Legacy Web services enable applications to interact with one another over the web in a platform-neutral, language independent environment.
Note:
The SOAP 1.1 specification is a W3C note. SOAP Version 1.2 specification is a W3C recommendation.
For information about Simple Object Access Protocol (SOAP) see:
http://www.w3.org/TR/SOAP/
Parent topic: Managing Application Data
In a typical Web services scenario, a business application sends a request to a service at a given URL by using the protocol over HTTP. The service receives the request, processes it, and returns a response. You can incorporate calls with external Web services in applications developed in App Builder.
Web services are typically based on Simple Object Access Protocol (SOAP) or Representational State Transfer (REST) architectures. SOAP is a World Wide Web Consortium (W3C) standard protocol for sending and receiving requests and responses across the Internet. SOAP messages can be sent back and forth between a service provider and a service user in SOAP envelopes. RESTful Web services are resource oriented. The scope of the Web service is found in the URI and the method of the service is described by the HTTP method that is used such as GET, POST, PUT, HEAD, and DELETE.
SOAP offers two primary advantages:
SOAP is based on XML, and therefore easy to use.
SOAP messages are not blocked by firewalls because this protocol uses simple transport protocols, such as HTTP.
Tip:
If you run Oracle Application Express with Oracle Database 11g Release 1 (11.1), you must enable network services to use Web services.
REST offers similar advantages:
REST messages are also not blocked by firewalls because this protocol uses the HTTP protocol.
REST requests do not require the overhead of XML and SOAP envelopes and inputs are typically provided in the URI.
Parent topic: Managing Legacy Web Services
To use Web services in Oracle Application Express, you create a Web service reference using a wizard. Web service references can be based on a Web Services Description Language (WSDL) document, RESTful style, or created manually by supplying information about the service.
See Also:
Parent topic: Managing Legacy Web Services
You manage Web service references on the Web Service References page.
To access the Web Service References page:
Parent topic: Creating Web Service References
If your environment requires a proxy server to access the Internet, you must either specify a proxy server address on the Application Attributes page, or your instance administrator must define an instance proxy, before you can create a Web service reference.
To specify a proxy address for an application:
Parent topic: Creating Web Service References
Secure Sockets Layer (SSL) is an industry standard protocol that uses RSA public key cryptography with symmetric key cryptography to provide authentication, encryption, and data integrity.
If the Web service that you need to interact with is SSL-enabled (that is, https
displays in the URL to the Web service), you must create a wallet and configure Oracle Application Express to use the wallet. A wallet is a password-protected container that stores authentication and signing credentials (including private keys, certificates, and trusted certificates) needed by SSL.
See Also:
"Configuring Wallet Information" in Oracle Application Express Administration Guide
Parent topic: Managing Legacy Web Services
You can create Web service reference based on a Web Services Description Language (WSDL) document.
Parent topic: Managing Legacy Web Services
Before you create a Web service reference based on a WSDL, you must decide how to locate the WSDL. You locate a WSDL by entering the URL to the WSDL document.
You then run a wizard which analyzes the WSDL and collects all the necessary information to create a valid SOAP message, including:
The URL used to post the SOAP request over HTTP(S)
A Universal Resource Identifier (URI) identifying the SOAP HTTP request
Operations of the Web Service
Input parameters for each operation
Output parameters for each operation
Parent topic: Creating Web Service References Based on a WSDL
To create a Web service by specifying a URL to a specific WSDL document:
Parent topic: Creating Web Service References Based on a WSDL
After you have created a Web service reference, you can test it on the Test Web Service Reference page.
To test a Web service reference:
See Also:
Parent topic: Creating Web Service References Based on a WSDL
You can create a Web service reference manually.
Parent topic: Managing Legacy Web Services
When you create a Web service reference manually, you supply the necessary information to create a valid SOAP request, including:
The URL used to post the SOAP request over HTTP(S)
A Universal Resource Identifier (URI) identifying the SOAP HTTP request
The SOAP envelope for the request, including any item substitutions
Optionally the name of a collection to store the response from the Web service
Parent topic: Creating Web Service References Manually
Creating a Web service reference manually, adds it to Web Service References Repository.
To create a Web service reference manually:
See Also:
Parent topic: Creating Web Service References Manually
After you have created a Web service reference, you can test it on the Test Web Service Reference page.
To test a Web service reference:
See Also:
Parent topic: Creating Web Service References Manually
You can create a Representational State Transfer (REST) or RESTful web service.
Parent topic: Managing Legacy Web Services
RESTful Web services are resource oriented. The scope of the Web service is found in the URI and the method of the service is described by the HTTP method that is used such as GET, POST, PUT, HEAD, and DELETE. When you create a RESTful Web service reference, you supply the necessary information about the structure of the request and response including:
A Universal Resource Identifier (URI) identifying the RESTful request
The HTTP method identifying the method of the Web service
HTTP Headers, if required, that are part of the request
The type of input expected by the Web service
The format of the response and how to identify the response parameters
Parent topic: Creating RESTful Web Service References
To create a RESTful Web service reference:
The Create Web Service Reference Success page appears. The Web service reference is added to the Web Service References Repository.
See Also:
"Creating a Proxy Server for an Instance" in Oracle Application Express Administration Guide
Parent topic: Creating RESTful Web Service References
After you have created a Web service reference, you can test it on the Test Web Service Reference page.
To test a Web service reference:
See Also:
Parent topic: Creating RESTful Web Service References
Web service references are stored in the Web Service Reference Repository.
To access the Web Service References Repository:
Parent topic: Managing Legacy Web Services
This section describes how to create an input form and report on a Web service.
Parent topic: Managing Legacy Web Services
The Create Form and Report on Web Service Wizard creates an input form, a submit button, and a report for displaying results. You can execute this wizard directly after creating the Web service reference from a WSDL or a RESTful style Web service, or by adding a page.
Use this wizard when you expect a nonscalar result from the Web service. The Amazon Product API Web service is a good example. This Web service returns many results based on the search criteria entered in an input form.
Parent topic: Creating an Input Form and Report on a Web Service
This section describes how to create a form on a Web service.
Parent topic: Managing Legacy Web Services
The Create Form on Web Service Wizard creates a form and a submit button. You can execute this wizard after creating the Web service reference from a WSDL or on a RESTful style Web service, or by running the Create Page Wizard.
Use this wizard when you expect a scalar result from the Web service. A Web service that looks up a stock price is a good example because the input is a stock symbol and the output is the scalar value price.
Parent topic: Creating a Form on a Web Service
To create a report in which to display Web Service request results:
Parent topic: Managing Legacy Web Services
You can invoke a Web service as a process on the page. The process is created for you if you run one of the Create Form wizards for Web services. Running the process submits the request to the service provider. You can then display the request results in the report.
Parent topic: Managing Legacy Web Services
After you create a process of type Web service on a Web service reference created from a WSDL or a RESTful style Web reference, you can change the attributes of the input and output parameters to the service.
To edit a Web service process:
See Also:
Parent topic: How to Invoke a Web Service as a Process
The Web Services History displays changes to Web service references for the current application by application ID, Web service references name, developer, and date.
To view a history of Web service reference changes:
Note:
The History button only appears on the Web Service Reference page if at least one reference exists.
Parent topic: Managing Legacy Web Services