在php中从SOAP请求获取数据

Question

我有一个php网站。我需要实现航班搜索功能和预订功能。我使用了来自arzoo的付费API，但我无法得到响应，我也是SOAP概念的新手。这是我的代码

$input_xml = '<AvailRequest>
            <Trip>ONE</Trip>
            <Origin>BOM</Origin>
            <Destination>JFK</Destination>
            <DepartDate>2013-09-15</DepartDate>
            <ReturnDate>2013-09-16</ReturnDate>
            <AdultPax>1</AdultPax>
            <ChildPax>0</ChildPax>
            <InfantPax>0</InfantPax>
            <Currency>INR</Currency>
            <PreferredClass>E</PreferredClass>
            <Eticket>true</Eticket>
            <Clientid>xxx</Clientid>
            <Clientpassword>xxxx</Clientpassword>
            <Clienttype>xxx</Clienttype>
            <PreferredAirline>AI</PreferredAirline>
    </AvailRequest>';

$client = new SoapClient('http://59.162.33.102/ArzooWS/services/DOMFlightAvailability?wsdl');
 $result = $client->__call('getAvailability',array($input_xml));

$result的输出为invalid xml format。请帮我解决此问题