COMP3322A Modern Technologies on World Wide Web
Assignment 1: A Simple Webmail System (20%)
[Learning Outcomes 1, 2]
Due by: 23:59, Wednesday November 6, 2019
Total mark is 100.
Overview
In this assignment, you are going to develop a simple web-based email system using
NodeJS/Express.js, MongoDB, JavaScript, AJAX, HTML and CSS. The webmail system
implements a few simplified functionalities, including displaying emails in your mailboxes,
moving emails from one mailbox to another and compose new messages. The web-based
email system is to be implemented by the following code in an Express app:
app.js
./public/webmail.html
./public/javascripts/script.js
./public/stylesheets/style.css
and accessed at http://127.0.0.1:8081/webmail.html.
Preparations
1. Following steps in setup_nodejs_runtime_and_examples_1.docx, install the Node.js
environment and the Express framework, and create an Express project named WebMail.
2. Following steps in Lab 4, install MongoDB, run MongoDB server, and create a database
“assignment1” in the database server.
Insert a number of email documents into an emailList collection in the database in the
format as follows:
db.emailList.insert({'sender':'amy@cs.hku.hk', 'recipient':'john@cs.hku.hk',
'title':'Meeting today', 'time':'20:32:01 Fri Oct 11 2019', 'content':'Shall we meet at the
library at 5pm?', 'mailbox':'Inbox'})
Each email document in the emailList collection contains the following key-value pairs: _id: The unique ID of the document, which you do not need to include when
inserting a document, and MongoDB server will add automatically into each
inserted document. You can find out such a _id using db.emailList.find().
sender – The email address of the sender.
recipient – The email address of the recipient. title – The title of the email.
time – The time when the email was sent.
content – The content of the email.
mailbox – The mailbox which the email belongs to, among Inbox, Important, Sent
and Trash.
Please prepare at least 3 pages of emails in each mailbox in the emailList collection. That is to
say, if you set the number of emails to display on each page in the email division to be 3,
then you should prepare at least 9 email documents for each mailbox in the collection.
Task 1 (15 marks) Create basic webmail.html and app.js
1. Client side
Create webmail.html which renders the layout shown in the following figure, i.e., the page
has four main divisions: heading, function buttons, mailbox list and email list. You can design
any heading, showing the name of your webmail system. In the function division, there
should be four buttons: “Compose”, “Move to …”, “<” and “>”. You can implement the
buttons using any elements you like, as long as they are clickable and upon clicking, the
corresponding functionality can be achieved. In the mailbox division, include four links:
“Inbox”, “Important”, “Sent” “Trash”. In the email division, the email entries will be
dynamically loaded from the server side, to be implemented in Task 2.
Fig. 1
2. Server side
In app.js, add necessary code for loading the MongoDB database you have created, creating
an instance of the database, and passing the database instance for usage of all middlewares.
Also load any other modules and add other middlewares which you may need to implement
this application.
Add the middleware for serving static file in the “./public” directory.
We will let the server run on the port 8081 and launch the Express app using command
“node app.js”.
Task 2 (25 marks) Display the email list
When webmail.html is first loaded, it should be showing the “Inbox” view (Fig. 1): The
“Inbox” link in the mailbox division should be in a different color (e.g., “color 1”) from the
color of the other mailbox links (e.g., “color 2”); when the “Move to …” button is clicked, a
drop-down list should be shown, containing three entries: “Important”, “Sent”, and “Trash”. A fixed number of emails in the inbox are listed in the email division, following the format
shown in Fig. 1 (checkbox, sender, title, time). You can specify the number of emails for
display on a page.
After you click “Important” in the mailbox division, the web page should be showing the
“Important” mailbox view: The “Important” link turns into color 1 and the other three links
are in color 2; when the “Move to …” button is clicked, the drop-down list contains three
entries: “Inbox”, “Sent”, and “Trash”. A fixed number of emails in the “Important” mailbox
will be listed in the email division according to the format in Fig. 1 and the number you
specified.
When you click “Trash” in the mailbox division, the web page should be showing the “Trash”
mailbox view: The “Trash” link turns into color 1 and the other three links are in color 2;
when the “Move to …” button is clicked, the drop-down list contains three entries: “Inbox”,
“Sent”, and “Important”. A fixed number of emails in the “Trash” mailbox will be listed in the
email division according to the format in Fig. 1 and the number you specified.
When you click “Sent” in the mailbox division, the web page should be showing the “Sent”
mailbox view (Fig. 2): The “Sent” link turns into color 1 and the other three links are in color
2; when the “Move to …” button is clicked, the drop-down list contains three entries: “Inbox”,
“Important” and “Trash”. A fixed number of emails in the “Sent” mailbox will be listed in the
email division according to the format in Fig. 2 (checkbox, recipient, title, time) and the
number you specified.
If there are more than one page of emails in the corresponding mailbox, emails on other
pages are displayed when you click “<” or “>” in the function division.
Please note that switching the mailbox view, and clicking “<” or “>” should load the
corresponding email list in the email division without reloading the entire web page.
Fig. 2
Implement the following to achieve the above functionalities:
1. Client Side.
1.1 When webmail.html is first loaded, load your specified number of emails in the
Inbox in the email division, and order them in reverse chronological order. (Hint: register a JS
event onload in the tag)
1.2 When a mailbox link in the mailbox division is clicked, retrieve your specified
number of the newest emails in the corresponding mailbox from the server side and display
them in the email division, order them in reverse chronological order, and display the
corresponding function buttons in the function division. (Hint: use the JS event onclick).
1.3 Whenever “<” or “>” is clicked, newer or older emails in the corresponding mailbox
(of your specified number) will be retrieved and listed in the email division. (Hint: use the JS
event onclick).
1.4 Implement AJAX codes in the event handler functions to communicate with the
server for retrieval of emails from the database.
2. Server Side.
In app.js, create the following middleware to handle requests from the client side:
HTTP GET requests for http://127.0.0.1:8081/retrieveemaillist. In the middleware,
retrieve information of a number of emails in the respective mailbox from the emailList
collection in the database, according to the request from the client, and send them to
the client (note that only necessary information for the email list display should be
retrieved and sent to the client, e.g., the email content is not retrieved/sent). You should
decide what data the HTTP request should carry for the server side to retrieve emails
from the database accordingly, and the format of the data sent back to the client in the
response body.
Task 3 (15 marks) Display email content
When you click each email entry in an email list display (on sender/recipient, title or time), a
request will be sent to the server, which will retrieve the content of the email from the
emailList collection in the database, and send it back to the client. The client should display
the content in the email division, replacing the email list, in the format as shown in Fig. 3.
This should not cause reload of the entire web page as well.
Fig. 3
On this page view, when “<” or “>” is clicked, the content of the previous (i.e., immediately
newer) email or the next (i.e., immediately older) email in the same mailbox will be retrieved
and displayed. If the current email is the newest one when “<” is clicked or the oldest one
when “>” is clicked, the page view remains unchanged.
1. Client Side.
Similar to Task 2, you should decide the JS events to trigger, implement the corresponding
event handling AJAX code on the client side.
2. Server Side.
In app.js, create the following middleware to handle corresponding requests from the client
side:
HTTP GET requests for http://127.0.0.1:8081/getemail. In the middleware, retrieve
information of the specific email from the emailList collection in the database, according
to the request from the client, and send them to the client. You should decide what data
the HTTP request should carry for the server side to retrieve the correct email from the
database accordingly, and the format of the data sent back to the client in the response
body.
Task 4 (20 marks) Move emails
To the left of each email entry in an email list display, there is a checkbox, which you can click
to check and uncheck. When the web page is displaying a particular mailbox view, after you
select some emails in the email list and select an entry in the drop-down list of “Move to …”,
a request will be sent to the server to update the “mailbox” field of the corresponding email
documents to the selected mailbox correspondingly.
After these updates have been successfully done on the server side, the server will further
retrieve information of Y older emails (if you moved Y emails in the current email list display),
and send them to the client. On the client side, you should remove the selected email entries
from the email list display in the email division, and append the Y newly retrieved email
entries to the bottom of the list, such that the total number of email entries displayed is still
the same as before (or smaller only if all older emails have been retrieved). All these should
not cause reload of the entire web page as well.
On an email content page view as shown in Fig. 3, if you select an entry in the drop-down list
of “Move to …”, the current email being displayed should be moved to the selected mailbox,
i.e., a request should be sent to the server to update the “mailbox” field of the
corresponding email document to the selected mailbox. Then the page view should go back
to the email list display as shown in Fig. 1 or Fig. 2, showing the first page of emails in the
mailbox which the moved email originally belonged to.
1. Client Side.
Similar to previous tasks, you should decide the JS event to trigger, and implement the event
handling AJAX code on the client side. 2. Server Side.
In app.js, create the following middleware to handle corresponding requests from the client
side:
HTTP POST requests for http://127.0.0.1:8081/changemailbox. In the middleware,
update the mailbox field of the corresponding email document(s) in the emailList
collection, according to the request from the client; then retrieve information of emails
according to the email list to be generated on the client side, and send them to the client.
You should decide what data the request should carry for the server side to update the
email document(s) accordingly, and the format of the data sent back to the client in the
response body.
Task 5 (15 marks) Compose new email
When the “Compose” button is clicked, the page view should be as shown in Fig. 4. The “Move
to …”, “<” and “>” buttons should be disabled on this page view. You can compose a new email
message on the page; when “Send” is clicked, a request should be sent to the server side for
inserting a new email document into the emailList collection, containing information of the newly
composed email. Upon receiving success response from the server side, the page view should go
back to the email list display as shown in Fig. 1 or Fig. 2, showing the first page of emails in
the mailbox – the one whose email or email list you were viewing before clicking the
“Compose” button.
Fig. 4
1. Client Side.
Implement the “To” and “Subject” fields using text input boxes and the message content field
using