Next we'll implement our book list page. This page needs to display a list of all books in the database along with their author, with each book title being a hyperlink to its associated book detail page.
The book list controller function needs to get a list of all
Book
objects in the database, sort them, and then pass these to the template for rendering.
打开
/controllers/bookController.js
. Find the exported
book_list()
controller method and replace it with the following code.
// Display list of all Books.
exports.book_list = function(req, res, next) {
Book.find({}, 'title author')
.sort({title : 1})
.populate('author')
.exec(function (err, list_books) {
if (err) { return next(err); }
//Successful, so render
res.render('book_list', { title: 'Book List', book_list: list_books });
});
};
The method uses the model's
find()
function to return all
Book
objects, selecting to return only the
title
and
作者
as we don't need the other fields (it will also return the
_id
and virtual fields), and then sorts the results by the title alphabetically using the
sort()
method. Here we also call
populate()
on
Book
, specifying the
作者
field—this will replace the stored book author id with the full author details.
On success, the callback passed to the query renders the
book_list
(.pug) template, passing the
title
and
book_list
(list of books with authors) as variables.
创建 /views/book_list.pug and copy in the text below.
extends layout
block content
h1= title
ul
each book in book_list
li
a(href=book.url) #{book.title}
| (#{book.author.name})
else
li There are no books.
The view extends the
layout.pug
base template and overrides the
block
named '
content
'. It displays the
title
we passed in from the controller (via the
render()
method) and iterates through the
book_list
variable using the
each
-
in
-
else
syntax. A list item is created for each book displaying the book title as a link to the book's detail page followed by the author name. If there are no books in the
book_list
那么
else
clause is executed, and displays the text 'There are no books.'
注意：
使用
book.url
to provide the link to the detail record for each book (we've implemented this route, but not the page yet). This is a virtual property of the
Book
model which uses the model instance's
_id
field to produce a unique URL path.
Of interest here is that each book is defined as two lines, using the pipe for the second line. This approach is needed because if the author name were on the previous line then it would be part of the hyperlink.
Run the application (see
Testing the routes
for the relevant commands) and open your browser to
http://localhost:3000/
. Then select the
All books
link. If everything is set up correctly, your site should look something like the following screenshot.
最后修改： , 由 MDN 贡献者