save image in mysql database using php script from xamarin.forms

Question

I'm trying to save image from my xamarin.Forms code to mysql database using php webservice and json

I'm getting following error while runing php script

** [20-Dec-2016 00:17:08] PHP Warning: mysqli_prepare() expects parameter 1 to be mysqli, null given in /home7/gsakolac/public_html/BBA/prod_update_image.php on line 13 [20-Dec-2016 00:17:08] PHP Warning: mysqli_stmt_bind_param() expects parameter 1 to be mysqli_stmt, null given in /home7/gsakolac/public_html/BBA/prod_update_image.php on line 14 [20-Dec-2016 00:17:08] PHP Warning: mysqli_stmt_execute() expects parameter 1 to be mysqli_stmt, null given in /home7/gsakolac/public_html/BBA/prod_update_image.php on line 15 [20-Dec-2016 00:17:08] PHP Warning: mysqli_stmt_affected_rows() expects parameter 1 to be mysqli_stmt, null given in /home7/gsakolac/public_html/BBA/prod_update_image.php on line 17 **

My php script

<?php
$conn = mysqli_connect('localhost', 'username', 'password', 'dbname');

if($_SERVER['REQUEST_METHOD'] == "POST"){
    $id = isset($_POST['id']) ? $_POST['id'] : "";
    $image = isset($_POST['image']) ? $_POST['image'] : ""; 

    if(!$image==null)
    {
        $sql = "UPDATE tbl_image SET Image = ? WHERE id=$id";

        $stmt = mysqli_prepare($con, $sql);
        mysqli_stmt_bind_param($stmt, "s", $image);
        mysqli_stmt_execute($stmt);

        $check = mysqli_stmt_affected_rows($stmt);
        if($check==1)
            $json=array("status" => 1, "msg" => "Image updates successfully");
            else
            $json=array("status" => 0, "msg" => "error happend while updating image to server.");
    }
    else
        $json=array("status" => 0, "msg" => "Image not uploaded");  
}else{
    $json = array("status" => 0, "msg" => "Request Not Accepted.");
}
@mysqli_close($conn);

/* Output header */
header('Content-type: application/json');
echo json_encode($json);
?>

My xamarin.forms code that converts image file (imgFile Name (string)) to base64string and calls php script

var bytes = default(byte[]);
using (var StreamReader = new StreamReader(imgFile))
{
    using (var mstream = new MemoryStream())
    {
        StreamReader.BaseStream.CopyTo(mstream);
        bytes = mstream.ToArray();
    }
}
string imgstr = Convert.ToBase64String(bytes);

using (var client = new HttpClient())
{
    var url = "url";
    var content = new FormUrlEncodedContent(new[] {
    new KeyValuePair<string,string>("id", id.ToString()),
    new KeyValuePair<string, string>("image", imgstr)
});

    var resp = await client.PostAsync(new Uri(url), content);
    if (!resp.IsSuccessStatusCode)
        General.GSErr("Nothing retrieved from server.");
    else
    {
        var result = JsonConvert.DeserializeObject<General_Response>(resp.Content.ReadAsStringAsync().Result);
        if (result.status == 0)
            General.GSErr(result.msg);
    }
}

I'm new with php codeing please help me.

Amit Saraf

Error reporting level for your application is insufficient – Your Common Sense Dec 20 '16 at 07:30 — Your Common Sense, Dec 20 '16 at 07:30

Logan Wayne · Accepted Answer · 2016-12-20T07:39:27.030

2

Because your first parameter is $con, which should be $conn

$stmt = mysqli_prepare($conn, $sql);

And don't bind variables directly to your query. You're already using prepared statement, utilize it.

$sql = "UPDATE tbl_image SET Image = ? WHERE id = ?";

$stmt = mysqli_prepare($conn, $sql);
mysqli_stmt_bind_param($stmt, "si", $image, $id);

edited Dec 20 '16 at 07:39

answered Dec 20 '16 at 07:29

Logan Wayne

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you need to re-read your book on mysqli prepared statements – Your Common Sense Dec 20 '16 at 07:31
Thanks. sily mistake. thanks for pointing it out. – Amit Saraf Dec 20 '16 at 07:37
when viewing data using MySQL Workbench viewer is not showing image but only text. (what might be wrong) i'm trying to save image file to mysql BLOB field – Amit Saraf Dec 20 '16 at 07:38
@YourCommonSense - will do! Thanks for pointing that one out! – Logan Wayne Dec 20 '16 at 07:39

save image in mysql database using php script from xamarin.forms

1 Answers1