Check if POST data is set, can't get it working - php

I want to use PHP to check if $_POST["pass"] is set, and do something if it's not, and do something else if it is.... But I can't get it working, I'm sure my logic is wrong.
I have a php code that looks something like this...
if (!isset($_POST["pass"])) {
...some form with an input type text here...
if (...wrote the wrong thing in input type text...) {
echo "something is wrong....";
}
else {
$pass_var = "Pass";
$pass_var = $_POST["pass"];
}
}
else {
echo "This thing is working...";
}
If I type the right thing in my input type text, I wan't to get to "This thing is working", and if not I wan't to echo "something is wrong....".
It works almost fine, except that if I type the right thing in my form, I never get to "This thing is working...".
The page just does nothing..
I'm sure it's the
$pass_var = "Pass";
$pass_var = $_POST["pass"];
that I'm doing wrong.
I know that I could set this up in another way to make it work, but I have a large script that is set up like this, and I really want it to work...

You test in the form against the $_POST NOT being set (See the !). You want however the post to be set!
if(isset($_POST["pass"]))
{
print_r($_POST); // basic debugging -> Test the post array
echo "The form was submitted";
// ...some form with an input type text here...
if(...wrote the wrong thing in input type text...)
{
echo "something is wrong with the input....";
}
else
{
// Valid user input, process form
echo "Valid input byy the user";
$pass_var = "Pass";
$pass_var = $_POST["pass"];
}
}
else
{
echo "The form was not submitted...";
}

You can use the empty() function of php
if(!empty($_POST['pass'])){
// do something
}else{
// do something else
}
Hope this will work for you .

Make sure you have "method='POST'" in your html form else $_POST isn't accessible in php, and logic was a bit screwy, try this?
e.g.
if (!isset($_POST["pass"])) {
//no POST so echo form
echo "<form action='".$_SERVER['PHP_SELF']."' method='POST'>
<input type='text' name='txtInput' />
<input type='submit' name='pass' />
</form>";
} elseif (isset($_POST["pass"])) {
//have POST check txtInput for "right thing"
if ($_POST["txtInput"] == "wrong thing") {
echo "something is wrong....";
} elseif ($_POST["txtInput"] == "right thing") {
//$pass_var = "Pass";
$pass_var = $_POST["pass"];
echo "This thing is working...";
}
}

Well, if (!isset($_POST["pass"])) means if $_POST["pass"] is not set, so you might want to remove the '!' which stands for not.

Related

Form submission results in a blank page in PHP

I am trying to make a login system and i want to create a conditional statement that checks whether the global variable $_POST['submit-form'] is set.
If the global variable $_POST['submit-form'] is set then i want to echo out the fields of the submitted forms. This works fine..
The problem comes when i want to check whether the global variable $_POST['submit-form'] is empty, i get a blank page when i submit the form with nothing. It is supposed to echo out something like "You have entered nothing, please try again'.
I don't know what is wrong.
This is the code for the form.
<form action="test-form2.php" method="POST">
Name: <input type="text" name="name"><br>
E-mail: <input type="text" name="email"><br>
<input type="submit" name="submit-form" value="submit">
</form>
..and this is the code for the form handler.
<?php
if(isset($_POST['submit-form'])) {
$name = $_POST['name'];
$email = $_POST['email'];
if(($_POST['name'] != "") && ($_POST['email']!= "")) {
echo "This is your name: ".$name."<br>";
echo "This is your email: ".$email;
// header('refresh=3;url = ../leden/index.php');
}
} else {
echo "You have entered nothing or your username and/or password is incorrect, please try again.";
// header('refresh=3;url = /test-form1.php');
}
?>
Your $_POST always have submit-form (and it's always not empty), so if statement always returns true. Try to check (for example) only that $_POST['name'] and $_POST['email'] are not empty.
The problem with your code is that checking if it's set isn't enough .. Because it may be set and be empty -- Realistically what you want is to check both isset and whether it's empty IE:
if (isset($_POST['submit-form'] && $_POST['submit-form'] != '' && $_POST['submit-form'] != null)
If the above if statement fails your value for $_POST['submit-form'] is most likely not being submitted.
UPDATE
Check for blank fields
if ($_POST['name'] != '' && $_POST['email'] != ''){
// Do stuff
}else{
if ($_POST['name'] == ''){
echo "name is empty";
}
if ($_POST['email'] == ''){
echo "email is empty";
}
}
That's because isset($_POST['submit-form']) returns true even if you don't input anything in Name and E-mail fields, it's value would be submit string when hit submit button to submit the form. This is the reason else part of below block is not getting executed.
if(isset($_POST['submit-form'])) {
} else {
echo "You have entered nothing or your username and/or password is incorrect, please try again.";
}
Use var_dump($_POST); to see the complete array structure. having said these, you can use the following snippet to achieve the desired result,
if(isset($_POST['submit-form'])) {
$name = $_POST['name'];
$email = $_POST['email'];
if(($_POST['name'] != "") && ($_POST['email']!= "")) {
echo "This is your name: ".$name."<br>";
echo "This is your email: ".$email;
// header('refresh=3;url = ../leden/index.php');
}else{
echo "You have entered nothing or your username and/or password is incorrect, please try again.";
}
}
Validation and scrutinization of user inputs should be your next action items in the list.

Passing php variables from php1 to php2, then having php2 return a new value assigning to variable from php1

This may sound really broken but essentially my intentions are for in php1, have a name for example validate to match a regex, if it fails to meet the conditions it will then redirect to php2 where there awaits a form where a user can retype it and submit it back to php1 where it will do the checks again. Then finally in the first php, if everything works ok it will echo it back.
Also how would i expand it so multiple things such as credit cards etc. can be validated too?
Thanks
php1
if (isset ($_POST["CardHolder"])) {
cardholder = $_POST["CardHolder"];
cardholder = sanitise_input($cardholder);
if (!preg_match("/^[a-zA-Z\s]{1,40}$/", $cardholder)) {
$errMsg .= "First name can only contain alpha characters, please re-enter";
$newcardholder = $_POST["newcardholder"];
$cardholder = $newcardholder;
}
else {
$cardholder = $_POST["CardHolder"];
}
if ($errMsg != "") {
header("Location: fix_order.php?errMsg=".$errMsg)
}
php2 (fix_order.php)
if (isset ($_GET["errMsg"])){
$cardholder = $_GET["errMsg"];
echo "<form action='process_order.php' method='post'>"
."<p><label>$cardholder:</label>"
."<input type='text' name='newcardholder'/></p>"
."<p><input type='submit' value='Submit'/>";
"</form>";
}
When calling header("Location:...") you need to give the full and absolute URL.
so header("Location: fix_order.php") will not work.

Global error message in php

I have a problem with the understanding of variable scopes.
I've got a huge .php file with many $_POST validations (I know that isn't not good practise). Anyways I want a little html-part above all the code which outputs an error message. This message I want to change in every $_POST validation function.
Example:
if($ERR) {
echo '<div class="error-message">'.$ERR.'</div>';
}
Now my functions are following in the same file.
if(isset($_POST['test']) {
$ERR = 'Error!';
}
if(isset($_POST['test2'] {
$ERR = 'Error 2!';
}
But that doesn't work. I think there's a huge missunderstanding and i'm ashamed.
Can you help me?
I didnt catch your question but maybe this is your answer:
<body>
<p id="error_message">
<?php if(isset($ERR)){echo $ERR;} ?>
</p>
</body>
and I suggest you to learn how to work with sessions.
and you should know that $_Post will be empty on each refresh or F5
You can do put the errors in array make them dynamic.
<?php
$error = array();
if (!isset($_POST["test"]) || empty($_POST["test"])) {
$error['test'] = "test Field is required";
} else if (!isset($_POST["test1"]) || empty($_POST["test1"])) {
$error['test1'] = "test Field is required";
}else{
//do something else
}
?>
You can also use switch statement instead of elseif which is neater.

PHP, display message if one or more fields is empty

What I want is to show the error (message), only if the user do a false action. For example, if the field is empty, it will show (Please fill all the fields). I've already done that, but the problem that I have is that it shows also if the user enter to the page for the first time, meaning it does NOT respects the (if condition) that I have written !
The question :
How to show the message only if one of the fields is empty ?
Any ideas on how I can solve it ?
Here is my code :
<?
$conn = mysqli_connect('localhost', 'db', 'db_pass', 'db_name') or die("Error " . mysqli_error($conn));
$email = filter_var(trim($_POST['email']), FILTER_VALIDATE_EMAIL);
$old_password = trim($_POST['old_pass']);
$new_password = trim($_POST['new_pass']);
$email = mysqli_real_escape_string($conn,$email);
$old_password = mysqli_real_escape_string($conn,$old_password);
$new_password = mysqli_real_escape_string($conn,$new_password);
if(empty($email) || empty($old_password) || empty($new_password)){
echo 'Please fill all the fields !<br>';
}
else{
$sql="UPDATE users SET pass='$new_password' WHERE email='$email' AND pass='$old_password'" or die("Error " . mysqli_error($conn));
$result = mysqli_query($conn,$sql);
mysqli_close($conn);
}
if($result){
echo'Password changed successfully !';
}
elseif(!$result) {
echo 'The email/password you provided is false !';
}
?>
Validation of any form happens in the "action" file within a condition i.e. the validation should be subjected to the event of user clicking the submit button. For this to work you should check that
1. Your form has a submit button with a name property set to say submit (can be anything)
eg: <input type="submit" name="submit" id="someid" value="Submit" />
2. The form must have action property pointing to a processor file
eg: <form action = "somefile.php" method = "post">
3. In the somefile.php file the validation code must be within a condition which checks for the event of form been submited
eg://somefile.php
<?php
if(isset($_POST['submit']{
//all the validation code goes here
}else{
//for a single page form and validation
// the code for displaying the form can go here
?>
I suggest you to do this:
First define a variable with plain $_POST[] for eg $name = $_POST['name'];
Then, check if all the vatiables you've define are empty or not.
Lastly, Use escape_string() or whatever you want.
The solution is to check for a variable that you know will always be set if the form is submitted, usually the submit button.
For example, if your form ends like this:
...
<input type="submit" name="change_password" value="Change password" />
</form>
then in the PHP code you could check
if(isset($_POST['change_password'])) {
// The submit button was in the POSTed data, so this is a form submit
} else {
// This is a new page load
}
Alternatively, if you are POSTing the data, you can check which HTTP method was used to call the form:
if($_SERVER['REQUEST_METHOD'] == 'POST') {
// Form was posted
} else {
// $_SERVER['REQUEST_METHOD'] == 'GET'
}
The pattern I commonly use is:
$showForm = true;
if( is_form_postback() ) {
if( data_is_valid() ) {
redirect_to_thank_you_page();
} else {
show_validation_errors();
$showForm = false;
}
}
if($showForm) {
// Print the form, making sure to set the value of each input to the $_POSTed value when available.
}

how to use isset for password

I'm giving this simple html form with password and with php I'm giving to do this
The only valid password shall be "testing" (without the quotes). If the user did not type a password, give them a warning to "Please type a password" and do no more processing on the data at all. If the user did not type the valid password "testing" (without the quotes), then tell the user "Invalid password, sorry" and do no more processing on the data at all. (Use an “if” statement to find out if they entered a password, etc…)
but I just can't seem to figure out
can someone give me a hand?
the html coding is
<form action = "lab.php" method = "post" name = "lab_form">
what is your last name: <input type = "text" name = "last"><br />
what is your student number (password): <input type = "password" name = "number">
</form>
what I did with my php is this....but didn't work at all...and all I've learned is $_POST and isset for now. I wonder how I can get this done with $_POST, isset and with if statement...
<?php
echo $_POST["last"] . "<br/>";
if (isset($_POST["number"]))
{
echo "The variable $_POST[number] exists.";
}
else if (!(isset($_POST["number"])))
{
echo "Please enter a password.";
}
else
{
echo "No variable called $_POST[number]";
}
?>
I know what I'm doing wouldn't make must sense....but...ya :(
Thanks in advance though ^_^
P.S. I know in the php code I should add something like
if($_POST["number"] == testing)
and continuing on but the thing is I couldn't even make it show the other parts so i didn't bother try the "testing" as password yet.
Small mistake. Use empty() too.
<?php
echo $_POST["last"] . "<br/>";
if (isset($_POST["number"]))
{
echo "The variable $_POST[number] exists.";
}
elseif (empty($_POST["number"]))
{
echo "Please enter a password.";
}
elseif (!isset($_POST["number"]))
{
echo "No variable called $_POST[number]";
}
?>

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