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OE Developers’ Notes

Project Organization:

Root Files:

Folder: /

These files are placed here for ease of use, visibility, or proper project structure

  • - used to kick of the build process to make an installer that can be used remotely
  • docker-compose.yml – used for local development options. In production, the docker-compose.yml file is generated from a file under /install/installerTemplate/linux/templates/docker-compose.yml
  • Dockerfile – used to create the docker image through docker build, or mvn dockerfile:build
  • pom.xml – used to control the maven build process, and update versions

Source Code:

Folder: /src

Code here is compiled and placed into the resulting .war that is deployed to Tomcat

Java code:

Folder: /src/main/java

Follows a package pattern of prefix.(s).module.layer (org.openelisglobal.patient.controller)

Application resources:

Folder: /src/main/resources

Resources used by the server to generate content, and control behaviour of the application Files placed here will exist in the classpath of the project and can be retrieved from the classloader

  • hibernate
  • persistence
  • languages
  • liquibase
  • reports
  • plugin
  • tiles
  • properties

Web Resources:

Folder: /src/main/webapp

Tomcat files such as web.xml, server.xml, and client resources such as jsps (css, and js can be moved here, but are under /src/main/resources as that is how I was able to get it to work)

Dev Resources:

Folder: /dev

Custom files to be used in development should be placed here All other files used in the project (except for /docker-compose.yml), should be agnostic of where it is being run. This means:

  • Don’t commit modifications to context.xml to connect to the database
  • Don’t hardcode property file locations to your machine

If you are running in docker, instead mount your file to where it needs to be in the docker image in the docker-compose.yml ie. if OE reads in a properties file at /var/lib/openelis-global/ in docker, add the following line under volumes under the openelis service ./dev/properties/

If you are running in eclipse, create a symlink that points to a file in your dev folder. The sym link should be in the same location on your machine that it would be in the docker container. ie. if OE reads in a properties file at /run/secrets/ in docker, make a symlink on your device at /run/secrets/ -> /path/to/project/dev/properties/ Using this strategy will keep all your files in your workspace which will enable you to edit them more easily. When the installer is run, it will actually create files in the specified locations.


Folder: /docs


Folder: /install

Only exception is / which is at the root of the project for convenience and visibility when running... sudo -ib develop ...the files under /install/installerTemplate/{os_name} are used as a template to build the installer package for the target operating system (currently only linux with no current plans to branch out)

Installer Template:

Folder: /install/installerTemplate/linux

Files here are used as is except /install/installerTemplate/linux/templates/ which are read into memory by with variables replaced when the setup script is ran. Variables in these files are written in the format [% variable_name %] General structure:

  • setup.ini - contains options that control the behaviour of This gets copied to /etc/openelis-global/setup.ini on install so it is preserved between upgrades
  • /scripts – folder that contains scripts that are run on installation
  • /initDB – folder that is ran to create the original database. Some files from /templates are placed here when setup is run.
  • /crosstab – folder that installs crosstab into the db
  • /dockerImage – folder that contains docker images to save on local bandwidth when installing For more information about how installation works, please read the code/comments in


Folder: /tools

Various tools used in conjunction with OpenELIS Some of these are archives of old process used (Liquibase-Outdated), while others are single use tools (Password-Migrator) OpenELIS_java_formatter.xml is an eclipse code format export file that can be imported back into eclipse so devs can use the same format rules across devices

Java Layers:


Controllers are a spring mvc concept that tie the front end requests from the client to the functionality. The are all singletons in the project, so avoid class level variables unless they are completely threadsafe. It is discouraged to place code that “does an action” in this layer. Code that should be placed here includes:

  • getting form data
  • validating form data
  • attaching error messages
  • adding things to the request or session
  • redirecting or forwarding requests, or retrieving a view
  • calling services that execute an action


Services are middle components that relate to business logic. Calling a service should begin a workflow, which is why @Transactional annotations are placed in this layer. They usually come in pairs, interfaces and implementations. This enables Spring to inject it’s own version of the class when services are injected into other classes, which is what allows annotation’s functionality to be properly called (such as @Transactional, @Async, etc.) By placing workflows into this layer instead of controllers, it allows greater code reuse to happen so multiple endpoints can execute the same or similar stories.


DAOs are back end components that retrieve objects from the database. Methods here usually represent small grained operations like CRUD.


Valueholders are usually simple bean objects that hold values, like the name implies. These are most often objects that map to the database via the files currently located at /src/main/resources/hibernate/*.hbm.xml. Validation annotations are placed in the valueholders to validate client values as well as values as they are entered into the db.


Forms are simple bean objects that carry values from the client to the server. Validation annotations are placed here to validate client values.


Workers are like Services but are usually not threadsafe and are usually not injected through autowiring

Important Java Modules:


Location: org.openelisglobal.config

Config classes have far reaching effects on the behaviour of the system and modifications to these files should be triple checked to ensure functionality, and security are not comprimised. Classes:

  • AnnotationWebAppInitializer – this class connects spring to tomcat and starts all the servlets. Without it the application will not be reachable by the client.
  • AppConfig – this is the main application configuration class. It configures the views, the locales, the message source, etc. If a configuration options doesn’t seem complex/large enough to have its own class, place it in here.
  • ControllerSetup – this class configures controllers globally, like trimming form strings of whitespace.
  • DatabaseConfig – this class configures the connection with the database
  • HibernateConfig – configures the entitiy manager and transaction manager used by Hibernate.


Location: org.openelisglobal.liquibase configures liquibase specifically. This calss can be moved into config


Location: org.openelisglobal.hibernate Contains objects used in the hibernate process such as the id generator, interceptors, and unique data types.

Security Concepts:


Validation is a key aspect of application security. By validating user input we drastically reduce the ability for an attacker to manipulate how our application behaves, and also stops users from accidentally submitting bad data. Validation should be as tight as possible without blocking functionality. The data type that is the most vulnerable and therefore requires the most validation is the String data type as it is very open ended. To minimize the risk of strings, try one of these options (ranked by effectiveness):

  1. Use a different data type if possible (Integer, Enum, etc.)
  2. Use a whitelist of Strings (Only allow “VL”, “EID”)
  3. Use a whitelist of characters (Only allow alphanumeric characters)
  4. Use a blacklist of dangerous characters (Depends on context but common ones are ;”/<)


Escaping is a process whereby you encode dangerous characters so that they cannot be interpreted in the context they are being output to. For example, &lt;eviltag>evil&lt;/eviltag> could be interpreted as xml if it were put into an xml text context, so it should first be xml escaped so it cannot be interpreted as xml. This would result in it becoming &lt;eviltag&gt;evil&lt;/eviltag&gt;. Escaping needs to be context aware, as special characters are different between different data types (ie xml vs html vs javascript). Not only is the kind of data important, but often the element within the context is important. For example, xml text is escaped differently than xml attributes &lt;tag attribute="attributeEscapeMe">textEscapeMe&lt;/tag> Escaping should be used even with validation as another layer of security.


CSRF protection is configured in SecurityConfig. Currently it is enabled for all pages that are accessed through the form login page, but is disabled for pages that are accessed through Http Basic Auth.


Passwords are stored in the database as cryptographically hashed versions of themselves, therefore there is no way to get a person’s original password from the stored value.