Transcript SOAP Messages

SOAP Web Services
Tim Carver
MRC HGMP-RC
Hinxton
Cambridge, UK.
Simple Object Access Protocol (SOAP)
• protocol for invoking methods on servers, services, components
and objects
• uses XML messaging to exchange info via XML documents
• transport via HTTP (circumventing firewalls)
• provides mechanism for distributing objects over the Web
• make method calls upon classes and objects that exist on a
remote server, without needing to know which language the
objects are written in
Application
e.g. Jemboss Client
on Win, MacOSX, Linux
written in Java
Application
SOAP
XML messaging
e.g. Jemboss Server
on Unix
written in Java/C
SOAP Messages
Header
-
optional
routing & delivery settings
authentication/authorisation information
transaction context
Body
-
required
data or message to be processed
can contain anything that can be expressed in XML
containing as many child nodes as required
SOAP Messages
SOAP envelope
Header
Body
SOAP over HTTP
HTTP
Server
HTTP POST SOAP Request
HTTP RESPONSE SOAP Response
HTTP
Client
Creating Web Services in Java with Apache SOAP
Apache SOAP
• designed to run as a servlet within any Java HTTP server.
• download either source only or precompiled version of SOAP.
Server side installation
• need a separate web server that supports servlets (Tomcat)
• add jar files or war files to the CLASSPATH of the server.
Client side installation
• soap.jar, mail.jar and activation.jar must be in the CLASSPATH.
• also any java aware XML parser, e.g. xerces.jar
Deployment Descriptor
<isd:service xmlns:isd="http://xml.apache.org/xml-soap/deployment"
id="JembossAuthServer">
<isd:provider type="java"
scope="Request"
methods="name version abouturl show_acd getWossname
show_help show_db run_prog show_saved_results
delete_saved_results list_saved_results call_ajax
update_result_status">
<isd:java class="org.emboss.jemboss.server.JembossAuthServer"
static="false"/>
</isd:provider>
<isd:faultListener>
org.apache.soap.server.DOMFaultListener
</isd:faultListener>
</isd:service>
Deployed with Service Manager Client:
java org.apache.soap.server.ServiceManagerClient \
http://hostname:port/soap/servlet/rpcrouter deploy service.xml
Deploying services with the SOAP Admin Tool
Axis
•
next generation of Apache SOAP
• essentially Apache SOAP 3.0
• only Beta release (release 1.0 summer 2002)
http://xml.apache.org/axis/
Web Service Description Language (WSDL)
• applications expose some type of functionality
• functionality can be invoked in different ways
• WSDL describes what the web service does and how it can be invoked
• toolkits available to generating WSDL automatically (e.g. Java2WSDL
is an Apache Axis utility)