |
| − | ===Creating - Deploying - Testing and Describing a Web Service using NetBeans===
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| − | | |
| − | *In Netbeans, you focus on the logic of the web service and let the IDE handle the web service’s infrastructure
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| − | | |
| − | *We first need to to do some configuration in NetBeans:
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| − | **Go to /usr/local/netbeans-8.2/etc/netbeans.conf:
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| − | ***Find the line: ''netbeans_default_options''
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| − | ***If ''-J-Djavax.xml.accessExternalSchema=all'' is not between the quotes then paste it in.
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| − | | |
| − | | |
| − | *If you are deploying to the ''GlassFish'' Server you need to modify the configuration file of the ''GlassFish'' Server (''domain.xml''):
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| − | **/usr/local/glassfish-4.1.1/glassfish/domains/domain1/config/domain.xml
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| − | ***Find : ''<java-config''
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| − | ***Check the ''jvm-options'' for the following configuration: '''''<jvm-options>-Djavax.xml.accessExternalSchema=all</jvm-options>'''''
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| − | ***It should be there by default, if not paste it in, save file and exit
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| − | ***You can now start Netbeans IDE
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| − | | |
| − | <br />
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| − | | |
| − | *'''Create a Web Service in NetBeans- Locally'''
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| − | **Choose File > New Project:
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| − | **Select Web Application from the Java Web category
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| − | **Change Project Name: to CalculatorWSApplication
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| − | **Set the server to GlassFish 4.1.1
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| − | **Set Java EE Version: Java EE 7 Web
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| − | **Set Context path: /CalculatorWSApplication
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| − | **After that you should now have a project created in the Projects view on the left hand side.
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| − | | |
| − | <br />
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| − | | |
| − | :*'''Creating a WS from a Java Class:'''
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| − | ::*Right-click the CalculatorWSApplication node and choose New > Web Service.
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| − | :::*If the option is not there choose Other > Web Services > Web Service
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| − | ::*Click Next
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| − | ::*Name the web service CalculatorWS and type ''com.hduser.calculator'' in Package. Leave Create Web Service from Scratch selected.
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| − | ::*Select Implement Web Service as a Stateless Session Bean.
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| − | ::*Click Finish. The Projects window displays the structure of the new web service and the source code is shown in the editor area. A default hello web service is created by Netbeans.
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| − | | |
| − | | |
| − | ::*'''Adding an Operation to the WS:'''
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| − | :::*Change to the Design view in the editor.
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| − | :::*Click the Add operation button.
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| − | :::*In the upper part of the Add Operation dialog box, type '''''add''''' in ''Name'' and type '''''int'''''' in the ''Return Type'' drop-down list.
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| − | :::*In the lower part of the Add Operation dialog box, click Add and create a parameter of type '''''int''''' named '''''num_1'''''.
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| − | :::*Click Add again and create a parameter of type int called num_2.
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| − | :::*Click OK at the bottom of the panel to add the operation.
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| − | :::*Remove the default hello operation: Right click on hello operation and choose: Remove Operation
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| − | :::*Click on the source view to go back to view the code in the editor.
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| − | :::*You will see the default hello code is gone and the new add method is now there instead.
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| − | :::*Now we have to alter the code to look like this.
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| − | | |
| − | <blockquote>
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| − | <blockquote>
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| − | <syntaxhighlight lang="java">
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| − | /*
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| − | * To change this license header, choose License Headers in Project Properties.
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| − | * To change this template file, choose Tools | Templates
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| − | * and open the template in the editor.
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| − | */
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| − | package com.adelo.calculator;
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| − | | |
| − | import javax.jws.WebService;
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| − | import javax.jws.WebMethod;
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| − | import javax.jws.WebParam;
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| − | import javax.ejb.Stateless;
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| − | | |
| − | @WebService(serviceName = "CalculatorWS")
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| − | @Stateless()
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| − | public class CalculatorWS {
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| − | | |
| − | /**
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| − | * Web service operation
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| − | */
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| − | @WebMethod(operationName = "add")
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| − | public int add(@WebParam(name = "num_1") int num_1, @WebParam(name = "num_2") int num_2) {
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| − | //TODO write your implementation code here:
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| − | int result = num_1 + num_2;
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| − | return result;
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| − | }
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| − | }
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| − | </syntaxhighlight>
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| − | </blockquote>
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| − | </blockquote>
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| − | | |
| − | :::*Well done, you have just created your first Web Service.
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| − | :::*To test the Web service drop down the Web Services directory and right click on CalculatorWSApplication.
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| − | :::*Choose Test Web service.
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| − | :::*Netbeans throws an error: It is letting us know that we have not deployed our Web Service.
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| − | :::*'''Right click on the main Project node and select deploy'''
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| − | | |
| − | | |
| − | *'''Testing the WS:'''
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| − | :*Deploying the Web Service will automatically start the GlassFish server. Allow the server to start, this will take a little while. You can check the progress by clicking on the GlassFish tab at the bottom of the IDE.
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| − | :*Wait until you see: «CalculatorWSApplication was successfully deployed in 9,912 milliseconds»
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| − | :*Now you can right click on the Web Service as before and choose Test Web Service.
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| − | :*The browser will open and you can now test the Web service and view the WSDL file.
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| − | :*You can also view the Soap Request and Response.
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| − | | |
| − | | |
| − | ===Consuming the Web Service===
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| − | | |
| − | ====From a Web Application project====
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| − | *Now that we have a web service we need a client to consume it.
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| − | *Choose File > New Project
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| − | *Select Web Application from the Java Web category
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| − | *Name the project ''CalculatorWSJSPClient''
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| − | *Leave the server and java version as before and click Finish.
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| − | | |
| − | | |
| − | *Expand the Web Pages node under the project node and delete index.html.
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| − | *Right-click the Web Pages node and choose New > JSP in the popup menu.
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| − | **If JSP is not available in the popup menu, choose New > Other and select JSP in the Web category of the New File wizard.
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| − | *Type index for the name of the JSP file in the New File wizard. Click Finish to create the JSP (Java Server Page)
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| − | | |
| − | | |
| − | *Right-click the ''CalculatorWSJSPClient'' node and choose ''New > Web Service Client''.
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| − | **If the option is not there choose ''Other > Web Services > Web Service Client''
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| − | *Select Project as the WSDL source. Click Browse. Browse to the CalculatorWS web service in the CalculatorWSApplication project. When you have selected the web service, click OK.
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| − | *Do not select a package name. Leave this field empty.
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| − | *Leave the other settings as default and click Finish.
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| − | *The WSDL gets parsed and generates the .java
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| − | *The Web Service References directory now contains the add method we created in our web service.
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| − | *Drag and drop the add method just below the H1 tags in index.jsp
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| − | *The Code will be automatically generated.
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| − | *Change the values of ''num_1'' and ''num_2'' to any two numbers e.g. 5 and 5 as per test earlier.
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| − | *Remove the TODO line from the catch block of the code and paste in:
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| − | | |
| − | ::out.println("exception" + ex);
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| − | ::If there is an error this will help us identify the problem.
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| − | | |
| − | *'''IMPORTANT Once you close Netbeans you are shutting down your server. If you want to reuse a Web Service you must re-deploy.'''
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| − | | |
| − | | |
| − | *'''Consuming Live WS:'''
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| − | **Again we are going to need a client.
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| − | **File > New Project > Java Web > Web Application.
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| − | **This time name it SortClient.
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| − | **Click Next
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| − | **Leave the Server and Java Version settings as before (should be default now)
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| − | **Context path : /SortClient
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| − | **Click Finish
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| − | | |
| − | ====From a Java project====
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| − | Netbeans 6.5 - 9 and Java EE enable programmers to "publish (deploy)" and/or "consume (client request)" web services
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| − | | |
| − | This document provides step-by-step instructions to consume a web service in Java using NetBeans IDE.
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| − | | |
| − | In the project, we will invoke a sorting web service through its WSDL link: http://vhost3.cs.rit.edu/SortServ/Service.svc?singleWsdl
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| − | | |
| − | | |
| − | *'''Step 1 - Createa JavaProject:'''
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| − | **We are going to name it: SortClient
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| − | | |
| − | | |
| − | *'''Step 2 - Generate a Web Service Client:'''
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| − | **After the Java Project has been created, go to the Project Tree Structure, Right click on Project and select New and then choose Web Service Client.
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| − | **Specify the WSDL URL as: http://vhost3.cs.rit.edu/SortServ/Service.svc?singleWsdl
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| − | **Click Finish
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| − | | |
| − | | |
| − | *'''Step 3 - Invoke the Service:'''
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| − | **Expand the Web Service References until you see the operation lists. Drag the operation you want to invoke to the source code window, such as "GetKey". A piece of code is automatically generated to invoke that operation.
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| − | **Drag MergeSort to the source code window and the corresponding code is automatically generated,too.
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| − | **In the main function, add the code to call the two functions: getKey() and mergeSort();As it is a call to a remote service, RemoteException needs to be listed in the throws cause
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| − | | |
| − | | |
| − | ==Rails==
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| − | https://guides.rubyonrails.org/getting_started.html
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| − | | |
| − | https://en.wikipedia.org/wiki/Ruby_on_Rails
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| − | | |
| − | Ruby on Rails, or Rails, is a server-side web application framework written in Ruby under the MIT License. Rails is a model-view-controller (MVC) framework, providing default structures for a database, a web service, and web pages. It encourages and facilitates the use of web standards such as JSON or XML for data transfer, HTML, CSS and JavaScript for user interfacing.
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| − | | |
| − | ===Installation===
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| − | Ruby installation:
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| − | <syntaxhighlight lang="bash">
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| − | sudo apt install ruby
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| − | </syntaxhighlight>
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| − | Rails installation:
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| − | <syntaxhighlight lang="bash">
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| − | sudo apt install ruby-railties
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| − | sudo apt-get install rails
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| − | </syntaxhighlight>
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| − | | |
| − | For gem installation:
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| − | <syntaxhighlight lang="bash">
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| − | sudo apt-get install gem
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| − | sudo apt-get install nodejs
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| − | sudo gem install bundler
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| − | </syntaxhighlight>
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| − | | |
| − | | |
| − | ==How to create a Rails Application==
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| − | When you install the Rails framework, you also get a new command-line tool, rails, that is used to construct each new Rails application you write.
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| − | | |
| − | Why do we need a tool? Why can't we just hack away in our favorite editor and create the source for our application from scratch? Well, we could just hack; after all, a Rails application is just Ruby source code. But Rails also does a lot of magic behind the curtain to get our application to work with a minumum of explicit configuration. To get this magic to work, Rails needs to find all the various componenets of your application. Aas we'll see later, this means we need to create a specific directory structure, slotting the code we write into the appropriate places. The rails command simply creates this directory structure for us and populates it with some standards Rails code.
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| − | | |
| − | To create your first Rails application:
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| − | rails new myrailsapp
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| − | | |
| − | The above command has created a directory named ''myrailsapp''.
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| − | | |
| − | Examine your installation using the following command:
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| − | rake about
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| − | | |
| − | Once you get ''rake about'' working, you have everything you need to start a standar-alone web server that can run our newly created Rails application. So, let's star our demos application:
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| − | rails server
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| − |
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| − | Rails 4.2.10 application starting in development on http://localhost:3000
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| − | | |
| − | At this point, we have a new application running, but it has none of our code in it.
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| − | | |
| − | ===Hello Rails===
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| − | Let's start by creating a "Hello, world!"
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| − | | |
| − | Rails is a Model-View-Controller framework. Rails accepts incoming request from a browser, decodes the request to find a controller, and calls an action method in that controller. The controller then invokes a particular view to display the results to the user. To write our simple "Hello World!" application, we need code for a ''controller and a ''view'', and we need a ''route'' to connect the two. We don't need code for a model, because we're not dealing with any data. Let's start with the controller.
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| − | | |
| − | In the same way that we used the ''rails'' commands to create a new Rails application, we can also use a generator script to create a new controller for our project. This command is called ''rails generate'' . So, to create a controller called ''say'', we run the command passing in the name of the controller we want to create and the names of the actions we intend for this controller to support:
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| − | | |
| − | rails generate controller Say hello goodbye
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| − | | |
| − | <syntaxhighlight lang="bash">
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| − | create app/controllers/say_controller.rb
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| − | route get 'say/goodbye'
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| − | route get 'say/hello'
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| − | invoke erb
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| − | create app/views/say
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| − | create app/views/say/hello.html.erb
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| − | create app/views/say/goodbye.html.erb
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| − | invoke test_unit
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| − | create test/controllers/say_controller_test.rb
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| − | invoke helper
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| − | create app/helpers/say_helper.rb
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| − | invoke test_unit
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| − | invoke assets
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| − | invoke coffee
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| − | create app/assets/javascripts/say.coffee
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| − | invoke scss
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| − | create app/assets/stylesheets/say.scss
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| − | </syntaxhighlight>
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| − | | |
| − | | |
| − | Notice the files that were generated for the ''rails generate'' command. The first source file we'll be looking at is the controller:
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| − | | |
| − | say_controller.rb
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| − | <syntaxhighlight lang="ruby">
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| − | class SayController < ApplicationController
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| − | def hello
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| − | end
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| − | | |
| − | def goodbye
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| − | end
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| − | end
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| − | </syntaxhighlight>
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| − | | |
| − | SayController is a class that inherits from ApplicationController, so it automatically gets all the default controller behavior. What does this code have to do? For now, it does nothing, we sinply have empty action methods named ''hello()'' and ''goodbye()''. To understand why these methods are named this way, we need to look at the way Rails handles requests.
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| − | | |
| − | ====Rails and Request URLs====
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| − | Like any other web application, a Rails application appears to its users to be associated with a URL. When you point your browser at that URL, you are talking to the application code, which generates a respondse to you.
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| − | | |
| − | Let's try it now. Navigate to the URL http://localhost:3000/say/hello
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| − | | |
| − | You'll see something that looks like this:
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| − | [[File:Rails_sey_hello1.png|400px|thumb|center|]]
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| − | | |
| − | | |
| − | ====Our first action====
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| − | At this point, we can see not only that we have connected the URL to our controller but also tat Rails is pointing the way to our next step, namely, to tell Rails what to display. That's where views come in. Remember when we ran the script to create the new controller? That command added several files and a new directory to our application. That directory contains the template files to the controller's view. In our case, we created a controller named ''say'', so the view will be in the directory ''app/views/say''.
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| − | | |
| − | By default, Rails looks for templates in a file with the same name as the action it's handling. In our case, that means we need to replace a file called ''hello.html.erb'' in the directory ''app/views/say''. (Why ''.html.erb''? We'll explain in a minute.) For now, let's just put some basic HTML in there:
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| − | | |
| − | <syntaxhighlight lang="html">
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| − | <h1>Hello from Rails!</h1>
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| − | </syntaxhighlight>
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| − | | |
| − | Save the file ''hello.html.erb'' and refresh your browser.
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| − | | |
| − | In total, we've looked at two files in our Rails application tree. We looked at the controller, and we modified a template to display a page in the browser.
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| − | | |
| − | These files live in standard locations in the Rails hierarchy: ''controllers'' go into ''app/controllers'', and ''views'' go into sub-directories of ''app/views'':
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| − | | |
| − | <syntaxhighlight lang="shell">
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| − | .
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| − | ├── app
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| − | │ ├── assets
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| − | │ │ ├── images
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| − | │ │ ├── javascripts
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| − | │ │ │ ├── application.js
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| − | │ │ │ └── say.coffee
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| − | │ │ └── stylesheets
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| − | │ │ ├── application.css
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| − | │ │ └── say.scss
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| − | │ ├── controllers
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| − | │ │ ├── application_controller.rb
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| − | │ │ ├── concerns
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| − | │ │ └── 'say_controller.rb'
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| − | │ ├── helpers
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| − | │ │ ├── application_helper.rb
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| − | │ │ └── say_helper.rb
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| − | │ ├── mailers
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| − | │ ├── models
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| − | │ │ └── concerns
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| − | │ └── views
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| − | │ ├── layouts
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| − | │ │ └── application.html.erb
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| − | │ └── say
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| − | │ ├── goodbye.html.erb
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| − | │ └── 'hello.html.erb'
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| − | ├── bin
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| − | │ ├── bundle
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| − | │ ├── rails
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| − | │ ├── rake
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| − | .
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| − | .
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| − | .
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| − | </syntaxhighlight>
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| − | | |
| − | | |
| − | ====Making it dynamic====
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| − | So far, our Rails application is pretty boring, it just displays a static page. To make it more dynamic, let's have it show the current time each time it displays the page.
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| − | | |
| − | To do this, we need to change the template file in the view, it now needs to include the time as a string. That raises two questions. First, how do we add dynamic content to a template? Second, where do we get the time from?
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| − | | |
| − | =====Dynamic content====
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| − | There are many ways of creating dynamic templates in Rails. The most common way, which we'll use here, is to embed Ruby code in the template. That's why we nemed our template file ''hello.html.erb''; the '.html.erb'' suffix tells Rails to expand the content in the file using a system called '''''ERB'''''.
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| − | | |
| − | ''ERB'' is a filter that is installed as part of the Rails installation that takes an ''.erb''file and outputs a tranformed version. The output file is often ''HTML'' in Rails, but it can be anyting. Normal content is passed through without being changed. However, content between ''<%= and ''%>'' is interpreted as Ruby code and executed. The result of that exwcution is converted into a string, and that value is subtituted in the file in place of the ''<%=...%>'' sequence. For example, chage ''hello.html.erb'' to display the current time:
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| − | | |
| − | <syntaxhighlight lang="html">
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| − | <h1>Hello from Rails!</h1>
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| − | <p>
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| − | It is now <%= Time.now %>
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| − | </p>
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| − | </syntaxhighlight>
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| − | | |
| − | [[File:Rails_sey_hello2.png|400px|thumb|center|]] | |
