From ec74f25b6ef7d8868283d27d0bf6a5ea326fd5f8 Mon Sep 17 00:00:00 2001
From: 1000TurquoisePogs <sgrady@rocketsoftware.com>
Date: Sun, 25 Oct 2020 22:27:36 -0400
Subject: [PATCH] Catch errors that occur before header is set up

Signed-off-by: 1000TurquoisePogs <sgrady@rocketsoftware.com>
---
 lib/proxy.js | 92 ++++++++++++++++++++++++++++------------------------
 1 file changed, 50 insertions(+), 42 deletions(-)

diff --git a/lib/proxy.js b/lib/proxy.js
index 5a0ef83c..6f3ab93f 100644
--- a/lib/proxy.js
+++ b/lib/proxy.js
@@ -80,54 +80,62 @@ function makeSimpleProxy(host, port, options, pluginID, serviceName) {
     } else {
       proxyLog.debug('ZWED0172I'); //proxyLog.debug('Callservice: no auth helper');
     }
-    const req2 = httpApi.request(requestOptions, (res2) => {
-      proxyLog.debug("ZWED0173I", res2.statusCode); //proxyLog.debug("status code" + res2.statusCode);
-      res1.status(res2.statusCode);
-      const headers = processProxiedHeaders ? 
-            processProxiedHeaders(req1, res2.headers) :
-            res2.headers;
-      
-      for (const header of Object.keys(headers)) {
-        if (header == 'location') {
-          const location = headers[header];
-          let pattern = /^http.+\/ZLUX\/plugins\/.+/;
-          if (!pattern.test(headers[header])) {
-            if (location.startsWith('/')) {
-	            res1.set(header, `${req1.protocol}://${req1.get('host')}/ZLUX/plugins/${pluginID}/services/${serviceName}/_current${location}`);
-            }
-            else if (location.startsWith('http')) {
-	            const locationParts = location.split(":");
-              let part;
-	            if (locationParts.length > 2) {
-	              part = locationParts[2];
-              } else {
-                part = locationParts[1]
+    try {
+      const req2 = httpApi.request(requestOptions, (res2) => {
+        proxyLog.debug("ZWED0173I", res2.statusCode); //proxyLog.debug("status code" + res2.statusCode);
+        res1.status(res2.statusCode);
+        const headers = processProxiedHeaders ? 
+              processProxiedHeaders(req1, res2.headers) :
+              res2.headers;
+        
+        for (const header of Object.keys(headers)) {
+          if (header == 'location') {
+            const location = headers[header];
+            let pattern = /^http.+\/ZLUX\/plugins\/.+/;
+            if (!pattern.test(headers[header])) {
+              if (location.startsWith('/')) {
+  	            res1.set(header, `${req1.protocol}://${req1.get('host')}/ZLUX/plugins/${pluginID}/services/${serviceName}/_current${location}`);
               }
-              const t = part.indexOf('/');
-              const newEnd = part.substring(t);
-              const newRedirect = req1.protocol + '://' + req1.get('host') + "/ZLUX/plugins/" + pluginID + "/services/_current" + serviceName + newEnd; 
-              proxyLog.debug('ZWED0174I', newRedirect); //proxyLog.debug('Redirecting to: ' + newRedirect);
-              res1.set(header, newRedirect);
-            }            
+              else if (location.startsWith('http')) {
+  	            const locationParts = location.split(":");
+                let part;
+  	            if (locationParts.length > 2) {
+  	              part = locationParts[2];
+                } else {
+                  part = locationParts[1]
+                }
+                const t = part.indexOf('/');
+                const newEnd = part.substring(t);
+                const newRedirect = req1.protocol + '://' + req1.get('host') + "/ZLUX/plugins/" + pluginID + "/services/_current" + serviceName + newEnd; 
+                proxyLog.debug('ZWED0174I', newRedirect); //proxyLog.debug('Redirecting to: ' + newRedirect);
+                res1.set(header, newRedirect);
+              }            
+            }
+          }
+          else {
+            res1.set(header, headers[header])
           }
         }
-        else {
-          res1.set(header, headers[header])
-        }
+        res2.pipe(res1);
+      });
+      req2.on('error', (e) => {
+        proxyLog.warn('ZWED0040W', e); //proxyLog.warn('Callservice: Service call failed.');
+        res1.status(500).send(`ZWED0040W - Unable to complete network request to ${host}:${port}: `
+            + e.message, null, null);
+      });
+      if ((req1.method == 'POST') || (req1.method == 'PUT')) {
+        proxyLog.debug('ZWED0175I'); //proxyLog.debug('Callservice: Forwarding request body to service');
+        req1.pipe(req2);
+      } else {
+        proxyLog.debug('ZWED0176I'); //proxyLog.debug('Callservice: Issuing request to service');
+        req2.end();
       }
-      res2.pipe(res1);
-    });
-    req2.on('error', (e) => {
+    // Node API states that errors are thrown when no error handler attached.
+    // Node has a timing issue around errors that occur before the error handler can be assigned, hence this catch
+    } catch (e) { 
       proxyLog.warn('ZWED0040W', e); //proxyLog.warn('Callservice: Service call failed.');
       res1.status(500).send(`ZWED0040W - Unable to complete network request to ${host}:${port}: `
-          + e.message, null, null);
-    });
-    if ((req1.method == 'POST') || (req1.method == 'PUT')) {
-      proxyLog.debug('ZWED0175I'); //proxyLog.debug('Callservice: Forwarding request body to service');
-      req1.pipe(req2);
-    } else {
-      proxyLog.debug('ZWED0176I'); //proxyLog.debug('Callservice: Issuing request to service');
-      req2.end();
+                            + e.message, null, null);      
     }
   }
 }