node-oracledb/examples/webappawait.js

217 lines
7.0 KiB
JavaScript

/* Copyright (c) 2015, 2019, 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
* webappawait.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
*
* In some networks forced pool termination may hang unless you have
* 'disable_oob=on' in sqlnet.ora, see
* https://oracle.github.io/node-oracledb/doc/api.html#tnsadmin
*
* Uses Oracle's sample HR schema. Scripts to create the HR schema
* can be found at: https://github.com/oracle/db-sample-schemas
*
* This example requires node-oracledb 3 or later.
*
* This example uses Node 8's async/await syntax.
*
*****************************************************************************/
const http = require('http');
const oracledb = require('oracledb');
const dbConfig = require('./dbconfig.js');
const httpPort = 7000;
// Main entry point. Creates a connection pool and an HTTP server
// that executes a query based on the URL parameter given.
// The pool values shown are the default values.
async function init() {
try {
await oracledb.createPool({
user: dbConfig.user,
password: dbConfig.password,
connectString: dbConfig.connectString
// edition: 'ORA$BASE', // used for Edition Based Redefintion
// events: true, // whether to handle Oracle Database FAN and RLB events or support CQN
// externalAuth: false, // whether connections should be established using External Authentication
// homogeneous: true, // all connections in the pool have the same credentials
// poolAlias: 'default', // set an alias to allow access to the pool via a name.
// poolIncrement: 1, // only grow the pool by one connection at a time
// 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
// poolPingInterval: 60, // check aliveness of connection if idle in the pool for 60 seconds
// poolTimeout: 60, // terminate connections that are idle in the pool for 60 seconds
// queueTimeout: 60000, // terminate getConnection() calls in the queue longer than 60000 milliseconds
// sessionCallback: myFunction, // function invoked for brand new connections or by a connection tag mismatch
// stmtCacheSize: 30 // number of statements that are cached in the statement cache of each connection
});
// Create HTTP server and listen on port httpPort
const server = http.createServer();
server.on('error', (err) => {
console.log('HTTP server problem: ' + err);
});
server.on('request', (request, response) => {
handleRequest(request, response);
});
await server.listen(httpPort);
console.log("Server running at http://localhost:" + httpPort);
} catch (err) {
console.error("init() error: " + err.message);
}
}
async function handleRequest(request, response) {
const urlparts = request.url.split("/");
const 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;
}
let connection;
try {
// Checkout a connection from the default pool
connection = await oracledb.getConnection();
const result = await connection.execute(
`SELECT employee_id, first_name, last_name
FROM employees
WHERE department_id = :id`,
[deptid] // bind variable value
);
displayResults(response, result, deptid);
} catch (err) {
handleError(response, "handleRequest() error", err);
} finally {
if (connection) {
try {
// Release the connection back to the connection pool
await connection.close();
} catch (err) {
console.error(err);
}
}
}
htmlFooter(response);
}
// Report an error
function handleError(response, text, err) {
if (err) {
text += ": " + err.message;
}
console.error(text);
response.write("<p>Error: " + text + "</p>");
}
// 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 (let col = 0; col < result.metaData.length; col++) {
response.write("<th>" + result.metaData[col].name + "</th>");
}
response.write("</tr>");
// Rows
for (let row = 0; row < result.rows.length; row++) {
response.write("<tr>");
for (let 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();
}
async function closePoolAndExit() {
console.log("\nTerminating");
try {
// Get the pool from the pool cache and close it when no
// connections are in use, or force it closed after 10 seconds
await oracledb.getPool().close(10);
console.log("Pool closed");
process.exit(0);
} catch(err) {
console.error(err.message);
process.exit(1);
}
}
process
.once('SIGTERM', closePoolAndExit)
.once('SIGINT', closePoolAndExit);
init();