Send POST data through PHP from one page to another - javascript

Short:
Is there a way to send POST data from a intermediate PHP page to another resultant page?
Long:
I have a page, let's say A.php where a form is present. The data is filled in the form, and send through POST to another page B.php
B.php checks the value and finds that the value entered is not correct (form validation). We redirect back to A.php with message "Invalid"
Right now I am sending data like this:
header("Location:A.php?msg=Invalid");
But I want to hide the msg part in URL from the user, by sending it in POST method or so.
I am not forced to use any particular method. This is just a project I am working on. So, please enlighten me.
So far I came to know that there is no way we can do that using header in PHP.

A better way to do this is to always post back to the same page. If there is an error you can then just display it without needing to redirect.
If there is no error then redirect to a results/response page.
The advantages of this are:
No need to send data that may be private through a redirect
If there was an error then refreshing the POST will continue to fail and will continue to only show the error message and allow the user to correct their mistake
If there was no error then the redirect will remove the POST operation and replace it with a new GET operation.
Refreshing the result page will not produce another POST operation, which might cause a problem with your data/database.
Example of what happens:
So first the browser sends a GET request for a.php.
On Form submission the browser sends a POST request for a.php.
If the code for a.php detects an error it just re-renders the same page with the form tags filled in with the POST values.
If the code for a.php does not detect an error then it does whatever it needs to do to save the data and then sends a redirect request for b.php.
The browser sends a GET request for b.php and removes the a.php from its history.
b.php displays some kind of thank you note or confirmation.

Related

Is there a way to send POST data to another form and return the result of that form?

I need to send form data to another page that will allow the user to do something in a form and return the result of that form back to the original page? Is this possible? I know it's not ideal, but the issue is that I need to make a "drop-in" solution that does not need to be integrated with other code. I know it's a very specific request and scenario.
I know how to send POST data that doesn't require any user input on the processing page. i.e. I can send POST data to 'calculate.php' which will do the math and send it back, but if I need additional user input on 'calculate.php', how can I still send it back?
An example of expected results would be:
Page #1: User enters a number and presses submit to go to next page.
Page #2: User enters a second number and presses submit to finish.
Back to Page #1: User receives sum of both numbers.
Obviously, this is a really redundant thing to do, but I'm trying to simplify the problem as much as possible.
EDIT: There a few restrictions I forgot to add.
Page #1 is not my application, I am developing Page #2 as a "drop-in" solution for Page #1. Essentially, I can only use Page #1 to call Page #2 and receive a response from it. The problem is that I need to be able to allow for user input on Page #2.
I know I can post to Page #2 and then post to Page #1 again, but what if I need to maintain the state of Page #1. For example, if there's an open Web Socket connection.
Please note, I understand that this may be impossible or extremely difficult, but if I don't ask I'll never know right?
You want it with PHP or any other language. If you are running Php on server side then you can use Global variables like $_GET and $_POST.
Page #1: Use Post/Get method to send data to second page.
Page #2: Receive all fields' values using Globe variables ($_GET and $_POST). You can use these values as default values of form fields. Now submit this data to page 1 using post or get method.
Back to Page #1: Here you will receive the data of first page from second page and newly posted data from page 2
Either of these should work:
Never leave the page - use AJAX / XMLHttpRequest to call out to other pages to process chunks of data
Do everything on page 1 using "postbacks" -- the form targets are the same page, there is a state variable like "stage=1", and you use JavaScript to add set hidden variables for any additional state that's needed.
... PHP state validation and processing for the different stages ...
... one or more blocks of HTML for the page (PHP if / else can be used to choose between multiple page views) ...
Edit for added restrictions:
Have page 2 use postbacks or AJAX to collect the additional information
I figured out a few ways to do it.
Update a Database (or Data Store of some sort, depends on security needs) and have Page #1 listen for events from a separate page (on the same server as the database). Very similar to the way PayPal's Instant Payment Notification (IPN) works. I was actually able to set up server sent events with it as well.
Essentially, Page #1 sends data to Page #2 where the user will perform the function and then Page #2 will send POST data to a listener somewhere (either on the same server or Page #1's server), the listener will update a database and Page #1 will be listening or pulling to an event handler that will send an update once the database updates.
Use JavaScript Child/Parent Window functions. This is okay if Page #1 and Page #2 are on the same server, but can get messy and browsers have a lot of restrictions and it varies depending on browser.
Page #1 will open Page #2 in a child window, after the user performs a function, Page #2 will call a function that accepts the result data on Page #1.

Post to another page without redirecting

I am building a movie recommended system. I want when a user login and rate a movie, the rating and movie name as well as user name will post to another page without going to that page automatically, i mean without pressing anything. How can I do that?
You can do that by executing an ajax request (after clicking the vote-button), which sends data (you can define the data to be what you want - rating, movie and user) to a php script that you will have to create.
the php script will read the posted data that the ajax has sent and can insert/update the database.
This way, the user will not be redirected. he won't even notice.
You can achieve this by using some kind of ajax requests triggered by vote event or callback.

Check if user is redirected from another page

I have a <form> that sends the user to an external page: action="http:/example.com/test/test.php". The test.php on the external page executes an SQL query and sends the user to my internal page test2.php. The second page test2.php also executes an SQL query and the process gets closed.
I want to perform an check operation in test2.php. I only want to run the SQL query if the user is redirected from the external page.
How can I do this?
You can check the Referer header with $_SERVER['HTTP_REFERER'] to see what page they were redirected from. This isn't reliable, though, since people can forge headers, but for the most part, if people are using browsers, you can use this to check if they were redirected.
Why not use a URL parameter like http://example.com/test/test.php?redirect=true
Instead of having your form use a cross-domain action, perhaps you can have your PHP code use curl to submit the information to the foreign server. Then your PHP code will know exactly what happened.

Validate a Django Form with external POST action

I have a Django form, which sends the form data to an external source(to be more precise, it is a PayPal payment form). The user enters the price for the product, clicks on the button and the POST request is send to PayPal triggering the normal payment process.
Now I want to use OTP (like Google Authenticator) to validate each payment.
How should the validation be realized? I thought of several scenarios, but none of them is really satisfying:
Should I send the request first to my site, validate the OTP and then redirect the User to the PayPal site with the data via a POST request, coming with the request? Problem: POST requests are not meant to be redirected and I don't know, how to realize it in django.
Should I write JavaScript code, which sends an ajax request to my site, and "activates" the form on success? Problem: smarter users could just activate the form from the browser console, without sending the ajax request. Does anybody know some kind of activation trick in JavaScript, which is not "hackable"
I would be glad to hear some more solutions from you or some suggestions, how the solutions above could be realized without the problems mentioned.
EDIT - My Solution so far:
I have done a work around and split the form in two. The first form checks the OTP and sends the data to my internal django view. It also creates a model instance with an generated invoice, which can then be checked in the PayPal IPN routine. The second form is a PayPal payment form, which sends the POST request to PayPal. You can find the simplified code in the following Github-Gist:
https://gist.github.com/BloodyD/2cd15f38d0f666cf3a73
First method - normal redirection after POST:
I don't know why do You think that there shouldn't be any redirect after POST request? In django it happens all the time, without that each page refresh directly after adding something to database will trigger adding it one more time.
To redirect user into proper paypal page, you can just send HttpResponseRedirect instead of normal response when form is submitted with valid form data. If not, display some error messages.
2nd solution: using javascript.
You can send url to redirect to (paypal url) in AJAX response, so user won't be able to bypass this. Simply put some form submitted by AJAX, if it returns URL to redirect, just redirect user. If not, display error message.

PHP or JS redirect to another page with reloading and url changing

I know there are a lot of similar questions, but no solution worked for me.
I have index.php with a login form. When a user tries to login, then the login-datas are send to login.php this file checks if the username and password are valid.
If so, the file map.php shell be loaded.
The only working solution I found for this is:
header("Location: map.php");
But when the page is loaded the url is still ../login.php how can I change this?
Another problem is, if I go from pageB.php to pageA.php, doing some database changes, then redirecting from pageA.php back to pageB.php with header("Location: pageB.php"); then pageB.php is loading, but doesn't show the changed database entries, just the old ones. How can I force to reload the page for just ONE time (means no Refresh:X)?
Your question is a bit confusing but the best way to handle client redirection is using Javascript rather than the headers being sent back from PHP unless you are redirecting due to a 404, 403 etc.
For the login use case when the client provides their info fire off an ajax post event containing the form data. Process the data using PHP and send back a response to the Javascript. Based on the return message from PHP use the window.location API to redirect / refresh as needed.

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