使用php插入json数据

Question

我正在尝试将数据插入到表格

的json中

[{"name":"name", "username": "xyz", "email":"xyz@gmail.com", "password":"password0387"}]

进入同一文件夹中的文件。使用post方法传递数据，php将数据插入到json文件中。这是我修改过的php代码：

    <?php


//checking if the script received a post request or not 

if($_SERVER['REQUEST_METHOD']=='POST'){

//Getting post data 

$name = $_POST['name'];

$username = $_POST['username'];

$password = $_POST['password'];

$email = $_POST['email'];


//checking if the received values are blank


if($name == '' || $username == '' || $password == '' || $email == ''){


//giving a message to fill all values if the values are blank


echo 'please fill all values';

        }else{

//If the values are not blank


//Load the file
$contents = file_get_contents('user_doc.json');

//Decode the JSON data into a PHP array.
$json = json_decode($contents, true);

$user = array_search($username, array_column( $json, 'username' ) );

if( $user !== False ) 
$json[$user] = array("name" => $name, "username" => $username, "password" => $password, "email" => $email);
else
$json[] = array("name" => $name, "username" => $username, "password" => $password, "email" => $email);


//Encode the array back into a JSON string.
$json = json_encode($json);

//Save the file.
file_put_contents('user_doc.json', $json);
}
}else{

echo "error";

}

我能够成功发布请求但是我收到了php错误，请帮助我是php的新手... logcat如下所示：

D/success: <br><table border='1' cellpadding='2' bgcolor='#FFFFDF' bordercolor='#E8B900' align='center'><tr><td><font face='Arial' size='1' color='#000000'><b>PHP Error Message</b></font></td></tr></table><br />