implements #137

lib/actions/table/MergeEntity.js

@@ -0,0 +1,22 @@
+'use strict';
+
+const AzuriteTableResponse = require('./../../model/table/AzuriteTableResponse'),
+    tableStorageManager = require('./../../core/table/TableStorageManager'),
+    ODataMode = require('./../../core/Constants').ODataMode,
+    N = require('./../../core/HttpHeaderNames');
+
+class MergeEntity {
+    constructor() {
+    }
+
+    process(request, res) {
+        tableStorageManager.mergeEntity(request)
+        .then((response) => {
+            response.addHttpProperty(N.ETAG, response.proxy.etag);
+            res.set(response.httpProps);
+            res.status(204).send();
+        });
+    }
+}
+
+module.exports = new MergeEntity;

lib/core/Constants.js

@@ -112,7 +112,8 @@ const Operations = {
         QUERY_TABLE: 'QueryTable',
         QUERY_ENTITY: 'QueryEntity',
         UPDATE_ENTITY: 'UpdateEntity',
-        INSERT_OR_REPLACE_ENTITY: 'InsertOrReplaceEntity'
+        INSERT_OR_REPLACE_ENTITY: 'InsertOrReplaceEntity',
+        MERGE_ENTITY: 'MergeEntity'
     }
 }
 

lib/core/table/TableStorageManager.js

@@ -132,6 +132,22 @@ class TableStorageManager {
         return BbPromise.resolve(new AzuriteTableResponse({ proxy: proxy }));
     }
 
+    mergeEntity(request) {
+        const coll = this.db.getCollection(request.tableName),
+            entity = EntityGenerator.generateEntity(request.payload, request.tableName),
+            res = coll.findOne({ partitionKey: request.partitionKey, rowKey: request.rowKey });
+
+        // A property cannot be removed with a Merge Entity operation (in contrast to an update operation).
+        for (const key of Object.keys(entity.attribs)) {
+            if (entity[key]) {
+                res.attribs[key] = entity.attribs[key];
+            }
+        }
+        res.odata = entity.odata;
+        coll.update(res);
+        return new EntityProxy(res);
+    }
+
     _getTable(name) {
         const coll = this.db.getCollection(Tables.Tables);
         const result = coll.chain()

lib/middleware/table/actions.js

@@ -8,6 +8,8 @@ const BbPromise = require('bluebird'),
     queryTable = require('./../../actions/table/QueryTable'),
     queryEntities = require('./../../actions/table/QueryEntities'),
     updateEntity = require('./../../actions/table/UpdateEntity'),
+    insertOrReplaceEntity = require('./../../actions/table/InsertOrReplaceEntity'),
+    mergeEntity = require('./../../actions/table/MergeEntity'),
     createTable = require('./../../actions/table/CreateTable');
 
 module.exports = (req, res) => {
@@ -54,5 +56,9 @@ actions[Operations.UPDATE_ENTITY] = (request, res) => {
 }
 
 actions[Operations.INSERT_OR_REPLACE_ENTITY] = (request, res) => {
-    updateEntity.process(request, res);
+    insertOrReplaceEntity.process(request, res);
+}
+
+actions[Operations.MERGE_ENTITY] = (request, res) => {
+    mergeEntity.process(request, res);
 }

lib/middleware/table/validation.js

@@ -86,4 +86,11 @@ validations[Operations.UPDATE_ENTITY] = (valContext) => {
 validations[Operations.INSERT_OR_REPLACE_ENTITY] = (valContext) => {
     valContext
         .run(TableExistsVal);
+}
+
+validations[Operations.MERGE_ENTITY] = (valContext) => {
+    valContext
+        .run(TableExistsVal)
+        .run(EntityExistsVal)
+        .run(EntityIfMatchVal);
 }

lib/routes/table/EntityRoute.js

@@ -40,5 +40,10 @@ module.exports = (app) => {
             req.azuriteOperation = Operations.DELETE_ENTITY;
             req.azuriteRequest = new AzuriteTableRequest({ req: req });
             next();
+        })
+        .merge((req, res, next) => {
+            req.azuriteOperation = Operations.MERGE_ENTITY;
+            req.azuriteRequest = new AzuriteTableRequest({ req: req, payload: req.payload });
+            next();
         });
 }