I'm trying to build a sort of resource allocation form. I'd like to be able to print a table from a database, and then allow users to click on each cell that they would like to reserve. Also, being able to drag and select multiple cells. Then send all of this via $_POST to another php script.
Problem is, I have no idea where to start.
Any suggestions?
The first and most critical thing you're going to need from what you described is a bunch of hidden fields to store the information you're interested in. You would have to write javascript code on the client side to store the users interaction with your page into these hidden fields.
To receive data via POST, you will need <input type="hidden" name"some_field"> for every bit of data you wish to "know" about that was changed on your page. Table information is not transmitted in a POST operation if it's just text, so you can't see the layout of the modified table on post back to the server.
If you don't have to POST this data to another form, it is probably a better idea to make callbacks via XMLHTTPREQUEST as the user interacts with your page, but I don't know the requirements of what you're trying to do.
I wrote one for my school recently; the trick is to either use buttons/links or addEventListener the cells to JavaScript. If you want the source code to my app, download this zip file:
http://azabani.com/files/busbook.zip
Edit:
My system works in the following way:
addEventListener to cell clicks, calling book()
book() then sets location to book.php
book.php does the database work
book.php sets the location header to immediately go back to the viewer
The system knows which week view to go back to based on session variables.
Related
Question about GET and POST in PHP. i wonder what is the difference between POST and GET and when do you use them respectively?
so as far from i tried, GET can also show the data in the link.
for example, the name of my link is Localhost/index.php then inside my php file is an input box and a submit button. if for example i use GET, if i click the submit button, it will take the data i put in inputbox(for example, name) and add it to the link. so the link now is Localhost/index.php/?name=Tina i think this is how GET works. but if i use POST, it will not show the input data in the link and it will remain Localhost/index.php. (atleast, from what i practice)
i wonder what are other differences between the two and when they should be use? for example im making a website(ex: sign up website) that will take information and send it to a database in MySQL..or the webpage should carry over the from this webpage to another webpage. should i use GET or POST?
You are kind of overthinking it. It is as simple as:
POST - used to post(send) data to the database.
GET - used to get(fetch) data from the database.
So in the case of the form, what you need to do is a POST request, so you send the data to MySQL. And in order to retrieve that data, you will perform a GET request.
See this https://www.geeksforgeeks.org/http-get-post-methods-php/ for a comprehensive explanation.
Keeping it very short:
You never-ever should pass any sensitive information over GET method, because it's visible by logs, by your internet provider/router, third parties.. such as google analytics and more.
A common use of GET is when you allow users to change the parameters of a page they see.. i.e. search parameters or the number of products per page.
POST when you want to send information to the server "privately" and (preferably) with a nonce to make it sendable only once.
But regardless of a method - POST or GET - sanitise, sanitise, sanitise.. that is what you need to really worry about. User input should not be accepted as is when you receive it, kinda #1 rule on the internet.
I am trying to pass the values of variables from one php page to another php page. Is it possible to include the previous php page in the next php page using include statement and use those variables and values rather than using $_SESSION['variable']="value".
If not, is there any other way to pass the values? Thanks in advance!
No. You'll run the code in the included file again, from scratch. Any data produced based on user input will have been lost.
If not, is there any other way to pass the values?
Passing the entire value to the browser and having it send the entire value back to the new script. (via form data, query strings in links, cookies, etc).
I am trying to create a script where a user can post something they want to sell and then I am using while loop in php to display the information from the database. Other users can click on the contact button and send an email to them. I was told that if I use 'session', the same email id will be stored for every listing. So I am wondering if I can use the hidden field and if so, how do I assign that php variable value to the html hidden field?
You can't use hidden fields for this. You need to store persistent data on the server. Store the email address with the rest of the information in the database. (You'll probably want a separate user table and associate the For Sale item with a user using a foreign key).
I have an application in which I display a form so a user can search for client records based on last name. After entering search parameters, the record or records (there could be multiple clients with the same last name) are displayed. I then want the user to be able to select a client record, possibly with a radio button, and hit one of two buttons: Display details, or Create Reservation. The Display Details button should cause a new display with details of the selected record. The Create Reservation button should cause a new form, with its own handling, to be displayed.
Now, I know I can set things up according to this login
<?php
if (display button was pressed)
{
php code to retrieve more data and display details
}
else if (create reservation button was pressed)
{
php code to generate and display the reservation form, with appropriate handling
}
?>
display the original form with the search results
The problem is, I end up with really ugly, hard to read code because the php code to generate and display the reservation form is lengthy, and needs its own validation, database interaction, and form handling. The code, to my Java-oriented eye, looks ugly and non-modular. Plus, the code for handling the reservation form is icky, with lots of flag setting to determine if we are in form entry mode or form handling mode. I would like a much cleaner way to do this. So my question is, what is the best practice for handling the situation where there are multiple buttons and the action associated with each button is complex?
I could call a function, obviously, but I still end up with the ugly flags determining which state the script is in (are we displaying the reservation form or handling it?). I could create another php file and include it, but the ugliness persists. Or, I could use header, and pass the client record id in a session variable to the new php script. But that would mean a second, unnecessary retrieve from the database to get the client information again.
All the code examples I see on the web show very simple processing after a form button is pressed. What is the best way to do complex processing and displaying a second form based on a button press?
Have you considered using a framework like Laravel for your site. It would seem to me that you must be doing this "manually". With the complexities you described, having a system with routes and "build-in" functionality (like Eloquent ORM) might serve to simplify things for you.
I would go for using ajax and a rich jQuery plugin (or some other framework) to do what you want.
Basically you will handle lists and the functionality that you mentioned with the php reading data and jQuery scripts to dysplay it. And the information that you have to show would be through ajax. Or when you want to edit.
Here is a cleaner example of what you need:
http://jqueryui.com/dialog/#modal-form
I want to make a webpage where an user can add the title from a book he has read. These changes are reflected in real time on a list that contains all books he has introduced on the database, without the need to press any "reload" button. By example: there is no need to refresh (F5) the page to see the last book added.
I don't know if I can do this in PHP or in any other language, so I would like to know which is the best suited for something like this.
Thank you.
I think you are looking for Ajax. Would be able to asynchronously update the section of the page (the post in this case) without the need for page refresh.
You will want to do this with javascript, using the onchange event, and for a discussion on this you can look at: Call Javascript onchange event by programatically changing textbox value.
Basically, you react to the data being changed, then just send it immediately over using ajax to the server, but, you need to be aware of two things.
First, how will you handle errors, such as there is no book with that title, or the length is too long. I tend to put the error message in or by the place where they had the bad data.
The other is that you need to pass back the id when the data was inserted, so that when they change it again you can just do an update, so you will need to store that. I tend to put the database id I need in the element id, but you can keep it in an array in javascript, since it will maintain state for you.
In a PHP application I'm building, I'd like to have an 'editable' table. The idea is that each row will have an edit button, which, when clicked, will replace certain fields with text fields and select lists and change to a save button. When the user clicks save, the data data should be validated and changed if appropriate.
I'm mainly tackling this as a learning project (I'm aware there's a ton of stuff already out there) and to see if I can get anything 'cool' working. I've created a PHP table-generating class that can take an array of objects as a datasource, and can have columns created based on those class methods.
e.g.
$table = new Table($dataSource);
$table->addColumn('Name', 'getName');
$table->addColumn('Amount Due', array('getOrdersManager', 'getTotalAmountDue')); //First calls getOrdersManager() on each data item and then calls the getTotalAmountDue() on the result
I'd like to try my hand at extending this to be able to the table row and have those changes reflect on the corresponding object in the data source.
I don't really have very much experience with AJAX although it's clearly going to play a very important role in getting this to work correctly.
Any tips on how I should approach such a task?
Edit: I'm not really interesting in looking at Ajax libraries at this point (I do have some experience with jQuery). I'm more interested in learning the basics of Ajax at this point.
my tip is to use jquery(does most of the heavy lifting for you and is easy to learn).
The idea is that each row will have an
edit button, which, when clicked, will
replace certain fields with text
fields and select lists and change to
a save button
http://api.jquery.com/click/
When the user clicks save, the data
data should be validated and changed
if appropriate.
http://api.jquery.com/jQuery.post/
Some things to be aware of/think about:
Are you going to send every field change to the server, or only the whole row (the latter is more resource efficient, but not necessarily as accurate)
How are you going to ensure the data displayed stays accurate even if the update to the server fails for some reason (either a network failure or a DB/validation error)
How will you ensure the user has permission to update the record and that you don't open a security hole by allowing the AJAX responder just to update whatever record it is told to. My approach has been that if a record is shown in the interactive table then the user has the permission to update it, so a cache of record IDs is held in the session when the table is created
Are you going to load options dynamically? If you don't, then a long table can end up containing a lot of HTML because of repetition of the select controls, but again it is more resource efficient not to have a request every time a user clicks into a dropdown. One compromise might be to put the options into a hidden HTML field and load them dynamically into the correct place when a user clicks a dropdown