pass value from page to another in PHP - php

I am sending login status = fail, back to my login page.Here is my code-
header("location:index.php?login=fail");
but that is sending through URL like-
http://localhost/303/index.php?login=fail
is there any way to pass value without showing in URL? And how to get this value on the second page?

You are passing that value via a GET request, which is why it appears in the URL. In order to pass a value without showing it in the URL, you want to pass it via a POST request.
In order to do this you aren't going to want to "return" the value to your login page. Instead, whatever php form is handling the process of logging in the user after they click the "login" button, will decide what to show the user.
In PHP post variables can be accessed by the global $_POST object -
$_POST['username'];
Would get the value with the name "username" that you passed via POST:
<form method="post" action="checkLogin.php">
Username:
<input type="text" name="username" maxlength="25" />
Password:
</td><td><input type="password" name="password" />
<input type="submit" name="submit" value="Login">
</form>
In order to dynamically save and show errors to the user, you can store them in the session, for example have a file called "errors.php"
<?php
if (isset($_SESSION['errors']))
{
echo $_SESSION['errors'];
}
unset($_SESSION['errors'])
?>
And in your php that checks the login, do:
session_start();
$_SESSION['errors'] = "Invalid username or password.";
Then redirect to your login page (don't pass any variables) and on your form always have this field:
<?php include("errors.php"); ?>
If you didn't have any errors, it won't show anything and the login page will look normal.
Note: In any php form that you use a session_start(), it HAS TO BE THE FIRST THING in the form.

Other ways are to use session or hidden fields but you what you are doing is fine for the purpose. You can later retrieve the value like this:
if ($_GET['login'] === 'fail')
{
// failed.......
}

there are several ways to accomplish your task
Modern AJAX way. Form being sent using AJAX. No page reload until password is correct. Errors shown in place. Requres javascript.
Post/Redirect/Get pattern. Form being sent using regular POST. No redirect on errors, shown in place.
sessions, when we store an error in the session

Related

how to make variable available in all files [duplicate]

It seems pretty simple but I can't find a good way to do it.
Say in the first page I create a variable
$myVariable = "Some text";
And the form's action for that page is "Page2.php". So in Page2.php, how can I have access to that variable? I know I can do it with sessions but I think it's too much for a simple string, and I do only need to pass a simple string (a file name).
How can I achieve this?
Thanks!
HTML / HTTP is stateless, in other words, what you did / saw on the previous page, is completely unconnected with the current page. Except if you use something like sessions, cookies or GET / POST variables. Sessions and cookies are quite easy to use, with session being by far more secure than cookies. More secure, but not completely secure.
Session:
//On page 1
$_SESSION['varname'] = $var_value;
//On page 2
$var_value = $_SESSION['varname'];
Remember to run the session_start(); statement on both these pages before you try to access the $_SESSION array, and also before any output is sent to the browser.
Cookie:
//One page 1
$_COOKIE['varname'] = $var_value;
//On page 2
$var_value = $_COOKIE['varname'];
The big difference between sessions and cookies is that the value of the variable will be stored on the server if you're using sessions, and on the client if you're using cookies. I can't think of any good reason to use cookies instead of sessions, except if you want data to persist between sessions, but even then it's perhaps better to store it in a DB, and retrieve it based on a username or id.
GET and POST
You can add the variable in the link to the next page:
Page2
This will create a GET variable.
Another way is to include a hidden field in a form that submits to page two:
<form method="get" action="page2.php">
<input type="hidden" name="varname" value="var_value">
<input type="submit">
</form>
And then on page two:
//Using GET
$var_value = $_GET['varname'];
//Using POST
$var_value = $_POST['varname'];
//Using GET, POST or COOKIE.
$var_value = $_REQUEST['varname'];
Just change the method for the form to post if you want to do it via post. Both are equally insecure, although GET is easier to hack.
The fact that each new request is, except for session data, a totally new instance of the script caught me when I first started coding in PHP. Once you get used to it, it's quite simple though.
Thanks for the answers above. Here's how I did it, I hope it helps those who follow. I'm looking to pass a registration number from one page to another, hence regName and regValue:
Create your first page, call it set_reg.php:
<?php
session_start();
$_SESSION['regName'] = $regValue;
?>
<form method="get" action="get_reg.php">
<input type="text" name="regName" value="">
<input type="submit">
</form>
Create your second page, call it get_reg.php:
<?php
session_start();
$regValue = $_GET['regName'];
echo "Your registration is: ".$regValue.".";
?>
<p>Back to set_reg.php
Although not as comprehensive as the answer above, for my purposes this illustrates in simple fashion the relationship between the various elements.
Passing data in the request
You could either embed it as a hidden field in your form, or add it your forms action URL
echo '<input type="hidden" name="myVariable" value="'.
htmlentities($myVariable).'">';
or
echo '<form method="POST" action="Page2.php?myVariable='.
urlencode($myVariable).'">";
Note this also illustrates the use of htmlentities and urlencode when passing data around.
Passing data in the session
If the data doesn't need to be passed to the client side, then sessions may be more appropriate. Simply call session_start() at the start of each page, and you can get and set data into the $_SESSION array.
Security
Since you state your value is actually a filename, you need to be aware of the security ramifications. If the filename has arrived from the client side, assume the user has tampered with the value. Check it for validity! What happens when the user passes the path to an important system file, or a file under their control? Can your script be used to "probe" the server for files that do or do not exist?
As you are clearly just getting started here, its worth reminding that this goes for any data which arrives in $_GET, $_POST or $_COOKIE - assume your worst enemy crafted the contents of those arrays, and code accordingly!
There are three method to pass value in php.
By post
By get
By making session variable
These three method are used for different purpose.For example if we want to receive our value on next page then we can use 'post' ($_POST) method as:-
$a=$_POST['field-name'];
If we require the value of variable on more than one page than we can use session variable as:-
$a=$_SESSION['field-name];
Before using this Syntax for creating SESSION variable we first have to add this tag at the very beginning of our php page
session_start();
GET method are generally used to print data on same page which used to take input from user. Its syntax is as:
$a=$_GET['field-name'];
POST method are generally consume more secure than GET because when we use Get method than it can display the data in URL bar.If the data is more sensitive data like password then it can be inggeris.
try this code
using hidden field we can pass php varibale to another page
page1.php
<?php $myVariable = "Some text";?>
<form method="post" action="page2.php">
<input type="hidden" name="text" value="<?php echo $myVariable; ?>">
<button type="submit">Submit</button>
</form>
pass php variable to hidden field value so you can access this variable into another page
page2.php
<?php
$text=$_POST['text'];
echo $text;
?>
Sessions would be the only good way, you could also use GET/POST but that would be potentially insecure.
**page 1**
<form action="exapmple.php?variable_name=$value" method="POST">
<button>
<input type="hidden" name="x">
</button>
</form>`
page 2
if(isset($_POST['x'])) {
$new_value=$_GET['variable_name'];
}
It works.
Send data throw URL, without form.
$upit = "SELECT * FROM usluga";
$data = $mysql->query($upit);
while ($row = mysqli_fetch_object($data))
{
echo "<a href='"."index.php?tretmanId=$row->tretman_id"."'>$row->naziv</a>";
echo "<br><br>";
}
and you can get this value on the target page with "$_GET['name from URL']", like this
$TrermanIdFromUrl = $_GET['tretmanId'];
You can for example call the page you want by including variables in the url:
header("Location: ../signup.php?newpwd=passwordupdated");
And on your signup.php page, you would have
if (isset($_GET['newpwd']) && $_GET['newpwd'] == "passwordupdated") {
//code here
}

Pass array from one php page to another php page [duplicate]

It seems pretty simple but I can't find a good way to do it.
Say in the first page I create a variable
$myVariable = "Some text";
And the form's action for that page is "Page2.php". So in Page2.php, how can I have access to that variable? I know I can do it with sessions but I think it's too much for a simple string, and I do only need to pass a simple string (a file name).
How can I achieve this?
Thanks!
HTML / HTTP is stateless, in other words, what you did / saw on the previous page, is completely unconnected with the current page. Except if you use something like sessions, cookies or GET / POST variables. Sessions and cookies are quite easy to use, with session being by far more secure than cookies. More secure, but not completely secure.
Session:
//On page 1
$_SESSION['varname'] = $var_value;
//On page 2
$var_value = $_SESSION['varname'];
Remember to run the session_start(); statement on both these pages before you try to access the $_SESSION array, and also before any output is sent to the browser.
Cookie:
//One page 1
$_COOKIE['varname'] = $var_value;
//On page 2
$var_value = $_COOKIE['varname'];
The big difference between sessions and cookies is that the value of the variable will be stored on the server if you're using sessions, and on the client if you're using cookies. I can't think of any good reason to use cookies instead of sessions, except if you want data to persist between sessions, but even then it's perhaps better to store it in a DB, and retrieve it based on a username or id.
GET and POST
You can add the variable in the link to the next page:
Page2
This will create a GET variable.
Another way is to include a hidden field in a form that submits to page two:
<form method="get" action="page2.php">
<input type="hidden" name="varname" value="var_value">
<input type="submit">
</form>
And then on page two:
//Using GET
$var_value = $_GET['varname'];
//Using POST
$var_value = $_POST['varname'];
//Using GET, POST or COOKIE.
$var_value = $_REQUEST['varname'];
Just change the method for the form to post if you want to do it via post. Both are equally insecure, although GET is easier to hack.
The fact that each new request is, except for session data, a totally new instance of the script caught me when I first started coding in PHP. Once you get used to it, it's quite simple though.
Thanks for the answers above. Here's how I did it, I hope it helps those who follow. I'm looking to pass a registration number from one page to another, hence regName and regValue:
Create your first page, call it set_reg.php:
<?php
session_start();
$_SESSION['regName'] = $regValue;
?>
<form method="get" action="get_reg.php">
<input type="text" name="regName" value="">
<input type="submit">
</form>
Create your second page, call it get_reg.php:
<?php
session_start();
$regValue = $_GET['regName'];
echo "Your registration is: ".$regValue.".";
?>
<p>Back to set_reg.php
Although not as comprehensive as the answer above, for my purposes this illustrates in simple fashion the relationship between the various elements.
Passing data in the request
You could either embed it as a hidden field in your form, or add it your forms action URL
echo '<input type="hidden" name="myVariable" value="'.
htmlentities($myVariable).'">';
or
echo '<form method="POST" action="Page2.php?myVariable='.
urlencode($myVariable).'">";
Note this also illustrates the use of htmlentities and urlencode when passing data around.
Passing data in the session
If the data doesn't need to be passed to the client side, then sessions may be more appropriate. Simply call session_start() at the start of each page, and you can get and set data into the $_SESSION array.
Security
Since you state your value is actually a filename, you need to be aware of the security ramifications. If the filename has arrived from the client side, assume the user has tampered with the value. Check it for validity! What happens when the user passes the path to an important system file, or a file under their control? Can your script be used to "probe" the server for files that do or do not exist?
As you are clearly just getting started here, its worth reminding that this goes for any data which arrives in $_GET, $_POST or $_COOKIE - assume your worst enemy crafted the contents of those arrays, and code accordingly!
There are three method to pass value in php.
By post
By get
By making session variable
These three method are used for different purpose.For example if we want to receive our value on next page then we can use 'post' ($_POST) method as:-
$a=$_POST['field-name'];
If we require the value of variable on more than one page than we can use session variable as:-
$a=$_SESSION['field-name];
Before using this Syntax for creating SESSION variable we first have to add this tag at the very beginning of our php page
session_start();
GET method are generally used to print data on same page which used to take input from user. Its syntax is as:
$a=$_GET['field-name'];
POST method are generally consume more secure than GET because when we use Get method than it can display the data in URL bar.If the data is more sensitive data like password then it can be inggeris.
try this code
using hidden field we can pass php varibale to another page
page1.php
<?php $myVariable = "Some text";?>
<form method="post" action="page2.php">
<input type="hidden" name="text" value="<?php echo $myVariable; ?>">
<button type="submit">Submit</button>
</form>
pass php variable to hidden field value so you can access this variable into another page
page2.php
<?php
$text=$_POST['text'];
echo $text;
?>
Sessions would be the only good way, you could also use GET/POST but that would be potentially insecure.
**page 1**
<form action="exapmple.php?variable_name=$value" method="POST">
<button>
<input type="hidden" name="x">
</button>
</form>`
page 2
if(isset($_POST['x'])) {
$new_value=$_GET['variable_name'];
}
It works.
Send data throw URL, without form.
$upit = "SELECT * FROM usluga";
$data = $mysql->query($upit);
while ($row = mysqli_fetch_object($data))
{
echo "<a href='"."index.php?tretmanId=$row->tretman_id"."'>$row->naziv</a>";
echo "<br><br>";
}
and you can get this value on the target page with "$_GET['name from URL']", like this
$TrermanIdFromUrl = $_GET['tretmanId'];
You can for example call the page you want by including variables in the url:
header("Location: ../signup.php?newpwd=passwordupdated");
And on your signup.php page, you would have
if (isset($_GET['newpwd']) && $_GET['newpwd'] == "passwordupdated") {
//code here
}

Reload php form data after Server side validation

I am doing server side validations for my html values. However when server side validation fails and I return back to the page, the form data is cleared. Is there anyway to do save and reload the form data in php without using any framwork?
Just put the submitted value (if there is any ) inside your value="" like this:
$set = isset($_POST['username']) ? $_POST['username'] : '';
The above is called the ternary operator. And, as I have done it, it will check if someone has already submitted a form with attribute "username" ($_POST['username']) in your form, if yes, then it sets the the value of that form to a variable called $set otherwise it just sets it '' nothing.
Now, all you have to do is just put the $set variable inside like: value=" <?= $set ?> ">
Well, sure. Assuming that you're submitting to a different script, and need to be directed back to your page with the form, use PHP Sessions. Save all of the data that you need to reload in the session, and then on your page use the session data to pre-populate the form if it's there. Once you're done using it (i.e. they've successfully completed their form), then you can clear the session on a subsequent interaction.
Yes,
Say you have your input:
<input type="text" name="email" />
If you did this:
<input type="text" name="email" value="<?php echo $_POST['email']?>"/>
It would repopulate with whatever they typed in.
Send the values to the server using an AJAX call, that wont refresh the page leaving your data intact in the page.

Same page processing

How can process a form on the same page vs using a separate process page. Right now for signups, comment submissions, etc I use a second page that verifies data and then submits and routes back to home.php. How can I make it so that on submit, the page itself verifies rather than using a second page.
You can tell the form to submit to the PHP's self, then check the $_POST variables for form processing. This method is very good for error checking as you can set an error and then have the form reload with any information the user's previously submitted still in tact (i.e. they don't lose their submission).
When the "submit" button is clicked, it will POST the information to the same page, running the PHP code at the top. If an error occurs (based on your checks), the form will reload for the user with the errors displayed and any information the user supplied still in the fields. If an error doesn't occur, you will display a confirmation page instead of the form.
<?php
//Form submitted
if(isset($_POST['submit'])) {
//Error checking
if(!$_POST['yourname']) {
$error['yourname'] = "<p>Please supply your name.</p>\n";
}
if(!$_POST['address']) {
$error['address'] = "<p>Please supply your address.</p>\n";
}
//No errors, process
if(!is_array($error)) {
//Process your form
//Display confirmation page
echo "<p>Thank you for your submission.</p>\n";
//Require or include any page footer you might have
//here as well so the style of your page isn't broken.
//Then exit the script.
exit;
}
}
?>
<form method="post" action="<?=$_SERVER['PHP_SELF']?>">
<?=$error['yourname']?>
<p><label for="yourname">Your Name:</label><input type="text" id="yourname" name="yourname" value="<?=($_POST['yourname'] ? htmlentities($_POST['yourname']) : '')?>" /></p>
<?=$error['address']?>
<p><label for="address">Your Address:</label><input type="text" id="address" name="address" value="<?=($_POST['address'] ? htmlentities($_POST['address']) : '')?>" /></p>
<p><input type="submit" name="submit" value="Submit" /></p>
</form>
The easiest construction is to detect whether the $_POST array is not empty
if(isset($_POST['myVarInTheForm'])) {
// Process the form
}
// do the regular job
you can check if it was POST request inside the page's code and then check the data. If it was GET request - just show the form.
But please remember that is is a good practice to show successfull form submission results on a different page served through GET request, i.e. any successfull form POST should be answered with redirect to the success page.
You could of course explore looking into AJAX requests, where you would make an asynchronous call to your handler script, and then update then update the sending page with a success message. This gives the impression of "Same page processing" i.e. The page doesn't have to refresh.
It really depends on the effect you are trying to achieve however.
#Michael Irigoyen: It works fine, but on first rn/load, it shows:
"Notice: Undefined variable: error in C:\xampp\htdocs\same_page.php on line 28"
How to handle this notice?
Got it now:
"Used isset, # etc. to supress errors..."
"Works like a charm!!!"
"Now i'll try it on my code..."
I have saved a thank you message and refreshed using session variables.
if(!is_array($error)){
$_SESSION['message'] = 'Thank You!';
header('Location: yourpage.php');
exit();
}
and then use this in the top of the form:
if(isset($_SESSION['message'])){
echo $_SESSION['message'];
unset($_SESSION['message'];
}
This should refresh the page and show the message and then if they refresh the page the session variable is empty so the thank you won't show. This is called a flash message.

PHP Pass variable to next page

It seems pretty simple but I can't find a good way to do it.
Say in the first page I create a variable
$myVariable = "Some text";
And the form's action for that page is "Page2.php". So in Page2.php, how can I have access to that variable? I know I can do it with sessions but I think it's too much for a simple string, and I do only need to pass a simple string (a file name).
How can I achieve this?
Thanks!
HTML / HTTP is stateless, in other words, what you did / saw on the previous page, is completely unconnected with the current page. Except if you use something like sessions, cookies or GET / POST variables. Sessions and cookies are quite easy to use, with session being by far more secure than cookies. More secure, but not completely secure.
Session:
//On page 1
$_SESSION['varname'] = $var_value;
//On page 2
$var_value = $_SESSION['varname'];
Remember to run the session_start(); statement on both these pages before you try to access the $_SESSION array, and also before any output is sent to the browser.
Cookie:
//One page 1
$_COOKIE['varname'] = $var_value;
//On page 2
$var_value = $_COOKIE['varname'];
The big difference between sessions and cookies is that the value of the variable will be stored on the server if you're using sessions, and on the client if you're using cookies. I can't think of any good reason to use cookies instead of sessions, except if you want data to persist between sessions, but even then it's perhaps better to store it in a DB, and retrieve it based on a username or id.
GET and POST
You can add the variable in the link to the next page:
Page2
This will create a GET variable.
Another way is to include a hidden field in a form that submits to page two:
<form method="get" action="page2.php">
<input type="hidden" name="varname" value="var_value">
<input type="submit">
</form>
And then on page two:
//Using GET
$var_value = $_GET['varname'];
//Using POST
$var_value = $_POST['varname'];
//Using GET, POST or COOKIE.
$var_value = $_REQUEST['varname'];
Just change the method for the form to post if you want to do it via post. Both are equally insecure, although GET is easier to hack.
The fact that each new request is, except for session data, a totally new instance of the script caught me when I first started coding in PHP. Once you get used to it, it's quite simple though.
Thanks for the answers above. Here's how I did it, I hope it helps those who follow. I'm looking to pass a registration number from one page to another, hence regName and regValue:
Create your first page, call it set_reg.php:
<?php
session_start();
$_SESSION['regName'] = $regValue;
?>
<form method="get" action="get_reg.php">
<input type="text" name="regName" value="">
<input type="submit">
</form>
Create your second page, call it get_reg.php:
<?php
session_start();
$regValue = $_GET['regName'];
echo "Your registration is: ".$regValue.".";
?>
<p>Back to set_reg.php
Although not as comprehensive as the answer above, for my purposes this illustrates in simple fashion the relationship between the various elements.
Passing data in the request
You could either embed it as a hidden field in your form, or add it your forms action URL
echo '<input type="hidden" name="myVariable" value="'.
htmlentities($myVariable).'">';
or
echo '<form method="POST" action="Page2.php?myVariable='.
urlencode($myVariable).'">";
Note this also illustrates the use of htmlentities and urlencode when passing data around.
Passing data in the session
If the data doesn't need to be passed to the client side, then sessions may be more appropriate. Simply call session_start() at the start of each page, and you can get and set data into the $_SESSION array.
Security
Since you state your value is actually a filename, you need to be aware of the security ramifications. If the filename has arrived from the client side, assume the user has tampered with the value. Check it for validity! What happens when the user passes the path to an important system file, or a file under their control? Can your script be used to "probe" the server for files that do or do not exist?
As you are clearly just getting started here, its worth reminding that this goes for any data which arrives in $_GET, $_POST or $_COOKIE - assume your worst enemy crafted the contents of those arrays, and code accordingly!
There are three method to pass value in php.
By post
By get
By making session variable
These three method are used for different purpose.For example if we want to receive our value on next page then we can use 'post' ($_POST) method as:-
$a=$_POST['field-name'];
If we require the value of variable on more than one page than we can use session variable as:-
$a=$_SESSION['field-name];
Before using this Syntax for creating SESSION variable we first have to add this tag at the very beginning of our php page
session_start();
GET method are generally used to print data on same page which used to take input from user. Its syntax is as:
$a=$_GET['field-name'];
POST method are generally consume more secure than GET because when we use Get method than it can display the data in URL bar.If the data is more sensitive data like password then it can be inggeris.
try this code
using hidden field we can pass php varibale to another page
page1.php
<?php $myVariable = "Some text";?>
<form method="post" action="page2.php">
<input type="hidden" name="text" value="<?php echo $myVariable; ?>">
<button type="submit">Submit</button>
</form>
pass php variable to hidden field value so you can access this variable into another page
page2.php
<?php
$text=$_POST['text'];
echo $text;
?>
Sessions would be the only good way, you could also use GET/POST but that would be potentially insecure.
**page 1**
<form action="exapmple.php?variable_name=$value" method="POST">
<button>
<input type="hidden" name="x">
</button>
</form>`
page 2
if(isset($_POST['x'])) {
$new_value=$_GET['variable_name'];
}
It works.
Send data throw URL, without form.
$upit = "SELECT * FROM usluga";
$data = $mysql->query($upit);
while ($row = mysqli_fetch_object($data))
{
echo "<a href='"."index.php?tretmanId=$row->tretman_id"."'>$row->naziv</a>";
echo "<br><br>";
}
and you can get this value on the target page with "$_GET['name from URL']", like this
$TrermanIdFromUrl = $_GET['tretmanId'];
You can for example call the page you want by including variables in the url:
header("Location: ../signup.php?newpwd=passwordupdated");
And on your signup.php page, you would have
if (isset($_GET['newpwd']) && $_GET['newpwd'] == "passwordupdated") {
//code here
}

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