IBM BPM, V8.0.1, All platforms > Authoring services in Integration Designer > Services and service-related functions > Access external services with HTTP

HTTP binding overview

The HTTP binding is described, which includes a description of its behavior at run time. It is compared with the web services binding.

The following sections provide an overview of the HTTP binding:

• What is the HTTP binding?
• Why has the HTTP binding grown in importance?
• Comparing the HTTP binding to the web services binding
• HTTP binding at run time

What is the HTTP binding?

Hypertext Transfer Protocol (HTTP) is a widely-used protocol for transferring information on the web. Though originally designed to publish and retrieve HTML pages, it has now become a standard request/response protocol between clients and server as defined by the HTTP protocol published by the World Wide Web consortium (W3C). Today many standard HTTP methods such as GET, POST, PUT, DELETE and so on are a part of this widely-used protocol.

When working with an external application using the HTTP protocol, an HTTP binding is necessary. The HTTP binding handles the transformation of data passed in as a message in a native format to a business object in a Service Component Architecture-based (SCA) application. The HTTP binding also can transform data passed out as a business object to the native format expected by the external application. for an incoming messaging.

Why has the HTTP binding grown in importance?

As the SOAP/HTTP (referred to as SOAP over HTTP) web services binding gained momentum, businesses began seeing the potential of the HTTP protocol for business needs and application integration. SOAP/HTTP web services became the most common means for business-to-business transactions over the Internet. However, adding more robustness to SOAP/HTTP to suit business needs such as the Web Service Description Language (WSDL), supporting the XML Schema specification and adding Quality of Service (QOS) led to interoperability problems among vendors and additional complexity of the initial specification. It also led to the need for more skills to use SOAP/HTTP.

Users realized that there were many situations that did not need the extra functions added to SOAP/HTTP but wanted to take advantage of the ubiquitous web infrastructure to send or receive relatively simple information using the HTTP protocol. They started using HTTP-based services to send and receive data in a set of different loosely-defined formats.

The HTTP binding is suited for this type of user as it combines the ease-of-use and simplicity of the original HTTP protocol with integration to large, scalable and secure SOA applications. Conversely, the HTTP binding allows SOA applications to take advantage of the many existing HTTP-based applications, bringing them into the SOA framework. The binding also provides access from an SOA application to services conforming to the Web 2.0 specification. In summary, the HTTP binding allows applications developed for IBM Process Server and WebSphere Enterprise Service Bus to communicate with and mediate between the many web services using HTTP and other protocols, which will make this binding only more important over time.

Comparing the HTTP binding to the web services binding

Another binding, the web services binding, also can be used with applications using the HTTP protocol. The difference between the web services binding and the HTTP binding is as follows:

• The web services binding only supports the SOAP (and JMS) protocols.

• The web services binding assumes that it is working with web services-based applications and so exposes the same model. In contrast, the HTTP binding assumes that it is working with native HTTP applications and exposes a model more familiar to this audience.

• Therefore, the web services binding provides first class support within the SCA architecture for web services applications communicating with the HTTP protocol and other protocols; whereas the HTTP binding allows IBM Process Server and WebSphere Enterprise Service Bus to mediate between, and communicate with, any HTTP application thus bringing any HTTP application into the Service Oriented Architecture framework.

HTTP binding at run time

In IBM Integration Designer, the HTTP binding can be used on imports and exports.

An import with an HTTP binding at run time sends a request with or without data in the body of the message from the SCA application to the external web service; that is, the request is made from the SCA application to the external web service. Optionally, the import with the HTTP binding may receive data back from the web application in a response to the request.

With an export, the request is made by a client application to a web service. The web service is a web application running on the server. The export is implemented in that web application as a servlet so the client sends its request to a URL address. The servlet passes the request to the SCA application at run time. Optionally, the export may send data to the client application in response to the request.

The interaction style of the HTTP import or export binding is synchronous.

Hypertext Transfer Protocol (HTTP) binding

Related concepts:
Uses of the HTTP binding
HTTP data bindings

Related tasks:
Generate an HTTP import binding
Generate an HTTP export binding

Related reference:
Example of the HTTP binding
Limitations of the HTTP binding