Update LOB examples

Author: Christopher Jones

.gitignore

@@ -13,6 +13,8 @@ node_modules
 /examples/clobstream2out.txt
 /examples/blobstream1out.jpg
 /examples/blobstream2out.jpg
+/examples/lobbindsout1.txt
+/examples/lobbindsout2.txt
 
 # Oracle Ignores
 sqlnet.log

examples/blobhttp.js

@@ -20,55 +20,94 @@
  *
  * DESCRIPTION
  *   Listens for an HTTP request and returns an image queried from a BLOB column
+ *   Also shows the connection pool's caching using a 'default' pool.
+ *
  *   Use demo.sql to create the required table or do:
  *     DROP TABLE mylobs;
  *     CREATE TABLE mylobs (id NUMBER, c CLOB, b BLOB);
- *   Run blobinsert1.js to load an image before running this example.
+ *
+ *   Run lobinsert1.js to load an image before running this example.
+ *
  *   Start the listener with 'node blobhttp.js' and then use a browser
- *   to load http://127.0.0.1:7000/getimage
+ *   to load http://localhost:7000/getimage
  *
  *****************************************************************************/
 
-var http = require('http');
 var url = require('url');
-
+var http = require('http');
 var oracledb = require('oracledb');
 var dbConfig = require('./dbconfig.js');
 
-var portid = 7000;
+var httpPort = 7000;
+
+// Main entry point.  Creates a connection pool which becomes the
+// 'default' pool.  The callback creates an HTTP server.
+function init() {
+  oracledb.createPool(
+    {
+      user: dbConfig.user,
+      password: dbConfig.password,
+      connectString: dbConfig.connectString
+    },
+    function(err) {
+      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);
+      })
+      .listen(httpPort);
 
-http.createServer(function(req, res){
-  var request = url.parse(req.url, true);
-  var action = request.pathname;
+      console.log("Server running.  Try requesting: http://localhost:" + httpPort + "/getimage");
+    });
+}
+
+// Handles each web request
+function handleRequest(request, response) {
+
+  var requrl = url.parse(request.url, true);
+  var action = requrl.pathname;
 
   if (action == '/getimage') {
-    oracledb.getConnection(
-      {
-        user          : dbConfig.user,
-        password      : dbConfig.password,
-        connectString : dbConfig.connectString
-      },
+    oracledb.getConnection(  // gets a connection from the 'default' connection pool
       function(err, connection)
       {
-        if (err) { console.error(err.message); return; }
+        if (err) {
+          console.error(err.message);
+          return;
+        }
 
         connection.execute(
-          "SELECT b FROM mylobs WHERE id = :id",
+          "SELECT b FROM mylobs WHERE id = :id",  // get the image
           { id: 2 },
           function(err, result)
           {
-            if (err) { console.error(err.message); return; }
-            if (result.rows.length === 0) { console.log("No results"); return; }
+            if (err) {
+              console.error(err.message);
+              return;
+            }
+
+            if (result.rows.length === 0) {
+              console.error("No results.  Did you run lobinsert1.js?");
+              return;
+            }
 
             var lob = result.rows[0][0];
-            if (lob === null) { console.log("BLOB was NULL"); return; }
+            if (lob === null) {
+              console.log("BLOB was NULL");
+              return;
+            }
 
             lob.on(
               'end',
               function()
               {
                 console.log("lob.on 'end' event");
-                res.end();
+                response.end();
               });
             lob.on(
               'close',
@@ -85,17 +124,29 @@ http.createServer(function(req, res){
               {
                 console.log("lob.on 'error' event");
                 console.error(err);
+                connection.close(function(err) {
+                  if (err) console.error(err);
+                });
               });
-            res.writeHead(200, {'Content-Type': 'image/jpeg' });
-            lob.pipe(res);
+            response.writeHead(200, {'Content-Type': 'image/jpeg' });
+            lob.pipe(response);  // write the image out
           });
       });
 
   } else {
-    res.writeHead(200, {'Content-Type': 'text/plain' });
-    res.end('Try requesting: http://127.0.0.1:7000/getimage\n');
+    response.writeHead(200, {'Content-Type': 'text/plain' });
+    response.end("Try requesting: http://localhost:" + httpPort + "/getimage\n");
   }
-}).listen(portid, '127.0.0.1');
+}
+
+process
+.on('SIGTERM', function() {
+  console.log("\nTerminating");
+  process.exit(0);
+})
+.on('SIGINT', function() {
+  console.log("\nTerminating");
+  process.exit(0);
+});
 
-console.log("Server running at http://127.0.0.1:" + portid);
-console.log("Try requesting: http://127.0.0.1:7000/getimage");
+init();