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SOAP::WSDL::Manual::FAQ - Frequently Asked Questions (and answers)

Development status

Can I use SOAP::WSDL in a production environment?

Yes. SOAP::WSDL is used in production environments. You should - as always - apply common sense and take appropriate safety measures, especially if running SOAP::WSDL as a server.

Can I throw the WSDL away after generating?

Please don't. Future versions of SOAP::WSDL may require you to re-generate interfaces in order to use them.

SOAP/WSDL Version and message styles

Which SOAP / WSDL versions does SOAP::WSDL support?

SOAP1.1 and WSDL1.1. SOAP1.2 and WSDL2 are not supported yet.

Which SOAP message Styles are supported?

document/literal.

The message / encoding styles rpc/encoded and rpc/literal are not supported (rpc/literal is hardly used).

rpc/literal is not implemented yet.

Unfortunately, SOAP::WSDL can't even parse many rpc/encoded WSDL definitions, and thus cannot inform you about unsupported message styles in some situations.

Aren't rpc variants bad anyway?

No. They can be as well-defined and useful as the document/literal variant.

The difference between rpc and document is that rpc SOAP messages have an additional container named after the remote procedure called.

rpc/literal is RPC with named parameters, whereas rpc/encoded corresponds to positional parameters.

rpc/encoded is prohibited by the WS-I Basic Profile. However, rpc/encoded is still popular, especially for scripting languages like perl, python or php.

You should probably use SOAP::Lite for rpc/encoded web services.

All the document/rpc literal/encoded discussion will cede with WSDL2.0: These variants are dropped in favour of an extensible operation style mechanism.

XML Parsing / Generation

Does SOAP::WSDL support namespaces?

Well, sort of. SOAP::WSDL can use WSDL definitions containing namespaces, and emits SOAP messages with namespace information.

Its SOAP message parser however, is not namespace sensitive but uses the pre-shared information from the WSDL for looking up what each XML node means.

SOAP::WSDL can parse SOAP messages including namespace information up to the point where equally named elements from different namespaces may appear at the same position.

This is a long-standing feature request and will eventually be resolved.

Validation

Does SOAP::WSDL perform XML Schema Validation?

No, SOAP::WSDL does not perform XML Schema Validation. It does, however, enforce the correct structure on both XML and perl data. Occurrence, ordering, value-spaces, and identity constraints are not checked.

Does SOAP::WSDL perform XML Validation?

No, SOAP::WSDL does not perform XML Validation (that is, validation against a DTD). WS-I prohibits the use of DTDs in WSDL definitions.

Isn't validation required for XML?

No. The XML Specification does not require validation from XML processors. It states how validating and non-validating parsers must react on errors.

Note: Validation in the context of (only) XML actually means DTD validation.

And doesn't XML Schema require validation?

The XML Schema specification requires conformant XML Schema processors to be able to validate XML Schema constraints.

SOAP::WSDL is not a conformant XML Schema processor in this sense, as it does not validate all XML Schema constraints.

And does SOAP require XML Schema Validation?

No. The SOAP1.1 note does not say anything about validation. The SOAP1.2. specification explicitly states that XML Schema validation is not required for the SOAP envelope, and that applications may decide whether they need XML Schema Validation for the SOAP payload or not.

The WSDL 1.1. specification does not mandate XML Schema validation. It does actually not even mandate the use of XML Schema for type definitions.

Can SOAP::WSDL parse SOAP message fragments?

No. SOAP::WSDL can parse neither well-formed nor not-well-formed SOAP message chunks.

Persistence

Can I use Storable to freeze/thaw SOAP::WSDL's objects?

You can freeze almost all of SOAP::WSDL's objects. The only exceptions are the objects used in parsing WSDL definitions itself - they cannot be frozen.

Note that freezing/thawing inside-out objects comes with a performance penalty and is at around the speed of XML generation/parsing.

Performance and memory consumption

How fast is SOAP::WSDL?

As of this writing, SOAP::WSDL is the fastest SOAP Client toolkit for perl available on CPAN. There are no published server benchmarks yet.

If you need extra speed you can try SOAP::WSDL_XS available from SOAP::WSDL's subversion repository at:

https://soap-wsdl.svn.sourceforge.net/svnroot/soap-wsdl/SOAP-WSDL_XS/trunk

Note however that SOAP::WSDL_XS is not very mature yet and only suitable for use in trusted environments - you definitely should not use it on a public internet SOAP server yet.

Note further that SOAP::WSDL's inside-out objects come with a big performance penalty when freezing/thawing them with Storable.

There's a lot of perl modules generated. Don't they eat up all my memory?

SOAP::WSDL usually uses a bit more memory than SOAP::Lite, but less than XML::Compile. Test if in question.