Develop Reference

Error 500 When Updating MySql Database from WordPress - Same Code Works Fine Outside of WordPress

I need to update a MySql database from inside a JS function within a WordPress Woocommerce page. I'm using Ajax to do this. The following code works fine as a stand-alone code but when I put it into the WordPress page (on my localhost) it throws an error 500. Also I put the required data (which will eventually be a variable) onto the end of the url (?test=14230) because I couldn't get it to send the data when using the data: line in the Ajax.
Here's the Ajax:
function db()
{
$.ajax({
url: 'update_db.php?test=14230',
type: 'post',
data: 0,
success: function(output)
{
alert('Success, server says '+output);
}, error: function()
{
alert('Something went wrong.');
}
});
}
Here's the update_db.php:
<?php
if(isset($_GET['test']) ){
$id = $_GET['test'];
}
include 'database-handler.php';
$sql = "UPDATE db_name SET column = 'Some Value' WHERE id = $id";
if(mysqli_query($conn, $sql)){
//echo ('<p>'."Success.".'</p>');
} else {
//echo ('<p>'."Something went wrong. $sql. " . mysqli_error($conn).'</p>');
}
mysqli_close($conn);
?>
So I'm just wondering why this works as a stand-alone code but not when it's inside WordPress?
Edit: Here is the error log:
[Wed Nov 09 15:16:47.543162 2022] [php:error] [pid 4564:tid 1828] [client ::1:5888] PHP Fatal error: Uncaught TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, null given in C:\xampp\htdocs\my-sites\wowcard\wp-content\themes\blocksy-child\woocommerce\single-product\save-card-size.php:17\nStack trace:\n#0 C:\xampp\htdocs\my-sites\wowcard\wp-content\themes\blocksy-child\woocommerce\single-product\save-card-size.php(17): mysqli_query(NULL, 'UPDATE new_card...')\n#1 {main}\n thrown in C:\xampp\htdocs\my-sites\wowcard\wp-content\themes\blocksy-child\woocommerce\single-product\save-card-size.php on line 17, referer: http://localhost/my-sites/wowcard/product/polka-dot-brush-strokes-two-photo-birthday-card-purple/?card=complete&id=14230

Edit:
I believe the issue I had was due to the Ajax being embedded within more than one WordPress function and also a Woocommerce action. The variable I needed was not being passed from my PHP to the Ajax like it normally would be. I used a session variable instead, which fixed that particular issue.
The Ajax now uses the "data:" line to pass the data over to save-card-size.php rather than passing it inside the url. I would show the code but the editor is too glitchy on this site, it wouldn't allow me to copy and paste my code properly.
I also had to replace the include in save-card-size.php with the contents of database-handler.php.
Everything is now working.

WordPress has its own database handler which is automatically loaded, there are most likely conflicts between your code and WordPress, but without seeing the actual error, I can not give more information.
Check this out https://developer.wordpress.org/reference/classes/wpdb/
Example:
global $wpdb;
$results = $wpdb->query($wpdb->prepare( 'UPDATE db_name SET column = 'Some Value' WHERE id = %d' , $id ));

From JS to PHP; yet another CORS issue (seems to be)

Good morning community,
currently Im writing a plugin (account managing for a dev-tool called "Construct 2" (scirra.com)) in Javascript which uses a PHP backend and communicates with it via AJAX.
When the backend script only contains simple tasks, like...
<?php header("Access-Control-Allow-Origin:*"); // Allow all origins
$InputAction = $_POST["Action"]; // Eventhandler
if ($InputAction == "Register") {
echo("-400") } ?>
everything works fine. But when I put in the bit more complex stuff I wanted to include, Im always getting a CORS denial:
XMLHttpRequest cannot load http://api.proxy.wtf/debug.php. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://192.168.0.14:50001' is therefore not allowed access. The response had HTTP status code 500.
The code I used for the above error:
<?php
header("Access-Control-Allow-Origin:*"); // Allow all origins
require('includes/config.php'); // Prerequisite
/** Numeric callbacks (!negative values!)
-200 Registration successful; validation mail sended
-250 Username OK
-300 Username too short
-301 Username already in use
-302 Password too short
-303 Invalid email address
-304 Email already in use
-305 Error while registration
-400 Illegal request
**/
$InputAction = $_POST["Action"]; // Eventhandler
$InputUsername = $_POST["Username"]; // Requesting username
$InputMailaddress = $_POST["Mailaddress"]; // Requesting mail address
$InputPassword = $_POST["Password"]; // Requesting password
if ($InputAction == "Register") { // Action: Register
if(strlen($InputUsername) < 3){ // Check Username length
$error[] = 'Username is too short.';
echo("-300");
} else { // Check if username already exists
$stmt = $db->prepare('SELECT username FROM members WHERE username = :username');
$stmt->execute(array(':username' => $InputUsername));
$row = $stmt->fetch(PDO::FETCH_ASSOC);
echo("-250");
if(!empty($row['username'])){ // If username already taken
$error[] = 'Username provided is already in use.';
echo("-301");
}
}
}
else {
echo("-400");
}
?>
Has someone an idea for me, what Im doing wrong? The syntax doesnt contain errors (as far as I can see). Unless Im no expert in php/ajax, I think that some minds here could help me out/point me where my mistake is at. Im willing to learn - so if Im doing something like a common mistake, please tell me :s
Have a great day,
Tan
Edit:
Heres the JS part http://pastebin.com/iABkRmt0 (reuqesting stuff starts at line ~115 - its the complete JS SDK script for C2, sorry for that - but at least its complete ;))

You have to use jsonp,
I am giving you an example of Jsonp usage, hope this will help u
$.ajax({
url: "http://data.acgov.org/resource/k9se-aps6.json?city=Alameda",
jsonp: "$jsonp",
dataType: "jsonp"
}).done(function(data) {
console.log("Request received: " + data);
});

you have not mentioned about ajax code.. is that ajax request also initiated from same url or it is seperate...?

How can I convert this PHP code in a way that will allow me to add it in .JS using Ajax?

I have a .js file hosted on domain1.com, but for this to work correctly I need to add a PHP code at the beginning. The reason for this is to bypass some restriction on Safari for my script and it requires me to create a session. The PHP code creates a session through a url to domain2.com. There is no browser redirection or anything, the user stays in the domain1.com. I want to have a single .js file in domain1.com so maybe an AJAX solution is what I need. Here it is:
<?php
session_start();
if (!isset($_SESSION['isIFrameSessionStarted']))
{
$_SESSION['isIFrameSessionStarted'] = 1;
$redirect = rawurlencode('http://' . "{$_SERVER['HTTP_HOST']}{$_SERVER['REQUEST_URI']}");
header('Location: domain2.com/start-session.php?redirect=' . $redirect);
exit;
}
?>
The start-session.php file is hosted on domain2.com does not need any changes, it contains this:
<?php
session_start(); // create the session cookie
$redirect = rawurldecode($_GET['redirect']);
header('Location: ' . $redirect); // redirect back to domain
exit;
?>

Let me combine what you requested in comments:
I have a .js file hosted on domain1 ... I want to have a single js file and I can't put PHP into that ... the whole purpose of this is for domain1 to not have any php code or php file. ... The reason is because I want it cross-domain and the session to be created from domain2.
It sounds like your issue might be related to the Safari iFrame session cookie problem, especially because you have if (!isset($_SESSION['isIFrameSessionStarted'])) in one of your code blocks. I will continue with this assumption.
Summary of the problem for other readers:
Upon embeding an IFrame from one domain into a website of a different domain, you will quickly realise that Internet Explorer and Safari are blocking the cookies (and thus the session variables) of the website inside the IFrame (ref).
Attempted solutions that didn't pan out:
Safari 3rd party cookie iframe trick no longer working?
Internet Explorer & Safari: IFrame Session Cookie Problem
IFrame must die
Safari: Setting third party iframe cookies
PHP Session in iFrame in Safari and other browsers
My solution:
Essentially, PHP session "hijacking". It works surprisingly well where the above solutions failed. This is the essential solution. Please do any security enhancements* and URL-prettifying you like. Basically, we retrieve the PHP session ID through redirects and pass this to the iframe. Instructions are in the comments.
In your domainA.com head place this:
<script src="session.js"></script>
session.js (on domainA.com):
// Location of the domain B session starter
var sessionScriptURL = "http://domainB.com/start-session.php";
var refQSparam = "phpsessionid";
// Check if we have the phpsessionid in the query string
var phpsessionid = getParameterByName(refQSparam);
if(phpsessionid === null) {
// Not in the query string, so check if we have it in session storage
var sessionStore = sessionStorage.getItem(refQSparam);
if(sessionStore === null) {
// We have no session storage of the PHP session ID either, redirect to get it
top.location = sessionScriptURL + "?redirect=" + encodeURIComponent(self.location.href);
} else {
// phpsessionid was found in session storage. Retrive it
phpsessionid = sessionStore;
}
} else {
// Save the phpsessionid to session storage for browser refresh
sessionStorage.setItem(refQSparam, phpsessionid);
// Optional: Redirect again to remove the extra query string data
}
// Helper to get QS values
function getParameterByName(name) {
return decodeURIComponent((new RegExp('[?|&]' + name + '=' + '([^&;]+?)(&|#|;|$)').exec(location.search)||[,""])[1].replace(/\+/g, '%20'))||null;
}
session-starter.php (on domainB.com):
<?php
session_start(); // create the session cookie
$redirect = rawurldecode($_GET['redirect']);
// redirect back with the php session ID
// Optional: encode this information
$href = $redirect . '?phpsessionid=' . session_id();
header('Location: ' . $href);
exit;
HTML (in the body, on domainA.com):
Append PHP session information to the iframe src.
<script>
document.write('<iframe src="http://domainB.com/embedded-script.php?phpsessionid='+phpsessionid+'"></iframe>');
</script>
embedded-script.php (on domainB.com, in an iframe):
<?php
// Use the phpsessionid passed in
$phpsessionid = rawurldecode($_GET['phpsessionid']);
// REF: http://php.net/manual/en/function.session-id.php
function session_valid_id($session_id) {
return preg_match('/^[-,a-zA-Z0-9]{1,128}$/', $session_id) > 0;
}
// Check that this is potentially a valid session ID
if(session_valid_id($phpsessionid)) {
// Set the session to the one obtained in session-start.php
session_id($phpsessionid);
}
session_start(); // Only call this after session_id()!
// Rest of your code
*Considerations:
Don't actually use document.write, use jQuery or document selectors.
Encode the PHP session ID
Perform another redirect back to the base URL of domainA.com to remove the ?phpsessionid= in the URL for a cleaner look.
If you decide to call session-starter.php with AJAX instead, you will get a new PHP session ID every time for the same reason. The iframe will successfully use this session ID, but if you open a new page to domainB.com, the session will yet again be different.

If you want to run PHP within a file extended with .js, you can do this by telling your apache web server. Add the following directive to the .htaccess or directly to the apache config:
AddType application/x-httpd-php .js
After this is done, your server will run the included PHP code as soon as the file is requested from the server.
Update:
If you want to use sessions with JavaScript, you can do this with an AJAX solution. For this implement a web service on the server which should store the session values. Programming language for implementation can be PHP or another one which can be run by the web server. Request the web service with JavaScript. Here is an answer with an example.

If you want to redirect in Javascript, you can't use a PHP redirect which you have called from AJAX. You can pass the URL you create in PHP and send it back to JavaScript and do the redirect from there. You can do something like:
PHP:
session_start();
if (!isset($_SESSION['isIFrameSessionStarted'])) {
$_SESSION['isIFrameSessionStarted'] = 1;
$redirect = rawurlencode('http://' . "{$_SERVER['HTTP_HOST']}{$_SERVER['REQUEST_URI']}");
echo json_encode(array('url' => $redirect));
}
JavaScript:
$.get('phpfile', function(result) {
if (!result) return;
var data = JSON.parse(result);
window.location.href = decodeURIComponent(data.url);
});

Don't know what you're trying to achieve exactly but let's say you want to go from php to js and back to php you could trying something like this:
Solution 1: Using XMLHttpRequest
In PHP (domain1.com):
<?php
$parameter = ""; //If you'll like to add a parameter here
echo "<script type='text/javascript'>window.addEventListener('DOMContentLoaded',". "function () { goToJS('$paramter');});</script>";
?>
In JS:
window.goToJS = function (parameter) {
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function () {
if (xmlhttp.readyState === 4 && xmlhttp.status === 200) {
//You can redirect back to a php file here
document.location.href = "domain1.com";
//You can view feedback from that php file you sent the stuff to here - just for testing
alert("feedback" + xmlhttp.responseText);
}
}
xmlhttp.open('GET', 'http://domain2.com/start-session.php?q=' + parameter, true);
xmlhttp.send();
}
Not sure about your redirect links and stuff but yeah this should pretty much work. Did something similar a while back
Solution 2: Using ajax
Using ajax you could have a JS script as follows. (type could be POST or GET, Used an example where you sent some json to the php file. Can change the data sent if you properly describe to me what you wish to send. Alternatively could be null also
In JS:
function init_() {
$.ajax({
type: 'POST',
url: 'http://domain2.com/start-session.php',
data: {json: JSON.stringify(selectedEvent)},
dataType: 'json'
}).done(function (data) {
console.log('done');
console.log(data);
}).fail(function (data) {
console.log('fail');
console.log(data);
});
}
In PHP:
Let's say you sent a javascript json to PHP. You could use it in PHP as follows:
<?php
$status_header = 'HTTP/1.1 ' . 200 . ' ' . 'OK';
header($status_header);
header('Content-type: text/javascript');
$json = json_decode($_POST['json']); //Do whatever you want with the json or data sent
echo "This is the returned data"; //Echo returned data back to JS or wherever
?>

why don't just use script directly (if you put this script on top of file it will wait the script to finish creating session in domain2 anyway. (I guess you have iframe in domain1 that call to domain2?)
<script src="http://domain2.com/start-session.php"></script>

USe jquery and jqxhr object for this request, no need send browser to second server, from domain1 you can request to browser load page to init session, and your client never see that.
//include jquery min library and do next code
$(document).ready(function (){
var jqxhr = $.get( "http://domain2.com/start-session.php", function() {
alert( "success" ); //some action for success
})
.done(function() {
alert( "second success" ); //when all is done (success done)
})
.fail(function() {
alert( "error" ); //some action for error
})
.always(function() {
alert( "finished" ); //some end action for anycase
});
});
you can delete .done function, .fail function, and always function as you wish.
NOTE: ready function is to make sure, that domain1 page completely load, and then run script.
reference https://api.jquery.com/jquery.get/

Trying to pull xml / json

Im having issues using trying to pull the first 15 words out of the file from the API. I have tried both as an XML and JSON and still seem to be getting this error:
XMLHttpRequest cannot load
No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.
Im using the We feel fine API.
Here is my code:
<script type="text/javascript">
(function() {
var WeFeelAPI = "http://api.wefeelfine.org:8080/ShowFeelings?display=json&returnfields=feeling,conditions&limit=15";
$.getJSON( WeFeelAPI,function (json){
var feel = json.results[15];
console.log('Our feelings : ', feel);
});
})();
</script>
Any help would be appreciated i'm very new to all this, thanks

Reading up on the We Feel Fine APIs, it doesn't seem like they support JSONP, or even JSON from what I can see.
The issue preventing you from calling it is known as the Same Origin Policy. It prevents a domain from making an illegal request to another domain because of the security concerns it poses. You can read on it here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Same_origin_policy_for_JavaScript
JSONP (JSON with Padding) is a way for sites to work around it by loading the response a an external script that then triggers a callback function to validate the response content. This actual provides good info on SOP and JSONP: http://www.codeproject.com/Articles/42641/JSON-to-JSONP-Bypass-Same-Origin-Policy.
Unfortunately, the API you're using doesn't look to support JSONP so it would require the proxy approach. There is a clever/creative/maybe hackish(opinion) approach using something called Yahoo Query Language (YQL). YQL allows you to perform a x-domain request by using Yahoo's query service as the "proxy." You pass a request with a SQL-like query to it and Yahoo handles the JSONP approach. You can read about that here: http://developer.yahoo.com/yql/ (sorry for all the reading.)
And now for some code to demonstrate this. Note the QUERY being used to retrieve your XML and the fact that it must be encoded for URI use:
(function () {
var url = 'http://api.wefeelfine.org:8080/ShowFeelings?display=xml&returnfields=feeling,conditions&limit=15'
// using yahoo query
var query = 'http://query.yahooapis.com/v1/public/yql?q=' + encodeURIComponent('select * from xml where url="' + url + '"') +
'&format=json&callback=?';
// make request via YQL and show data
$.getJSON( query, function(data) {
console.log(data);
// yql returns "results" in "query" from data
console.log(data.query.results);
});
})();
Play with the fiddle: http://jsfiddle.net/Ty3y2/
This same approach can actually be used to load HTML, and in fact is probably used for that more. The key is "select * from xml where..." which tells it to select everything inside the XML element found at the requested URL. Remember that XML data has a XML element at the root. Most times you will see this as "select * from html where..." because a typical web request returns HTML which is a HTML element at the root.
I have used this approach for a couple projects, though most of mine use a proxy via PHP or C#. However, I have had good success with this and it's useful when you don't want/need to put together a proxy for it.

Here's a simple PHP proxy you can run along-side your page with the JavaScript
<?php
// Saved as ShowFeelings-proxy.php
$options = array_merge($_GET, ['display' => 'xml']);
// if you don't have PHP 5.4+, you need to use the legacy array literal syntax, eg
// array('display' => 'xml')
$uri = 'http://api.wefeelfine.org:8080/ShowFeelings?' . http_build_query($options);
$xml = simplexml_load_file($uri);
// assuming you'd rather work with JSON (I know I would)
$data = [];
foreach ($xml->feeling as $feeling) {
$entry = [];
foreach ($feeling->attributes() as $attr => $val) {
$entry[$attr] = (string) $val;
}
$data[] = (object) $entry;
}
header('Content-type: application/json');
echo json_encode($data);
exit;
Then in your JavaScript...
+function($) {
var url = 'ShowFeelings-proxy.php',
options = {
'returnfields': 'feeling,conditions',
'limit': 15
};
$.getJSON(url, options, function(data) {
var feeling = data[14]; // array is zero-based
console.log(feeling);
});
}(jQuery);

How to send html ready to display from perl script?

#!/usr/bin/perl
# perl cgi script products2.cgi
use DBI;
print <<END_HTML;
Content-type: text/html
END_HTML
my $host = "xxx.xxx.xxx";
my $port = "xxxx";
my $database = "proj4";
my $username = "xxxxxx";
my $password = "xxxxx";
my $database_source = "dbi:mysql:$database:$host:$port";
my $dbh = DBI->connect($database_source, $username, $password)
or die 'Cannot connect to db';
my $sth = $dbh->prepare("SELECT distinct category FROM products");
$sth->execute();
#getting the categories and displaying them
while(my #row=$sth->fetchrow_array()) {
my $data =$row[0];
my #values = split(' ',$data);
my $pic = "/~xxxx/proj4/images/".$values[0].".jpg";
print <<END_HTML;
<div class="view view-first">
END_HTML
print"<img src=\"$pic\" alt=\"$row[0]\"/>";
print "<h2 class=\"choc\"><span>$row[0]</span></h2>";
print "<div class=\"mask\">";
print "<h2 class=\"eff\">\"$row[0]\"</h2>";
print <<END_HTML;
<p>One of Our best sellers</p>
Discover
</div>
</div>
END_HTML
}
$sth->finish();
$dbh->disconnect();
I am trying to replace the contents of
<div id="content"></div>
in my proj.html to the output of the above perl script when clicked on "products" link in the navigation bar.
//navigation bar for product
<li>
<a href="/perl/xxxxx/products2.cgi" id="productit">
Products
</a>
</li>
I know I have to use javascript and ajax, but not sure how to do it.
$('#productit').bind('click', function() {
var handle = document.getElementById('content');
var req = new HttpRequest('/perl/xxxxx/products2.cgi', callback);
//i know this ajax call only expects string to be returned from server
req.send();
handle.innerHTML= //not sure how to populate this
});
Could someone please guide me as to how to send html ready to display from the perl script

All you have to do is print the HTML and it gets sent to the client/browser.
However...
I notice one minor detail in your Perl code which would cause the web server to throw a 500 Internal Server Error: You forgot to print a blank line after your HTTP headers. The code posted would send the output
Content-type: text/html
<div class="view view-first">
...
which is not a valid HTTP response because <div is not a recognized HTTP header. It needs to send
Content-type: text/html
<div class="view view-first">
...
instead, with a blank line to indicate the end of headers before the content starts.
This is one of the reasons why it's generally a good idea to use a web framework (such as Dancer, Mojolicious, or Catalyst) or even the arcane CGI.pm instead of handling these things manually: there are so many minor details and strange edge cases that you need to get just right or else it will fail to work for no apparent reason. If this is a learning exercise, rolling your own is fine and it's good to learn where all those pitfalls are, but you're better off using a widely-used and well-tested module to deal with them in code whose purpose is to do something useful or important.

You can use the $.ajax() method since you are using jquery
$('#productit').bind('click', function(e) {
var handle = document.getElementById('content');
e.preventDefault();
$.ajax({
dataType : 'text', /* the datatype you are returning */
url: '/perl/xxxxx/products2.cgi',
success:function (data){ /* data is the data returned from the ajax call */
handle.innerHTML = data;
}
});
});