Internet of Things data server implementing Open Messaging Interface and Open Data Format
Latest commit 1277010 Dec 4, 2018

O-MI Node Server Latest release Build Status Coverage Status Codacy Badge Join the chat at

Internet of Things data server. Implementation of O-MI Node as specified in Open Messaging Interface (pdf) v1.0 standard with Open Data Format (pdf) standard. It is intended to be as reference implementation that shows how these standards work in more detail. Missing features and differences to the standard are collected to this (work in progress) document. Questions or problems with the server or the standards can be posted to Issues, email or gitter chat.

Supported communication protocols:

  • HTTP (http://)
  • HTTPS (https://)
  • WebSocket (ws://)
  • WebSocket Secure (wss://)

This project also includes:

  • a developer webapp for building and sending O-MI/O-DF messages.
  • some experimental extensions for the server which can be found in other branches:
    • omisec-omi-interface has O-MI/O-DF interface for authorization of O-MI messages in external service.
    • warp10integration has integration to Warp10 as the DB backend.

See development branch for latest progress.

Chat with dev team: Join the chat at




Download the pre-compiled zip, tgz or debian package from latest git releases here. Latest release

Extract the zip file and navigate to the /bin directory To run O-MI Node run the corresponding startup script from the bin directory for your OS:

  • bin/o-mi-node.bat for Windows
  • bin/o-mi-node for Unix and Mac

This will run O-MI Node with configuration in /conf/application.conf. By default it will start at url http://localhost:8080/ and has some example and demo agents. More Information in the Configuration section.

Compiling and packaging

  1. Follow the instructions 1-4 in Setup development environment below
  2. run sbt universal:packageBin (For other package types, use sbt release)
  3. Result can be found in ./target/universal/

See SBT Universal Plugin for more packaging methods.

Setup development environment

  1. git clone
  2. Install sbt
  3. (windows: logout, or put sbt into PATH yourself)
  4. Open a cmd or shell to the O-MI project directory
  5. Then run sbt and in opened the ">" prompt run reStart to compile and run the Node
  6. Visit http://localhost:8080/ to see that it's working

You can check the Simple Build Tool cheat sheet section to learn more

Setting up IDE

  • IntelliJ IDEA
    1. Install the IDE
      1. Download and install IntelliJ IDEA
      2. When running for the first time install Scala from the 'Featured plugins' tab (you can also install Scala plugin later from Settings/plugins)
      3. Open the IDE
    2. Import the project
      1. Select import project -> select O-MI directory and click OK
      2. Select import project from external model and select SBT and then click Next
      3. For the 'Project JDK' select 'New...' and select JDK and then locate your JDK 1.8 folder and select it and click Finish
      4. When prompted to select modules to include in the project, select: root, agents and omiNode and then click OK
      5. Wait for the IDE to finish indexing the files (might take a few minutes)
  • Eclipse
    1. Run sbt eclipse
    2. Open Eclipse IDE
    3. Select File->import Existing Projects into Workspace

Simple Build Tool cheat sheet

Native SBT commands

  • sbt compile: just compile the project
  • sbt clean: remove compiled and temporary files
  • sbt run: run the project; We don't use this much, so sometimes it's broken and we don't even notice. We use re-start from Revolver which allows us to recompile and restart the node without exiting sbt, because restarting sbt takes unnecessary extra time.
  • sbt doc: compile api documentation
  • sbt test: run all tests

Extra commands from plugins and other

  • We use sbt-revolver: run sbt and then write
    • reStart: compile&run the project in background
    • reStop: close the background process
  • We use sbt-native-packager:
    • sbt stage: creates file structure, used in packaged version, to the ./target/universal/stage/ directory
    • sbt debian:packageBin: create release debian package (requires dpkg program installed)
    • See native packager docs for configuring other packages. Our sbt configuration is in ./build.sbt.
  • We use sbt-scoverage:
    • sbt clean coverage test coverageReport: calculate test coverage and generate reports in O-MI-Node/target/scala-2.11/scoverage-report/
  • We also have some extra commands for convenience:
    • sbt systemTest: run only system tests (the used requests and responses can be found in ImplementationDetails.html)
    • sbt release: create release tar and zip packages

extra info:

  • automatically run any of above commands when there is a file change by adding ~ in front, like sbt ~re-start
  • all commands above compiles the needed files that are not yet compiled
  • run many commands in sequence faster if you open a single sbt command line with sbt


Basic configuration

See reference.conf for the defaults and configuration documentation.

Configuration Location

  • In package releases: /etc/o-mi-node/application.conf
  • In tar and zip releases: ./conf/application.conf
  • In development environment: ./O-MI-Node/src/main/resources/application.conf (create a new file if not found)
    • Default values are stored in ./O-MI-Node/src/main/resources/reference.conf

Library Config

application.conf can also have a lot of Akka (threading framework and HTTP server) and Slick (database) specific settings:

O-MI Extensions

This server supports the following extensions to O-MI v1.0:

  1. Websockets
  • Client can initiate websocket connection to O-MI Node server by connecting to the same root path as POST requests with http connection upgrade request. (url conventions: ws:// or secure wss://)
  • During a websocket connection the server accepts requests as in normal http communication. Immediate responses are sent in the same order as the corresponding requests were received.
  • During a websocket connection callback can be set to "0" in an O-MI message to tell O-MI Node to use current websocket connection as the callback target.
  • Keep in mind that depending on client and server configuration, a websocket connection will timeout if there is long period of inactivity. (Default is usually 1 minute). No callbacks can be sent after a timeout occurs (as websockets are always initiated by a client).
    • If your ws client library doesn't support the native ws ping, sending an empty websocket message is allowed for the purpose of keeping the connection alive and server will not send any special response for that.
  1. Delete operation
  • Delete operation is currently an extension until it is released in O-MI standard version 2.0