[RESOLVED] jQuery POST to PHP Script That Updates MySQL

[rsmith]

I'm still new to jQuery and if this isn't the proper forum, please move it to the proper forum.

I have the following jQuery function defined:

function cancel_file(id){	
			jQuery.ajax({
   			type: "POST",
   			url: "https://www.mysite.com/cancel.php",
   			data: 'id='+ id,
   			cache: false,
   			success: function(response){
						(response == 1){
		     				alert('File successfully cancelled!');
	     				}
	     	        error: function(response){
		     			if(response == "invalid_id"){
							alert('The file ID format is invalid');
						}else if(response == "no_record_found"){
							alert('No file found with ID specified');
	     				}

				}
		});
	}

That posts the data to cancel.php via a text link to update a column in a MySQL table

<a href="#" onclick="cancel_file(12)">Cancel</a>

The file id is dynamically passed to the link and that part works so I chose 12 for simplicity.

<?php
	// Get the zip id and make sure it's in a valid format
		$id = $_POST['id'];

	if(!ctype_digit($id)){
		$response = "invalid_id";
	}else{
		// If validation passes proceed to queries and cancellation process
			$q1 = "UPDATE `tbl_files` SET `is_invalid` = 1 WHERE `id` = '".$id."'";
			$r1 = mysql_query($q1) or die(mysql_error());

		if(mysql_affected_rows() > 0){
			$response = mysql_affected_rows();
		}else{
			$response = "no_record_found";
	}

	echo $response;
?>

$response = mysql_affected_rows(); should end up behing $response = 1 if the query is successful and that response passed back to the jQuery for alert. But the problem is nothing happens when I click the "Cancel" link. I verify that the MySQL table has a file with the ID passed to the script and the "is_invalid" column has not changed.

Thanks in advance for any advice and guidance.

[Weedpacket]

Is the missing "if" from your JavaScript a typo when you were copying it into your post?

How does the the Ajax handler distinguish between a "success" response and an "error" response (i.e., are you sending distinct http response codes)?

If the "is_invalid" column has not changed, does that mean it is still 0 after an attempt to cancel it?

What is the response that gets sent back? What are your callbacks actually receiving?

[rsmith]

Is the missing "if" from your JavaScript a typo when you were copying it into your post?

Yes. I accidentally deleted it when I was attempting to format for the code blocks, I re-copied it here:

function cancel_file(id){	
			jQuery.ajax({
   			type: "POST",
   			url: "https://www.mysite.com/cancel.php",
   			data: 'id='+ id,
   			cache: false,
   			success: function(response){
						if(response == 1){
		     				alert('File successfully cancelled!');
	     				}
	     	        error: function(response){
		     			if(response == "invalid_id"){
							alert('The file ID format is invalid');
						}else if(response == "no_record_found"){
							alert('No file found with ID specified');
	     				}

				}
		});
	}

How does the the Ajax handler distinguish between a "success" response and an "error" response (i.e., are you sending distinct http response codes)?

I am attempting to modify the success / error responses from a previous script I found that does work. That script just grabs the $response that is echoed to the screen, or so it seems

If the "is_invalid" column has not changed, does that mean it is still 0 after an attempt to cancel it?

Yes, exactly. The field "should" change to 1

What is the response that gets sent back? What are your callbacks actually receiving?

I'm not getting anything back, no alerts or anything.

[Weedpacket]

rsmith wrote:

I am attempting to modify the success / error responses from a previous script I found that does work.

So that script doesn't set the http response code either? So how does jQuery.ajax() distinguish between success and error responses?

rsmith wrote:

I'm not getting anything back, no alerts or anything.

An "alert" is not a response, and it's not what the callback is receiving. The response is what the server sends to the browser. Any decent browser these days will have a console that lets you look at this traffic.

You don't get any alerts. Okay, time to apply a bit of logical thought. Assuming everything else is working as it should, under what conditions will there fail to be an alert?

1. The "success" handler is called but the response is not equal to 1.

2. The "error" handler is called, but the response is neither "invalid_id" nor "no_record_found".

As well as looking at the http response, you could also add an alert that is always triggered, so that you can see what the response was even if those situations occur. You could, for example, add a complete() callback that alerts you with the response's responseText.

But what could the server be sending? Again, let's do a bit of thinking.

1. if $id doesn't pass the ctype_digit() test, the server sends back "invalid_id".

2. if the query succeeds, and at least one row is changed, then the server sends back a number greater than zero.

3. if the query succeeds, but no rows are changed, then the server sends back "no_record_found".

4. if the query fails, then the server sends back a MySQL error message.

Does your Ajax response handler cover all those bases?

include("obligatory note about the MySQL extension being outdated.php");

[rsmith]

Okay, so I added a console.log(response); statement and opened Chrome's Javascript Debugger. It's saying that "cancel_file" is not defined. Here's the updated code.

function cancel_file(id){	
			jQuery.ajax({
   			type: "POST",
   			url: "https://dev.filecipher.com/cancel.php",
   			data: 'id='+ id,
   			cache: false,
   			success: function(response, textStatus){
	   					console.log(response);
     				     }
	     	        error: function(response){
		     			console.log(response);
			         }
			});
		}

I include the file that contains this function in the <HEAD> section of my page as follows:

  <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
  <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.7.1/jquery-ui.min.js"></script>
  <script type="text/javascript" src="/js/jquery.js"></script>

I have verified that the path is valid and accessible and by going to mysite.com/js/jquery.js it comes up.

And I know MySQL is outdated but it's what I was given to work with. I'm not the lead developer so it's not my call. Thanks for the patience as I try to understand and grasp jQuery better.

[Ashley_Sheridan]

You're missing a comma after the closing brace on line 9 of that function in your Javascript.