Adding Exif node.

utility/exif/94-exif.html

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+<!--
+  Copyright 2014 IBM Corp.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+
+<script type="text/x-red" data-template-name="exif">
+    <div class="form-row">
+        <label for="node-input-name"><i class="fa fa-tag"></i> Name</label>
+        <input type="text" id="node-input-name" placeholder="Name">
+    </div>
+</script>
+
+<script type="text/x-red" data-help-name="exif">
+    <p>Extract <a href="http://en.wikipedia.org/wiki/Exchangeable_image_file_format">Exif</a> information from JPEG images.</p>
+    <p>This node expects an incoming JPEG image buffer. If Exif data is present,
+    it extracts the data into the <b>msg.exif</b> object.</p>
+    <p>The node then adds location data as <b>msg.location</b>, should the Exif data carry this information. 
+    <b>msg.payload</b> remains the original, unmodified image buffer. </p>
+</script>
+
+<script type="text/javascript">
+    RED.nodes.registerType('exif',{
+        category: 'utility',
+        color:"#f1c2f0",
+        defaults: {
+            name: {value:""}
+        },
+        inputs:1,
+        outputs:1,
+        icon: "watch.png",
+        label: function() {
+            return this.name||"exif";
+        },
+        labelStyle: function() {
+            return this.name?"node_label_italic":"";
+        }
+    });
+</script>

utility/exif/94-exif.js

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+/**
+ * Copyright 2014 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+module.exports = function(RED) {
+    "use strict";
+    var ExifImage = require('exif').ExifImage;
+    
+    function convertDegreesMinutesSecondsToDecimals(degrees, minutes, seconds) {
+        var result;
+        result = degrees + (minutes / 60) + (seconds / 3600);
+        return result;
+    }
+    
+    /***
+     * Extracts GPS location information from Exif data. If enough information is
+     * provided, convert the Exif data into a pair of single floating point number
+     * latitude/longitude data pairs. Populates msg.location with these.
+     * Assumes that the msg object will always have exifData available as msg.exif.
+     * Assume that the GPS data saved into Exif provides a valid value
+     */
+    function addMsgLocationDataFromExifGPSData(msg) {
+        if(msg.exif.gps) {
+            var gpsData = msg.exif.gps; // declaring variable purely to make checks more readable
+            if(gpsData.GPSAltitude) {
+                if(!msg.location) {
+                    msg.location = {};
+                }
+                msg.location.alt = gpsData.GPSAltitude;
+            }
+            if(gpsData.GPSLatitudeRef && gpsData.GPSLatitude && gpsData.GPSLongitudeRef && gpsData.GPSLongitude) { // location can be determined, OK
+                // The data provided in Exif is in degrees, minutes, seconds, this is to be converted into a single floating point degree
+                if(gpsData.GPSLatitude.length === 3) { // OK to convert latitude
+                    if(gpsData.GPSLongitude.length === 3) { // OK to convert longitude
+                        var latitude = convertDegreesMinutesSecondsToDecimals(gpsData.GPSLatitude[0], gpsData.GPSLatitude[1], gpsData.GPSLatitude[2]);
+                        latitude = Math.round(latitude * 100000)/100000;
+                        
+                        // (N)orth means positive latitude
+                        // (S)outh means negative latitude
+                        // (E)ast means positive longitude
+                        // (W)est means negative longitude
+                        if(gpsData.GPSLatitudeRef.toString() === 'S' || gpsData.GPSLatitudeRef.toString() === 's') {
+                            latitude = latitude * -1;
+                        }
+                        
+                        var longitude = convertDegreesMinutesSecondsToDecimals(gpsData.GPSLongitude[0], gpsData.GPSLongitude[1], gpsData.GPSLongitude[2]);
+                        longitude = Math.round(longitude * 100000)/100000;
+                        
+                        if(gpsData.GPSLongitudeRef.toString() === 'W' || gpsData.GPSLongitudeRef.toString() === 'w') {
+                            longitude = longitude * -1;
+                        }
+                        if(!msg.location) {
+                            msg.location = {};
+                        }
+                        msg.location.lat = latitude;
+                        msg.location.lon = longitude;
+                        return;
+                    } else {
+                        node.log("Invalid longitude data, no location information has been added to the message.");
+                    }
+                } else {
+                    node.log("Invalid latitude data, no location information has been added to the message.");
+                }
+            } else {
+                node.log("The location of this image cannot be determined safely so no location information has been added to the message.");
+            }
+        } else {
+            node.log("No location info found in this image.");
+        }
+    }
+
+    function ExifNode(n) {
+        RED.nodes.createNode(this,n);
+        var node = this;
+        this.on("input", function(msg) {
+            try {
+                
+                if(msg.payload) {
+                    var isBuffer = Buffer.isBuffer(msg.payload);
+                    if(isBuffer === true) {
+                        new ExifImage({ image : msg.payload }, function (error, exifData) {
+                                if (error) {
+                                    node.error('Failed to extract Exif data from image.');
+                                    node.log('Failed to extract Exif data from image. '+ error);
+                                } else {
+                                    //msg.payload remains the same buffer
+                                    if(exifData) {
+                                        msg.exif = exifData;
+                                        addMsgLocationDataFromExifGPSData(msg);
+                                    } else {
+                                        node.warn("The incoming buffer did not contain Exif data, nothing to do. ");
+                                    }
+                                }
+                                node.send(msg);
+                            });
+                    } else {
+                        node.error("Invalid payload received, the Exif node cannot proceed, no messages sent.");
+                        return;
+                    }
+                } else {
+                    node.error("No payload received, the Exif node cannot proceed, no messages sent.");
+                    return;
+                }
+            } catch (error) {
+                node.error("An error occurred while extracting Exif information. Please check the log for details.");
+                node.log('Error: '+error.message);
+                return;
+            }
+        });
+    }
+    RED.nodes.registerType("exif",ExifNode);
+}

utility/exif/package.json

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+{
+    "name"          : "node-red-node-exif",
+    "version"       : "0.0.1",
+    "description"   : "A Node-RED node that extracts Exif information from JPEG image buffers.",
+    "dependencies"  : {
+        "exif": "0.4.0"
+    },
+    "repository" : {
+        "type":"git",
+        "url":"https://github.com/node-red/node-red-nodes/tree/master/utility/exif"
+    },
+    "license": "Apache-v2.0",
+    "keywords": [ "node-red", "exif"],
+    "node-red"      : {
+        "nodes"     : {
+            "exif": "94-exif.js"
+        }
+    },
+    "contributors": [
+        {"name": "Dave Conway-Jones"},
+        {"name": "Zoltan Balogh"}
+    ]
+}