Creating Related Resources
The completed code for this lesson is on the create-related-resource branch of the MvcMovieStarter
Learning Goals
- Use a form to create a one-to-many relationship
Demo
Your instructor will demonstrate what our MvcMovie application will look like after today’s lesson. Our goal today is to:
- Use a form to create new reviews for a movie
Using a Form to Create Reviews
Similar to the form we use to create movies, we are going to use a form to create reviews.
In Small Groups Outline the components we will need in place to make the user stories below. Be sure to consider:
- What controller actions do we need?
- What views do we need?
- What data needs to be passed to and from the views?
Be Ready to Share out!
In Small Groups
- What tests will we add?
- Will we need to make any adjustments to our current implementation or tests?
Be Ready to Share out!
As a User
When I visit /movies/1/reviews
Then I see a link to 'Add a Review'
When I click on the link
Then I am on page /movies/1/reviews/new
As a User
When I visit /movies/1/reviews/new
Then I see a form to create a review with
A number Rating
A textfield Content
A button to 'Create Review'
As a User
When I fill in the New Review form
And click 'Create Review'
Then I am redirected to /movie/1/reviews
Then I see the review I created
Test the New View
Individually
Using the tests we created to verify the new movie page, write the tests for the first two user stories above.
One Solution
[Fact]
public async Task Index_ReturnsViewWithLinkToNewForm()
{
var context = GetDbContext();
var client = _factory.CreateClient();
Movie spaceballs = new Movie { Genre = "Comedy", Title = "Spaceballs" };
context.Movies.Add(spaceballs);
context.SaveChanges();
var response = await client.GetAsync($"/Movies/{spaceballs.Id}/Reviews");
var html = await response.Content.ReadAsStringAsync();
Assert.Contains($"<a href='/movies/{spaceballs.Id}/reviews/new'>", html);
}
[Fact]
public async Task New_ReturnsViewWithForm()
{
var context = GetDbContext();
var client = _factory.CreateClient();
Movie spaceballs = new Movie { Genre = "Comedy", Title = "Spaceballs" };
context.Movies.Add(spaceballs);
context.SaveChanges();
var response = await client.GetAsync($"/Movies/{spaceballs.Id}/Reviews/New");
var html = await response.Content.ReadAsStringAsync();
Assert.Equal(HttpStatusCode.OK, response.StatusCode);
Assert.Contains($"<form method='post' action='/movies/{spaceballs.Id}/reviews'", html);
}
This is a good opportunity to ask students to navigate through the implementation while you drive!
Now that we have some tests created, we can use them to guide our implementation!
One main difference between this new view and the one we created for our Movie form is the information that needs to be passed in to the action, and then on to the view:
// GET: /movies/:movieId/reviews/new
[Route("Movies/{movieId:int}/reviews/new")]
public IActionResult New(int movieId)
{
var movie = _context.Movies
.Where(m => m.Id == movieId)
.Include(m => m.Reviews)
.First();
return View(movie);
}
Test the Create Action
In Small Groups
Using the tests we created to verify the new movie create action, write the tests for the third user story above.
One Solution
[Fact]
public async Task Create_AddsReview_RedirectsToMovieReviewsIndex()
{
var context = GetDbContext();
var client = _factory.CreateClient();
Movie spaceballs = new Movie { Genre = "Comedy", Title = "Spaceballs" };
context.Movies.Add(spaceballs);
context.SaveChanges();
var formData = new Dictionary<string, string>
{
{ "Rating", "5" },
{ "Content", "Better than Star Wars" }
};
var response = await client.PostAsync($"/movies/{spaceballs.Id}/reviews", new FormUrlEncodedContent(formData));
var html = await response.Content.ReadAsStringAsync();
Assert.Equal(HttpStatusCode.OK, response.StatusCode);
Assert.Contains($"/Movies/{spaceballs.Id}/reviews", response.RequestMessage.RequestUri.ToString());
Assert.Contains("5: Better than Star Wars", html);
Assert.DoesNotContain("4: Good. But, when will then be now?", html);
}
In Small Groups
Using the tests we created to verify the new movie create action, write the tests for the third user story above.
One Solution
[HttpPost]
[Route("/Movies/{movieId:int}/reviews")]
public IActionResult Create(int movieId, Review review)
{
var movie = _context.Movies
.Where(m => m.Id == movieId)
.Include(m => m.Reviews)
.First();
movie.Reviews.Add(review);
_context.SaveChanges();
return RedirectToAction("index", new { movieId = movie.Id });
}
Checks for Understanding
- Imagine we are building an application for a Library, where Books can have many Authors (a book must have at least one author), and Authors may have many books.
- What might the routes look like for creating a new book?
- What might the routes look like for creating a new Author?
