Avoid duplicate items when creating contact in Php-Ews - php

Question

I'm using https://github.com/Garethp/php-ews/ library to access to my public contact folder on Exchange server.
This is how i create a contact.
$api = API::withUsernameAndPassword($server, $user, $pass);
$folder = $api->getFolderByDisplayName('Public', Enumeration\DistinguishedFolderIdNameType::PUBLICFOLDERSROOT);
$contattiTotali = $api->getFolderByDisplayName('Contacts', $folder->getFolderId());
$id=$contattiTotali->getFolderId()->getId();
$api->setFolderId($contattiTotali->getFolderId());
$api->createContacts(array(
'GivenName' => 'Homer',
'Surname' => 'Simpson',
'EmailAddresses' => array(
'Entry' => array('Key' => Enumeration\EmailAddressKeyType::EMAIL_ADDRESS_1, '_value' => 'h.simpson#gmail.com')
),
//Creating multiple entries
'PhoneNumbers' => array(
'Entry' => array(
array('Key' => Enumeration\PhoneNumberKeyType::HOME_PHONE, '_value' => '000'),
array('Key' => Enumeration\PhoneNumberKeyType::BUSINESS_PHONE, '_value' => '111'),
)
),
'PhysicalAddresses' => array(
'Entry' => array(
'Key' => Enumeration\PhysicalAddressKeyType::HOME,
'street' => '123 Street',
'city' => '123 City',
'state' => '123 State',
'countryOrRegion' => '123 Country',
'postalCode' => '12345',
)
),
));
The code, actually, works fine, but if i execute it several times, it duplicates the contact.
Is there a way to check if the contact (email address is good enough) already exists before creating a new one?

Answer 1

The easiest way to telling if a contact already exists with a particular email address is to use the ResolveName operation eg
$request = new EWSType_ResolveNamesType();
$request->UnresolvedEntry = "address#domain.com";
$request->ReturnFullContactData = true;
$return = $ews->ResolveNames($request);
if ($return->ResponseMessages->ResolveNamesResponseMessage->ResponseCode == "NoError") {
return $return->ResponseMessages->ResolveNamesResponseMessage->ResolutionSet->Resolution->Mailbox->EmailAddress;
}