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Single-page form with validations

From: PHP with MySQL Essential Training

Video: Single-page form with validations

In this movie, we're going to see how to take the single-page form that we were working with earlier and apply everything that we've learned about validations to it. You can think of this movie as also being known as putting everything together. It's the sum total of all that we've worked on. So we have a form and we're going to have validations on that form. As a starting point, let's go with our form single.php file. Let's open that up. Let's do a Save As on it and let's call it Form with Validation. Okay, so I'm going to save that there. The very first thing I want us to do, before we do anything else is jump down here to the action that was submitting to form single, and change that to match form with validation. Right? Otherwise it won't be submitting to itself anymore.

Single-page form with validations

In this movie, we're going to see how to take the single-page form that we were working with earlier and apply everything that we've learned about validations to it. You can think of this movie as also being known as putting everything together. It's the sum total of all that we've worked on. So we have a form and we're going to have validations on that form. As a starting point, let's go with our form single.php file. Let's open that up. Let's do a Save As on it and let's call it Form with Validation. Okay, so I'm going to save that there. The very first thing I want us to do, before we do anything else is jump down here to the action that was submitting to form single, and change that to match form with validation. Right? Otherwise it won't be submitting to itself anymore.

So now we have effectively the same form that submits to itself. So let's add our validations to it. Well the first thing we need to do is we need to require once our validation functions. Validation functions.php we also know we need an errors array initialized. Let's add that to the top and we know that we are going to want to display the errors down here. So after echo message let's also put parenthesis. Echo form errors, remember form errors is defined in my validations functions value.

So that will display the form errors if there are any. This will just set errors and then there are no errors. We don't have any validations actually happening though. They're being defined, we need them to actually take place. So we can use the validation that we had just in the last movie. I'll put it right here. Right before we do this is the actual action. This is the meat of our application, right, the try to login part. Just put a note here this is the try to login. So before we get to that we want to check and make sure that our data is valid. So has presence, username, not has presence then we're going to set an error.

So if an error's set, then we don't want to do this anymore. This step, this try to login should be conditional on that. So if,empty, errors then we'll do all of this try to login business. I'm going to change this, instead of saying there were some errors in the message, let's say username, password do not match. Okay that's a little more descriptive now. That should work for us. The one other change that we need to make sure we make is that has presence wants us to trim these values before we get there.

And it's up to you whether you would trim the password or not, whether you would allow spaces, I'm going to go ahead and do it. So the password can't have spaces at the beginning or the end or they will get trimmed off. So let's try this now. And note here this is our validations, so if the passes validations we'll do the action, if not, we should see an error message. Let's go to Firefox and this page is now going to be called form with validation, singular. There's my form. And let's just try submitting without putting a value in there. Let's hit submit. Oops, undefined variable message. that's because in the case where neither this happens or this happens, message never gets set.

I just need to set message up here. I'll just set it to an empty string, so it's initialized, it will never give me an error now. Let's just try that one more time, I'll just submit it again. There it is, please fix the following errors, user name can't be blank. Let's try submitting a username now. Kevin, submit. Now I get username password do not match. I don't get my validation errors anymore. So there we are. We now have our validations in place on a single form. Now I wanted us to try this in place because when we're working with post values, what's nice is that we have the ability to dynamically pick the string that we're going to look for inside there to assign that key. And that let's us do some nice things, for example, instead of having our validations like this we can have fields required are username and password. The we can actually check for our has_presence by doing a loop. So we can write a loop for each fields required as field and then inside there you move all this code and let's do each and every one value equals and let's make it $ post.

And then the field see what I mean about dynamically being able to specify that key. That's going to be the value. We'll trim it and then we'll ask it has presence of the value. If so well what key do we want to use, we want to use the field. And we can't use username here. Instead we need to provide the field, can't be blank. Which is a little clumsy. It's a little better if we do something like ucfirst to make it uppercase. You can do more elaborate transformations for that if these had underscores in them for example maybe you'd want to replace that with a space or something like that. So now it's going to loop through each one of my fields that I've required and it's going to call this function on it.

Let's save it and give it a shot. We'll come back over here and let's just try submitting it. Password can't be blank. Take out username, username can't be plank, password can't be blank. Right, see how we can use the power of loops along with our has presence function to speed things up. We can do the same thing with the validations working with associative arrays. Here's another one. I'll just paste it in, so you don't have to watch me type it all. So there we go, same thing. Checking the max length, here's the associative array with the key followed by the length that it's allowed to be. So I've got up to 30 for the username, password can only be eight. It's a little bit arbitrary but we're going to take each one of those and if has_max_length fails, then we'll add an error for it. Go up here and let's try it.

Let's try user name Kevin. Password is equal to verylongpassword, submit it. Password is too long is the error that we got. Now if I have this one be blank and I make a verylongpassword, right it combines the two. Username can't be blank, password is too long. Now you can go even farther with this. If you like this looping idea, we can take this whole associative array and let's go back over to our validation functions. And let's drop down, we'll do it right before we get to form errors.

And I'm going to make a new function, which I'm going to call validate_max length and its going to expect an associative array fields with max_lengths. Its the same name that I was using before and I'll just paste in that code from the other page. Uses an associative array field with max_lengths I don't need to find here I need it back over here. Let me just keep it there. And then it's going to loop through each one using fields_with max_length. It's going to go through each of the errors.

The one thing if you want to do this, if you want to wrap this whole thing up into a regular function that you can call. You're going to need to make sure that you have global errors. So that's going to bring in errors into this scope so that we can work with it. So if you're going to use functions and you're going to need to have access to errors you're going to need to bring that in and make sure it has the global scope. So now I'm validate max_length and just simply be called on field with max_length. Let's try that,. Let's go back to Firefox. Reload the page. This is a long password.

And there it is, password is too long. That's doing it by calling this validate max_lengths function. So there's no limit to what you can do with your validation library, to all the things that you can build up and all the ways that you can use it. Use it in the way that's useful to you. The overall point is to understand the flow of how things happen. The data comes in from the user, we're going to clean it up a little bit. We're going to run it through our validations. If it passes the validations, we'll execute one set of actions. If not, we'll do another set of actions.

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This video is part of

Image for PHP with MySQL Essential Training
PHP with MySQL Essential Training

131 video lessons · 36177 viewers

Kevin Skoglund
Author

 
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  1. 4m 8s
    1. Welcome
      1m 0s
    2. Using the exercise files
      3m 8s
  2. 15m 6s
    1. What is PHP?
      3m 52s
    2. The history of PHP
      2m 51s
    3. Why choose PHP?
      4m 10s
    4. Installation overview
      4m 13s
  3. 54m 53s
    1. Overview
      2m 33s
    2. Working with Apache Web Server
      6m 56s
    3. Changing the document root
      7m 24s
    4. Enabling PHP
      6m 16s
    5. Upgrading PHP
      3m 30s
    6. Configuring PHP
      10m 3s
    7. Installing MySQL
      5m 46s
    8. Configuring MySQL
      7m 24s
    9. Text editor
      5m 1s
  4. 31m 25s
    1. Overview
      3m 27s
    2. Installing WampServer
      5m 46s
    3. Finding the document root
      2m 24s
    4. Configuring PHP
      8m 12s
    5. Configuring MySQL
      5m 45s
    6. Text editor
      5m 51s
  5. 19m 12s
    1. Embedding PHP code on a page
      6m 43s
    2. Outputting dynamic text
      5m 55s
    3. The operational trail
      2m 27s
    4. Inserting code comments
      4m 7s
  6. 1h 18m
    1. Variables
      7m 50s
    2. Strings
      4m 38s
    3. String functions
      8m 54s
    4. Numbers part one: Integers
      6m 27s
    5. Numbers part two: Floating points
      5m 25s
    6. Arrays
      10m 0s
    7. Associative arrays
      6m 37s
    8. Array functions
      6m 33s
    9. Booleans
      3m 50s
    10. NULL and empty
      5m 15s
    11. Type juggling and casting
      8m 27s
    12. Constants
      4m 43s
  7. 27m 37s
    1. If statements
      6m 0s
    2. Else and elseif statements
      4m 16s
    3. Logical operators
      7m 30s
    4. Switch statements
      9m 51s
  8. 42m 15s
    1. While loops
      8m 41s
    2. For loops
      5m 59s
    3. Foreach loops
      8m 16s
    4. Continue
      8m 28s
    5. Break
      4m 8s
    6. Understanding array pointers
      6m 43s
  9. 37m 25s
    1. Defining functions
      8m 25s
    2. Function arguments
      5m 32s
    3. Returning values from a function
      7m 33s
    4. Multiple return values
      4m 53s
    5. Scope and global variables
      6m 2s
    6. Setting default argument values
      5m 0s
  10. 20m 18s
    1. Common problems
      3m 47s
    2. Warnings and errors
      8m 36s
    3. Debugging and troubleshooting
      7m 55s
  11. 57m 57s
    1. Links and URLs
      5m 33s
    2. Using GET values
      5m 35s
    3. Encoding GET values
      8m 41s
    4. Encoding for HTML
      9m 26s
    5. Including and requiring files
      7m 40s
    6. Modifying headers
      6m 45s
    7. Page redirection
      6m 43s
    8. Output buffering
      7m 34s
  12. 1h 3m
    1. Building forms
      7m 28s
    2. Detecting form submissions
      5m 59s
    3. Single-page form processing
      7m 57s
    4. Validating form values
      10m 40s
    5. Problems with validation logic
      9m 54s
    6. Displaying validation errors
      7m 23s
    7. Custom validation functions
      6m 28s
    8. Single-page form with validations
      7m 25s
  13. 28m 5s
    1. Working with cookies
      2m 49s
    2. Setting cookie values
      5m 55s
    3. Reading cookie values
      6m 1s
    4. Unsetting cookie values
      4m 51s
    5. Working with sessions
      8m 29s
  14. 48m 39s
    1. MySQL introduction
      6m 43s
    2. Creating a database
      7m 41s
    3. Creating a database table
      7m 42s
    4. CRUD in MySQL
      5m 48s
    5. Populating a MySQL database
      7m 32s
    6. Relational database tables
      6m 40s
    7. Populating the relational table
      6m 33s
  15. 56m 4s
    1. Database APIs in PHP
      4m 51s
    2. Connecting to MySQL with PHP
      7m 45s
    3. Retrieving data from MySQL
      8m 47s
    4. Working with retrieved data
      6m 12s
    5. Creating records with PHP
      6m 58s
    6. Updating and deleting records with PHP
      9m 6s
    7. SQL injection
      3m 5s
    8. Escaping strings for MySQL
      6m 45s
    9. Introducing prepared statements
      2m 35s
  16. 35m 58s
    1. Blueprinting the application
      7m 19s
    2. Building the CMS database
      5m 14s
    3. Establishing your work area
      4m 38s
    4. Creating and styling the first page
      4m 22s
    5. Making page assets reusable
      6m 36s
    6. Connecting the application to the database
      7m 49s
  17. 32m 49s
    1. Adding pages to the navigation subjects
      5m 58s
    2. Refactoring the navigation
      6m 7s
    3. Selecting pages from the navigation
      6m 2s
    4. Highlighting the current page
      5m 26s
    5. Moving the navigation to a function
      9m 16s
  18. 1h 45m
    1. Finding a subject in the database
      9m 48s
    2. Refactoring the page selection
      10m 52s
    3. Creating a new subject form
      6m 55s
    4. Processing form values and adding subjects
      11m 20s
    5. Passing data in the session
      9m 16s
    6. Validating form values
      9m 40s
    7. Creating an edit subject form
      8m 30s
    8. Using single-page submission
      7m 44s
    9. Deleting a subject
      9m 44s
    10. Cleaning up
      10m 37s
    11. Assignment: Pages CRUD
      4m 30s
    12. Assignment results: Pages CRUD
      6m 10s
  19. 39m 26s
    1. The public appearance
      8m 52s
    2. Using a context for conditional code
      11m 37s
    3. Adding a default subject behavior
      6m 9s
    4. The public content area
      5m 51s
    5. Protecting page visibility
      6m 57s
  20. 1h 3m
    1. User authentication overview
      4m 3s
    2. Admin CRUD
      8m 41s
    3. Encrypting passwords
      7m 26s
    4. Salting passwords
      5m 42s
    5. Adding password encryption to CMS
      11m 54s
    6. New PHP password functions
      3m 13s
    7. Creating a login system
      11m 28s
    8. Checking for authorization
      5m 48s
    9. Creating a logout page
      5m 40s
  21. 2m 4s
    1. Next steps
      2m 4s

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