Can't store a .pdf file in a blob in mySQL - php

Question

So I am trying to upload a PDF file into a mySQL blob, the table row gets inserted but in the fileContent which is the mediumBlob type it appears always as [BLOB 0 B] and when the file is downloaded, it is downloaded with 0 bytes. Ive echoed $content and it shows the special characters of the pdf file.
$erro = '';
$tipo = '';
if (isset($_POST['submit']) && isset($_POST['text']) && $_POST['text'] !== null && isset($_POST['userID']))
{
if(preg_match('/^[a-z0-9-]+$/',$_POST['text']) && strlen($_POST['text']) < 15 )
{
if (substr($_FILES['file']['name'], -3, 3) == "pdf" && $_FILES["file"]["size"] < 1000000)
{
if ($_FILES["file"]["error"] > 0)
{
$erro = "Problema: " . $_FILES["file"]["error"];
$tipo = 'erro';
}
else
{
$_FILES["file"]["name"] = $_POST['text'].'.pdf';
$erro = "Ficheiro guardado com sucesso.";
$tipo = 'sucesso';
}
}
else
{
$erro = "Apenas .PDF com menos de 10 Mb são permitidos!";
$tipo = 'erro';
}
}
else
{
$erro = "Nome inválido";
$tipo = 'erro';
}
if ($tipo == 'sucesso')
{
$content = $db->real_escape_string(file_get_contents($_FILES['file']['tmp_name']));
if ($_FILES["file"]["size"] > 0)
{
$smt = $db->prepare('INSERT into uploads (userRefID,fileName,fileType,fileSize,fileContent,uploadDate) values(?,?,?,?,?,?)');
$smt->bind_param('issibs', $_POST['userID'], $_FILES["file"]["name"], $_FILES["file"]["type"], $_FILES["file"]["size"], $content ,date(c));
$smt->execute();
$smt->close();
}
}
}
What am I doing wrong?

Answer 1

According to this comment you should not pass the blob directly in bind_param, but with send_long_data.
From the documentation of send_long_data here's an example:
$stmt = $mysqli->prepare("INSERT INTO messages (message) VALUES (?)");
$null = NULL;
$stmt->bind_param("b", $null);
$fp = fopen("messages.txt", "r");
while (!feof($fp)) {
$stmt->send_long_data(0, fread($fp, 8192));
}
fclose($fp);
$stmt->execute();