Converting string to json object or array in php

Question

I have to make a web service. Therefore I referred some tutorials in the internet and came up with the following codes

index.php

<html>
<head>
    <title>Form page</title>
</head>

<body>

    <form action="http://localhost:81/my%20web%20service/webservice" method="get">
        Table name:<br>
        <input type="text" name="s" value=""><br>
        <input type="submit" value="Submit">
    </form>
</body>
</html>

webservice.php

<?php

    include('connectdb.php');

    $something = $_GET['s'];
    $sqlcode = mysql_query("Select * from $something");

    $jsonObj= array();
    while($result=mysql_fetch_object($sqlcode))
    {
        $jsonObj[] = $result;
    }

    $final_res =json_encode($jsonObj) ;
    echo $final_res;
?>

connectdb.php

<?php
    $hostname="localhost";
    $username="root"; //write your username
    $password=""; //write your password
    $db_name="webservice_trial"; //write your db name
    $con=mysql_connect($hostname,$username,$password);
    mysql_select_db($db_name,$con) or die ("Cannot connect the Database");
    mysql_query("SET NAMES 'utf8'",$con); 

?>

The above codes works fine. When I enter a name of a table from form.php, it will retrieve all tuples in that particular table.

Now what I want to do is to make data display on another page. i.e. I want to transfer data from webservice.php to another page from json format. so I edited my webservice.php as following

webservice.php

<?php

    include('connectdb.php');

    $something = $_GET['s'];
    $sqlcode = mysql_query("Select * from $something");

    $jsonObj= array();
    while($result=mysql_fetch_object($sqlcode))
    {
        $jsonObj[] = $result;
    }

    $final_res =json_encode($jsonObj) ;
    echo $final_res;

    $jsonArray = (array) json_decode($final_res);
    echo $jsonArray[0];

?>

it gives the following error

[{"name":"hilton","town":"colombo","telephone":"774933705","description":"excellent"},{"name":"galadari","town":"colombo","telephone":"112894143","description":"best"},{"name":"mt. lavinia","town":"mt. lavinia","telephone":"773580324","description":"good"}]

Catchable fatal error: Object of class stdClass could not be converted to string in C:\xampp\htdocs\json_folder\my web service\webservice.php on line 18

The very last line of the posted code. Needs a $ in front of jsonArray. — Source Matters, Feb 21 '16 at 18:53
You'll also want to address the gaping SQL injection issue present in the code posted. :) — Source Matters, Feb 21 '16 at 18:54
Hello [SQL Injection](http://php.net/manual/en/security.database.sql-injection.php) — BugHunterUK, Feb 21 '16 at 19:04
**Danger**: You are using [an **obsolete** database API](http://stackoverflow.com/q/12859942/19068) and should use a [modern replacement](http://php.net/manual/en/mysqlinfo.api.choosing.php). You are **vulnerable to [SQL injection attacks](http://bobby-tables.com/)** that a modern API would make it easier to [defend](http://stackoverflow.com/questions/60174/best-way-to-prevent-sql-injection-in-php) yourself from. — Quentin, Feb 21 '16 at 19:13

IeuanG · Answer 1 · 2016-02-21T19:11:05.077

3

You can either change

$jsonArray = json_decode($final_res);

to

$jsonArray = json_decode($final_res, True);

or, to access the name of the first item use

print $jsonArray[0]->name;

edited Feb 21 '16 at 19:11

answered Feb 21 '16 at 18:56

IeuanG

504
5
13

score 0 · Answer 2 · answered Feb 21 '16 at 19:05

Instead of trying to typecast the decoded string to an array, use this, which is the right way to do it.

$jsonArray = json_decode($final_res, TRUE);

Now, you will have an array, which you can echo or var_dump.

var_dump($jsonArray);

As in your question, what your error says is that, you are trying to echo it as a variable, where what you are trying to echo is actually an object class. Probably because it isnt being typecasted.

Advices:

Please stop using mysql functions. Its deprecated. Use mysqli or PDO.
Read about SQL Injections. Never trust userinputs. Always sanitize them or use prepared statements.

Converting string to json object or array in php

2 Answers2