how to use JSON.stringify and json_decode() properly

Question

Im trying to pass a mulitidimensional Javascript array to another page on my site by:

using JSON.stringify on the array
assigning the resultant value to an input field
posting that field to the second page
using json_decode on the posted value
then var_dump to test
(echo'ing the posted variable directly just to see if it came through at all)

Javascript on page one:

var JSONstr = JSON.stringify(fullInfoArray); document.getElementById('JSONfullInfoArray').value= JSONstr;

php on page two:

$data = json_decode($_POST["JSONfullInfoArray"]); var_dump($data); echo($_POST["JSONfullInfoArray"]);

The echo works fine but the var_dump returns NULL

What have I done wrong?

This got me fixed up:

$postedData = $_POST["JSONfullInfoArray"]; $tempData = str_replace("\\", "",$postedData); $cleanData = json_decode($tempData); var_dump($cleanData);

Im not sure why but the post was coming through with a bunch of "\" characters separating each variable in the string

Figured it out using json_last_error() as sugested by Bart which returned JSON_ERROR_SYNTAX

A little bit HTML of the form would help too. Look into the request using your browser's inspector, do you see what you expect? — UltraInstinct
– UltraInstinct, Commented Apr 13, 2013 at 9:33

S. A. Malik · Accepted Answer · 2018-03-07 11:54:14Z

65

When you save some data using JSON.stringify() and then need to read that in php. The following code worked for me.

json_decode( html_entity_decode( stripslashes ($jsonString ) ) );

Thanks to @Thisguyhastwothumbs

answered Mar 7, 2018 at 11:54

S. A. Malik

3,6756 gold badges41 silver badges59 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Priyanka Ahire Over a year ago

Thanks this is work for me!!! ... In $request["reporthead"] data as string which is from javascript $tempData = \html_entity_decode(stripslashes ($request["reporthead"])); $reportheaddata = json_decode($tempData, true);

user1881928 · Accepted Answer · 2014-07-01 18:03:20Z

35

When you use JSON stringify then use html_entity_decode first before json_decode.

$tempData = html_entity_decode($tempData); $cleanData = json_decode($tempData);

edited Jul 1, 2014 at 18:03

answered Mar 26, 2014 at 10:27

user1881928

6166 silver badges8 bronze badges

1 Comment

treyBake Over a year ago

worth noting in wp I used the above with stripslashes within the html_entity_decode to make work :

Bart · Accepted Answer · 2014-10-25 19:49:39Z

You'll need to check the contents of $_POST["JSONfullInfoArray"]. If something doesn't parse json_decode will just return null. This isn't very helpful so when null is returned you should check json_last_error() to get more info on what went wrong.

Yuv · Accepted Answer · 2016-06-04 05:38:22Z

None of the other answers worked in my case, most likely because the JSON array contained special characters. What fixed it for me:

Javascript (added encodeURIComponent)

var JSONstr = encodeURIComponent(JSON.stringify(fullInfoArray)); document.getElementById('JSONfullInfoArray').value = JSONstr;

PHP (unchanged from the question)

$data = json_decode($_POST["JSONfullInfoArray"]); var_dump($data); echo($_POST["JSONfullInfoArray"]);

Both echo and var_dump have been verified to work fine on a sample of more than 2000 user-entered datasets that included a URL field and a long text field, and that were returning NULL on var_dump for a subset that included URLs with the characters ?&#.

I also had to use urldecode on PHP for it to work properly.
As @Albion points out, the string needs to be URI decoded before json_decode is invoked. json_decode(urldecode($_POST["JSONfullInfoArray"]));

Gerard de Visser · Accepted Answer · 2014-09-24 08:28:51Z

8

stripslashes(htmlspecialchars(JSON_DATA))

edited Sep 24, 2014 at 8:28

Gerard de Visser

8,1009 gold badges54 silver badges62 bronze badges

answered Sep 24, 2014 at 7:12

LOVEPIN

891 silver badge2 bronze badges

1 Comment

Bayu Over a year ago

I am not sure why htmlspecialchars() must there. It will convert the quote character ( " ) to " which is mean can't be processed by json_decode(). I am sure JSON format must be something like {"key":"value"}, but by using htmlspecialchars() it will convert to {"key":"value"} how come json_decode() processing it?

J-J · Accepted Answer · 2018-01-22 11:10:30Z

3

jsonText = $_REQUEST['myJSON']; $decodedText = html_entity_decode($jsonText); $myArray = json_decode($decodedText, true);`

edited Jan 22, 2018 at 11:10

J-J

5,9206 gold badges43 silver badges58 bronze badges

answered Jan 22, 2018 at 10:30

KRISHNA KANT SINGH

771 silver badge5 bronze badges

Comments

user10971804 · Accepted Answer · 2020-03-02 07:21:13Z

I don't how this works, but it worked.

$post_data = json_decode(json_encode($_POST['request_key']));

Collectives™ on Stack Overflow

how to use JSON.stringify and json_decode() properly

7 Answers 7

1 Comment

1 Comment

Comments

2 Comments

1 Comment

Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

7 Answers 7

1 Comment

1 Comment

Comments

2 Comments

1 Comment

Comments

Comments

Linked

Related