node-oracledb/examples/webapp.js

/* Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved. */

/******************************************************************************
 *
 * You may not use the identified files except in compliance with the Apache
 * License, Version 2.0 (the "License.")
 *
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * NAME
 *   webapp.js
 *
 * DESCRIPTION
 *   Shows a web based query using connections from connection pool.
 *
 *   This displays a table of employees in the specified department.
 *
 *   The script creates an HTTP server listening on port 7000 and
 *   accepts a URL parameter for the department ID, for example:
 *   http://localhost:7000/90
 *
 *   Uses Oracle's sample HR schema.  Scripts to create the HR schema
 *   can be found at: https://github.com/oracle/db-sample-schemas
 *
 *****************************************************************************/

var http = require('http');
var oracledb = require('oracledb');
var dbConfig = require('./dbconfig.js');
var httpPort = 7000;

// Main entry point.  Creates a connection pool, on callback creates an
// HTTP server that executes a query based on the URL parameter given.
// The pool values shown are the default values.
function init() {
  oracledb.createPool(
    {
      user: dbConfig.user,
      password: dbConfig.password,
      connectString: dbConfig.connectString
      // Default values shown below
      // externalAuth: false, // whether connections should be established using External Authentication
      // poolMax: 4, // maximum size of the pool. Increase UV_THREADPOOL_SIZE if you increase poolMax
      // poolMin: 0, // start with no connections; let the pool shrink completely
      // poolIncrement: 1, // only grow the pool by one connection at a time
      // poolTimeout: 60, // terminate connections that are idle in the pool for 60 seconds
      // poolPingInterval: 60, // check aliveness of connection if in the pool for 60 seconds
      // queueRequests: true, // let Node.js queue new getConnection() requests if all pool connections are in use
      // queueTimeout: 60000, // terminate getConnection() calls in the queue longer than 60000 milliseconds
      // poolAlias: 'myalias' // could set an alias to allow access to the pool via a name
      // stmtCacheSize: 30 // number of statements that are cached in the statement cache of each connection
    },
    function(err, pool) {
      if (err) {
        console.error("createPool() error: " + err.message);
        return;
      }

      // Create HTTP server and listen on port - httpPort
      http
        .createServer(function(request, response) {
          handleRequest(request, response, pool);
        })
        .listen(httpPort);

      console.log("Server running at http://localhost:" + httpPort);
    }
  );
}

function handleRequest(request, response, pool) {
  var urlparts = request.url.split("/");
  var deptid = urlparts[1];

  htmlHeader(
    response,
    "Oracle Database Driver for Node.js",
    "Example using node-oracledb driver"
  );

  if (deptid == 'favicon.ico') {
    htmlFooter(response);
    return;
  }

  if (deptid != parseInt(deptid)) {
    handleError(
      response,
      'URL path "' + deptid + '" is not an integer.  Try http://localhost:' + httpPort + '/30',
      null
    );

    return;
  }

  // Checkout a connection from the pool
  pool.getConnection(function(err, connection) {
    if (err) {
      handleError(response, "getConnection() error", err);
      return;
    }

    // console.log("Connections open: " + pool.connectionsOpen);
    // console.log("Connections in use: " + pool.connectionsInUse);

    connection.execute(
      `SELECT employee_id, first_name, last_name
       FROM employees
       WHERE department_id = :id`,
      [deptid], // bind variable value
      function(err, result) {
        if (err) {
          connection.close(function(err) {
            if (err) {
              // Just logging because handleError call below will have already
              // ended the response.
              console.error("execute() error release() error", err);
            }
          });
          handleError(response, "execute() error", err);
          return;
        }

        displayResults(response, result, deptid);

        /* Release the connection back to the connection pool */
        connection.close(function(err) {
          if (err) {
            handleError(response, "normal release() error", err);
          } else {
            htmlFooter(response);
          }
        });
      }
    );
  });
}

// Report an error
function handleError(response, text, err) {
  if (err) {
    text += ": " + err.message;
  }
  console.error(text);
  response.write("<p>Error: " + text + "</p>");
  htmlFooter(response);
}

// Display query results
function displayResults(response, result, deptid) {
  response.write("<h2>" + "Employees in Department " + deptid + "</h2>");
  response.write("<table>");

  // Column Title
  response.write("<tr>");
  for (var col = 0; col < result.metaData.length; col++) {
    response.write("<th>" + result.metaData[col].name + "</th>");
  }
  response.write("</tr>");

  // Rows
  for (var row = 0; row < result.rows.length; row++) {
    response.write("<tr>");
    for (col = 0; col < result.rows[row].length; col++) {
      response.write("<td>" + result.rows[row][col] + "</td>");
    }
    response.write("</tr>");
  }
  response.write("</table>");
}

// Prepare HTML header
function htmlHeader(response, title, caption) {
  response.writeHead(200, {"Content-Type": "text/html"});
  response.write("<!DOCTYPE html>");
  response.write("<html>");
  response.write("<head>");
  response.write("<style>" +
    "body {background:#FFFFFF;color:#000000;font-family:Arial,sans-serif;margin:40px;padding:10px;font-size:12px;text-align:center;}" +
    "h1 {margin:0px;margin-bottom:12px;background:#FF0000;text-align:center;color:#FFFFFF;font-size:28px;}" +
    "table {border-collapse: collapse;   margin-left:auto; margin-right:auto;}" +
    "td, th {padding:8px;border-style:solid}" +
    "</style>\n");
  response.write("<title>" + caption + "</title>");
  response.write("</head>");
  response.write("<body>");
  response.write("<h1>" + title + "</h1>");
}

// Prepare HTML footer
function htmlFooter(response) {
  response.write("</body>\n</html>");
  response.end();
}

process
  .on('SIGTERM', function() {
    console.log("\nTerminating");
    process.exit(0);
  })
  .on('SIGINT', function() {
    console.log("\nTerminating");
    process.exit(0);
  });

init();