How Web Services Query the Virtual Dataport Server

When a Web service receives a request, it executes a SQL statement (SELECT, INSERT, UPDATE, etc.). To do this, it behaves as any other Virtual DataPort client: it connects to Virtual DataPort with certain credentials and executes a query equivalent to the request received. This query may fail if the user associated to these credentials is not granted the appropriate privileges.

SOAP Web services: when you deploy a view as a SOAP Web service, by default the service has four operations:

  • getXXX: when invoked, the services executes a SELECT statement.
  • insertXXX: when invoked, the service executes an INSERT statement.
  • updateXXX: when invoked, the service executes an UPDATE statement.
  • deleteXXX: when invoked, the service executes a DELETE statement.

You can delete any of these operations if you do not want any client to perform them.

REST Web services: as opposed to SOAP Web services, REST Web services publish views and not operations over view. Therefore, when you publish a view, you are allowing external clients to perform the following operations on them:

  • SELECT statements: when the service receives GET requests.
  • INSERT statements: when the service receives POST requests
  • UPDATE statements: when the service receives PUT requests.
  • DELETE statements: when the services receives DELETE requests.

The credentials used by the Web service to connect to Virtual DataPort depend on the authentication method selected. They fall into two categories (see the last two columns of the table Authentication methods support by SOAP and REST Web services):

  1. “Uses the credentials of the Web service”: during the deployment of the Web service, the administrator selects a user, whose credentials will be used by the Web service to execute all the queries. In order for these queries to succeed, the selected user needs to have the right privileges to perform these queries.

    The section Web Service Container Status Table will explain how the administrator selects a user for the service.

  2. “Uses the Credentials of the Web Service’s Clients”: in order for these queries to succeed, the users that invoke the Web service need to have the right privileges to perform the queries that the service will execute on their behalf.

    For example, if the user bruce invokes an operation of the service, the service connects to Virtual DataPort with the credentials provided by bruce in his request. The query may or may not be executed depending on the privileges assigned to bruce. If later, the user scott invokes the same operation of the service, the service will connect to Virtual DataPort with the credentials provided by scott.

A Web service is a JEE web application, which contains a web.xml file. When you deploy a Web service or generate its WAR, and the service uses one of the authentication methods of the column “Uses the credentials of the Web service”, the user name and the encrypted password of the user selected during the deployment of the Web service are stored in the web.xml file. At runtime, the service uses these credentials to connect to Virtual DataPort and execute queries.

For the services that use one of these types of authentication, if you change the password of the user selected to deploy the Web service, you have to redeploy the Web service. Otherwise, all the invocations to this service will fail because the password send by the service will not be correct.