Get alert response from external site - php

Question

I'm trying ot figure out away to get a response from this website:
https://www.primarycare.nhs.uk/publicfn/catchment.aspx?oc=P91012&h=600&w=800&if=0
oc=P91012 - this is the practice identifier.
We then have a postcode field where a user checks if they are in the catchment area
The site issues a javascript alert to inform the user if they are / or not in the catchment area.
Is it possible to send a PHP Curl request that sends a postcode to this website and checks whether or not the postcode is in the catchment area and send a reponse back to my site?
<?php
$POSTurl = 'https://www.primarycare.nhs.uk/publicfn/geocode.ashx';
$fields = array(
'postcode' => urlencode('M41 0UX'),
);
foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; }
rtrim($fields_string, '&');
$ch = curl_init();
curl_setopt($ch,CURLOPT_URL, $POSTurl );
curl_setopt($ch,CURLOPT_POST, count($fields));
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
$result = curl_exec($ch);
$url = 'https://www.primarycare.nhs.uk/publicfn/catchment.aspx?oc=P91012&h=600&w=800&if=0';
$ch = curl_init();
$result = curl_exec($ch);
curl_close($ch);
?>

Answer 1

So, here it is:
the problem, why you were not unable to pick proper response is because all valid coordinates was in source code of NHS. I stripped out unwanted code, and checked coordinates by postcode with existing coordinates from the list. Keep in mind, that if anything will be changed in the list in original source, you will need to update that also.
Also, this code, technically is not 100% correct and probably you will spent more time to make it more correct for your needs. As i said in the comment, this will work as little hack.
Just copy/paste into your php file, and refresh the page.
Code:
<?php
$postcode = 'M41 0UX';
$postcode = urlencode($postcode);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://www.primarycare.nhs.uk/publicfn/geocode.ashx");
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "PostCode=".$postcode);
curl_setopt($ch, CURLOPT_POST, 1);
$result = curl_exec($ch);
if (curl_errno($ch)) {
echo 'Error:' . curl_error($ch);
}
else {
echo $result;
echo '<input id="checker" type="hidden" value="'.$result.'" />';
?>
<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"></script>
<script src="https://www.primarycare.nhs.uk/Private/js/gpos.js" type="text/javascript"></script>
<script type="text/javascript" src="https://maps-api-ssl.google.com/maps/api/js?v=3.7&sensor=false"></script>
<script type="text/javascript">
var point;
var poly1=[{x:53.45801,y: -2.33768},{x:53.46046,y: -2.32996},{x:53.45882,y: -2.32447},{x:53.45637,y: -2.3188},{x:53.45351,y: -2.31709},{x:53.44932,y: -2.31468},{x:53.44523,y: -2.31365},{x:53.44216,y: -2.31279},{x:53.43961,y: -2.31417},{x:53.43858,y: -2.31657},{x:53.4394,y: -2.32155},{x:53.44001,y: -2.32893},{x:53.44145,y: -2.33408},{x:53.44329,y: -2.33751},{x:53.44053,y: -2.33648},{x:53.4395,y: -2.34095},{x:53.43838,y: -2.34352},{x:53.44083,y: -2.34627},{x:53.44022,y: -2.35107},{x:53.43899,y: -2.35193},{x:53.43787,y: -2.35107},{x:53.43797,y: -2.35399},{x:53.43715,y: -2.35622},{x:53.43562,y: -2.3576},{x:53.43592,y: -2.35949},{x:53.43449,y: -2.36103},{x:53.43275,y: -2.36017},{x:53.43153,y: -2.36137},{x:53.43275,y: -2.36343},{x:53.43183,y: -2.36515},{x:53.43347,y: -2.36738},{x:53.4349,y: -2.36704},{x:53.43664,y: -2.36738},{x:53.43736,y: -2.3679},{x:53.43705,y: -2.37167},{x:53.43725,y: -2.37459},{x:53.43592,y: -2.37511},{x:53.43664,y: -2.377},{x:53.43623,y: -2.37974},{x:53.43787,y: -2.38077},{x:53.43858,y: -2.37888},{x:53.4395,y: -2.3782},{x:53.43981,y: -2.38197},{x:53.4392,y: -2.38403},{x:53.43797,y: -2.38352},{x:53.43848,y: -2.38609},{x:53.4395,y: -2.38592},{x:53.44073,y: -2.3842},{x:53.44063,y: -2.38747},{x:53.44001,y: -2.3909},{x:53.43776,y: -2.39193},{x:53.43603,y: -2.39141},{x:53.4348,y: -2.38884},{x:53.43255,y: -2.39038},{x:53.43388,y: -2.39553},{x:53.43459,y: -2.39914},{x:53.43684,y: -2.40051},{x:53.43766,y: -2.40223},{x:53.4394,y: -2.4012},{x:53.44012,y: -2.40429},{x:53.4394,y: -2.40824},{x:53.43868,y: -2.41219},{x:53.44533,y: -2.40807},{x:53.4485,y: -2.40669},{x:53.4529,y: -2.40309},{x:53.45545,y: -2.39965},{x:53.45995,y: -2.39313},{x:53.46363,y: -2.38438},{x:53.46608,y: -2.37614},{x:53.46894,y: -2.3703},{x:53.46588,y: -2.36532},{x:53.46455,y: -2.35931},{x:53.46281,y: -2.35296},{x:53.46158,y: -2.3461},{x:53.45995,y: -2.34198},{x:53.4577,y: -2.33974}];
function isPointInPoly(poly, pt){
for(var c = false, i = -1, l = poly.length, j = l - 1; ++i < l; j = i)
((poly[i].y <= pt.y && pt.y < poly[j].y) || (poly[j].y <= pt.y && pt.y < poly[i].y))
&& (pt.x < (poly[j].x - poly[i].x) * (pt.y - poly[i].y) / (poly[j].y - poly[i].y) + poly[i].x)
&& (c = !c);
return c;
};
function ispostcodein(postcode) {
var ok = 1;
if (ok == 1) {
var responseText = $('#checker').val();
point = responseText.split(';');
}
var incatch = 0;
if (isPointInPoly(poly1, {x: point[0],y: point[1]})) { incatch = 1 };
if (incatch==0) {
alert("We're sorry, but your postcode is outside the catchment area for PRIMROSE AVENUE SURGERY.");
}
else {
alert("Your postcode is in the catchment area for PRIMROSE AVENUE SURGERY. You are able to register with this practice.");
}
}
ispostcodein('<?= $result; ?>');
</script>
<?php
}
curl_close($ch);
?>