filtrex expressions

alarm/sensor.html

@@ -6,7 +6,13 @@
             name: { value : "", required: true },
             panel: { type: 'AnamicoAlarmPanel', required: true },
             alarmStates: { value : "1", required: true, validate:RED.validators.regex(/.{1,}/) },
-            triggerType: { value : null, required: false }
+            triggerType: { value : null, required: false }, // Legacy property
+            triggerCondition: { value : "", required: false, validate:function(v) { return !this.triggerConditionError; } },
+            // Use the triggerConditionError property to let Node-RED know whether the trigger expression contains a syntax error or not.
+            // This way the flow editor knows whether a red triangle should be drawn for this node or not.
+            // The triggerConditionError property will be filled in the oneditsave.
+            // This way we can avoid running the expression check every time the validator is called, since the expression won't change meanwhile anyway...
+            triggerConditionError: { value : false},
         },
         inputs: 1,
         outputs: 0,
@@ -18,8 +24,47 @@
         paletteLabel: 'Alarm Sensor',
         oneditprepare: function() {
             //called at launch time
+
+            var node = this;
+
+            // Check the expression syntax (at server side), for every change made in the expression input
+            $('#node-input-triggerCondition').keyup(function() {
+                var triggerExpression = this.value;
+
+                $.ajax({
+                    method: 'POST',
+                    url: 'anamico-alarm-sensor/check/',
+                    data: {expression: btoa(triggerExpression)},
+                    success: function(response){
+                        // Draw a red border around the expression input field if necessary (similar how the validation functions do it)
+                        if (response.result === "error") {
+                            $('#node-input-triggerCondition').addClass("input-error");
+                            node.triggerConditionError = true;
+                        }
+                        else { // "ok"
+                            $('#node-input-triggerCondition').removeClass("input-error");
+                            node.triggerConditionError = false;
+                        }
+                    }
+                });
+            });
 
-
+            // For older nodes (version 1.2.5 and below) there was a dropdown triggerType, but no triggerCondition expression.
+            // When the config screen of this node is being opened, the triggerType should be migrated to a corresponding triggerCondition expression.
+            if (!this.triggerCondition) {
+                if (this.triggerType == "1") {
+                    $('#node-input-triggerCondition').val("msg.payload.open == true");
+                }
+                else {
+                    // "Any message" means no trigger condition
+                    $('#node-input-triggerCondition').val("");
+                }
+            }
+            else {
+                // Make sure the condition is checked when the config screen is opened
+                $('#node-input-triggerCondition').val(this.triggerCondition);
+                $('#node-input-triggerCondition').keyup();
+            }
 
             $.get('allow2/paired/' + configId, function( data, textStatus, jqXHR ) {
                 //write access token value back out to the form
@@ -145,6 +190,13 @@
                 });
             });
         },
+        oneditsave: function() {
+            // Store the result of the last (server side) trigger expression check
+            this.triggerConditionError = false;
+            if ($('#node-input-triggerCondition').hasClass("input-error")) {
+               this.triggerConditionError = true;
+            }
+        },
         exportable: false
     });
 </script>
@@ -172,13 +224,10 @@
 
     <div class="form-row"></div>
     <div class="form-row">
-        <label for="node-input-triggerType"><i class="fa fa-filter"></i> Trigger</label>
-        <select id="node-input-triggerType">
-            <option value="">Any Message</option>
-            <option value="1">msg.payload.open == true</option>
-        </select>
+        <label for="node-input-triggerCondition"><i class="fa fa-filter"></i> Trigger</label>
+        <input type="text" id="node-input-triggerCondition" placeholder="Logical (boolean) expression">
     </div>
-    <div class="form-tips">Tip: Having no triggers defined will make this sensor trigger on ANY message. Otherwise, define a condition under which the sensor is considered "tripped".</div>
+    <div class="form-tips">Tip: Having no trigger condition defined will make this sensor trigger on ANY message. Otherwise, define a condition under which the sensor is considered "tripped".</div>
 </script>
 
 <script type="text/x-red" data-help-name="AnamicoAlarmSensor">

alarm/sensor.js

@@ -3,6 +3,23 @@
 //const async = require('async');
 
 module.exports = function(RED) {
+    const { compileExpression, useDotAccessOperatorAndOptionalChaining } = require("filtrex");
+
+    function compileFiltrexExpression(expression) {
+        const options = {
+            // Allow boolean values in the Filtrex expressions.  For example "msg.payload == true".
+            // See https://github.com/m93a/filtrex/issues/46#issuecomment-922105858
+            constants: { 
+                true: true,
+                false: false
+            },
+            // Allow dot operators in the Filtex expressions.  For example "msg.payload".
+            // See https://github.com/m93a/filtrex/issues/44#issuecomment-925914796
+            customProp: useDotAccessOperatorAndOptionalChaining
+        }
+
+        return compileExpression(expression, options);
+    }
 
     function AnamicoAlarmSensor(config) {
         RED.nodes.createNode(this, config);
@@ -12,10 +29,51 @@ module.exports = function(RED) {
         this.alarmStates = JSON.parse("[" + config.alarmStates + "]");
 
         this.resetTimer = null;
+
+        var triggerCondition = config.triggerCondition;
+
+        // For older nodes (version 1.2.5 and below) there was a dropdown triggerType, but no triggerCondition expression.
+        // When such a node is started, the triggerType should be migrated to a corresponding triggerCondition expression.
+        if (!triggerCondition) {
+            if (config.triggerType == "1") {
+                triggerCondition = "msg.payload.open == true"; 
+            }
+            else {
+                triggerCondition = "";
+            }
+        }
+
+        // No trigger condition should be converted to a trigger expression that matches all messages
+        if (triggerCondition.trim() == "") {
+            triggerCondition = "true == true";
+        }
+
+        // For performance reasons, the trigger expression will be compiled once at the start.
+        // Under the hood a trigger function is being generated.
+        if (triggerCondition) {
+            try {
+                node.triggerFunction = compileFiltrexExpression(triggerCondition);
+            }
+            catch(err) {
+                node.error("Invalid trigger condition expression: " + err);
+            }
+        }
 
         node.on('input', function(msg) {
 
             //node.log(node.alarmStates);
+
+            if (!node.triggerFunction) {
+                node.warn("Invalid trigger condition expression cannot evaluate message");
+                return;
+            }
+
+            var trigger = node.triggerFunction({msg: msg});
+
+            if (trigger !== true && trigger !== false) {
+                // Invalid input (e.g. "5" instead of 5) will result in trigger containing "TypeError: expected ..."
+                trigger = false;
+            }
 
             node.status({ fill:"blue", shape:"dot", text:"trigger" });
 
@@ -69,4 +127,23 @@ module.exports = function(RED) {
 
     }
     RED.nodes.registerType("AnamicoAlarmSensor", AnamicoAlarmSensor);
+
+    // Make the expression syntax check available to the config screen in the Node-RED editor
+    RED.httpAdmin.post('/anamico-alarm-sensor/check', function(req, res){
+        // Decode the base64-encoded trigger condition in the body of the post request
+        var buff = new Buffer(req.body.expression, 'base64');
+        var triggerExpression = buff.toString('ascii');
+
+        // Try to compile the trigger expression
+        try {
+            // When no trigger condition is available, that will be considered as a valid expression also
+            if (triggerExpression.trim() != "") {
+                compileFiltrexExpression(triggerExpression);
+                res.json({result: "ok"});
+            }
+        }
+        catch(err) {
+            res.json({result: "error", error: err});
+        }
+    });
 };

package.json

@@ -31,7 +31,8 @@
   ],
   "dependencies": {
     "debug": "^4.3.1",
-    "async": "^2.6.1"
+    "async": "^2.6.1",
+    "filtrex": "^3.0.0-rc11"
   },
   "description": "Nodes to build your own home alarm system. Designed to work easily with (but does not require) homekit.",
   "devDependencies": {},