PHP Form Validation and Submit to Database - php

Question

I would like to ask how do I set PHP "form validation" and "submit to database" in one single php file? This is what I tried to do in PART 1 and PART 2.
$latErr = $lngErr = $messageErr = "";
$lat = $lng = $message = "";
$tbl_name="stickers";
$datetime=date("d-m-y H:i:s");
//PART 1 - form validation method
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["inputfield1"])) {
$latErr = "* Latitude is required. Please enable your browser geolocation settings.";
} else {
$lat = test_input($_POST["inputfield1"]);
}
if (empty($_POST["inputfield2"])) {
$lngErr = "* Longitude is required. Please enable your browser geolocation settings.";
}else{
$lng = test_input($_POST["inputfield2"]);
}
if (empty($_POST["message"])) {
$messageErr = "* Please enter your message.";
} else {
$message = test_input($_POST["message"]);
}
}
//PART 2 - check if all 3 parameters are filled, if yes then insert into database
if (isset($lat, $lng, $message)){
$sql="INSERT INTO $tbl_name(username, message, datetime, lat, lng )VALUES('$user- >username','$message', '$datetime', '$lat', '$lng')";
$result=mysql_query($sql);
//check if query successful
if($result){
$post_info = "Your msg is successfully posted!";
}else{
$post_info = "Oops, there is an error posting the msg.";
}
mysql_close();
}
function test_input($data){
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
It doesn't work. It just insert blanks into the database. Something is wrong but I dunno what is it? Anyone can advice. Thanks.

Answer 1

Maybe you need to use empty() instead of isset()?
//PART 1 - form validation method
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["inputfield1"])) {
$latErr = "* Latitude is required. Please enable your browser geolocation settings.";
} else {
$lat = test_input($_POST["inputfield1"]);
}
if (empty($_POST["inputfield2"])) {
$lngErr = "* Longitude is required. Please enable your browser geolocation settings.";
}else{
$lng = test_input($_POST["inputfield2"]);
}
if (empty($_POST["message"])) {
$messageErr = "* Please enter your message.";
} else {
$message = test_input($_POST["message"]);
}
}
//PART 2 - check if all 3 parameters are filled, if yes then insert into database
if ( !empty($lat) && !empty($lng) && !empty($message) ){
$sql="INSERT INTO $tbl_name(username, message, datetime, lat, lng )VALUES('$user- >username','$message', '$datetime', '$lat', '$lng')";
$result=mysql_query($sql);
//check if query successful
if($result){
$post_info = "Your msg is successfully posted!";
}else{
$post_info = "Oops, there is an error posting the msg.";
}
}
else {
$post_info = "Empty content.";
}
mysql_close();