Location Finder

What is Location Finder?

A web application written with a backend in Java and a front-end in JavaScript that enables approved individuals to:

• Share on a map their office location
• See the location of other individuals
• Receive periodic email updates listing individuals working closeby

Code Configuration

The only file you need to change to configure your version of Location Finder is the Configuration.java file in org.ericbeach.location

Any additional configuration variables necessary for additional features should be specified in the Configuration.java file.

Development Environment

The development environment consists of three parts:

• Eclipse - While you don't technically need this, it integrates very nicely with the Google Plugin for Eclipse, thereby making development much easier than via command-line or another IDE. Google Cloud Tools for Eclipse requires Eclipse 4.6 or higher.
• Google Cloud Tools for Eclipse
• Google Cloud SDK

In the Eclipse project, under Properties, under Java Build Path, you need to make sure that the Google Cloud Platform Libraries is included. Further, within Google Cloud Platform Libraries, you need to make sure that "App Engine API" is selected (under App Engine Standard Libraries) and "Cloud Datastore" is selected (under Cloud Datastore).

Local Setup

Within Eclipse, generate a New Web Application Project.

• Project name is location_finder
• Package is org.ericbeach.location
• Unselect Use Google Web Toolkit
• Unselect Generate Project Sample Code

After doing these steps, clone this Git repository into the root. To do this, you will need to first clone the repository into a temporary folder, delete war/ and src/ from the Eclipse-created folder, and then move all the Git repository into the Eclipse folder.

git clone https://github.com/EricBeach/LocationFinder.git
# a folder LocationFinder now exists that encapsulates everything from GitHub
# in the root of the Eclipse workspace, you should now see LocationFinder and
# location_finder
cp -r LocationFinder/* location_finder/

# Copy the Git repository into the new folder
cp -r LocationFinder/.git/ location_finder/.git/
cp LocationFinder/.gitignore location_finder/.gitignore

Note: To build locally, you might need to add the Google App Engine SDK to the Java build path.

Code Style

• Java - Style conforms to Google's Java style guide. So, for example, line length should not exceed 100 characters, imports should be ordered such that the project's classes come first then Java classes, no tabs, etc.
• JavaScript -Style conforms to Google's JavaScript style guide. So, for example, line length should not exceed 80 chars, always declare variables with var, annotate JavaScript per the Closure Compiler, tend to avoid Closures, define classes via prototype, avoid associative arrays, etc.

Application Architecture Overview

• org.ericbeach.location.models - The application architecture is driven by the datastore models which persist from the back of the stack (Google App Engine datastore) to the front of the stack (JSON objects used in the user interface). The models are stored in this package.

• org.ericbeach.location.servlets - The servlets control the HTTP requests and HTTP associated responses. In general, the servlets simply dispatch to the services, which then call the datastore.

Extending App to Support Custom Login

The code has been built to make it easy to extend, especially when it comes to changing the process for authorizing users and identifying those users.

In short, the application comes with a default set of base classes that implement standard App Engine logic for authorization. The application calls shell subclasses which currently invoke the default set of base classes. However, all you need to do to setup a new login scheme, for example, is change the methods in the subclass to no longer call the default baseclass but instead use your own logic. You will need to keep the method signature the same.

• LockoutUnauthorizedUsersService - Modify the public methods in this class to change how users are authorized.
• UsersService - Modify the public methods in this class to change how a user is identified.

If you do wish to change how authentication is done and in particular wish to remove the Google App Engine login, you will need to remove the <security-constraint> from war/WEB-INF/web.xml that forces all users to authenticate with Google.

Security

The application has been built with security in mind from the ground up. The war/WEB-INF/web.xml file contains a <transport-guarantee> that forces SSL for all HTTP connections. Further, all content sits behind a Java class which enables more complicated authentication.

If you add a new servlet, you must call the authorization class (LockoutUnauthorizedUsersService) in order to ensure that the HTTP request is served only after authorization is performed.

Open Issues

• The application does not properly handle the use-case when two individuals work at the exact same location.
• The application does not properly handle the use-case when an individual enters an address that cannot be properly geo-coded.