Introduction to SALT Programming

This chapter includes the following topics:

•	SALT Web Services Programming

SALT Web Services Programming

SALT provides bi-directional connectivity between Oracle Tuxedo applications and Web service applications. Existing Oracle Tuxedo services can be easily exposed as Web Services without requiring additional programming tasks. SALT generates a WSDL file that describes the Oracle Tuxedo Web service contract so that any standard Web service client toolkit can be used to access Oracle Tuxedo services.

Web service applications (described using a WSDL document), can be imported as if they are standard Oracle Tuxedo services and invoked using Oracle Tuxedo ATMIs from various Oracle Tuxedo applications (for example, Oracle Tuxedo ATMI clients, ATMI servers, Jolt clients, COBOL clients, and .NET wrapper clients).

•	SALT Proxy Service

•	SALT Message Conversion

•	SALT Programming Tasks Quick Index

•	REpresentational State Transfer (REST) Message Conversion

SALT Proxy Service

SALT proxy services are Oracle Tuxedo service entries advertised by the GWWS SALT Gateway. The proxy services are converted from the Web service application WSDL file. Each WSDL file wsdl:operation object is mapped as one SALT proxy service.

The SALT proxy service is defined using the Service Metadata Repository service definition syntax. These service definitions must be loaded into the Service Metadata Repository. To invoke proxy services from an Oracle Tuxedo application, you must refer to the Oracle Tuxedo Service Metadata Repository to get the service contract description.

For more information, see ?$paratext>?.

SALT Message Conversion

To support Oracle Tuxedo application and Web service application integration, the SALT gateway converts SOAP messages into Oracle Tuxedo typed buffers, and Oracle Tuxedo typed buffers into SOAP messages. The message conversion between SOAP messages and Oracle Tuxedo typed buffers is subject to a set of SALT pre-defined basic data type mapping rules.

When exposing Oracle Tuxedo services as Web services, a set of Tuxedo-to-XML data type mapping rules are defined. The message conversion process that conforms to Tuxedo-to-XML data type mapping rules is called “Inbound Message Conversion”.

When importing external Web services as SALT proxy services, a set of XML-to-Tuxedo data type mapping rules are defined. The message conversion process that conforms to XML-to-Tuxedo data type mapping rules is called “Outbound Message Conversion”.

For more information, see ?$paratext>?.

SALT Programming Tasks Quick Index

Table 1‑1 lists a quick index of SALT programming tasks. You can locate programming tasks first, and then click on the corresponding link for detailed description.

 

Table 1‑1 SALT Programming Tasks Quick Index

	Tasks	Refer to ...
Invoking Oracle Tuxedo services (inbound) through SALT	Develop Web service client programs for Oracle Tuxedo services invocation.	SALT Web Service Client Programming Tips.
	Understand inbound message conversion and data type mapping rules.	Understanding SALT Message Conversion. Tuxedo-to-XML Data Type Mapping for Oracle Tuxedo Services.
	Develop inbound message conversion plug-in.	Programming Message Conversion Plug-ins.
Invoking external Web services (outbound) through SALT	Understand the general outbound service programming concepts.	Oracle Tuxedo ATMI Programming for Web Services.
	Understand outbound message conversion and data type mapping rules.	Understanding SALT Message Conversion. XML-to-Tuxedo Data Type Mapping for External Web Services.
	Develop outbound message conversion plug-in.	Programming Message Conversion Plug-ins.
	Develop your own plug-in to map Oracle Tuxedo user name with user name for outbound HTTP basic authentication.	Programming Outbound Authentication Plug-Ins.

REpresentational State Transfer (REST) Message Conversion

The basic REST design principle establishes a one-to-one mapping between create, read, update, and delete (CRUD) operations and HTTP methods.

The REST principles around are as follows:

•	Use HTTP methods explicitly.

•	Be stateless.

•	Expose directory structure-like URIs.

•	Transfer XML, JavaScript Object Notation (JSON), or both.

For more information, see Data Type Mapping and Message conversion, and SALT Configuration Tool in the SALT Configuration Guide.