AJAX function for retrieving postgres data not working

Question

I have a simple AJAX function bound to a button that should execute a PostgreSQL query. However, when I click the button that I bound the ajax query to, all I get is the confirmation that the database connection was successful. Nothing seems to happen withe the ajax result (should be printing to console in the handleAjax() function. What am I doing wrong?

This is the javascript code (with jquery):

$(document).ready(function() {

    function sendAjax() {

        $.ajax({
            url: "db/database.php",
            success: function (result) {
                handleAjax(result);
            }
        });
    }

    function handleAjax(result) {
        console.log(result);
    }

    $("#submit-button").on("click", sendAjax);

});

And this it the contents of database.php:

    <?php

    function dbconn(){

        ini_set('display_errors', 1); // Displays errors

        //database login info
        $host = 'localhost';
        $port = 5432;
        $dbname = 'sms';
        $user = 'postgres';
        $password = 'postgres';
        // establish connection
        $conn = pg_connect("host=$host port=$port dbname=$dbname user=$user password=$password");
        if (!$conn) {
            echo "Not connected : " . pg_error();
            exit;
        } else {
            echo "Connected.";
        }
    }

    $conn = dbconn();
    $sql = "SELECT * FROM numbers;";

    $result = pg_query( $sql ) or die('Query Failed: ' .pg_last_error());
    $count = 0;
    $text = 'error';
    while( $row = pg_fetch_array( $result, null, PGSQL_ASSOC ) ) {
        $text = $row['message'];
        //echo $text;
    }
    pg_free_result( $result );

?>

toto1911 · Accepted Answer · 2017-12-29 13:00:32Z

1

The problem is in the database.php file, all you get is "Connected." because you don't print your result at the end. Ajax only receive the output of the php file.

So at the end of your php file you should add :

echo $text;

And you also should remove the echo "Connected.";

answered Dec 29, 2017 at 13:00

toto1911

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Comments

Wolen · Accepted Answer · 2017-12-29 13:07:10Z

AJAX is not a magic wand that in magic way reads PHP code. Let's say AJAX is a user. So what does user do.

Open web page
Wait until PHP execute code and display data
Tells you what he sees

If you don't display anything, ajax can't tell you what he saw.

In thi's place is worth to say that the best way to communicate between PHP and AJAX is using JSON format.

Your code generally is good. All you have to do is to display your data. All your data is in your $text var. So let's convert your array ($text) to JSON.

header('Content-Type: application/json');
echo json_encode($text);

First you set content-type to json, so ajax knows that he reads json. Then you encode (convert) your PHP array to js-friendly format (JSON). Also delete unnecessary echoes like 'Conntected' because as I said, AJAX reads everything what he sees.

Milan Palangetic · Accepted Answer · 2017-12-29 13:06:53Z

0

You should return $conn from dbconn()

 if (!$conn) {
        echo "Not connected : " . pg_error();
        exit;
    } else {
        echo "Connected.";
        return $conn;
    }

answered Dec 29, 2017 at 13:06

Milan Palangetic

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