Fixing: Fatal Error Call To Undefined Function Json_decode

Posted on July 29, 2011 by Tayeb

Introduction

On moving to my new CentOS server (with php version 5.1.6), the php code for automatically twitting latest posts from my forums to Twitter stopped working (check the php code here  A Twitbot Using OAUTH).

I will explain below how the errors were determined and fixed. This post may help others to fix a similar problem.

Determine the symptoms

  1. Enable error messages to be shown by writing ini_set( ‘ display_errors ‘,  ‘ 1’);  in your PHP code.
  2. If the error message is “Fatal Error Call to Undefined Function Json_decode ()”, read on…

The solution by installing JSON PHP Extension

1 . Ssh into your webserver with root privileges

2 .  Install gcc make:
# yum install gcc make

3 .  Install php-pear and php-devel :
# yum install php-pear php-devel

4 .  Install  json:
# pecl install json

If there are no dependency errors, or other, and all packages duly install you will next:
<

  1. Open your php.ini file  (ex. nano /etc/php.ini)
  2. Find in php.ini a section called Dynamic Extensions
  3. Add a line: extension = json.so
  4. Save php.ini and restart Apache (ex. service httpd restart)

You can check if json is enabled, installing in your httpdocs folder a php file (ex. test.php) with the following code:

<?php
phpinfo();
?>

If you open this page in your browser, you will see information on what your server’s php supports, and surely json will be one fo them:

phpinfo() showing json enabled

Finally test json, with following php code (ex. test_json.php) in your httpdocs folder as shown in  php.net website

<?php
$json = ‘{“a”:1,”b”:2,”c”:3,”d”:4,”e”:5}’;
var_dump(json_decode($json));
var_dump(json_decode($json, true));
?>
If you open the file in your browser, the result will be:

object(stdClass)#1 (5) {
[“a”] => int(1)
[“b”] => int(2)
[“c”] => int(3)
[“d”] => int(4)
[“e”] => int(5)
}
array(5) {
[“a”] => int(1)
[“b”] => int(2)
[“c”] => int(3)
[“d”] => int(4)
[“e”] => int(5)
}

Json_decode is now working in your server, and there will be no more error reports such as “Fatal Error Call to Undefined Function Json_decode()”.

About Tayeb

Electronics engineer, part-time webmaster and owner of "Aliatron", a tech-oriented company registered in Portugal and Mozambique. Owner of "EU Halal", a trading and consulting company in Halal & Tayyib, 100% stun-free compliant.
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42 Responses to Fixing: Fatal Error Call To Undefined Function Json_decode

  1. pete says:
    September 1, 2011 at 7:38 pm

    Excellent – worked great – thanks so much!!

    Reply
  2. idham says:
    October 21, 2011 at 5:05 am

    Thank very much, yes i need it and working 😀

    Reply
  3. Thomas says:
    November 23, 2011 at 10:09 am

    thanks for this post, solves my problems

    Reply
  4. Anatoliy says:
    February 10, 2012 at 5:23 pm

    Hi,
    I am on RedHat (Oracle Enterprise Linux to be more exact). And I have issue installing or enabling the json. Would appreciate if you could through an idea. I did
    cd /home/oracle/php-5.3.10/ext/json
    [root@e6400l json]# phpize
    Configuring for:
    PHP Api Version: 20090626
    Zend Module Api No: 20090626
    Zend Extension Api No: 220090626
    Then added the line
    extension = /usr/local/lib/php/extensions/no-debug-non-zts-20090626/json.so
    to php.ini, in my case the php.ini is under /usr/local/lib, but I am still getting the error.
    And the

    doesn’t show I have json support. How do I enable the json in my PHP, this is 5.1.6
    Thanks much
    Anatoliy

    Reply
    • Tayeb says:
      February 11, 2012 at 11:46 pm

      Welcome to my blog. I don’t know sincerely how to help you. I shared here CentOS solution as I was also learning how to do it and since it worked perfectly others could benefit

      Reply
  5. Keith says:
    May 10, 2012 at 4:21 am

    Great! you saved me a lot of time.

    Reply
  6. Connor Tobin says:
    May 27, 2012 at 8:52 pm

    THANK YOU. Sincerely. I was on a tight deadline to get facebook graph data integrated into a site, and I ran into this problem.
    Great fix, thank you.

    Reply
  7. David says:
    June 18, 2012 at 5:35 pm

    Dude, you’re awesome!

    Reply
  8. Marcos says:
    June 25, 2012 at 1:18 pm

    Thanks! Works great! Nice explain.

    Reply
  9. live chat says:
    July 2, 2012 at 1:57 pm

    Cheers, Worked fine here on:

    Red Hat Enterprise Linux Server release 5.4 (Tikanga)

    Bit strange why the yum install itself didnt create the .so file. odd why you needed to compile.
    But yeah, worked fine.

    Reply
  10. John Wolgamot says:
    July 9, 2012 at 7:40 am

    Brilliant.
    I moved up to Centos 6 and was getting a white screen upon joomla admin login. I googled
    PHP Fatal error: Call to undefined function json_decode() in /home/
    I found your page, followed your instructions and it fixed the issue.

    Thanks so much for posting this.

    Reply
  11. luxy says:
    July 13, 2012 at 12:38 pm

    This work great but when i reinstalled JCE, it came back to the same problem, no i can even have an editor working on the site, i have to select no editor in global config else i get this ”
    Fatal error: Call to undefined function json_decode() in /var/www/html/…/administrator/components/com_jce/models/model.php on line 31″ or a blank page

    Reply
  12. Rio says:
    July 17, 2012 at 4:43 am

    salam,
    what if I just a website administrator, not the one who handle the server? can I fix it through my admin page?
    thanks

    Reply
  14. ron says:
    February 11, 2013 at 12:18 pm

    Excellent solution! Got php working with json real quick. Thanks

    Reply
  15. ppiper says:
    March 26, 2013 at 10:38 am

    This helped a LOT! Thx m8!
    Btw. I needed to install the php-json mod as well .. so this might be another blocker.

    Reply
  16. mikeb says:
    April 1, 2013 at 3:40 pm

    Thanks alot!
    That fixed an error I got when trying to send call notifications into an asterisk pbx to twitter

    Reply

  17. Pingback: Ngihik Centos: JSON di PHP 5.1.x | [go2n@buglink:~] $

  18. Sok Sovat says:
    November 27, 2013 at 2:10 am

    That is great! But i have a problem with installing JSON PHP Extension. I’m using CentOS 5.3, 64bits. When i try to install using command yum, it is unknown command yam. Do you know how to install command yum?

    Thank in advance!

    Reply
    • Tayeb says:
      December 1, 2013 at 8:56 am

      Welcome to my blog. My server has yum pre-installed by the Net Center. So effectively to use yum you need to access RPM repository. I suggest you do a bit of reading before going ahead. The following Wiki has the reputation of giving good guidelines:

      http://wiki.centos.org/AdditionalResources/Repositories/RPMForge

      If you succeed, or not, please post here what happened. It may be useful to others.

      Note you must have some basic skills in doing what you want to do, otherwise I advise you seek help from your server’s providers, or from more knowledgeable friends or colleagues.

      Reply
  19. Tony says:
    March 8, 2016 at 7:46 am

    Thank you! Works perfectly for Google reCaptcha which needs JSON

    Reply

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