Empty response by JQuery.ajax and object and php

Question

I am stuck by creating my first universal code for ajax responses. I simply do not get an output here, neither in php nor in the ajax response. This must have something to be in the post data.

This is my ajax request:

        var info = {};
        //get id info
        info["ses-id"] = $("#theme").attr("scene");
        //get template info
        info["ses-template"] = $("#theme").attr("template");

        $.ajax({
            dataType: "json",
            contentType: "application/json; charset=UTF-8",
            data: JSON.stringify(info),
            type: "POST",
            url: "query.php"
        }).done(function(data, textStatus, jqXHR) {
            alert (data);
            //window.location = "?szenen";
            console.log("Data sent.");
        }).fail(function(jqXHR, textStatus, errorThrown) {
            console.log("There was an error." + errorThrown);
        });

This is my query.php so far:

    <?php 
        $return = $_POST;
        $return["json"] = json_encode($return);
        print(json_encode($return));

The output is an object where only the json entry is filled with [].

The stringified variable looks good, it's a string like this:

    {"ses-id":"1","ses-template":"2"}

Thanks for any advice!

@Naruto succes(), error() and complete() are deprecated in JQuery 1.8 — Matheno
– Matheno, Commented Mar 12, 2015 at 14:05
@Naruto From the jQuery docs: An alternative construct to the success callback option, the .done() method replaces the deprecated jqXHR.success() method — robbmj
– robbmj, Commented Mar 12, 2015 at 14:05

cwurtz · Accepted Answer · 2015-03-12 14:35:51Z

1

Your problem is you are sending a json encoded string as the POST body, and then using $_POST to access it. $_POST is an array of key/value POST data. Since your data doesn't have a key, you can't access it from the $_POST array. It's just a value (a string value at that).

If you change your PHP script to be:

<?php
echo file_get_contents("php://input");
?>

It will output the JSON you passed in. Note that there is no need to do a json_encode() because the value is a string, not an array. The json you passed it was never decoded.

Alternatively, if your javascript was:

$.ajax({
    data: { "data": JSON.stringify(info) },
    type: "POST",
    url: "query.php"
})

then your post body would be:

data={"ses-id":"1","ses-template":"2"}

you could then do

<?php
echo $_POST["data"];
?>

Again noting the data you sent it was never decoded, so it's still just a string. PHP does not json_decode for you.

edited Mar 12, 2015 at 14:35

answered Mar 12, 2015 at 14:23

cwurtz

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5 Comments

Daniel Over a year ago

I changed the line to data: { "data": JSON.stringify(info) },, but the $_POST["data"] is still empty. I don't get it.

cwurtz Over a year ago

Check if the echo file_get_contents("php://input"); works. Also updated my answer, removed the json data/content types defined. Try without those defined

Daniel Over a year ago

I am getting data (whoooho) but it seems urlencoded. I will try to get it into the post variable.

n-dru Over a year ago

When you remove contentType and JSON.stringify, like in my answer, then $_POST is normal array with those key value pairs as expected.

cwurtz Over a year ago

np, sorry i wasn't spot on, I assumed the jquery was correct and was just testing the POST call manually, and saw the data go through fine. Also just checked the docs, don't remove the dataType: "json" I said to, it's what decodes the json response

Community · Accepted Answer · 2017-05-23 11:43:24Z

1

The dataType and contentType both must be deactivated, then I got responses.

    $.ajax({
        //dataType: "json",
        //contentType: "application/json; charset=UTF-8",
        data: JSON.stringify(info),
        type: "POST",
        url: "query.php"

Varying the info object results in varies of the php var but that wasn't my problem.

BIG thanks to everyone especially CJ_Wurtz who pushed me the right way.

edited May 23, 2017 at 11:43

CommunityBot

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answered Mar 12, 2015 at 14:52

Daniel

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Comments

n-dru · Accepted Answer · 2015-03-12 14:34:19Z

0

It works when you drop contentType and JSON.stringify:

    var info = {};
    //get id info
    info["ses-id"] = $("#theme").attr("scene");
    //get template info
    info["ses-template"] = $("#theme").attr("template");

    $.ajax({
        dataType: "json",
        data: info,
        type: "POST",
        url: "query.php"
    }).done(function(data, textStatus, jqXHR) {
       console.log(data);
        //window.location = "?szenen";
        console.log("Data sent.");
    }).fail(function(jqXHR, textStatus, errorThrown) {
        console.log("There was an error." + errorThrown);
    });

answered Mar 12, 2015 at 14:34

n-dru

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1 Comment

Daniel Over a year ago

Thanks, the result is that contentType and dataType must be removed.

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