Build a Web Application

This section shows you how to build an application with AnMVC without understanding the details of its implementation.

Derive from HttpApplet

An HttpApplet is a building-block of a web application. You must begin with implementing this interface. Build a class deriving from HttpApplet:

class HelloApplet : public virtual HttpApplet {
    // ...
};

Request Pattern

An applet must be appointed a way of access, a request pattern, which map and distributes requests to many applets. Edit HttpDispatcher::registerApplets() in file /src/http/HttpDispatcher.cpp to specify a pattern for your applet.

void HttpDispatcher::registerApplets() {
    /*
    A request with directory "/"
    should be handled by an pInstance of HelloApplet
    */
    requestMap.put(SString("/"), new HelloApplet());
}

Set up Behavior

The interface HttpApplet has many methods corresponding to the different request methods (GET, POST, etc). Override one of them to specify applet behaviour under certain request method. The applet does nothing if the correpsonding method is not overridden.

void onGet() override;  // specify behavior for GET requests
// does nothing for POST requests and others

Resource Directory

The static resource directory contains static files such as html, css, js, and images. The directory should be specified by static variable HttpApplet::staticResources of /src/http/HttApplet.cpp. The default directory is my working directory, therefore definitely not valid for you. It is recommended to use an absolute directory.

anarion::StaticResources anarion::HttpApplet::staticResources(SString("/path/to/static"));

It is also recommended to have subdirectories html, css, js, and img, or some of these, under your static directory, for the convenience of finding files. Files should be put into these subdirectories according to their suffix. I used the following directory structure when writing and testing this project.

static
└── html
    └── hello.html

Return a Page

To have the applet return a page to the browser, you must explicitly ask for the page resource in the onXxx() method.

void anarion::HelloApplet::onGet() {
    // request for resource by name
    Payload *payload = staticResources.getPayload(SString("hello.html"));
    // load resource into the response
    response->setPayload(payload);
}

The string passed to the function staticResources.getPayload is a relative directory of the file hello.html. With the valid suffix html, the program goes to the subdirectory html of the static directory to find the file with that name. Once the file is found, associate it with the response by function response->setPayload.

Try Your Server

The server should be ready by now. Run it and try it with a browser of Postman. If you have any problem, feel free to raise an issue.