Object Oriented PHP #14 - Validation Class (part 3)

Key Takeaways

or rather gang so we're nearly at the finish line now we just need to do a few more things but now we have our user validator class and all we need to do is create a new instance of this class after a user submits the form and pass in the post data which they entered into these fields and then it can do all the validation it can spit back any errors if there are any and then we can output those to the user in the screen if there are any so let's go back to index dot PHP and first of all right here this is where we need to validate the entries so let's delete that echo statement first of all and instead create a new instance of the user validator class now before I do that I need to use that class inside this file so I need to then say at the top or require and we're going to require user underscore validator dot PHP right so now we can use that class inside this file so down here I can create a new instance of that class and I'll call this a validation and set it equal to new user validator okay so now we need to pass in the post data to this which is just dollar sign underscore and post like so that is an array and it's going to contain keys which should be username and email ok so now we need to call this method this method right here validate form because that's what kicks everything off we check the fields to see if they exist and if you do we call these two methods down here to check the individual fields then we return any areas at the end so first of all let's say errors because that's what's ultimately returned to us let's not do this in capitals errors is equal to validation which is our instance and then we'll invoke the validate form method and by the way I just want to say at this point and it's a funny point to say it I should have said it at the start there's many many ways to do this kind of validation I'm just doing one particular way here right so if you are a hundred programmers to do this you'll probably get at least about 75 different ways probably a hundred different ways of doing this so don't feel like this is all set in stone and this is exactly how you should be doing it I'm just showing you an example of creating a class and using it right here and there are many ways of doing this but anyway I digress let's carry on with this we're calling this method which is ultimately going to return us an array of errors that could be empty if there's no errors but we'll still store that empty array right here now at this point if the errors were empty this is where we'd probably save data to a database right if that's what we're doing with it now if there are errors then instead what we're going to do is output them to the form I'm not going to do this check right here and save anything to the database that's not what this course is all about we're just focused on our class and the form at the minute so instead what I'm going to do is I'm going to check if there's any errors down here inside the actual template and then output them all right so before I do that what I want to do is save this and just refresh over here then I'm going to continue and I'm going to now do all this stuff right here and okay this happened without any errors but check this out if I now go to this form down here and change this to emails for example and save it I'm going to refresh over here I'm going to continue and then if I try to enter some stuff in now we get an error it says email is not present in the data so that was this error before right here so remember when we checked each of the fields and to check that those fields right here exist right now I say actually it can't find this field in the post data because now we don't have that field inside our form it's now emails and it should be email so if we change that back then we're not going to get any error if I submit this now then it sure work okay we need to actually reload the page because that's there now but anyway if I do it now then we don't get that error okay so the next thing to do is actually output any errors if there are any now I'm going to do a separate div under each of these input fields and this is actually going to have a class equal to error so we can style this in a second just color it red or coral or something in a minute then we need to echo something out so PHP tags first of all PHP closed that off and we're going to echo and we're going to use the null coalesce operator to do this so if something has a value it outputs that if it doesn't have a value it outputs something else so we're gonna check if errors and then username has a value now if there is an error with that key inside that errors array then it will help put it then we do double question mark and then this is the alternate value double output if this is null so if that error doesn't exist then when I actually output in anything just an empty string right again you can learn more about this norco let's operate it in my PHP for beginners series anyway so now we need to duplicate that dude and paste it downhill and this time we want to check the email one all right so if we save this now all let's check this out so if I submit now we can see these two things right here username cannot be empty an email cannot be empty if I change this to something like SG then it says username must be six to twelve characters and alpha numeric so it's no longer empty but we're getting this different error and the same for this one if I enter something that's not a valid email it says email must be a valid email so these are working the thing is we're not persisting the data that a user types into these fields so if I submit something like that and it's wrong even though it's wrong or rather that wasn't but if I submit something that's wrong like that I want that to remain here when the page reloads so a user doesn't have to type out the whole thing again so to do that we need to go to the value properties of these input fields so what I'm going to do is say value is equal to something and then we're going to output the actual data in the post array right because that's what a user actually submitted so let's do our PHP tags now we have to surround whatever we output with the function HTML special cars because that is going to make our code more secure so that if a user tries to input some kind of JavaScript or something like that it's not actually going to run that a script okay so that's what this function kind of does so let's echo HTML special chars again this is all discussed in my beginners series and then inside this we need to pass through the post data so dollar sign underscore post and then the value we want is the username from that okay so now we're outputting this data right here as the value when it reloads now we need to actually do a null coalesce operator here as well because the first time the page loads this is not going to exist and it's going to output some kind of error so instead we doing null coalesce operator so if it doesn't exist then we just output a simple blank string instead so what I'm going to do is actually grab this thing right here and then down on the other input field I'm going to say value is equal to we need our PHP tags again close that off I'm going to paste this dude right in here and this time I need the email instead oops can I spell no it's been a long day so I'm saved that now and if I are refresh I'm gonna see this right here so if I type something else in now and something else down here refresh I do get the errors this is valid by the way but I do get the errors but I still get this data inside the input field so it still shows now if I type something not valid up here we get the error but this still shows awesome so that is just about in the friends there's one more thing to do and that's just to add this tiny lip style down here so we're grabbing the error class and we're cloning it coral save it and let's go over here do this again and now we can see no we don't let's have refresh and now we can see this error is in coral so it difficult so what my friends we have reached the finish line now we have successfully created this user validator class and okay it's only checking two fields but you could extend this class if you wanted to you could make additional fields for different things like a password and then you could make sure that two password fields are the same or something like that if you do that if you extend it leave your links down below so we can all check it out but there we go that is this series well and truly over so hopefully I've taught you a little bit along the way about object-oriented programming in PHP and hopefully as well you can see the benefits of using classes in your code if you've enjoyed this series guys please do not forget to share subscribe and like that really means a lot and I'm going to see you in the very next series [Music]