Basic NGSI-LD active measures support

CHANGES_NEXT_RELEASE

@@ -2,4 +2,5 @@ Refresh Documentation
 Add NGSIv2 metadata support to device provisioned attributes
 Fix: Error message when sending measures with unknown/undefined attribute
 Add Null check within executeWithSecurity() to avoid crash (#829)
+Basic NGSI-LD active measures support (#841)
 Add NGSIv2 metadata support to attributeAlias plugin.

doc/installationguide.md

@@ -30,6 +30,20 @@ These are the parameters that can be configured in the global section:
 }
 ```
 
+-   If you want to use NGSI-LD (experimental):
+
+```javascript
+{
+    host: '192.168.56.101',
+    port: '1026',
+    ngsiVersion: 'ld',
+    jsonLdContext: 'http://context.json-ld''
+}
+```
+
+Where `http://context.json-ld` is the location of the NGSI-LD `@context` element which provides additional information allowing the computer to
+interpret the rest of the data with more clarity and depth. Read the [JSON-LD specification](https://w3c.github.io/json-ld-syntax/#the-context) for more informtaion.
+
 -   **server**: configuration used to create the Context Server (port where the IoT Agent will be listening as a Context
     Provider and base root to prefix all the paths). The `port` attribute is required. If no `baseRoot` attribute is
     used, '/' is used by default. E.g.:
@@ -262,3 +276,4 @@ overrides.
 | IOTA_POLLING_DAEMON_FREQ  | `pollingDaemonFrequency`        |
 | IOTA_AUTOCAST             | `autocast`                      |
 | IOTA_MULTI_CORE           | `multiCore`                     |
+| IOTA_JSON_LD_CONTEXT      | `jsonLdContext`                 |

lib/commonConfig.js

@@ -91,7 +91,8 @@ function processEnvironmentVariables() {
              'IOTA_APPEND_MODE',
              'IOTA_POLLING_EXPIRATION',
              'IOTA_POLLING_DAEMON_FREQ',
-             'IOTA_MULTI_CORE'
+             'IOTA_MULTI_CORE',
+             'IOTA_JSON_LD_CONTEXT'
         ],
         iotamVariables = [
             'IOTA_IOTAM_URL',
@@ -146,6 +147,9 @@ function processEnvironmentVariables() {
     if (process.env.IOTA_CB_NGSI_VERSION) {
         config.contextBroker.ngsiVersion = process.env.IOTA_CB_NGSI_VERSION;
     }
+    if (process.env.IOTA_JSON_LD_CONTEXT){
+        config.contextBroker.jsonLdContext = process.env.IOTA_JSON_LD_CONTEXT;
+    }
 
     // North Port Configuration (ensuring the configuration sub-object exists before start using it)
     if (config.server === undefined) {
@@ -377,6 +381,21 @@ function checkNgsi2() {
     return false;
 }
 
+/**
+ * It checks if the configuration file states the use of NGSI-LD
+ *
+ * @return     {boolean}  Result of the checking
+ */
+function checkNgsiLD() {
+    if (config.contextBroker &&
+        config.contextBroker.ngsiVersion &&
+        config.contextBroker.ngsiVersion === 'ld') {
+        return true;
+    }
+
+    return false;
+}
+
 function setSecurityService(newSecurityService) {
     securityService = newSecurityService;
 }
@@ -394,5 +413,6 @@ exports.getGroupRegistry = getGroupRegistry;
 exports.setCommandRegistry = setCommandRegistry;
 exports.getCommandRegistry = getCommandRegistry;
 exports.checkNgsi2 = checkNgsi2;
+exports.checkNgsiLD = checkNgsiLD;
 exports.setSecurityService = setSecurityService;
 exports.getSecurityService = getSecurityService;

lib/plugins/attributeAlias.js

@@ -76,7 +76,7 @@ function extractAllMappings(typeInformation) {
 function applyAlias(mappings) {
     return function aliasApplier(attribute) {
         if (mappings.direct[attribute.name]) {
-            if (config.checkNgsi2()) {
+            if (config.checkNgsi2() || config.checkNgsiLD()) {
                 /*jshint camelcase: false */
                 attribute.object_id = attribute.name; // inverse not usefull due to collision
             }
@@ -96,7 +96,7 @@ function applyAlias(mappings) {
  */
 function updateAttribute(entity, typeInformation, callback) {
     var mappings = extractAllMappings(typeInformation);
-    if (config.checkNgsi2()) {
+    if (config.checkNgsi2() || config.checkNgsiLD()) {
         var attsArray = utils.extractAttributesArrayFromNgsi2Entity(entity);
         attsArray = attsArray.map(applyAlias(mappings));
         entity = utils.createNgsi2Entity(entity.id, entity.type, attsArray, true);

lib/plugins/bidirectionalData.js

@@ -134,7 +134,7 @@ function sendSubscriptions(device, attributeList, callback) {
 
     logger.debug(context, 'Sending bidirectionality subscriptions for device [%s]', device.id);
 
-    if (config.checkNgsi2()) {
+    if (config.checkNgsi2() || config.checkNgsiLD()) {
         async.map(attributeList, sendSingleSubscriptionNgsi2, callback);
     } else {
         async.map(attributeList, sendSingleSubscriptionNgsi1, callback);

lib/plugins/expressionParser.js

@@ -177,7 +177,7 @@ function expressionApplier(context, typeInformation) {
         };
 
         /*jshint camelcase: false */
-        if (config.checkNgsi2() && attribute.object_id) {
+        if (config.checkNgsi2() || config.checkNgsiLD() && attribute.object_id) {
             newAttribute.object_id = attribute.object_id;
         }
 

lib/plugins/expressionPlugin.js

@@ -88,7 +88,7 @@ function update(entity, typeInformation, callback) {
     }
 
     try {
-        if (config.checkNgsi2()) {
+        if (config.checkNgsi2() || config.checkNgsiLD()) {
             var attsArray = utils.extractAttributesArrayFromNgsi2Entity(entity);
             attsArray = processEntityUpdateNgsi2(attsArray);
             entity = utils.createNgsi2Entity(entity.id, entity.type, attsArray, true);

lib/plugins/multiEntity.js

@@ -324,7 +324,7 @@ function updateAttributeNgsi2(entity, typeInformation, callback) {
 }
 
 function updateAttribute(entity, typeInformation, callback) {
-    if (config.checkNgsi2()) {
+    if (config.checkNgsi2() || config.checkNgsiLD()) {
         updateAttributeNgsi2(entity, typeInformation, callback);
     } else {
         updateAttributeNgsi1(entity, typeInformation, callback);

lib/plugins/pluginUtils.js

@@ -105,7 +105,7 @@ function createProcessAttribute(fn, attributeType) {
             attribute.value = fn(attribute.value);
         }
 
-        if (config.checkNgsi2()) {
+        if (config.checkNgsi2() || config.checkNgsiLD()) {
             // This code is backwards compatible to process metadata in the older NGSIv1-style (array) 
             // as well as supporting the newer NGSIv2-style (object). The redundant Array Check can be 
             // therefore be removed if/when NGSIv1 support is removed from the library.
@@ -152,7 +152,7 @@ function createUpdateFilter(fn, attributeType) {
             return entity;
         }
 
-        if (config.checkNgsi2()) {
+        if (config.checkNgsi2() || config.checkNgsiLD()) {
             entity = processEntityUpdateNgsi2(entity);
         } else {
             entity.contextElements = entity.contextElements.map(processEntityUpdateNgsi1);
@@ -186,7 +186,7 @@ function createQueryFilter(fn, attributeType) {
             return entity;
         }
 
-        if (config.checkNgsi2()) {
+        if (config.checkNgsi2() || config.checkNgsiLD()) {
             entity = processEntityQueryNgsi2(entity);
         } else {
             entity.contextResponses = entity.contextResponses.map(processEntityQueryNgsi1);

lib/plugins/timestampProcessPlugin.js

@@ -132,7 +132,7 @@ function updatePluginNgsi1(entity, entityType, callback) {
  * @param {Object} entity           NGSI Entity as it would have been sent before the plugin.
  */
 function updatePlugin(entity, entityType, callback) {
-    if (config.checkNgsi2()) {
+    if (config.checkNgsi2() || config.checkNgsiLD()) {
         updatePluginNgsi2(entity, entityType, callback);
     } else {
         updatePluginNgsi1(entity, entityType, callback);

lib/services/common/genericMiddleware.js

@@ -58,7 +58,7 @@ function handleError(error, req, res, next) {
 function traceRequest(req, res, next) {
     logger.debug(context, 'Request for path [%s] from [%s]', req.path, req.get('host'));
 
-    if (req.is('json')) {
+    if (req.is('json') || req.is('application/ld+json')) {
         logger.debug(context, 'Body:\n\n%s\n\n', JSON.stringify(req.body, null, 4));
     }
 
@@ -100,6 +100,8 @@ function getLogLevel(req, res, next) {
 function ensureType(req, res, next) {
     if (req.is('json')) {
         next();
+    } else if (req.is('application/ld+json')) {
+        next();
     } else {
         next(new errors.UnsupportedContentType(req.headers['content-type']));
     }
@@ -113,7 +115,7 @@ function ensureType(req, res, next) {
  */
 function validateJson(template) {
     return function validate(req, res, next) {
-        if (req.is('json')) {
+        if (req.is('json') || req.is('application/ld+json')) {
             var errorList = revalidator.validate(req.body, template);
 
             if (errorList.valid) {