@RestResource(urlMapping='/v1/getreceiptInfo/*')
global with sharing class REST_GetDocInfo {

@HttpPost
global static postJson doPOST(Details customer) {

RestRequest req = RestContext.request;
RestResponse res = RestContext.response;
postJson response = new postJson();

validateInput(customer, response);

if(response.status != 'Failure') {
if(isAuthorizedUser(customer.Id)) {
    response.rawRecord.addAll(getResponseModelList(customer, response));
    if(response.status != 'Failure') {
    response.status = 'Success';
    response.errorCode.add('000');
    response.message.add('Operation successful');
    }
} else {
    response.status = 'Failure';
    response.errorCode.add('003');
    response.message.add('You are not allowed to view the information');
    }
}

return response;
 }

//this class has the response data fields
global class postJson {
public List<ResponseModel> rawRecord;
public String status;
public String [] message;
public String [] errorCode;
public Boolean leadcustomer;

public postJson(){
rawRecord = new List<ResponseModel>();
message = new List<String>();
errorCode = new List<String>();
}
}

//this is custom response data model
global class ResponseModel {
public String receiptId;
public String customerName;
public String customerNumber;
public String receiptType;
public String valReceipt ;
public String receiptName;
public String leadcustomer;
public Decimal isReceiptListAvailable;
public String recOrderNumber;


public ResponseModel(String receiptId, String customerName, String
customerNumber, String receiptType,
String valReceipt , String receiptName, String leadcustomer, Decimal
isReceiptListAvailable, String recOrderNumber){
this.receiptId = receiptId;
this.customerName = customerName;
this.customerNumber = customerNumber;
this.receiptType = receiptType;
this.valReceipt  = valReceipt ;
this.receiptName = receiptName;
this.leadcustomer = leadcustomer;
this.isReceiptListAvailable = isReceiptListAvailable;
this.recOrderNumber = recOrderNumber;
}

    public ResponseModel(){}
 }

 //call to server and return info as string
 private static String getInfo(String receipt , postJson response){
    String valReceipt ;

    JSONToApex jsonRequest = new JSONToApex();
    jsonRequest.receiptUrl = receipt ;


    Http http = new Http();
    HttpRequest req = new HttpRequest();
    Custom_Settings__c settings = Custom_Settings__c.getValues('App');
    String reqBody= JSON.serialize(jsonRequest);
    req.setEndPoint(settings.RECEIPT_URL__c);
    req.setMethod('POST');
    req.setHeader('content-type','application/json');
    req.setHeader('x-api-key', settings.INFO_API_header_key__c);
    req.setBody(reqBody);

    try {
    HTTPResponse res = http.send(req);
    valReceipt  = res.getBody();
    } catch(Exception e) {
    valReceipt  = 'blank';
    response.status = 'Failure';
    response.errorCode.add('007');
    response.message.add('Not able to get receipt. ' + e);
    }
    return valReceipt ;
    }
 }