CS130 - Software Engineering - Winter 2017
Alfred Lucero
Brandon Haffen
Jordan Miller
Creating a webserver using Boost with GTest Unit Testing, GCov Test
Coverage, Bash Integration Testing, and Nginx-inspired parsing of config
files - modeling the HTTP Restful API
The program depends on libssl which can be installed via
sudo apt-get install -y libboost-all-dev
sudo apt-get install -y libssl-dev
If running a newer version of Ubuntu, you may need to downgrade libssl first
sudo apt-get install libssl1.0.0=1.0.1f-1ubuntu2
In order to create the executable and try our webserver, just run "make"
in the project directory. Our tests can be run via "make test", and test
coverage can be measured with "make test_gcov". We also implement "make
clean" which we find necessary after running our tests.
Our code is all in the root directory of the project folder. It starts
main.cc, which loads up the config file via our server_config_parser.cc then
quickly yields most the heavy-duty work to server.cc. Within server.cc,
our request.cc file parses incoming requests from clients, and then server.cc
uses the handlers it parsed from the config file and the interface in
request_handler.h to process these parsed requests. Finally, a response is
generated using the response.cc interface and forwarded back to the client.
In order to add a new handler, you will need to first create a header and
implementation file for it. Then, add the file to be built via the
Makefile. This is as easy as adding the implementation file to the SRC
variable. Adding a test is more involved, and requires adding to both the
TESTEXEC and the GCOVEXEC variables as well as making a *_test and *_gcov
target for your test. You should use the tests already there to see how to
do this.
When creating a handler, you only need to edit your own files in order to
expose the handler to the entire system. The REGISTER_REQUEST_HANDLER
macro in your header file will fulfill this duty. You should model your
header file off of one of ours. We recommend using echo_handler.h for a
simple example, and static_file_handler.h for a more complete one. All
that is left after making the header file is to fill your implementation
with code that takes advantage of our virtual functions Init and
HandleRequest. Please read our comments and check out our own handlers for
more information.
Once you are all done with making your handler, you can use it by running the
server with a config file that gives your handler a path. Please see
example_config for an example on how to do that.
In order to build a compressed image of the server using docker, use the "make
docker" command. This shrunken image is intended to be used to run the
webserver on cloud hosts such as Amazon Web Services. Docker must be installed
prior to making or using the image. In addition, in order to deploy
your most recent docker image to the AWS instance, run "make deploy",
which saves the image, transfers the file to the AWS instance, kills
the old server process, and starts a new server with the updated
docker image.
One can check out our AWS web server instance running at the following link:
54.213.82.160:2020 (type into the browser and add requests like /echo)
Side note: In order to properly SSH and run "make deploy", one must have the
"team05-pk.pem" file from AWS in the same directory as the Makefile.
The server begins with a single thread that accepts TCP connections. Any time
a connection is accepted, the server creates a new thread for that connection.
This thread reads any data sent and writes back a response. The thread closes
as soon as it writes back a response or the connection closes. This means that
the server can respond to many different requests all at the same time.
There is support for scripting Lua in files to make custom request handlers.
To do this, just add Lua tags to served HTML files as documented below:
<?lua chunk ?>
Processes the Lua chunk execution results. The alternative form
<% chunk %> can also be used.
<?lua= expression ?>
Processes the Lua expression and outputs its results into the HTML
file. The alternative form <%= expression %> can also be used.
The file "test.htm" goes over all custom Lua functions added. These allow the
script writer to access the HTTP request and modify the HTTP response. An
example usage is shown where SQLLite is used to create a chatbox. To access
it, please open the server and visit localhost:2020/static/chatbox.htm in a
browser.
An additional example is given below that shows off the recursive addition of
the HTML <li> tag for each item in a Lua list. This shows off a unique usage
that the chatbox example does not take advantage of.
<ul>
<% for i, item in ipairs(list) do %>
<li><%= item %></li>
<% end %>
</ul>
HTTPS support was added to the reverse proxy handler. It takes advantage of
Boost implementations that uses OpenSSL. As a result, the command "sudo apt-get
install libssl-dev" needs to be run in order to install the dependencies needed
for OpenSSL. In order to see it in action, run "./webserver https_proxy_config".
Visiting "localhost:4343" will load the page from "https://www.google.com".