New Feature: Playlist Center! Pick a topic and let our playlists guide the way.

Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Adding a default subject behavior

From: PHP with MySQL Essential Training

Video: Adding a default subject behavior

At the top of this chapter, I mentioned that one of the other differences between the public area. And the admin area is going to be the way that we handle what happens when a user clicks on a subject. We need to add a default subject behavior for the public. What I mean is, is that in the admin area, it's acceptable for the user to click on a subject and not get any content over on the right side. But I think that's not a great thing for our public. I think it's better if they actually get some content when they click on a subject. And to do that, what we'll do is we'll bring up the default page for the subject.

Adding a default subject behavior

At the top of this chapter, I mentioned that one of the other differences between the public area. And the admin area is going to be the way that we handle what happens when a user clicks on a subject. We need to add a default subject behavior for the public. What I mean is, is that in the admin area, it's acceptable for the user to click on a subject and not get any content over on the right side. But I think that's not a great thing for our public. I think it's better if they actually get some content when they click on a subject. And to do that, what we'll do is we'll bring up the default page for the subject.

It seems to me that that default page ought to just be the first page, right? We should go ahead and just set that first page to be the default page. So, if you click on products, you ought to be seeing the content for large widgets. If you click on services, you ought to be seeing the content for retrofitting. Not just something about the subject generally here. Now we could have built our content management system differently so that every subject could have had its own blurb of text, but that's not what I'm after here. What I want is to just show you how we can have this default behavior built in. So, the place that I think we can add this is in our functions.php, and in our find_selected_page function that we already have, that's where we're determining what the subject and what the page is. So, if a subject is set, then we find that subject. What is the page in that case? Well it's null. But what if we went ahead and instead of just making it null, what if we went ahead and had it find a default page? Let's write a function, first of all, that'll find a default page for us, and then we can call it here. So, let's put it right here, above it.

Function, and we'll call it find the default_page_ for_subject. And that will take a subject id will be passed in. So, how can we find the first page of the subject? Well, the easiest way is we can find the list of all the pages for the subject. We know how to do that. We've got find pages for subject right here. Which also takes a subject ID. So, let's do that. Let's say page_set equals find pages for subject, subject_id.

And then, once we have that page set, then we know we want to get the first one out of there. So, it's the same thing that we did to find_page_by_id, right? Find_page_by_id executed a query and then it went ahead and it fetched the association and returned either the page or null. If it found one, then it returned it. Let's do the same thing here, I'm just going to actually copy this and we'll just use that and make it slightly different. Because we have, let's see, fetch association from page set and I'm just going to call this first page just so it's clear, if we find a first page, return it. Otherwise return nothing.

So, that'll do it for us. This function now will return a default page for the subject. So, given a subject id, we can find it. So, let's do that, let's say find_page_for_subject and then we can just pass in current subject id. See how that works? We find the subject by it's id. Now it's equal to current subject, then we ask that for it's id, and pass that in to find default page for the subject. Let's try it. Let's save it, let's come back over here.

This could become products. Okay, now wait a minute. We're not seeing anything different, we're still seeing our subject. That's because, even that we now got a page, we're not displaying it. We need to come back over here to index.php. And if we have a current subject, we've said manage subject. If we have a current page, then we've said display the page. Well, now, we don't want to actually have this in here at all anymore. If we have a current subject, we don't care. All we care about is, do we have a current page? If we have a current page then it will display.

So, that's it just take out that conditional from index.php, reload the page and there you go. See, click on services retrofitting pops up that's what that is right there. Our mission or our history but clicking just the subject on its own defaults so you can see it goes ahead and highlights it even. Because our highlighting and our navigation is all based on what we set in this find selected page function. So now at this point we're done and we have it working. However, I just want us to think about one other thing which is just that in the admin area. When we're clicking around on all these pages.

It still works. Everything works exactly as expected. Right? We're still seeing the, the subject, and that's because our managed contentpage.php still has this if we have a current subject. Right? So, it checks for that first, and it never gets to this second block down here for if we have a different page, right? Because that's different we can do both, however given the fact that we just got through learning about context. And how we can pass in different context I think we can make use of that here. Why do this extra MySQL query for all of those admin pages, right? We're doing some extra work every time we load a page, and we don't need to if we're in the admin area. We could have something that just checks to see if public. And so, if we're in the public context.

Then do that extra work. But if not, then don't. Go ahead, and just go back to our original behavior. Which was that the current page is equal to null. So, if we're in the public context, and then all we have to do is have something up here that says public. And by default I'm going to say that we are going to not be in the public context. That's different than what I was doing before where I was saying by default the public ought to be true, here I'm setting it by default to false. So, just be careful about that. And so then all I have to do is on my index.php.

In addition to asking for the selected page. I also have to pass in, true, for the fact that we are in the public side of things. And that will do that extra work for us. Let's go back and make sure we didn't break anything. As we click around we still get it. But when we're on the admin area, we don't make those extra MySQL calls because our context doesn't require it.

Show transcript

This video is part of

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

131 video lessons · 31648 viewers

Kevin Skoglund
Author

 
Expand all | Collapse all
  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

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold

Are you sure you want to delete this note?

No

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.