Product Overview

BEA SALT Overview

The following sections provide an overview to the BEA SALT product:

Understanding BEA SALT

BEA SALT (Service Architecture Leveraging Tuxedo) runs on top of Tuxedo. BEA SALT allows external Web service applications to invoke native Tuxedo services (inbound), and conversely, allows Tuxedo applications to invoke external Web services (outbound).

BEA SALT complies with standard Web service specifications (SOAP 1.1, SOAP 1.2, and WSDL 1.1), allowing BEA SALT to interoperate with other Web service products and development toolkits. Tuxedo applications can easily integrate with Web Services applications using BEA SALT.

What Are Web Services?

Web services are a set of functions packaged into a single entity made available to other systems on a network. They can be shared and used as a component of distributed Web-based applications. The network can be a corporate intranet or the Internet. Other systems, such as customer relationship management (CRM) systems, order-processing systems, and other existing back-end applications, can call these functions to request data or perform an operation. Because Web services rely on standard technologies which most systems provide, they are an excellent means for connecting distributed systems together.

The software industry has evolved toward loosely coupled service-oriented applications that interact dynamically over the Web. The applications break down the larger software system into smaller modular components, or shared services. These services can reside on different computers and can be implemented by vastly different technologies. They are packaged and made accessible using standard Web protocols, such as XML and HTTP.

Web services share the following properties that make them easily accessible from heterogeneous environments:

Why Use BEA SALT?

BEA SALT is a native Tuxedo Web service integration solution. It reduces Tuxedo/Web Service integration costs and decreases conversion processes that may exist with other solutions for accessing Tuxedo services. It enables seamless connectivity between Tuxedo applications and external Web service applications.

BEA SALT allows existing Tuxedo services (inbound) to be easily exposed as Web services without additional programming tasks. It also allows you to create native Tuxedo applications that access external Web services (outbound) transparently.

Major Web services benefits include:

Figure 1 illustrates how the BEA SALT gateway is used in the Tuxedo framework.

A Brief History of BEA SALT

BEA SALT is the latest add-on to the Tuxedo product family. Developed in 2006, BEA SALT is designed to provide a seamless Tuxedo solution of integrating Tuxedo applications and standard Web services application.

Release 1.1

Release 1.1 is the initial BEA SALT release. Made available in 2006, SALT 1.1 introduced the following major features:

Release 2.0

The current BEA SALT 2.0 release incorporates significant enhancements based on SALT 1.1 release. SALT 2.0 introduces the following major features:

What’s New in SALT 2.0?

Outbound Support

The BEA SALT 2.0 release provides external Web service access capability from Tuxedo applications. You can easily extend Tuxedo integration capability without having an extensive understanding of Web services.

New WS-* Specification Support

Customer Enhancements

BEA SALT Feature Summary

BEA SALT consists of the following features:

Configuration-Driven Deployment

BEA SALT supports a configuration-driven deployment and management style. The BEA SALT deployment file is a single root XML file. The BEA SALT deployment file allows you to specify a list of GWWS processes and how they work for Web services.

Leveraging the Tuxedo Service Metadata Repository

Service contract information for all listed Tuxedo services must be made accessible via the Tuxedo Service Metadata Repository service provided by the local Tuxedo domain. BEA SALT leverages the Tuxedo Service Metadata Repository for mapping Tuxedo services and Web services.

Data Type Mapping and Message Conversion

BEA SALT provides a complete set of mapping rules for use between Tuxedo buffer/field types and XML primitive data types. The GWWS server provides automatic message transformation from Tuxedo buffers to SOAP messages (and vice versa), based on these mapping rules. SALT message conversion capability tremendously reduces programming effort when integrating Tuxedo applications with Web service applications. If BEA SALT pre-defined data type mapping rules are not sufficient, you can also develop customized conversion routines for any service to replace the default message conversion logic.

Asynchronous and Reliable Messaging

BEA SALT provides an asynchronous communication model that complies with the Web Service Addressing (WS-Addressing 1.0, Aug., 2004) specification. BEA SALT also supports reliable message delivery between Web service clients and Tuxedo servers conforming to the Web Service ReliableMessaging (WS-ReliableMessaging 1.0, Feb., 2005) specification.

The Web Service ReliableMessaging specification allows Web service instances to reliably communicate with the GWWS server in case of network failure or other scenarios. In particular, this feature provides for an interoperable protocol in which a message sent from a source endpoint to a destination endpoint is guaranteed with a defined delivery policy. The WS-Policy specification is supported to define the delivery policy for WS-ReliableMessaging.

Security

BEA SALT uses the Tuxedo security framework for inbound service authentication. Security is supported on three levels:

Web Service Security Support

BEA SALT supports Web Service Security for inbound service authentications. User name tokens and X.509 tokens are supported to perform authentication based on the Tuxedo security framework.

HTTP Basic Authentication

BEA SALT supports HTTP Basic Authentication for both inbound and outbound services. For inbound services, the GWWS server supports Tuxedo user profiles passed from the Web service client via HTTP basic authentication protocol.

For outbound services, the GWWS server provides programming interfaces that allows customers to map Tuxedo user profiles to user profiles needed for outbound HTTP endpoints.

SSL Link-Level Security

The GWWS server handles both HTTP and HTTP/S requests. Certificate information for setting up an SSL connection can be specified in the BEA SALT Deployment file.

BEA SALT Components

BEA SALT consists of the following major components:

BEA SALT Gateway (GWWS)

The BEA SALT provided Tuxedo system server (GWWS), connects with other Web service applications via SOAP over HTTP/S protocol. The GWWS server acts as a Tuxedo gateway process and is managed in the same manner as general Tuxedo system servers. Each GWWS server has bi-directional (inbound/outbound) capability. The GWWS server:

You can have multiple GWWS instances in one Tuxedo domain. The same functionality for multiple GWWS instances is provided by specifying the same BEA SALT configuration to improve throughput and failover protection. You can also group multiple GWWS instances in different configuration files for different purposes.

When the GWWS server boots, it loads the specified SALT configuration file and Tuxedo service contract information from the Tuxedo Service Metadata Repository.

The GWWS server also acts as a simple HTTP Web server for WSDL document and XML Schema file download.

WSDL Assistant Utilities

The Web Services Description Language (WSDL) is an XML-based specification that describes a Web service. A WSDL document describes Web service operations, input and output parameters, and how a client application connects to the Web service. BEA SALT provides two utilities (tmwsdlgen and wsdlcvt) to map Tuxedo applications and Web Service WSDL descriptions.

WSDL Generator from Tuxedo Definitions

When using BEA SALT to publish Tuxedo services as Web services, you do not need to compose a WSDL document manually; it is automatically generated as part of the SALT Web service development process. The generated WSDL document can be integrated using Web service development tools, or can be published to a UDDI server.

There are two ways to obtain a WSDL document:

WSDL Convertor to Tuxedo Definitions

To support external Web Service applications, external WSDL documents need to be converted. The BEA SALT conversion utility, wsdlcvt, converts external WSDL documents to Tuxedo specific definition files (SALT Web Service Definition file, Tuxedo Service Metadata Repository Definition file and FML32 Field Table Definition file).

The SALT Web Service Definition file can be imported into a SALT Deployment file and utilized by a particular GWWS server. The Tuxedo Service Metadata Repository Definition file and FML32 Field Table Definition file provide service interface descriptions for Tuxedo client programming.

BEA SALT Use Cases

The following sections describe the most common BEA SALT Web services use cases:

Use Case 1: Exposing Native Tuxedo Services as Web Services

Native Tuxedo services can be exposed as Web services using standard Web service SOAP protocol. The GWWS server accepts SOAP requests through HTTP/S and then converts them into Tuxedo ATMI calls. SALT generates a WSDL document that describes the open standard Web service interfaces for Tuxedo services.The Tuxedo Service Metadata Repository is used to define Tuxedo service contract information. This is an “inbound” use case.

Figure 2 illustrates a generic inbound Web service call.

Use Case 2: Invoking Web Services from Tuxedo Applications

Web service applications can be imported into a Tuxedo domain, advertised as Tuxedo services through the GWWS server, and invoked from Tuxedo applications. SALT converts and maps each wsdl:operation as a particular Tuxedo service. The GWWS server advertises the mapped services (called SALT proxy services), and accepts Tuxedo ATMI requests from Tuxedo applications.

The Tuxedo Service Metadata Repository is used to store converted Tuxedo service contract information and helps Tuxedo programmers understand what type of Tuxedo buffers are expected for the imported SALT proxy services. This is an “outbound” use case.

Figure 3 illustrates a generic outbound Web service call.

Use Case 3: Connecting Tuxedo Domains Using SOAP Protocol

BEA SALT also allows you to connect two different Tuxedo domains using GWWS servers as an alternative to using /T domain. The GWWS server in the calling domain works in an outbound direction, the GWWS server in the receiving domain works in an inbound direction.

The receiving Tuxedo domain must propagate the Tuxedo service definition to the calling Tuxedo domain. This means that the calling domain Tuxedo Service Metadata Repository must contain the Tuxedo service definition file that runs in the receiving domain.

The WSDL document is not required. BEA SALT provides simple configurations to allow two GWWS servers to work together for domain connectivity using SOAP protocol without needing to exchange WSDL documents.

Figure 4 illustrates how to use BEA SALT to connect two domains.

Two GWWS servers should not be used to create connections within the same Tuxedo domain, see Figure 5. Also, a single GWWS server cannot connect to itself, see Figure 6.

In either scenario, the GWWS server advertises the same Tuxedo services which are already advertised by other application servers. This might result in dead-loop service dispatching.

Configuring Web Services with BEA SALT

The following steps are used typically when yo configure Web services using BEA SALT:

Invoking Tuxedo Services Using Web Service Client Toolkits

Invoking Web Services Using Tuxedo Programming Interfaces

BEA SALT Supported Standards

BEA SALT supports the following Web service standards:

What Next?

After becoming familiar with the BEA SALT Product Overview, refer to the following topics for installing, configuring, and running Web services using the SALT product: