Detect if agent-base has patch https.request and undo it

Fixes #3072

packages/node_modules/@node-red/nodes/core/network/21-httprequest.js

@@ -28,8 +28,43 @@ module.exports = function(RED) {
     var cookie = require("cookie");
     var hashSum = require("hash-sum");
 
+
+    // Cache a reference to the existing https.request function
+    // so we can compare later to see if an old agent-base instance
+    // has been required.
+    // This is generally okay as the core nodes are required before
+    // any contrib nodes. Where it will fail is if the agent-base module
+    // is required via the settings file or outside of Node-RED before it
+    // is started.
+    // If there are other modules that patch the function, they will get undone
+    // as well. Not much we can do about that right now. Patching core
+    // functions is bad.
+    const HTTPS_MODULE = require("https");
+    const HTTPS_REQUEST = HTTPS_MODULE.request;
+
+    function checkNodeAgentPatch() {
+        if (HTTPS_MODULE.request !== HTTPS_REQUEST) {
+            RED.log.warn(`
+
+---------------------------------------------------------------------
+Patched https.request function detected. This will break the
+HTTP Request node. The original code has now been restored.
+
+This is likely caused by a contrib node including an old version of
+the 'agent-base@<5.0.0' module.
+
+You can identify what node is at fault by running:
+   npm list agent-base
+in your Node-RED user directory (${RED.settings.userDir}).
+---------------------------------------------------------------------
+`);
+            HTTPS_MODULE.request = HTTPS_REQUEST
+        }
+    }
+
     function HTTPRequest(n) {
         RED.nodes.createNode(this,n);
+        checkNodeAgentPatch();
         var node = this;
         var nodeUrl = n.url;
         var isTemplatedUrl = (nodeUrl||"").indexOf("{{") != -1;
@@ -65,6 +100,7 @@ module.exports = function(RED) {
         }
 
         this.on("input",function(msg,nodeSend,nodeDone) {
+            checkNodeAgentPatch();
             //reset redirectList on each request
             redirectList = [];
             var preRequestTimestamp = process.hrtime();