I created a script to check for potential issues. You can find it here: github.com/robwent/joomla-json-db-check

Nice one Robert!!
Thanks.

Thank you very much @smarterweb – it was the metadata, just had the same problem and could solve it.

@Mohammed, what do need mate?
I'd love to help.

I head the same problem. deleting "{"robots":"","author":"","rights":"","xreference":""}" from the DB solved it. Thanks...

Nice to hear that :)

Same issue here. Some articles throw the error, some don't. The k2_items metadata seems to be the culprit. I have one of 2 things in my metadata.

If I have {"robots":"","author":"","rights":"","xreference":""} then it doesn't work.

If I have the following it does work.

robots=
author=

So first I deleted the nonworking data and left it blank. That works. But then I replaced it with the working data and that seems to work.

I'm going to fix these on an as needed basis and maybe a more robust fix will arrive.

Hello, I have an issue like all of this topic, but I can access to K2 items or category (screenshot attached), I check the metadata items erasing or replacing with the correct form, I check one by one the params content with a JSON Validator and all its OK and still with the same issue. If I open a item from K2 Stats Admin I can show a line error. (screenshot attached). Can some one help me?

http://imgur.com/a/Gnq24

http://imgur.com/a/12Hg6

Hello Jimenez,

I'm not an expert but your error messages are not the 0 Error decoding JSON data: Syntax Error.
They show that it is the JCE Editor component which is having problems: "...com_jce\models\editor.php
Start by checking your Site > Global Configuration > Default editor.

And please start a new topic if you have not been able to resolve it from there..

Best wishes.

Hello,
These errors are coming from the JCE editor not K2.
Disable error reporting to get rid of them.

Mohamed Abdelaziz wrote: Hello All,

I've found this issue while I'm editing some K2 items, after upgrading to Joomla 3.6.4
After some debugging on my personal website, I fixed this issue by hacking the file /administrator/components/com_k2/views/item/view.html.php
I replaced this statement:

FilterOutput::objectHTMLSafe($item, ENT_QUOTES, array(
			'video',
			'params',
			'plugins'
		));

With this one:

FilterOutput::objectHTMLSafe($item, ENT_QUOTES, array(
			'video',
			'params',
			'plugins',
                        'metadata'
		));

You can give it a try, may be it fix your issue.

Thank you, This resolved the issue for me as well. Joomla 3.6.5 / K2 v2.6.9

Cleaning the metadata is the only thing that worked for me - quick DIY post here:
goo.gl/vmaf80

-Alan

Nice one Alan.

I tried running your query like this [note my database prefix is 'jml3_']

SELECT * FROM `jml3_k2_items` SET `metadata` = 'robots=author=' WHERE `metadata` = '{"robots":"","author":"","rights":"","xreference":""}'

but I got the following message:

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'SET `metadata` = 'robots=author=' WHERE `metadata` = '{"robots":"","author":"","' at line 1


I tried this query as suggested by someone else on the first page of this forum:

UPDATE `jml3_k2_items` SET `metadata` = ''

This one went through but in the SQL query page, but in Joomla in K2, the error message when opening any item didn't dissapear.

Finally, I tried changing the view.html.php file as suggested by Mohamed Abdelaziz on the first page, and that did work in removing the error message in K2 and allowing me to see my items. However, I fear that perhaps I might not be able to use metadata in my K2 items anymore by carrying out his solution. So I was wondering Concerto Designs LLC if you know why I'm getting this error message in the SQL query page when running your query with the correct database prefix?

Thanks!

My solution:
Step 1: Edit "(JOOMLA_PATH)/libraries/vendor/joomla/registry/src/Registry.php"
Step 2:
In line 366 replace:
$obj = $handler->stringToObject($data, $options);
to
$obj_count = json_decode($data);
if(count($obj_count) > 0) {
$obj = $handler->stringToObject($data, $options);
} else {
$obj = $obj_count;
}

And everything is back to normal!

Keep in mind that this is a core hack, which will be lost when you update.

Geo Ce wrote: My solution:
Step 1: Edit "(JOOMLA_PATH)/libraries/vendor/joomla/registry/src/Registry.php"
Step 2:
In line 366 replace:
$obj = $handler->stringToObject($data, $options);
to
$obj_count = json_decode($data);
if(count($obj_count) > 0) {
$obj = $handler->stringToObject($data, $options);
} else {
$obj = $obj_count;
}

And everything is back to normal!

Thank you Geo Ce... it managed to overcome my problem

Thank you very much
greetings from me , I hope you succeed

With K2 2.8 the error with the decoding still exists. Why does no fix has been integrated in the newest version?

This is not directly related to K2.
Some items might have been saved or imported incorrectly.
We cannot alter existing items.

This is not directly related to K2.
Some items might have been saved or imported incorrectly.
We cannot alter existing items.

Using Joomla 3.75, PHP7.0 and new install of K2 v2.8, after importing Joomla Content.

When accessing the imported content results in 0 Error decoding JSON data: syntax Error.
Note: The error did not occur until after the installation of K2.

One explanation of the issue is:
The Issue
Joomla stores rules and parameters in the database in JSON format. Previously, if that data was invalid JSON it would silently fail and the site would continue working.

In the 3.6.3 update, the validation of the syntax was improved, so issues that would previously go unnoticed now result in an error page with the aforementioned error message.
Known Causes

JBLibrary plugin - Causes errors on the frontend of the site, fixed in version 2.1.7
Jupgrade - Sites migrated from Joomla 1.5 using this extension.
Many other 3rd party extensions and core extensions have been mentioned.

How to Fix

Sites that have been migrated using Jupgrade may have empty parameter fields set as {""} which should either be {} or {"":""} to be valid syntax. This may be the same with other 3rd party extensions added to any site.

This is the easiest issue to fix and can be done with a simple search and replace on the database.
reference:
www.robertwent.com/blog/fixing-json-data-errors-after-updating-to-joomla-3-6-3/