Programming Languages & Frameworks

Running Carsten Czarski's node-oracledb WebSocket Example

(originally posted on Chris Jones' blog)

By cj on Feb 19, 2015

My colleague Carsten Czarski recently presented on the node-oracledb driver for Node.js. One of his demos used WebSockets. It was a live demo, not captured in slides. I thought I'd explain how I got it to run in my Oracle Linux 64 bit environment.

• Download and extract the Node 0.10.36 bundle from here. (At time of writing, the node-oracle driver requires Node.js 0.10). Add the bin to your PATH, for example: 

  $ export PATH=/opt/node-v0.10.36-linux-x64/bin:$PATH 

• Download and install the 'basic' and 'devel' Instant Client RPMs from OTN: 

  # rpm -ivh oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64.rpm # rpm -ivh oracle-instantclient12.1-devel-12.1.0.2.0-1.x86_64.rpm 

• Download Carsten's demo code from here and extract it: 

  $ cd /home/cjones $ mkdir wsdemo $ cd wsdemo $ mv $HOME/Downloads/nodejs-beispielprogramme.zip . $ unzip nodejs-beispielprogramme.zip 

• Create a new package.json file: 

  { "name": "ccwebsockets", "version": "1.0.0", "description": "Carsten's WebSocket Demo application using node-oracledb 0.3.1.", "scripts": { "start": "node 05-websockets.js" }, "dependencies": { "oracledb": "oracle/node-oracledb#619e9a8fa6625a2c5ca3e1a2ba10dbdaab5ae900", "websocket": "^1.0", "express": "^4.11" } } 

• Edit 05-websockets.js and change the database credentials at line 111. The schema needs to have the EMP table. 

  oracledb.createPool( { user          : "scott", password      : "tiger", connectString : "localhost/pdborcl", poolMin       : 5, poolMax       : 10 }, 

• Also in 05-websockets.js, change the path name at line 65 to your current directory name: 

  filename = path.join("/home/cjones/wsdemo", uri); 

• Use npm to automatically install the node-oracle driver and the "websocket" and "express" dependencies listed in package.json: 

  $ npm install 

• To run the demo, use the package.json script "start" target to load 05-websockets.js: 

  $ npm start 

  The server will start:

  > ccwebsockets@1.0.0 start /home/cjones/wsdemo > node 05-websockets.js  Websocket Control Server listening at http://0.0.0.0:9000 Database connection pool established 

• Open a couple of browser windows to http://127.0.0.1:9000/html/websocket.html. These are the clients listening for messages.   

  The output is the starting point of the demo. Let's send a message to those clients.

• Open a third browser window for the URL http://127.0.0.1:9000/update/CLARK. The two listening windows will be updated with the "message" containing the query result payload. My screenshot shows this, and also has evidence that I had previously visited http://127.0.0.1:9000/update/KING :   

You might have noticed the screen shots were made on OS X. If you are not on Linux, refer to INSTALL to see how to install Node.js and node-oracledb. The package.json file I created will download node-oracledb 0.3.1 so you don't need to manually get it from GitHub. You will have to set OCI_LIB_DIR and OCI_INC_DIR during installation, and then set LD_LIBRARY_PATH, DYLD_LIBRARY_PATH or PATH when you want to run node.

You can follow Carsten at @cczarski.