Designing Interoperable Web Services Lawrence Chan Jeff Pennal OpenRoad Communications Ltd. Vancouver Java Users group http:// www.openroad.ca/vanjug /

Overview The promise and reality of Web Services Designing flexible web services Debugging web services Designing for performance Recommendations Fabulous prizes! http://www.flickr.com/photos/josefstuefer/9500503/

The promise and reality of Web Services

Designing flexible web services

Debugging web services

Designing for performance

Recommendations

Fabulous prizes!

The Promise It’s just XML! Cross Platform! A standard! Network Transparent! http://www.flickr.com/photos/tookie/183503927/

The Reality Hard to debug Poor Performance Poor compatibility http://www.flickr.com/photos/tom_vac/373021521/

So why bother? It works.

Real World Examples : Performance

Court Services Online Java e-commerce for searching and filing court records https:// webapps.ag.gov.bc.ca/cso Multiple backend content providers in different locations with different technologies Technical solution: Use Web Services!

Java e-commerce for searching and filing court records

https:// webapps.ag.gov.bc.ca/cso

Multiple backend content providers in different locations with different technologies

Technical solution: Use Web Services!

Challenges Dealing with large databases Performance, performance, performance Security

Dealing with large databases

Performance, performance, performance

Security

Solutions Benchmarked different Java SOAP providers Systinet vs. Axis vs. Oracle Optimized web service API calls to match screens Used Layer 7 XML Firewall to inspect and secure network traffic

Benchmarked different Java SOAP providers

Systinet vs. Axis vs. Oracle

Optimized web service API calls to match screens

Used Layer 7 XML Firewall to inspect and secure network traffic

Real World Examples : Debugging

Supreme Court Scheduling System .NET web application for Supreme Court, hosted in Vancouver New project goal: Integrate with Java based Ministry of AG case tracking application in Victoria Technical solution: Use Web Services!

.NET web application for Supreme Court, hosted in Vancouver

New project goal: Integrate with Java based Ministry of AG case tracking application in Victoria

Technical solution: Use Web Services!

Challenges Client was .Net 1.1 talking to Systinet Server for Java Interoperability ended up being a huge problem! Kept seeing NoSuchMethodError How to debug?

Client was .Net 1.1 talking to Systinet Server for Java

Interoperability ended up being a huge problem!

Kept seeing NoSuchMethodError

How to debug?

Debugging SOAP Recommendation: use proxy-based SOAP debugger Microsoft Soap Toolkit 3.0 Proxy debuggers sit between SOAP client and server, and display traffic

Recommendation: use proxy-based SOAP debugger

Microsoft Soap Toolkit 3.0

Proxy debuggers sit between SOAP client and server, and display traffic

How .NET encoded the method parameters <soap:Body> <p1 xmlns=&quot;http://systinet.com/xsd/SchemaTypes/&quot;>772</p1> <p0_10 xmlns=&quot;http://systinet.com/xsd/SchemaTypes/&quot;>16882</p0_10> </soap:Body> versus How Systinet encoded the method parameters <e:Body> <n0:p0_10 xmlns:n0= http://systinet.com/xsd/SchemaTypes/ i:type=&quot;d:decimal&quot; >772</n0:p0_10> <n1:p1 xmlns:n1= http://systinet.com/xsd/SchemaTypes/ i:type=&quot;d:decimal&quot; >16882</n1:p1> </e:Body> .NET vs Systinet

How .NET encoded the method parameters

<soap:Body>

<p1 xmlns=&quot;http://systinet.com/xsd/SchemaTypes/&quot;>772</p1>

<p0_10 xmlns=&quot;http://systinet.com/xsd/SchemaTypes/&quot;>16882</p0_10>

</soap:Body>

versus

How Systinet encoded the method parameters

<e:Body>

<n0:p0_10 xmlns:n0= http://systinet.com/xsd/SchemaTypes/ i:type=&quot;d:decimal&quot; >772</n0:p0_10>

<n1:p1 xmlns:n1= http://systinet.com/xsd/SchemaTypes/

i:type=&quot;d:decimal&quot; >16882</n1:p1>

</e:Body>

Real World Examples: Flexibility

Hip Digital B2B provider specializing in digital music downloads of over 1 million tracks from the 4 majors Clients include Pepsi, Nissan and Country Music Television Needed both a web front end and an API Technical Solution: Use Web Services!

B2B provider specializing in digital music downloads of over 1 million tracks from the 4 majors

Clients include Pepsi, Nissan and Country Music Television

Needed both a web front end and an API

Technical Solution: Use Web Services!

Hip Digital Challenges API must integrate seamlessly into any platform Must keep track downloads secure Need to keep Hip Digital hidden from end users Need to integrate with varied payment models

API must integrate seamlessly into any platform

Must keep track downloads secure

Need to keep Hip Digital hidden from end users

Need to integrate with varied payment models

Hip Digital Solutions Kept API to simple data types - strings and ints Used one-time passwords that could be revoked at any time to authorize every download Authorization, redemption and error handling handled via web services Only direct connection to HD for actual track download and DRM authorization

Kept API to simple data types - strings and ints

Used one-time passwords that could be revoked at any time to authorize every download

Authorization, redemption and error handling handled via web services

Only direct connection to HD for actual track download and DRM authorization

Summary Not all implementations are equal Network trace tools are useful for debug Minimize the data being sent Design your Web Services with reuse in mind Keep your interfaces simple http://www.flickr.com/photos/jerryjohn/63351338

Not all implementations are equal

Network trace tools are useful for debug

Minimize the data being sent

Design your Web Services with reuse in mind

Keep your interfaces simple

Interop Gotchas: Arrays Problem: Arrays can be bad Solution: Keep them simple

Problem: Arrays can be bad

Solution: Keep them simple

Interop Gotchas: Naming Problem: Code compiles but there are runtime errors Solution: Make class names unique, don’t rely on the namespace

Problem: Code compiles but there are runtime errors

Solution: Make class names unique, don’t rely on the namespace

Interop Gotchas: Datatypes Problem: Datatype conversion Solution: Keep it simple

Problem: Datatype conversion

Solution: Keep it simple

Java vs .NET type comparison System.DateTime DateTime DateTime Calendar System.Double Double double double System.Single Single float float System.Int64 Long long long System.Int32 Integer int int System.Int16 Decimal short short System.SByte -N/A- sbyte byte System.Boolean Boolean bool boolean System.String String string String .NET Framework Type VB.NET C#.NET Java

Interop Gotchas: OO Problem: Object Oriented features do not translate well across platforms. Solution: Denormalize your objects, stick to simple types

Problem: Object Oriented features do not translate well across platforms.

Solution: Denormalize your objects, stick to simple types

Pop Quiz! This technology originally developed by Dave Winer, is considered to be the precursor to SOAP. What is XML-RPC?

Pop Quiz! This technology provides a platform-independent , XML-based registry for businesses worldwide to list themselves on the Internet. What is Universal Description, Discovery, and Integration (UDDI)?

Pop Quiz! These are the two encoding mechanisms for SOAP attachments. What are MIME and DIME?

Any Questions? Jeff Pennal [email_address] Lawrence Chan [email_address] VanJug www.openroad.ca/vanjug http://www.flickr.com/photos/feaverish/19544565

Jeff Pennal

[email_address]

Lawrence Chan

[email_address]

VanJug www.openroad.ca/vanjug