Question

I need to update a json list of object via url post data. For example, with url:

http://myweb.com/index.php?name=Peter&surname=Brown

in php, using get method:

$name = $_GET["name"];
$surname = $_GET["surname"];
$json = array();

        $json["nombre"] = $name;
        $json["lat"] = $lat;
        $data[] = $json;

$json_end= json_encode($data);

and json_end efectively is done like I want:

[{"name":"Peter","surname":"Brown"}]

My question is about how I can do it incrementing the json, in order to build an array like:

[{"name":"Peter","surname":"Brown"}]
[{"name":"newname","surname":"newsurname"}]
// and so on

each time user use the url with new parameters.

Do I need to write to a file, or to database? Any tips will be apreciated.

The idea is to be able that any user can add some dat using url. I tried to store the json to a fiel but the storing is durable only along the current session.

Answer 1

<?
/* This needs to be at the top of your file, without ANYTHING above it */
session_start();

/* ... */

if(!array_key_exists('entries', $_SESSION))
{
    $_SESSION['entries'] = array();
}

$_SESSION['entries'][] = array("name" => $_GET["name"], "surname" => $_GET["surname"]);

$json_string = json_encode($_SESSION['entries']);

This would produce a single JSON. However I don’t know whether you meant to or not, but your output is a series of separate JSONs. You could do this by replacing the last line above with:

$json_string = '';
foreach($_SESSION['entries'] as $entry){ 
    $json_string.= json_encode($entry) . "\n";
}

You would also probably want a way to reset/empty the array. In which case I’d change the if test from:

if(!array_key_exists('entries', $_SESSION))

to:

if(!array_key_exists('entries', $_SESSION) || array_key_exists('reset', $_GET))

Which you could use by visiting

http://myweb.com/index.php?reset

---

Edit: If somewhere you add the following code:

foreach($_SESSION['entries'] as $id=>$entry){ 
    printf("%2d: %s\n", $id, json_encode($entry));
}

You’ll get a list of the json elements enumerated by their respective keys. For example, it might look like:

 0: "[{\"name\":\"Peter\",\"surname\":\"Brown\"}]"
 1: "[{\"name\":\"newname\",\"surname\":\"newsurname\"}]"
 2: "[{\"name\":\"George\",\"surname\":\"Washington\"}]"
 3: "[{\"name\":\"John\",\"surname\":\"Adams\"}]"

If you then add the following code:

if(array_key_exists('del', $_GET) && is_numeric($_GET['del']))
{
    $key = (int)$_GET['del'];
    if(array_key_exists($key, $_SESSION['entries']))
    {
        unset($_SESSION['entries'][$key]);
    }
    else
    {
        printf('<strong>ERROR: $_GET['del'] = %d but $_SESSION['entries'][%d] doesn't exist.</strong>', $key, $key);
    }
}

you’ll be able to delete individual json entries by specifying id as the del GET parameter.

For example,

http://myweb.com/index.php?del=2

would delete the entry corresponding to '[{"name":"George","surname":"Washington"}]';

And the remaining entries would be:

 0: "[{\"name\":\"Peter\",\"surname\":\"Brown\"}]"
 1: "[{\"name\":\"newname\",\"surname\":\"newsurname\"}]"
 3: "[{\"name\":\"John\",\"surname\":\"Adams\"}]"
 4: "[{\"name\":\"Thomas\",\"surname\":\"Jefferson\"}]"