If you’re trying to access a resource with Javascript that is on a different server than the location of your website, you probably have got a error similar to “has been blocked by CORS policy: Response to preflight request doesn’t pass access control check ” in your Javascript console when you try to make the request.

If you are using Java Spring framework, you can fix at the class level or method level by adding @CrossOrigin at the top of the class or method. Adding it before the class will apply it to all functions within the class.

import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@CrossOrigin(origins = "https://example.com")
@RequestMapping(value ="/endpoint")
public class MyClass{
}

If you have XML data you need to download, you can download it with file_get_contents($url), which will return file as a string. Then you use simplexml parser to parse through the XML.

You may need to add allow_url_fopen=1 to the php.ini to allow for the file download with file_get_contents.

<?php
$url = 'https://www.example.com/file.xml';
$xml_str = file_get_contents($url);
$xml_feed = simplexml_load_string($xml_str);
//then you can do a foreach on each row returned on the xml, like so..
foreach($xml_feed as $key => $data){
	
}
?>

If you need to POST json to a url with CURL and PHP, in this case making a POST to https://www.example.com this sample code should help you.

<?php				
$json_data = array(
    'field1'=>'data1',
    'field2' => 'data2');
$url = 'https://www.example.com';
$json_string = json_encode($json_data);
//curl php library
$ch = curl_init();
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $json_string); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);  
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Content-Type: application/json',
    'Content-Length: ' . strlen($data_string)
    )
);
$result = curl_exec($ch);
?>

With PHP, you can not use $_POST variable if the content you are POSTing, is JSON. Instead, you must use a different method for getting the JSON data from the POST.

<?php
//assures the content being posted is content-type of application/json
if($_SERVER["CONTENT_TYPE"] == 'application/json')
{
$json_string = file_get_contents('php://input');
$json = json_decode($json_string);
//$json will be an object with the data that was in the POST
}
?>

select TIMESTAMPDIFF(SECOND,startTime,endTime) as timeDifference from myTable ;

This will return the difference in seconds between the startTime and endTime in timeDifference. You can use other units other than SECOND. You may replace SECOND with MINUTE, HOUR, DAY, WEEK, MONTH, QUARTER YEAR or FRAC_SECOND.

The following CSS will make a image rotate from the center point. This will work with Chrome and Firefox and IE.

#spin{
    position:fixed;
    -webkit-animation-name: spinnerRotate;
    -webkit-animation-duration: 4s;
    -webkit-animation-iteration-count: infinite;
    -webkit-animation-timing-function: linear;
    -moz-animation-name: spinnerRotate;
    -moz-animation-duration: 4s;
    -moz-animation-iteration-count: infinite;
    -moz-animation-timing-function: linear;
    -ms-animation-name: spinnerRotate;
    -ms-animation-duration: 4s;
    -ms-animation-iteration-count: infinite;
    -ms-animation-timing-function: linear;
}
@-webkit-keyframes spinnerRotate
{
    from{-webkit-transform:rotate(0deg);}
    to{-webkit-transform:rotate(360deg);}
}
@-moz-keyframes spinnerRotate
{
    from{-moz-transform:rotate(0deg);}
    to{-moz-transform:rotate(360deg);}
}
@-ms-keyframes spinnerRotate
{
    from{-ms-transform:rotate(0deg);}
    to{-ms-transform:rotate(360deg);}
}

With the following HTML

<div id="spin">
<img src="yourImage.png"></img>
</div>

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