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javascriptphpjsonajaxsplice

Writing JavaScript Data To JSON File via AJAX or PHP

I have the following code that displays information on a person in a table, and when a button labeled "learn" is clicked that information gets stored in a key/value type array that is then spliced into the specified JSON object.

All of this works just fine, but I want to alter the file that holds the JSON object itself, meaning I need to deal with server-side code. How can I take this insertion into my JSON object and actually change the textfile it is stored in (such that if I were to open it, the new information would be there)?

My code is as follows -->

index.html

<!DOCTYPE html>
<html>
<head>
    <script type="text/javascript" src="list.js"></script>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
    <title></title>
</head>
<body>
    <table>
        <tr>
            <td>
                <table>
                    <tr><td>Name</td><td class="name">Jenkins</td></tr>
                    <tr><td>Job</td><td class="job">Accountant</td></tr>
                    <tr><td>Size</td><td class="size">Small</td></tr>
                </table>
            </td>
            <td class="description">average joe.</td>
            <td>
                <button class="learn">Learn</button>
            </td>
        </tr>
    </table>


    <script type="text/javascript">
        $(".learn").click(function(){

        // look at jsonData in list.js and append this element to the items list in the 
        // first element, at the first index without removing any content
        jsonData[0].items.splice(0, 0, {
            name: $(this).closest("table").find(".name").text(),
            job: $(this).closest("table").find(".job").text(),
            size: $(this).closest("table").find(".size").text(),
            description: $(this).closest("td").siblings(".description").text()
        });

        // to show that it is properly appending the new information to the existing JSON object
        console.log(jsonData);
    });
    </script>

</body>
</html>

list.js -->

var jsonData = [
  {
    name: "Friends",
    items: [
      {
        name: "Steve",
        job: "pro bowler",
        size: "tall",
        description: "Steve's my man!"
      },
      {
        name: "Jessica",
        job: "HR",
        size: "average",
        description: "a dear friend"
      }
    ]
  },
  {
    name: "Co-Workers",
    items: [
      {
        name: "Martin",
        job: "my boss",
        size: "tall",
        description: "I don't like him"
      },
      {
        name: "Susan",
        job: "Intern",
        size: "average",
        description: "It's not like I have a crush on her or anything..."
      }
    ]
  }
]

So again, it can be seen in the console that jsonData has the information for "jenkins" added to it; however, the textfile itself remains unchanged and I would like it to reflect this addition. Thank you.

Solution

  • It is not possible to change files on the local file system using JavaScript (at least not in all browsers). I would suggest something like:

    JavaScript:

    $(".learn").click(function(){
    $.ajax({
        url: "save.php?action=save",
        method: "POST",
        data: { elem: {
            name: $(this).closest("table").find(".name").text(),
            job: $(this).closest("table").find(".job").text(),
            size: $(this).closest("table").find(".size").text(),
            description: $(this).closest("td").siblings(".description").text()
        }},
        success: function (data){
            console.log("Saved!");
        }
    });
}

    PHP (save.php):

    <?php
    if (!empty($_REQUEST["action"]) && $_REQUEST["action"] == "save" && !empty($_REQUEST["elem"])){
        $data = json_decode(file_get_contents("data.json"), true);
        $data[0]["items"][] = $_REQUEST["elem"];
        file_put_contents("data.json", json_encode($data));
    }
?>

    This is just a very small example. Additionally, you should take care about escaping, checking for the fields, error handling, simultanious updates (more than one client) etc. - but it shows a possible way to do this.