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We can throw exceptions to let our users know when things don't work quite right.
Throwing Exceptions
First we need to tell our Course class to use \App\Exception\ApiException;. Then we can throw exceptions to let our users know what's going on.
We should throw and exception in the following situations:
- With getCourses
- if there are no courses
- With getCourse
- if we can't find a course
- With createCourse
- check that the proper data has been passed
- check if the course has actually been added
- With updateCourse
- check if the proper data has been passed
- check if the course has actually been added
- check if the course exists before trying to add the course. Instead of writing this again here, we can use the getCourse method
- With deleteCourse
- check if the course exists first. Again we can use getCourse
- check that the database has been affected by our statement
We can close these two files,
and we'll open our course.
0:01
The first thing we need to do is tell our
course to use our new exception, use App,
0:06
\Exception\ApiException.
0:17
So for our first method, getCourses,
if there are no courses,
0:30
we want to throw an exception.
0:34
We'll set this to courses.
0:41
And then we'll return courses.
0:45
Then we'll check if empty courses.
0:50
If so,
we want to throw a new ApiException.
0:57
And then we can use our ApiException with
1:02
COURSE_NOT_FOUND, and 404.
1:07
Let's do the same thing for the getCourse.
1:12
Course =, and return course.
1:21
If not, we'll throw an exception.
1:29
Before we move on,
let's test this out in Postman.
1:32
Line 21.
1:46
Great, we see course not found.
2:04
Let's go back and
add some more exceptions.
2:08
Our next method is createCourse.
2:13
First, we should check that
the proper data has been passed.
2:16
If empty data title.
2:24
Or empty data url.
2:31
Then we're going to throw
a new ApiException.
2:37
And we're gonna call ApiException.
2:42
And we're going to say COURSE,
2:45
_INFO_REQUIRED.
2:52
Also, we want to check if
the course has actually been added.
2:55
After the execute, we can check, If
3:00
the statement affected rowCount,
3:05
and that is less than 1.
3:13
So if nothing changed,
we want to throw a new ApiException,
3:18
and then we can say ApiException,
3:24
COURSE_CREATION_FAILED.
3:31
Next is updateCourse.
3:37
We're going to do the same
thing that we did for create.
3:39
So let's copy these lines here and
paste them here.
3:42
We also need to check if
empty data course_id.
3:48
And again, we'll need the rowCount,
helps if we spell it right.
3:59
So after execute,
we'll check if anything was updated.
4:06
If not, we'll throw another exception,
UPDATE_FAILED.
4:10
Finally, we have our deleteCourse.
4:18
First, we want to check that
our course actually exists.
4:20
So again, we can use this getCourse,
and pass the course_id.
4:24
Once again, we can check that a row
has been affected by our statement.
4:32
So after execute, we'll do our rowCount.
4:36
And if not, COURSE_DELETE_FAILED.
4:41
Let's check this out in Postman.
4:47
So trying to find a course that doesn't
exist gives us the course not found.
4:50
If we want to add a course,
but we don't pass any data,
5:02
It's giving us an error,
COURSE_INFO_REQUIRED.
5:11
Missing an R.
5:15
Course, course, course.
5:18
Okay, course.
5:23
All the rest look good.
5:26
Required course data missing.
5:31
Great, and
if we try to update a course, Without
5:35
any information,
Required course data missing.
5:40
And if we try to delete a course that
doesn't exist, Course Not Found.
5:51
This is just an example.
5:59
You can go ahead and
play around a little bit more.
6:00
Your next challenge is to add
exceptions in your review class.
6:03
Go ahead and give it a try and
I'll show you what I did in the next step.
6:08
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