Web Service

Write trigger


    if(Trigger.isAfter)
    {
            If(Trigger.IsInsert)
            {
             
                CaseHandlerCls.sendSMSInsert(trigger.new);
             
            }
            If(Trigger.IsUpdate)
            {
             
                CaseHandlerCls.sendSMS(trigger.new,trigger.oldmap,trigger.newmap);
                system.debug('this is first case');
             
            }
}
======================================
Helper class:

**********************************************************************/
public class CaseHandlerCls
{
    public static void sendSMSInsert(List<Case> clist)
    {
        system.debug(''+clist);
        for(case c:clist)  // for each loop to iterate over the list of the case object
        {
            if(c.Case_Type__c!='Child Case')
            {
                String mobile=c.ContactMobile;// asssigning the phone number enter by user to a string variable mobile.
                system.debug(mobile);  // display the value of phone.
                String caseNo =c.CaseNumber;  // asssigning the case number of the user to a string variable caseNo.
                Boolean newCaseRecord = c.Status.equals('Open'); // assigning the value of the status to the boolean variable newCaseRecord
                system.debug(newCaseRecord);   // display the value of the status enter by the user while creating a new Case.
                if(newCaseRecord)  // condition check if the value of the status field is true than it will call the webservice class
                {
                    webpostservice.sendSMSInsertNewMethod('Open',mobile,caseNo);
                    // calling the web service class with three parameters, one for status,second for the phone numbe and third for case number.
                }
            }
        }
    }
 
    public static void sendSMS(List<Case> caselist ,map<Id,Case> oldmap,map<Id,case> newmap)
    {
        for (case case1 : caselist) // for each loop to iterate over the list of the case object
        {
            if(case1.Case_Type__c!='Child Case')
            {
                // Access the "old" record by its ID
                case oldcase = oldmap.get(case1.Id);
                Boolean oldCaseNew = oldcase.Status.equals('Open');
                Boolean oldCaseNew1 = oldcase.Status.equals('On Hold');
                Boolean oldCaseNew2 = oldcase.Status.equals('Escalated');
                Boolean oldCaseNew3 = oldcase.Status.equals('Critical');
                Boolean oldCaseNew4 = oldcase.Status.equals('Working');
                Boolean oldCaseNew5 = oldcase.Status.equals('Assigned to FT');
                Boolean oldCaseNew6 = oldcase.Status.equals('Assigned to SPOC');
                Boolean oldCaseNew7 = oldcase.Status.equals('Satisfied and Closed');
                Boolean oldCaseNew8 = oldcase.Status.equals('FTR and Closed');
             
                // Access the new value of the status field
                case newcase = newmap.get(case1.Id);
                Boolean newCaseNew  = newcase.Status.equals('Open');
                Boolean newCaseNew1 = newcase.Status.equals('On Hold');
                Boolean newCaseNew2 = newcase.Status.equals('Escalated');
                Boolean newCaseNew3 = newcase.Status.equals('Critical');
                Boolean newCaseNew4 = newcase.Status.equals('Working');
                Boolean newCaseNew5 = newcase.Status.equals('Assigned to FT');
                Boolean newCaseNew6 = newcase.Status.equals('Assigned to SPOC');
                Boolean newCaseNew7 = newcase.Status.equals('Satisfied and Closed');
                Boolean newCaseNew8 = newcase.Status.equals('FTR and Closed');

                String mobile=newcase.ContactMobile; // access the new value of the phone and store in the variable mobile
                String caseNo1 =newcase.CaseNumber;
                if (oldCaseNew && newCaseNew7)   // condition check for the old value as New and new Value as closed
                {
                    webpostservice.sendSMSUpdateClosedMethod('Satisfied and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew1 && newCaseNew7)     // condition check for the old value as On Hold and new Value as closed
                {
                    webpostservice.sendSMSUpdateClosedMethod('Satisfied and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew2 && newCaseNew7)     // condition check for the old value as Escalated and new Value as closed
                {
                    webpostservice.sendSMSUpdateClosedMethod('Satisfied and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew3 && newCaseNew7)     // condition check for the old value as Critical and new Value as closed
                {
                    webpostservice.sendSMSUpdateClosedMethod('Satisfied and Closed',mobile,caseNo1);
                    // call the webservice class
           
                if(oldcaseNew4 && newCaseNew7)     // condition check for the old value as Working and new Value as closed
                {
                    webpostservice.sendSMSUpdateClosedMethod('Satisfied and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew5 && newCaseNew7)     // condition check for the old value as Assigned to FT and new Value as closed
                {
                    webpostservice.sendSMSUpdateClosedMethod('Satisfied and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew6 && newCaseNew7)     // condition check for the old value as Assigned to SPOC and new Value as closed
                {
                    webpostservice.sendSMSUpdateClosedMethod('Satisfied and Closed',mobile,caseNo1);
                    // call the webservice class
                }       
                if(oldCaseNew8 && newCaseNew7)
                {
                    webpostservice.sendSMSUpdateClosedMethod('Satisfied and Closed',mobile,caseNo1);
                }
             
             
                if (oldCaseNew && newCaseNew8)   // condition check for the old value as New and new Value as FTR and Closed
                {
                    webpostservice.sendSMSUpdateClosedMethod1('FTR and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew1 && newCaseNew8)     // condition check for the old value as On Hold and new Value as FTR and Closed
                {
                    webpostservice.sendSMSUpdateClosedMethod1('FTR and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew2 && newCaseNew8)     // condition check for the old value as Escalated and new Value as FTR and Closed
                {
                    webpostservice.sendSMSUpdateClosedMethod1('FTR and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew3 && newCaseNew8)     // condition check for the old value as Critical and new Value asFTR and Closed
                {
                    webpostservice.sendSMSUpdateClosedMethod1('FTR and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew4 && newCaseNew8)     // condition check for the old value as Working and new Value asFTR and Closed
                {
                    webpostservice.sendSMSUpdateClosedMethod1('FTR and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew5 && newCaseNew8)     // condition check for the old value as Assigned to FT and new Value as FTR and Closed
                {
                    webpostservice.sendSMSUpdateClosedMethod1('FTR and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew6 && newCaseNew8)     // condition check for the old value as Assigned to SPOC and new Value as FTR and Closed
                {
                    webpostservice.sendSMSUpdateClosedMethod1('FTR and Closed',mobile,caseNo1);
                    // call the webservice class
                }
                if(oldcaseNew7 && newCaseNew8)     // condition check for the old value as Satisfied and Closed and new Value as FTR and Closed
                {
                    webpostservice.sendSMSUpdateClosedMethod1('FTR and Closed',mobile,caseNo1);
                    // call the webservice class
                }
             
            }
        }
    }

    }

}

=====================================================

Helper WebService:

public class webpostservice
{
 
    @future (callout=true)
    public static void sendSMSInsertNewMethod(String status3 ,String Mob3,String caseNo)
    {
     
        system.debug(status3+''+Mob3+''+caseNo);
        HttpRequest req3 = new HttpRequest();  // declare variable for request.
        HttpResponse res3 = new HttpResponse(); // declare variable to store the response.
        Http http3 = new Http();                 // for authentication purpose 
        String message3 = 'default';              // default message stored in the variable message3.
        if(status3 == 'Open')
        { // condition check, if the status of the lead is New
            list<Case__mdt> l=[SELECT MasterLabel,sms__c FROM Case__mdt];
            system.debug('The metadata list is:'+l);
            List<Case__mdt> metalist=[select id,Check_SMS__c,sms__c,MasterLabel from Case__mdt];
            for(Case__mdt cm:metalist)
            {
                if(cm.MasterLabel=='Create Record' && cm.Check_SMS__c==True)
                {
                    message3=cm.sms__c+' '+caseNo; 
                }
                system.debug(message3);
            }
        }
     
        String msg3 = EncodingUtil.urlEncode(message3, 'UTF-8'); // encoding the message
        req3.setEndpoint('http://www.teleshoppe.com/serv/BulkPush/?user==12378&msisdn='+Mob3+'&sender=IND&type=text&message='+msg3);
        // req3.setEndpoint('http://bulkpush.mytoday.com/BulkSms/SingleMsgApi?feedid=378&username=11111&password=1111djwgt&To='+Mob3+'&Text='+msg3);
        // set the end point to hit the bulk sms api with few parameters.
        system.debug(msg3); // display the message.
        req3.setMethod('POST');  // POST requests are used to send data to the API sever to create or udpate a resource.
        req3.setTimeout(20000);   // set the time out.
        req3.setCompressed(true);  // If true , the request body is compressed,
     
        try
        {
            res3 = http3.send(req3);       // sending request to the bulk sms through variable req3
            System.debug('Res : '+res3.toString());  // display the response.
            System.debug('Req : '+req3.toString());  // display the request.
        }
        catch(Exception e)
        {
            System.debug('Callout error: '+ e);       // display the error
            System.debug(req3.toString());
        }

    }