From b2f06b6777acba3de5e70efe969c355450dfcbc1 Mon Sep 17 00:00:00 2001
From: Nick O'Leary <nick.oleary@gmail.com>
Date: Mon, 9 Jul 2018 15:12:09 +0100
Subject: [PATCH] Add async mode to evaluateJSONataExpression

---
 red/runtime/util.js           | 33 +++++++++++++++++++++++++++++++--
 test/red/runtime/util_spec.js | 24 ++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/red/runtime/util.js b/red/runtime/util.js
index f4c0e1fa7..b6a5a7e7b 100644
--- a/red/runtime/util.js
+++ b/red/runtime/util.js
@@ -394,15 +394,44 @@ function prepareJSONataExpression(value,node) {
     })
     expr.registerFunction('clone', cloneMessage, '<(oa)-:o>');
     expr._legacyMode = /(^|[^a-zA-Z0-9_'"])msg([^a-zA-Z0-9_'"]|$)/.test(value);
+    expr._node = node;
     return expr;
 }
 
-function evaluateJSONataExpression(expr,msg) {
+function evaluateJSONataExpression(expr,msg,callback) {
     var context = msg;
     if (expr._legacyMode) {
         context = {msg:msg};
     }
-    return expr.evaluate(context);
+    var bindings = {};
+
+    if (callback) {
+        // If callback provided, need to override the pre-assigned sync
+        // context functions to be their async variants
+        bindings.flowContext = function(val) {
+            return new Promise((resolve,reject) => {
+                expr._node.context().flow.get(val, function(err,value) {
+                    if (err) {
+                        reject(err);
+                    } else {
+                        resolve(value);
+                    }
+                })
+            });
+        }
+        bindings.globalContext = function(val) {
+            return new Promise((resolve,reject) => {
+                expr._node.context().global.get(val, function(err,value) {
+                    if (err) {
+                        reject(err);
+                    } else {
+                        resolve(value);
+                    }
+                })
+            });
+        }
+    }
+    return expr.evaluate(context, bindings, callback);
 }
 
 
diff --git a/test/red/runtime/util_spec.js b/test/red/runtime/util_spec.js
index f7bd3e950..1be194f42 100644
--- a/test/red/runtime/util_spec.js
+++ b/test/red/runtime/util_spec.js
@@ -458,6 +458,30 @@ describe("red/util", function() {
               var result = util.evaluateJSONataExpression(expr,{payload:"hello"});
               should.not.exist(result);
           });
+          it('handles async flow context access', function(done) {
+              var expr = util.prepareJSONataExpression('$flowContext("foo")',{context:function() { return {flow:{get: function(key,callback) { setTimeout(()=>{callback(null,{'foo':'bar'}[key])},10)}}}}});
+              util.evaluateJSONataExpression(expr,{payload:"hello"},function(err,value) {
+                  try {
+                      should.not.exist(err);
+                      value.should.eql("bar");
+                      done();
+                  } catch(err2) {
+                      done(err2);
+                  }
+              });
+          })
+          it('handles async global context access', function(done) {
+              var expr = util.prepareJSONataExpression('$globalContext("foo")',{context:function() { return {global:{get: function(key,callback) { setTimeout(()=>{callback(null,{'foo':'bar'}[key])},10)}}}}});
+              util.evaluateJSONataExpression(expr,{payload:"hello"},function(err,value) {
+                  try {
+                      should.not.exist(err);
+                      value.should.eql("bar");
+                      done();
+                  } catch(err2) {
+                      done(err2);
+                  }
+              });
+          })
 
       });