getting a json string in php from jquery ajax post

Question

I am tring to write a page, which takes a RSS feed from a news site via AJAX and then sends it to PHP where I can work with it. The news feed is returned as an object array. I have tried posting it as it is, and also as a json string. The post method seems to be a success, but PHP gives an undefined index notice. This is my first time using AJAX and PHP and I seem to have problem with getting the data from the PHP side.

The error:

Notice: Undefined index: data in ...\index.php on line 33

Current code is the following:

ajax side

url = 'http://feeds.bbci.co.uk/news/rss.xml?edition=int';

$.ajax({
    type: "GET",
    url: document.location.protocol + '//ajax.googleapis.com/ajax/services/feed/load?v=1.0&num=1000&callback=?&q=' + encodeURIComponent(url),
    dataType: 'json',
    error: function(){
            alert('LOAD ERROR, INVALID URL');
    },
    success: function(xml){
            values = xml.responseData.feed.entries;
            var senddata = JSON.stringify(values);
            console.log(senddata);
            $.ajax({
                type: "POST",
                url: "index.php",
                data: {data : senddata},
                success: function(){
                    alert("postdone!");
                },
                error: function(){
                    alert("posterror!")
                }
            });
        }
});

php side

<?php
    $data = json_decode(stripslashes($_POST['data']));
    echo $data;         
?>

nevermind, I didn't notice the nested ajax. Does console.log(senddata); return anything? — Hieu Nguyen
– Hieu Nguyen, Commented Jul 21, 2013 at 14:48
Two suggestions: First, rename your parameter 'data' to something else. Perhaps there is some confusion since the parameter name matches the .ajax key name. Second, dump the contents of $_POST (var_dump($_POST);`) to see what it contains. Is your data there, perhaps in a place you didn't expect? — George Cummins
– George Cummins, Commented Jul 21, 2013 at 15:12

Hieu Nguyen · Accepted Answer · 2013-07-22 14:18:26Z

2

Wrap your code in an if to avoid that warning:

if (isset($_POST['data'])) {
    $data = json_decode(stripslashes($_POST['data']));
    echo $data;  
}

The problem is when you visit that index.php from browser, there is no POST request, so of course $_POST is empty and $_POST['data'] is not set.

Hope you get the point.

EDIT:

Hmm I can't see anything seriously wrong. And actually now I recommend you to use php.net/manual/en/book.curl.php to get the data directly from the RSS, instead of nesting 2 ajax calls.

edited Jul 22, 2013 at 14:18

answered Jul 21, 2013 at 14:54

Hieu Nguyen

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4 Comments

Reins Over a year ago

Thank you for the answer! Not sure if i get the point. The if condition will just ignore the warning. I can see via the console log that the ajax GET is done and I also get the alert that the ajax POST is done. I guess my question in a nutshell would be - how can I get the newsitems (values OR senddata) from the RSS into PHP, so i can work with these (put certain attributes into a database etc)?

Hieu Nguyen Over a year ago

So both ajax are sent successfully. You can do a var_dump($_POST); in PHP part to debug your call then.

Reins Over a year ago

var_dump($_POST) returns array(0) { } So I'd assume the problem is that I am sending an empty array, hence there is something wrong with the ajax POST method? console.log(senddata), which is before the ajax POST, returns me an array of key:value pairs, which most certainly are present. Any ideas what could be wrong with the POST method?

Hieu Nguyen Over a year ago

Hmm I can't see anything seriously wrong. ANd actually now I recommend you to use php.net/manual/en/book.curl.php to get the data directly from the RSS, instead of nesting 2 ajax calls

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