Add fetchValue method

Author: nuustik

README.rst

@@ -253,10 +253,6 @@ client.find(path)
 
     Promise containing requested INode object when fulfilled.
 
-- Restriction
-
-    The requested node must reside in the application client was connected to.
-
 - Usage
 
     The provided path must contain dot separated path to target node. **Root node is not considered part of the path.**
@@ -357,6 +353,21 @@ node.info()
     |                  |                              | - eNodeIsImportant                                            |
     +------------------+------------------------------+---------------------------------------------------------------+
 
+node.requestValue()
+^^^^^^^^^^^^^^^^^^^
+
+- Returns
+
+    Promise containing fetched value when fulfilled.
+
+- Example
+
+    .. code:: javascript
+
+        client.requestValue().then(function (value) {
+
+        });
+        
 node.lastValue()
 ^^^^^^^^^^^^^^^^
 

index.js

@@ -337,6 +337,7 @@ studio.internal = (function(proto) {
     var childMap = new Map();
     var givenPromises = new Map();
     var childIterators = [];
+    var valuePromises = [];
     var valueSubscriptions = [];
     var structureSubscriptions = [];
     var eventSubscriptions = [];
@@ -446,6 +447,10 @@ studio.internal = (function(proto) {
 
     this.receiveValue = function (nodeValue, nodeTimestamp) {
       lastValue = nodeValue;
+      for (var i = 0; i < valuePromises.length; i++) {
+        valuePromises[i](lastValue);
+        valuePromises.splice(i, 1);
+      }
       for (var i = 0; i < valueSubscriptions.length; i++) {
         valueSubscriptions[i][0](nodeValue, nodeTimestamp);
       }
@@ -534,6 +539,14 @@ studio.internal = (function(proto) {
       //when offline must queue or update pending set request and call set callbacks ...???
     };
 
+    this.async.requestValue = function() {
+      let promise = new Promise(function (resolve, reject) {
+        valuePromises.push(resolve);
+      });
+      app.makeGetterRequest(id, 0, 0, false);
+      return promise;
+    };
+
     this.async._makeGetterRequest = function() {
       if (valueSubscriptions.length > 0) {
         var maxFs = Math.max.apply(Math, valueSubscriptions.map(v => v[1]));
@@ -658,6 +671,10 @@ studio.internal = (function(proto) {
       } 
     };
 
+    this.async.requestValue = function() {
+
+    };
+
     this.async.subscribeToValues = function(valueConsumer, fs=5, sampleRate=0) {
 
     };
@@ -830,7 +847,9 @@ studio.internal = (function(proto) {
       var msg = new proto.Container();
       var request = new proto.ValueRequest();
       request.node_id = id;
-      request.fs = fs;
+      if (fs) {
+        request.fs = fs;
+      }
       if (sampleRate) {
         request.sample_rate = sampleRate;
       }
@@ -1107,6 +1126,7 @@ studio.api = (function(internal) {
     this.info = function() {
       return node.info();
     };
+
     /**
      * Access the last known value.
      *
@@ -1190,6 +1210,15 @@ studio.api = (function(internal) {
      * @param {number} timestamp
      */
 
+    /**
+     * Fetch current value.
+     *
+     * @returns {Promise.<number>} A promise containing fetched value when fulfilled.
+     */
+    this.requestValue = function() {
+      return node.async.requestValue();
+    };
+
     /**
      * Subscribe to value changes on this node.
      *
@@ -1433,3 +1462,4 @@ studio.api = (function(internal) {
 export default studio
 
 
+

package.json

@@ -1,6 +1,6 @@
 {
   "name": "cdp-client",
-  "version": "2.1.1",
+  "version": "2.2.1",
   "description": "A simple Javascript interface for the CDP Studio development platform that allows Javascript applications to interact with",
   "main": "index.js",
   "scripts": {