Servicii web

Realizarea serviciilor web

Vom crea un nou proiect utilizand Visual Studio 2008. Proiectul creat va fi de tipul C#-->WEB-->ASP.NET web Service Application

Se va genera automat un serviciu web Service1.asmx de forma:

Se ruleaza acest serviciu si se observa startarea unui server ASP.NET in acest caz pe portul 49707. Adresa portului este data aleator in momentul generarii serviciului. Adresa "http://tempuri.org/" va trebui inlocuita cu "http://localhost:49707/Service0"

Utilizarea serviciilor web

    Odata realizat un serviciu web, acesta poate fi utilizat de clienti constituiti din pagini web.
    Vom adauga deci o pagina web care sa foloseasca acest serviciu. Pagina se va numi "Test_Service1.html"
    Adaugarea se face cu Click dreapta pe Webservice0-->Add-->New Ittem-->Html Page
    Continutul fisierului html fiind:

    Vom crea un nou serviciu WebService1 mai complex, serviciu care permite accesul la o baza de date MySQL
    Fisierul Service1.asmx de forma:

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml.Linq;
using System.Data.Odbc;

namespace WebService1
{
    /// <summary>
    /// Summary description for Service1
    /// </summary>
    [WebService(Namespace = "http://localhost:50430/Service1")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    [System.Web.Script.Services.ScriptService]
    public class Service1 : System.Web.Services.WebService
    {

[WebMethod]
        public string HelloWorld()
        {
            return "Hello World";
        }

[WebMethod(Description = "Returneaza valorile masurate in TP")]
        public double val_tp(int act, int cod)
        {

String myConnString = "driver={MySQL ODBC 5.1 Driver};server=193.226.19.29;database=cons_el;uid=student;pwd=psw;";
            String mySelectQuery = "SELECT tp_id, val FROM t_points WHERE tp_id=" + System.Convert.ToString(act);
            OdbcConnection myConnection = new OdbcConnection(myConnString);
            OdbcCommand myCommand = new OdbcCommand(mySelectQuery, myConnection);
            myConnection.Open();
            OdbcDataReader myReader;
            myReader = myCommand.ExecuteReader();
            // Always call Read before accessing data.
            //while (myReader.Read()) {
            //  Console.WriteLine("{0}, {1}", myReader.GetInt32(0), myReader.GetString(1));
            //}
            // always call Close when done reading.
            myReader.Read();
            double x = myReader.GetDouble(1);
            myReader.Close();
            // Close the connection when done with it.
            myConnection.Close();

return x;
        }
    }
}

Dupa cum se observa, serviciul presupune ca exista deja instalata o conexiune ODBC spre baza de date cons_el care se afla pe serverul 193.226.19.20, username "student" parola "psw"

Pagina web care sa foloseasca acest serviciu, va fi:

<html>
  <title> Service1 Web Service </title></head>
   <body>

<p class="heading1">Service1</p><br>
 
          <p class="intro">Click <a href="Service1.asmx">here</a> for a complete list of operations.</p>
          <h2>val_tp</h2>
          <p class="intro">Returneaza valorile masurate in TP</p>
 
          <h3>Test</h3>
 
      <form target="_blank" action='http://localhost:50430/Service1.asmx/val_tp' method="POST">                                              
        <table cellspacing="0" cellpadding="4" frame="box" bordercolor="#dcdcdc" rules="none" style="border-collapse: collapse;">
         <tr>
        	<td class="frmHeader" background="#dcdcdc" style="border-right: 2px solid white;">Parameter</td>
	        <td class="frmHeader" background="#dcdcdc">Value</td>
        </tr>
        <tr>
           <td class="frmText" style="color: #000000; font-weight: normal;">act:</td>
           <td><input class="frmInput" type="text" size="50" name="act"></td>
        </tr>
        <tr>
          <td class="frmText" style="color: #000000; font-weight: normal;">cod:</td>
          <td><input class="frmInput" type="text" size="50" name="cod"></td>
       </tr>
       <tr>
         <td></td>
         <td align="right"> <input type="submit" value="Invoke" class="button"></td>
        </tr>
      </table>
  </form>
</body>
</html>

Dupa incarcarea paginii obtinem:

Aplicatia web poate fi lansata din orce browser ruland cu conditia sa fie pornit serviciul web

Dupa invocarea serviciului, se obtine valoarea ceruta in baza de date in format XML sub forma:

Utilizarea protocolului SOAP

Vom folosi in continuare protocolul SOAP bazat pe XML pentru a citi date prin intermediul serviciului web creat
Aplicatia este realizata in JavaScript si folosete protocolul SOAP pentru a citi date prin intermediul serviciului Service1.

<html>
<head>
<title>Web Service Test </title>
<script type="text/javascript">
	var SERVICE_URL = "http://localhost:51655/Service1.asmx";
	var SOAP_ACTION_BASE = "http://localhost:51655/Service1";
	var bEnabled;
	var oXmlHttp;
	function setUIEnabled(bEnabled)
	{
		var oButton = document.getElementById("cmdRequest");
		oButton.disabled = false;
		var oList = document.getElementById("lstMethods");
		oList.disabled = false;
	}

function performOperation()
	{
		var oList = document.getElementById("lstMethods");
		var sMethod = oList.options[oList.selectedIndex].value;
		var sact = document.getElementById("txtact").value;
		var scod = document.getElementById("txtcod").value;
		//Clear the message panes
		document.getElementById("txtRequest").value = "";
		document.getElementById("txtResponse").value = "";
		document.getElementById("txtResult").value = "";
		performSpecificOperation(sMethod, sact, scod);
	}
	var iCallId = 0;

function getRequest(sMethod, sact, scod)
	{
		var sRequest ="<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"+
		"<soap:Envelope xmlns:xsi=\""
		+ "http://www.w3.org/2001/XMLSchema-instance\" "
		+ "xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" "
		+ "xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">\n"
		+ "<soap:Body>\n"
		+ "<" + sMethod + " xmlns=\"" + SOAP_ACTION_BASE + "\">\n"
		+ "<act>" + sact + "</act>\n"
		+ "<cod>" + scod + "</cod>\n"
		+ "</" + sMethod + ">\n"
		+ "</soap:Body>\n"
		+ "</soap:Envelope>\n";
		return sRequest;
	}
	function CreateCallObject ()
	{

try {
			  xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
		     } 
		catch (e) 
		{
		  try {
			   xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
		      }
		  catch (E) 
		     {
			   xmlhttp = false;
              }
		 }
		if (!xmlhttp) 
        {
		try {
			xmlhttp = new XMLHttpRequest();
	        } 
        catch (e)
           {
			xmlhttp=false;
		   }
	    }
	    return xmlhttp;
	    }

function performSpecificOperation(sMethod, sact, scod) 
	{
		oXmlHttp = CreateCallObject();
        //alert(oXmlHttp);
	    var sRequest = getRequest(sMethod, sact, scod);
		var sSoapActionHeader = SOAP_ACTION_BASE + "/" + sMethod;
	
		oXmlHttp.open("POST", SERVICE_URL, true);

oXmlHttp.onreadystatechange = handleResponse;
		oXmlHttp.setRequestHeader("Content-Type", "text/xml");
		oXmlHttp.setRequestHeader("SOAPAction", sSoapActionHeader);
		oXmlHttp.send(sRequest);
		document.getElementById("txtRequest").value = sRequest;
	}
	function handleResponse()
	{
		if (oXmlHttp.readyState == 4)
		{
			setUIEnabled(true);
			var oResponseOutput = document.getElementById("txtResponse");
			var oResultOutput = document.getElementById("txtResult");
			var oXmlResponse = oXmlHttp.responseXML;
			var sHeaders = oXmlHttp.getAllResponseHeaders();
			if (oXmlHttp.status != 200 || !oXmlResponse.xml)
			{
				alert("Error accessing Web service.\n"+ oXmlHttp.statusText+ "\nSee response pane for further details.");
				
				var sResponse = (oXmlResponse.xml ? oXmlResponse.xml : oXmlResponseText);
				var sResponse =oXmlResponse.xml;
				oResponseOutput.value = sHeaders + sResponse;
				return;
			}
			oResponseOutput.value = sHeaders + oXmlResponse.xml;
			var sResult =oXmlResponse.documentElement.firstChild.firstChild.firstChild.firstChild.data;
			oResultOutput.value = sResult;
		}
	}
</script>
</head>
<body>

Operation:
	<select id="lstMethods" style="width: 200px">
	<option value="val_tp" selected="selected">Valoare TP</option>
	<option value="stare_act">Stare Actuator</option>
	<option value="poz_act">Pozitie Actuator</option>
	<option value="torq_act">Cuplu Actuator</option>
	</select>

<br/><br/>
	Operand 1: <input type="text" id="txtact" size="10"/><br/>
	Operand 2: <input type="text" id="txtcod" size="10"/><br/><br/>
	<input type="button" id="cmdRequest" value="performOperation" onClick="performOperation();"/>
	<br/><br/>
	Result: <input type="text" size="20" id="txtResult">
<br/>
	<textarea rows="12" cols="120" id="txtRequest"> </textarea>
	<textarea rows="14" cols="120" id="txtResponse"> </textarea>
	<textarea rows="3" cols="120" id="oXmlResponseText"> </textarea>
</body>
</html>

Dupa lansarea paginii si completarea cu parametrii ceruti, obtinem:

Aplicatia web poate fi lansata local din orice browser ruland cu conditia sa fie pornit serviciul web

    Cererea este in format XML sub forma:

    Raspunsul fiind tot in format XML sub forma:

    In acest moment serverul "Webservice1" poate fi imbogatit cu noi servicii. Sa adaugam Service2 care citeste valorile maxime din tabela t_points
    Fisierul Service2.asmx are forma:

namespace WebService1
{
    /// <summary>
    /// Summary description for Service2
    /// </summary>
    [WebService(Namespace = "http://localhost:50430/Service2")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    // [System.Web.Script.Services.ScriptService]
    public class Service2 : System.Web.Services.WebService
    {

[WebMethod]
        public string HelloWorld()
        {
            return "Hello World";
        }

[WebMethod(Description = "Returneaza valorile maxime in TP")]
        public double max_tp(int act, int cod)
        {

String myConnString = "driver={MySQL ODBC 5.1 Driver};server=193.226.19.29;database=cons_el;uid=student;pwd=psw;";
            String mySelectQuery = "SELECT tp_id, v_max FROM t_points WHERE tp_id=" + System.Convert.ToString(act);
            OdbcConnection myConnection = new OdbcConnection(myConnString);
            OdbcCommand myCommand = new OdbcCommand(mySelectQuery, myConnection);
            myConnection.Open();
            OdbcDataReader myReader;
            myReader = myCommand.ExecuteReader();
            // Always call Read before accessing data.
            //while (myReader.Read()) {
            //  Console.WriteLine("{0}, {1}", myReader.GetInt32(0), myReader.GetString(1));
            //}
            // always call Close when done reading.
            myReader.Read();
            double x = myReader.GetDouble(1);
            myReader.Close();
            // Close the connection when done with it.
            myConnection.Close();

return x;
        }
    }
}

Pagina html client este similara cu clientul seviciului Service1

Aplicatie SCADA ce utilizeaza serviciul SOAP

    Sa realizam acum un serviciu web si o aplicatie pentru monitorizarea unei instalatii de gaz in care exista mai multe puncte de masura si mai ulte actuatoare care trebuiesc monitorizate.

    Vom crea un nou server "ScadaWebServer" care contine serviciul Service1 in care vom include mai multe operatii cum ar fi: citeste valori t_points, citire stare actuatoare, citire pozitia actuatorului etc.
    Fisierul Service1.asmx are forma:

namespace ScadaWebService
{
    /// <summary>
    /// Summary description for Service1
    /// </summary>
    [WebService(Namespace = "http://localhost:51655/Service1")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    //[System.Web.Script.Services.ScriptService]
    public class Service1 : System.Web.Services.WebService
    {
        [WebMethod(Description = "Returneaza valorile masurate in TP")]
        public double val_tp(int act, int cod)
        {
            String myConnString = "driver={MySQL ODBC 5.1 Driver};server=193.226.19.29;database=cons_el;uid=student;pwd=psw;";
            String mySelectQuery = "SELECT tp_id, val FROM t_points WHERE tp_id=" + System.Convert.ToString(act);
            OdbcConnection myConnection = new OdbcConnection(myConnString);
            OdbcCommand myCommand = new OdbcCommand(mySelectQuery, myConnection);
            myConnection.Open();
            OdbcDataReader myReader;
            myReader = myCommand.ExecuteReader();
            myReader.Read();
            double x = myReader.GetDouble(1);
            myReader.Close();
            // Close the connection when done with it.
            myConnection.Close();
            return x;
        }
        [WebMethod(Description = "Returneaza stare actuator")]
        public string stare_act(int act, int cod)
        {
            String myConnString = "driver={MySQL ODBC 5.1 Driver};server=193.226.19.29;database=cons_el;uid=student;pwd=psw;";
            String mySelectQuery = "SELECT act_id, valve_close, valve_open, valve_closing, valve_opening, warnings FROM actuators WHERE act_id=" + System.Convert.ToString(act);
            OdbcConnection myConnection = new OdbcConnection(myConnString);
            OdbcCommand myCommand = new OdbcCommand(mySelectQuery, myConnection);
            myConnection.Open();
            OdbcDataReader myReader;
            myReader = myCommand.ExecuteReader();
            myReader.Read();
            string x = myReader.GetString(1) + myReader.GetString(2) + myReader.GetString(3) + myReader.GetString(4) + myReader.GetString(5);
            myReader.Close();
            // Close the connection when done with it.
            myConnection.Close();
            return x;
        }

[WebMethod(Description = "Returneaza pozitie actuator")]
        public double poz_act(int act, int cod)
        {
            String myConnString = "driver={MySQL ODBC 5.1 Driver};server=193.226.19.29;database=cons_el;uid=student;pwd=psw;";
            String mySelectQuery = "SELECT act_id, position FROM actuators WHERE act_id=" + System.Convert.ToString(act);
            OdbcConnection myConnection = new OdbcConnection(myConnString);
            OdbcCommand myCommand = new OdbcCommand(mySelectQuery, myConnection);
            myConnection.Open();
            OdbcDataReader myReader;
            myReader = myCommand.ExecuteReader();
            myReader.Read();
            double x = myReader.GetDouble(1);
            myReader.Close();
            // Close the connection when done with it.
            myConnection.Close();
            return x;
        }
        [WebMethod(Description = "Returneaza cuplul actuator")]
        public double torq_act(int act, int cod)
        {
            String myConnString = "driver={MySQL ODBC 5.1 Driver};server=193.226.19.29;;database=cons_el;uid=student;pwd=psw;";
            String mySelectQuery = "SELECT act_id, torque FROM actuators WHERE act_id=" + System.Convert.ToString(act);
            OdbcConnection myConnection = new OdbcConnection(myConnString);
            OdbcCommand myCommand = new OdbcCommand(mySelectQuery, myConnection);
            myConnection.Open();
            OdbcDataReader myReader;
            myReader = myCommand.ExecuteReader();
            myReader.Read();
            double x = myReader.GetDouble(1);
            myReader.Close();
            // Close the connection when done with it.
            myConnection.Close();
            return x;
        }
        private void InitializeComponent()
        {

}

}
}

Vom crea acum o aplicatie client intr-o pagin web de forma:

<html>
<head>
<title>Scada Web Service </title>
<script type="text/javascript">
	var SERVICE_URL = "http://localhost:51655/Service1.asmx";
	var SOAP_ACTION_BASE = "http://localhost:51655/Service1";
	var bEnabled;
	var oXmlHttp;
	var rq="";
	var rasp="";
	function set_val(){
		window.open("val_tp_m.php","Wtpt","resizable=no,width=400,height=300");
	}
	function set_act(){
		window.open("set_act_m.php","Wac","resizable=no,width=600,height=150");
	}
	function webs(){
		window.open("http://localhost:51655/Service1.asmx","Wac","resizable=no,width=600,height=350");
	}
	function setUIEnabled(bEnabled)
	{
		var oButton = document.getElementById("cmdRequest");
		oButton.disabled = false;
		var oList = document.getElementById("lstMethods");
		oList.disabled = false;
	}

function performOperation()
	{
		var oList = document.getElementById("lstMethods");
		var sMethod = oList.options[oList.selectedIndex].value;
		var sact = document.getElementById("txt_act").value;
		var scod = document.getElementById("txt_cod").value;
		//Clear the message panes
		//document.getElementById("txtRequest").value = "";*******
		//document.getElementById("txtResponse").value = "";******
		document.getElementById("txtResult").value = "";
		performSpecificOperation(sMethod, sact, scod);
	}
	var iCallId = 0;

function getRequest(sMethod, sact, scod)
	{
		var sRequest ="<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"+
		"<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">\n"
		+ "<soap:Body>\n"
		+ "<" + sMethod + " xmlns=\"" + SOAP_ACTION_BASE + "\">\n"
		+ "<act>" + sact + "</act>\n"
		+ "<cod>" + scod + "</cod>\n"
		+ "</" + sMethod + ">\n"
		+ "</soap:Body>\n"
		+ "</soap:Envelope>\n";
		return sRequest;
	}
	function CreateCallObject ()
	{

<center><table border="1" bgcolor="WhiteSmoke" width=400><tr>
	<td colspan=2><center> Serviciul WEB SCADA : Service1 </center></td></tr>
	<tr><td>Operatia</td><td>
	<select id="lstMethods" style="width: 150px">
	<option value="val_tp" selected="selected">Citeste valoare TP</option>
	<option value="stare_act">Citeste stare Actuator</option>
	<option value="poz_act">Citeste pozitie Actuator</option>
	<option value="torq_act">Citeste cuplu Actuator</option>
	</select></td></tr>
	
	<tr><td>Actuator nr:</td>
	<td><input type="text" id="txt_act" size="10"/></td></tr>

<tr><td>Cod:</td>
	<td> <input type="text" id="txt_cod" value="1" size="5"/></td></tr>
	
	<tr><td colspan="2"><center><input type="button" id="cmdRequest" value="Executa operatia" onClick="performOperation()"/></center></td>
	<tr><td>Valoare citita : </td> <td> <input type="text" size="20" id="txtResult"></td></tr>
	</table>
<br><br>
<center><table border="1" bgcolor="WhiteSmoke" width=400><tr>
<td colspan=2><center> XML  </center></td></tr>
<tr><td><center><input type="button" id="rq" value="Cerere-XML" onClick="alert(rq);"></center></td>
<td><center><input type="button" id="rasp" value="Raspuns-XML" onClick="alert(rasp);"></center></td>
</tr></table>
<br><br>
<center><table border="1" bgcolor="WhiteSmoke" width=400><tr>
<td><center>  Web Service1 - operatii oferite   </center></td></tr>
<td><center><input type="button" id="db" value="Web service" onClick="webs()"></center></td>
</tr></table>
</td></tr></table></center>	
</body>
</html>

Dupa lansarea paginii si completarea cu parametrii ceruti, obtinem:

Aplicatia web poate fi lansata local din orice browser ruland cu conditia sa fie pornit serviciul web