17.7.1.SOAP CLIENT API Extensions

The SOAP Client API is used for handling, building and accessing complex types required to perform a SOAP request. It allows you to build a structures to access their elements and to build values suitable for passing to the SOAP_CLIENT() function. It also allows to de-serialize a SOAP response to a soap_parameter and access its members and attributes safely.

Vectors are used to pass or retrieve a complex type using SOAP These vectors contain special content or UDTs. In SOAP, structures are allowed to have multiple members of the same name, or conditional members (choices). Thus it is not possible to cover all variants of XSD types with UDTs (which would be the most elegant way to represent structures). So to cover all variants of structure handling or to express structures containing attributes, we have to use vectors. Since we used a special structure with vectors for expressing such complex types we introduce the following API to deal with them.

The base of API is a UDT 'soap_parameter':

create type soap_parameter as
                  s any default null,
                  param_type int default 1,
                  param_xsd varchar default null,
                  ver int default 11
                temporary self as ref

Its members are:

's' - a vector representing a structure, array or simple type.
'param_type' - designates what is kept in 's' : 1 is struct ; 0 - simple type; 2 - array
'param_xsd' - URL; QName of the type stored in 's'
'ver' - soap version to be used for serialization/deserialization if RPC style is used.

Its Constructors are:

constructor method soap_complex_parameter ()
Instantiate an empty structure placeholder;
constructor method soap_simple_parameter (val any),
Instantiate an empty simple type placeholder
constructor method soap_array_parameter (n int),
Instantiate an array placeholder
constructor method soap_single_parameter (elm soap_parameter),
Instantiate an element of containing a type of 'elm'

Its Methods are:

method get_length () returns any,
Returns the  length of the parameter
method add_member (name varchar, val any) returns any,
Add a new member element to the structure placeholder
method set_member (name varchar, val any) returns any
Sets the value of an existing member by name or will add a new member  if  the member does not exist
method set_member (pos int, val any) returns any,
the same as above but using ordinal position of the member;
method get_member (name varchar) returns any,
Returns a member's value by name
method get_member (pos int) returns any,
Returns member value by ordinal position
method get_value () returns any,
Returns value for simple types. Only for simple type is applicable
method set_value (val any) returns any,
Sets the value of a simple type
method set_attribute (name varchar, val any) returns any,
Set an attribute value of a structure or simple type
method get_attribute (name varchar) returns any,
Return an attribute value of a structure or simple type
method get_call_param (name varchar) returns any,

Serializes the parameter in a form suitable for passing to the SOAP_CLIENT() function. When several parameters needs to be passed to it, then result of those calls must be concatenated (see vector_concat()) Important: set_xsd have to be called with valid ExQName, before doing get_call_param call.

method set_xsd (xsd varchar) returns any,

Establish a SOAP data-type Expanded QName, referencing the data kept in the soap_parameter. This is a reference to a SOAP complex data-type already defined with soap_dt_define () function (see function reference). This method only sets the relation between data kept in soap_parameter and doesn't check its validity unless serialize is performed. The data-type Expanded QName also will be included into output of the get_call_param method.

Example17.30.Complex WS Type Example

Consider the following complex type:

        <xsd:element minOccurs="1" maxOccurs="1" name="varInt" type="xsd:int" />
        <xsd:element minOccurs="0" maxOccurs="1" name="varString" type="xsd:string" />
        <xsd:element minOccurs="1" maxOccurs="1" name="varFloat" type="xsd:float" />

declare s soap_parameter ;
s := new soap_parameter ();
s.set_xsd ('http://soapinterop.org/xsd:SOAPComplexType');
s.add_member ('varString', 'string');
s.serialize ('mystruct'); -- will generate an error as, varInt and varFloat are
                                      -- missing but they are declared as minOccurs="1"

So if we add two more members, and remove varString, to the statements above.

s.add_member ('varInt', 123);
s.add_member ('varFloat', 3.14);
s.serialize ('mystruct');

Will produce valid output:


and finally we can make a parameter for the SOAP_CLIENT() function:

par := s.get_call_param ('par1');

here are the contents of 'par':

  ("par1", "http://soapinterop.org/xsd:SOAPComplexType" ), -- designates parameter par1, with type SOAPComplexType
  (<COMPOSITE>, "",       -- this is a marker that it's a struct
        "varInt", 123,  -- the members name/value pairs follows
        "varFloat", 3.14

Further methods are:

method deserialize (xs any, elem varchar) returns any,

Deserializes a element 'elem' from 'xs' (XML tree object) the the soap_parameter.

method serialize (tag varchar) returns any,

Returns an XML document representing the data kept into the soap_parameter.

method set_struct (s any) returns any

Explicitly sets the structure/array/simple type kept in the soap_parameter UDT. This can be used to disassemble a nested complex type into its components.

Example17.31.Example Using WS-RM

echoStruct invocation

declare ret any;
declare pa soap_parameter;

pa := new soap_parameter ();
pa.add_member ('varString', 'My String');
pa.add_member ('varInt', 12345);
pa.add_member ('varFloat', 3.1415926);
pa.set_xsd ('http://soapinterop.org/xsd:SOAPStruct');

ret := SOAP_CLIENT (url=>'http://.../interop',
  operation=>'echoStruct', parameters=>pa.get_call_param ('inputStruct'));

pa := new soap_parameter ();
pa.set_xsd ('http://soapinterop.org/xsd:SOAPStruct');
pa.deserialize (ret, 'CallReturn');
return pa.get_member ('varString');

echoDocument invocation

declare ret any;
declare doc, pa soap_parameter;

doc := new soap_parameter ('The document content');
doc.set_attribute ('ID', uuid());
doc.set_xsd ('http://soapinterop.org/xsd:x_Document');

ret := SOAP_CLIENT (url=>'http://.../r3/Compound1', operation=>'echoDocument',
  parameters=>doc.get_call_param ('x'), style=>1);

pa := new soap_parameter ();
pa.set_xsd ('http://soapinterop.org/xsd:Document');
pa.deserialize (ret, 'result_Document');
dbg_obj_print (pa.s);

return pa.get_attribute ('ID');

[Tip] See Also: