How to unset a json object

问题

What I am writing is a temporarely banning script for people who like to pester my site with small botnets.

The only problem I am having is how to unset a json object.

I have the following code

/* JSON blocking script written by Michael Dibbets
 * Copyright 2012 by Michael Dibbets
 * http://www.facebook.com/michael.dibbets - mdibbets[at]outlook.com
 * Licenced under the MIT license http://opensource.org/licenses/MIT
 */
    // Turn on error reporting
    ini_set("display_errors", 1);
    error_reporting(E_ALL);  
    // Create our codeigniter filepath
    $filepath = FCPATH.'pagemodules/blocked.json';
    // Load file helper to be able to be lazy
    $this->load->helper('file');
    // Read the json file
    $data = read_file($filepath,'c+');
    // Have we succeeded? Then continue, otherwise fail graciously
    if($data !== false)
        {
            // Let's make it readable
        $json = json_decode($data);
            // Display it for debug purposes
        echo $data;
            // Iterate through every object, get the key to be able to unset it
        foreach($json as $key => $obj)
            {
                    // Dump the object for debug purposes
            var_dump($obj);
            echo "<P>";
                    // Has it's life time expired?
            if((int)$obj->{'endtime'} < strtotime("+2 hours 2 minutes"));
                {
                            // remove the object from the array
                unset($json[$key]);
                }
            }
            // Remove the file so we can overwrite it properly
        unlink($filepath); 
        }
    // Add some values to our array
    $json[] = array('ip' => $_SERVER['REMOTE_ADDR'],'endtime' => strtotime('+2 hours'));
    // Encode it
    $data = json_encode($json);
    // Write it to file
    write_file($filepath,$data,'c+'); 

The problem I am having is that json encode doesn't encode it as array but as an object. The problem is that the following doesn't work:

// This gives the error Fatal error: Cannot use object of type stdClass as array in /public_html/ocs_application/controllers/quick.php on line 37
unset($json[$key]);
// This doesn't report anything, and does nothing
unset($json->{$key});

How do I unset the json object?

回答1:

Dude when you use json json_decode pass it a boolean true as a second parameter.

this way you will get ride of the bloody stdClass.

Now if you want to delete a json object basically it's a string so just do something link $var = null;

if you want to unset part of it then you have to decode it first then encode it.

$my_var = json_decode($json, true); // convert it to an array.

unset($my_var["key_of_value_to_delete"]);

$json = json_encode($my_var);

Always pass to true as a second param to json_decode in order to force it to do recursive conversion of the json object.

回答2:

Just to make clear that unset() works with both JSON objects and arrays:

$json_str = '{"foo": 1, "bar": 2, "baz": 3}';
$json_obj = json_decode($json_str);
$json_arr = json_decode($json_str, true);

var_dump($json_obj); // object(stdClass)#1 (3) { ["foo"]=> int(1) ["bar"]=> int(2) ["baz"]=> int(3) }
var_dump($json_arr); // array(3) { ["foo"]=> int(1) ["bar"]=> int(2) ["baz"]=> int(3) }    

unset($json_obj->baz);
unset($json_arr['baz']);

var_dump($json_obj); // object(stdClass)#1 (2) { ["foo"]=> int(1) ["bar"]=> int(2) }
var_dump($json_arr); // array(2) { ["foo"]=> int(1) ["bar"]=> int(2) }

$key = 'bar';
unset($json_obj->$key);
unset($json_arr[$key]);

var_dump($json_obj); // object(stdClass)#1 (1) { ["foo"]=> int(1) }
var_dump($json_arr); // array(1) { ["foo"]=> int(1) }

来源：https://stackoverflow.com/questions/11791221/how-to-unset-a-json-object