OpenSession Method

This method verifies the access credentials. If the credentials are valid a new API session is opened, otherwise an error code is returned.
The method must be invoked prior to any other method within the service. A session will expire after 20 minutes of inactivity, it is strongly recommended to close session explicitly by using the CloseSession method.
Method Signature:
OpenAPISessionResponse OpenAPISession(string accountId, string username, string password);
Parameters:

Parameter Name	Description
accountId	Id of the account
username	Username of the user account being authenticated
password	Password of the user account being authenticated

The method returns an object of type "OpenAPISessionResponse" that contains the following fields:

Field Name	Type	Description
ErrorCode	Integer	Error code describing the outcome of the operation (0 = Success)
Description	String	Message describing the error condition if applicable
SessionId	String	ID of the API session that was created (if successful, Empty otherwise).