PHP To Edit Existing XML Entry - php

Question

Ok, please bear with me as I explain this app. The first view shows a tableview, where each row is a 'request' that someone has made, also using the app. The requests are actually a parsed xml file that looks something like this:
<item>
<title>Request</title>
<name>Name</name>
<Responses>0</Responses>
</item>
Using the script listed underneath this paragraph, I am able to run some code in iOS that will take text from text-boxes in the app, and append the XML with a new item set.
<?php
$firstName = $_POST['firstName'];
$lastName = $_POST['lastName'];
$request = $_POST['request'];
$anon = $_POST['anon'];
$pubDate = $_POST['pubDate'];
$loc = $_POST['loc'];
//This line will load the XML file
$xml = simplexml_load_file("URL.xml") or die("Not loaded!\n");
//print_r($xml);
//This line gets the channel element (from an array returned by the xpath method)
$channel = $xml->xpath('//channel');
$channel = $channel[0];
//print_r($channel);
$person = $channel->addChild("item");
$person->addChild("first_name", $firstName);
$person->addChild("last_name", $lastName);
$person->addChild("title", $request);
$person->addChild("date", $pubDate);
$person->addChild("anonymous", $anon);
$person->addChild("responses", "0");
$person->addChild("location", $loc);
//This next line will overwrite the original XML file with new data added
$xml->asXML("Test.xml");
?>
The actual XML has much more listed than what I put at the beginning, I just edited it down to save space, so that's why it and the PHP don't quite match up.
All of this works great, the app parses the XML to show what has been requested, and a user can make a new request that will then show in the app.
My problem is that when someone responds to an existing request, I would like the <Responses> to increase by 1. Is there something I can do with a different script that would find that entry, and +1 to whatever number currently exists in that item's Response tag?
I have seen this script, but it appears to go through and search for all of a certain tag, and change all tags of that name in the XML. I am looking to just find one specific one and change it. Suggestions?
$str = <<<XML
<ScrapBook>
<Event>
<Name> Name of Event </Name>
<Blah>glop glop</Blah>
</Event>
</ScrapBook>
XML;
$xmlDoc = new DOMDocument();
$xmlDoc->loadXml($str);
$events = $xmlDoc->getElementsByTagName("Event");
foreach($events as $event){
$eventNames = $event->getElementsByTagName("Name");
$eventN = $eventNames->item(0)->nodeValue;
if(' Name of Event ' == $eventN){
$eventNames->item(0)->nodeValue = 'New name';
}
}
var_dump($xmlDoc->saveXML());

Answer 1

You can go with simplexml to do that; first, select the <item> to be changed, then store the new <Responses>:
$xml = simplexml_load_string($x); // assume XML in $x
// select <Responses> with xpath by title and name
$responses = $xml->xpath("/items/item[title = 'Foo' and name = 'Bar']/Responses");
// store number + 1
$responses[0][0] = $responses[0] + 1;
see it working: https://eval.in/127882