XML — SOAP

What is SOAP?

SOAP (Simple Object Access Protocol) is a protocol for exchanging XML-based messages over networks.

SOAP Message Structure

<?xml version="1.0"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
    <soap:Body>
        <getPrice>
            <item>Apple</item>
        </getPrice>
    </soap:Body>
</soap:Envelope>

SOAP vs REST

Feature	SOAP	REST
Protocol	Protocol	Architectural style
Format	XML only	JSON, XML, etc.
Complexity	More complex	Simpler
Security	WS-Security	HTTPS
Speed	Slower	Faster

SOAP Headers

<soap:Envelope>
    <soap:Header>
        <auth>
            <username>user</username>
            <password>pass</password>
        </auth>
    </soap:Header>
    <soap:Body>
        <request/>
    </soap:Body>
</soap:Envelope>

WSDL

WSDL (Web Services Description Language) describes SOAP services:

<definitions>
    <service name="PriceService">
        <port name="PricePort">
            <soap:address location="http://example.com/price"/>
        </port>
    </service>
</definitions>

Mini Practice

1. Create a SOAP message
2. Add headers and body
3. Parse a WSDL file
4. Compare with REST API

Up Next

Continue with Web Services — web service fundamentals.