feature/Add connector method checkExternalUserExists

obp-api/src/main/scala/code/bankconnectors/Connector.scala

@@ -420,6 +420,13 @@ trait Connector extends MdcLoggable {
     * @return
     */
   def checkExternalUserCredentials(username: String, password: String, callContext: Option[CallContext]): Box[InboundExternalUser] = Failure(setUnimplementedError)
+  
+  /**
+    * This method is for checking external User via connector
+    * @param username
+    * @return
+    */
+  def checkExternalUserExists(username: String, callContext: Option[CallContext]): Box[InboundExternalUser] = Failure(setUnimplementedError)
 
   /**
     * This is a helper method

obp-api/src/main/scala/code/bankconnectors/ConnectorBuilderUtil.scala

@@ -357,7 +357,8 @@ object ConnectorBuilderUtil {
     // The follow methods's parameter or return type are special
     "getCurrentFxRate",
     "getBankAccountOld",    // old method, but v3.0.0 apis use a lot
-    "checkExternalUserCredentials"
+    "checkExternalUserCredentials",
+    "checkExternalUserExists"
   ).distinct
 
   /**

obp-api/src/main/scala/code/model/dataAccess/AuthUser.scala

@@ -121,9 +121,30 @@ class AuthUser extends MegaProtoUser[AuthUser] with MdcLoggable {
     override def displayName = S.?("Username")
     override def dbIndexed_? = true
     override def validations = isEmpty(Helper.i18n("Please.enter.your.username")) _ :: 
-                               valUnique(Helper.i18n("unique.username")) _ :: 
+                               valUnique(Helper.i18n("unique.username")) _ ::
+                               valUniqueExternally(Helper.i18n("unique.username")) _ :: 
                                super.validations
     override val fieldId = Some(Text("txtUsername"))
+
+    /**
+     * Make sure that the field is unique in the CBS
+     */
+    def valUniqueExternally(msg: => String)(value: String): List[FieldError] ={
+      if (APIUtil.getPropsAsBoolValue("connector.user.authentication", false)) {
+        Connector.connector.vend.checkExternalUserExists(value, None).map(_.name) match {
+          case Full(name) =>
+            value match {
+              case username if username == name => List(FieldError(this, Text(msg))) // issue 179
+              case _ => Nil
+            }
+          case _ => List(FieldError(this, Text(msg))) // issue 179
+        }
+      } else {
+        Nil
+      }
+    }
+      
+      
   }
 
   override lazy val password = new MyPasswordNew
@@ -820,7 +841,7 @@ def restoreSomeSessions(): Unit = {
       user.validated_? && !LoginAttempt.userIsLocked(usernameFromGui) &&
         !isObpProvider(user)
     }
-
+    
     def loginAction = {
       if (S.post_?) {
         val usernameFromGui = S.param("username").getOrElse("")

obp-commons/src/main/scala/com/openbankproject/commons/dto/JsonsTransfer.scala

@@ -1277,4 +1277,7 @@ case class InBoundDeleteCustomerAttribute(inboundAdapterCallContext: InboundAdap
 
 case class OutBoundCheckExternalUserCredentials(outboundAdapterCallContext: OutboundAdapterCallContext, username: String, password: String) extends TopicTrait
 case class InBoundCheckExternalUserCredentials(inboundAdapterCallContext: InboundAdapterCallContext, status: Status, data: InboundExternalUser) extends InBoundTrait[InboundExternalUser]
+
+case class OutBoundCheckExternalUserExists(outboundAdapterCallContext: OutboundAdapterCallContext, username: String) extends TopicTrait
+case class InBoundCheckExternalUserExists(inboundAdapterCallContext: InboundAdapterCallContext, status: Status, data: InboundExternalUser) extends InBoundTrait[InboundExternalUser]
 // --------------------- some special connector methods corresponding InBound and OutBound -- end --