2021-04-01 12:48:37 +08:00
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/* Copyright (c) 2015, 2021, Oracle and/or its affiliates. All rights reserved. */
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2015-08-17 14:03:41 +08:00
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/******************************************************************************
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*
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* You may not use the identified files except in compliance with the Apache
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* License, Version 2.0 (the "License.")
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*
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* You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0.
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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*
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* NAME
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* blobhttp.js
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*
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* DESCRIPTION
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* Listens for an HTTP request and returns an image queried from a BLOB column
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2017-06-14 09:23:10 +08:00
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* Also shows the connection pool's caching using a 'default' pool.
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*
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2015-08-17 14:03:41 +08:00
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* Start the listener with 'node blobhttp.js' and then use a browser
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2017-06-14 09:23:10 +08:00
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* to load http://localhost:7000/getimage
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*
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2019-05-28 15:51:53 +08:00
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* This example uses Node 8's async/await syntax.
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*
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2015-08-17 14:03:41 +08:00
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*****************************************************************************/
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2019-11-19 10:26:03 +08:00
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const url = require('url');
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const http = require('http');
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const oracledb = require('oracledb');
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const dbConfig = require('./dbconfig.js');
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const demoSetup = require('./demosetup.js');
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2015-08-17 14:03:41 +08:00
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2021-05-20 14:47:23 +08:00
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// On Windows and macOS, you can specify the directory containing the Oracle
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// Client Libraries at runtime, or before Node.js starts. On other platforms
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// the system library search path must always be set before Node.js is started.
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// See the node-oracledb installation documentation.
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// If the search path is not correct, you will get a DPI-1047 error.
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if (process.platform === 'win32') { // Windows
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oracledb.initOracleClient({ libDir: 'C:\\oracle\\instantclient_19_11' });
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} else if (process.platform === 'darwin') { // macOS
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oracledb.initOracleClient({ libDir: process.env.HOME + '/Downloads/instantclient_19_8' });
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}
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2019-11-19 10:26:03 +08:00
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const httpPort = 7000;
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// Main entry point. Creates a connection pool which becomes the
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// 'default' pool, and then creates an HTTP server.
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async function init() {
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try {
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await oracledb.createPool(dbConfig);
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console.log('Connection pool started');
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2019-11-19 10:26:03 +08:00
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// create the demo table
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const connection = await oracledb.getConnection();
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await demoSetup.setupLobs(connection, true);
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await connection.close();
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2019-05-28 15:51:53 +08:00
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// Create HTTP server and listen on port httpPort
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const server = http.createServer();
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server.on('error', (err) => {
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throw err;
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});
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server.on('request', (request, response) => {
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handleRequest(request, response);
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});
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await server.listen(httpPort);
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console.log("Server is running. Try loading http://localhost:" + httpPort + "/getimage");
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2019-05-28 15:51:53 +08:00
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} catch (err) {
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console.error('init() error: ' + err.message);
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}
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}
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// Handles each web request
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async function handleRequest(request, response) {
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const requrl = url.parse(request.url, true);
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const action = requrl.pathname;
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if (action == '/getimage') {
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2019-05-28 15:51:53 +08:00
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let connection;
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try {
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connection = await oracledb.getConnection(); // gets a connection from the 'default' connection pool
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const result = await connection.execute(
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"SELECT b FROM no_lobs WHERE id = :id", // get the image
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{ id: 2 }
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);
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if (result.rows.length === 0) {
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throw new Error("No data selected from table.");
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}
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const lob = result.rows[0][0];
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if (lob === null) {
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throw new Error("BLOB was NULL");
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}
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const doStream = new Promise((resolve, reject) => {
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lob.on('end', () => {
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// console.log("lob.on 'end' event");
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response.end();
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});
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lob.on('close', () => {
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// console.log("lob.on 'close' event");
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resolve();
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});
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lob.on('error', (err) => {
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// console.log("lob.on 'error' event");
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reject(err);
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});
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response.writeHead(200, {'Content-Type': 'image/jpeg' });
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lob.pipe(response); // write the image out
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});
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await doStream;
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} catch (err) {
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console.error(err);
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await closePoolAndExit();
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} finally {
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if (connection) {
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try {
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await connection.close();
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} catch (err) {
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console.error(err);
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}
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}
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}
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2015-08-17 14:03:41 +08:00
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} else {
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2017-06-14 09:23:10 +08:00
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response.writeHead(200, {'Content-Type': 'text/plain' });
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response.end("Try requesting: http://localhost:" + httpPort + "/getimage\n");
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2015-08-17 14:03:41 +08:00
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}
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2017-06-14 09:23:10 +08:00
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}
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2019-05-28 15:51:53 +08:00
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async function closePoolAndExit() {
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console.log('\nTerminating');
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try {
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// Get the pool from the pool cache and close it when no
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// connections are in use, or force it closed after 2 seconds.
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// If this hangs, you may need DISABLE_OOB=ON in a sqlnet.ora file.
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// This setting should not be needed if both Oracle Client and Oracle
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// Database are 19c (or later).
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2019-11-19 10:26:03 +08:00
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await oracledb.getPool().close(2);
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2019-05-28 15:51:53 +08:00
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console.log('Pool closed');
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2017-11-17 19:50:42 +08:00
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process.exit(0);
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2021-04-01 12:48:37 +08:00
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} catch (err) {
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2019-05-28 15:51:53 +08:00
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console.error(err.message);
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process.exit(1);
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}
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}
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process
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.once('SIGTERM', closePoolAndExit)
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.once('SIGINT', closePoolAndExit);
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2015-08-17 14:03:41 +08:00
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2017-06-14 09:23:10 +08:00
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init();
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