Collect meta attributes from XSD files

[veewee]

Hello,

In WSDLs, it is possible that additional arguments are being added to the XSD configurations.
This information gets lost currently.

This PR introduces a system to collect this kind of information.
Currently it is only added for attributes, but it could as well be added for other types as well.

Example:

    <complexType name="testType">
        <complexContent>
            <restriction base="SOAP-ENC:Array">
        <attribute ref="SOAP-ENC:arrayType" wsdl:arrayType="int[]"/>
        </restriction>
    </complexContent>
    </complexType>

Currently the wsdl:arrayType="int[]" information gets lost.
When this PR is merged, you will be able to read this additional (non standard XSD) information by doing:

$meta = $attr->getMeta();
$arrayType = $meta[0]; // or rather find by name + schema targetnamespace

This will return:

^ array:1 [
  0 => GoetasWebservices\XML\XSDReader\Schema\MetaInformation^ {#1514
    -contextSchema: GoetasWebservices\XML\XSDReader\Schema\Schema^ {#554
      #targetNamespace: "http://www.w3.org/2001/XMLSchema"
      ....
    }
    -namespaceURI: "http://schemas.xmlsoap.org/wsdl/"
    -name: "arrayType"
    -value: "int[]"
  }
]

[veewee]

There currently was no way to get a schema based on a namespace URI.
Not sure if this is the best way, but couldn't really find a different way.

[goetas]

I think that there are way too many possibilities here (nodes, attributes) to fit them in the "metadata", have you considered exposing the underlying DOM Node and let the consumer parse as it prefers?

Having just something as $type->getNode()?

[veewee]

I agree that metadata might not be the best name for the data. Maybe rather something like ExtensionAttributes.

I was trying to build code in line of what there is in the package today. However, it could make sense to introduce the link to the node so that people can collect whatever they want from the XML directly.

Let me know what you all prefer, I can take a look at creating an alternative PR for the node implementation.

[veewee]

Just took an additional look and found a "con" argument for the node approach: having the node only is a bit harder because of the difference between reference and definition schema items.

When it is pre-parsed, the information gets proxies instantly.

[goetas]

By looking at https://www.w3schools.com/xml/el_complextype.asp it seems that XMLSchema allows only attributes to be used as extensions, while nodes are reserved to XSD... that would simplify a lot things... do you anything about it?

[veewee]

By looking at https://www.w3schools.com/xml/el_complextype.asp it seems that XMLSchema allows only attributes to be used as extensions, while nodes are reserved to XSD... that would simplify a lot things... do you anything about it?

That is correct indeed. I changed the naming to CustomAttribute - which better indicates what the information is being used for.

[goetas]

looks good, thank you

[goetas]

Released as https://github.com/goetas-webservices/xsd-reader/releases/tag/0.4.5

[Guite]

Thank you @veewee