See Also: Home Links Personal Site Blogroll  FriendFeed CV

Wiki Menu:

FrontPage
Edit
References
Delete
Changes
Formatting
Index

Tags:
Topic Image

SOAP : Simple Object Access Protocol

the following points are taken from a presentation I did to colleagues in 2004 outlining web services, and SOAP in particular, its a contrived example and not functional but serves to illustrate some key concepts

Overview

  • Platform agnostic
  • Open and evolving standard
  • Authored by Microsoft, IBM, Develop-mentor and Userland
  • Makes use of XML namespaces
  • Uses XML::Schema for data-type descriptions
  • Accessible through WSDL and UDDI
  • Usable over other protocols SMTP, POP3, JABBER

Data Types

Uses named parameters and data types are all identified through attributes using XML::Schema, e.g.

<firstname xsi:type="xsd:string">Fred</firstname>

Primitive Types

Similar set to XML-RPC primitives (int, double, string, boolean, dateTime, base64) but with the following additional types... duration, anyURI, hexBinary, byte, unsignedShort (Long/Byte/Int)

And the ability to define custom types using base XML::Schema components like...

TOKEN, ELEMENT, ID, ENTITY

And can provide dimension and bounds limits on data values (e.g. when assembling arrays)

Compound Types

Basically structs and arrays as you'd expect and similar to XML-RPC, but using the full set of SOAP primitives

Client Example

my $userName = $q->param('user');
my $userDetails = SOAP::Lite
  -> uri('/MyAppPackageName')   # static despatch, class name
  -> proxy('http://mydomain.co.nz/soap/MyScript.cgi')
  -> getPhoneNumber($userName);
my @results = $userDetails ->paramsout;
unless ($userDetails ->fault) {
  print "<strong>Params fetched:</strong>";
  foreach my $tempVar (@results) {
    print "<br>$tempVar\n";
  }
} else {
  print "<h2>SOAP Error!!!</h2>" .
  "<br>FaultCode: $userDetails ->faultcode" .
  "<br>FaultString: $userDetails ->faultstring" .
  "<br>FaultDetail: $userDetails ->faultdetail";
}

Server Example

use SOAP::Transport::HTTP;
SOAP::Transport::HTTP::CGI
    -> dispatch_to('MyAppPackageName')   # static dispatch to package
    -> handle;

package MyAppPackageName;
sub getPhoneNumber{
  use DBI;
  my ($packageName, $userName) = @_;
  my $returnValue = "unkown";
  my $dbh = DBI->connect("DBI:mysql:MyDatabaseName:localhost",
     "USER", "PASSWORD");
  my $sql="SELECT phone FROM people WHERE username = '$userName'";
  my $sth = $dbh->prepare($sql);
  $sth->execute or die ("SQL error occured\n");
  if ($sth->rows()) {
    my @row=$sth->fetchrow;
    $returnValue = $row[0];
  }
  return ($returnValue);
}

Sample Request

POST /soap/MyScript.cgi HTTP/1.1
Host: me.mydomain.co.nz
Content-Type: text/xml
Content-Length: 306

<?xml version="1.0"?>
<soap:Envelope
  xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"
  soap:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">

<soap:Body xmlns:myns="http://mynamespace">
  <myns:getPhoneNumber><user>FRED</user></myns:getPhoneNumber>
</soap:Body>

</soap:Envelope>

Sample Response

HTTP/1.1 200 OK
Date: Sun, 07 Sep 2003 22:06:03 GMT
Server: Apache/1.3.27 (Unix) etc etc...
SOAPServer: SOAP::Lite/Perl/0.55
Content-Length: 604
Content-Type: text/xml; charset=utf-8

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope
  soap:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
  xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"
  xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance"
  xmlns:xsd="http://www.w3.org/1999/XMLSchema">

<soap:Body>
<myns:getPhoneNumberResponse
   xmlns:myns="http://mynamespace">
   <s-gensym5 xsi:type="xsd:string">07 555 2313</s-gensym5>
</myns:getPhoneNumberResponse>
</soap:Body>

</soap:Envelope>

See Also: XML Technologies | REST | Web Services | Notes Index