From 873636d613397b5e1cb01c8cf73bbe7302044fa9 Mon Sep 17 00:00:00 2001
From: Adan Wattad <adanwat@amazon.com>
Date: Thu, 5 Oct 2023 17:55:34 +0300
Subject: [PATCH] added hmget command in node.

---
 node/src/BaseClient.ts      | 13 +++++++++++++
 node/src/Commands.ts        |  7 +++++++
 node/src/Transaction.ts     | 14 ++++++++++++++
 node/tests/SharedTests.ts   | 27 +++++++++++++++++++++++++++
 node/tests/TestUtilities.ts | 14 +++++++++++++-
 5 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/node/src/BaseClient.ts b/node/src/BaseClient.ts
index fa25e9ca00..808840d57a 100644
--- a/node/src/BaseClient.ts
+++ b/node/src/BaseClient.ts
@@ -13,6 +13,7 @@ import {
     createGet,
     createHDel,
     createHGet,
+    createHMGet,
     createHSet,
     createIncr,
     createIncrBy,
@@ -434,6 +435,18 @@ export class BaseClient {
         return this.createWritePromise(createHDel(key, fields));
     }
 
+    /** Returns the values associated with the specified fields in the hash stored at key.
+     *
+     * @param key - The key of the hash.
+     * @param fields - The fields in the hash stored at key to retrieve from the database.
+     * @returns a list of values associated with the given fields, in the same order as they are requested.
+     * For every field that does not exist in the hash, a null value is returned.
+     * If key does not exist, it is treated as an empty hash and it returns a list of null values.
+     */
+    public hmget(key: string, fields: string[]): Promise<(string | null)[]> {
+        return this.createWritePromise(createHMGet(key, fields));
+    }
+
     private readonly MAP_READ_FROM_REPLICA_STRATEGY: Record<
         ReadFromReplicaStrategy,
         connection_request.ReadFromReplicaStrategy
diff --git a/node/src/Commands.ts b/node/src/Commands.ts
index 36e570fb89..335208bb89 100644
--- a/node/src/Commands.ts
+++ b/node/src/Commands.ts
@@ -319,6 +319,13 @@ export function createHDel(
     return createCommand(RequestType.HashDel, [key].concat(fields));
 }
 
+export function createHMGet(
+    key: string,
+    fields: string[]
+): redis_request.Command {
+    return createCommand(RequestType.HashMGet, [key].concat(fields));
+}
+
 export function createCustomCommand(commandName: string, args: string[]) {
     return createCommand(RequestType.CustomCommand, [commandName, ...args]);
 }
diff --git a/node/src/Transaction.ts b/node/src/Transaction.ts
index c48c9d89df..20ec77b4dd 100644
--- a/node/src/Transaction.ts
+++ b/node/src/Transaction.ts
@@ -14,6 +14,7 @@ import {
     createGet,
     createHDel,
     createHGet,
+    createHMGet,
     createHSet,
     createIncr,
     createIncrBy,
@@ -298,6 +299,19 @@ export class BaseTransaction {
         this.commands.push(createHDel(key, fields));
     }
 
+    /** Returns the values associated with the specified fields in the hash stored at key.
+     *
+     * @param key - The key of the hash.
+     * @param fields - The fields in the hash stored at key to retrieve from the database.
+     *
+     * Command Response - a list of values associated with the given fields, in the same order as they are requested.
+     * For every field that does not exist in the hash, a null value is returned.
+     * If key does not exist, it is treated as an empty hash and it returns a list of null values.
+     */
+    public hmget(key: string, fields: string[]) {
+        this.commands.push(createHMGet(key, fields));
+    }
+
     /** Executes a single command, without checking inputs. Every part of the command, including subcommands,
      *  should be added as a separate value in args.
      *
diff --git a/node/tests/SharedTests.ts b/node/tests/SharedTests.ts
index f84d8d7273..6429fbd95f 100644
--- a/node/tests/SharedTests.ts
+++ b/node/tests/SharedTests.ts
@@ -34,6 +34,7 @@ type BaseClient = {
     ) => Promise<number>;
     hget: (key: string, field: string) => Promise<string | null>;
     hdel: (key: string, fields: string[]) => Promise<number>;
+    hmget: (key: string, fields: string[]) => Promise<(string | null)[]>;
     customCommand: (commandName: string, args: string[]) => Promise<ReturnType>;
 };
 
@@ -528,6 +529,32 @@ export function runBaseTests<Context>(config: {
         },
         config.timeout
     );
+
+    it(
+        "testing hmget with multiple existing fields, an non existing field and an non existing key",
+        async () => {
+            await runTest(async (client: BaseClient) => {
+                const key = uuidv4();
+                const nonExistingKey = uuidv4();
+                const field1 = uuidv4();
+                const field2 = uuidv4();
+                const nonExistingField = uuidv4();
+                const value = uuidv4();
+                const fieldValueMap = {
+                    [field1]: value,
+                    [field2]: value,
+                };
+                expect(await client.hset(key, fieldValueMap)).toEqual(2);
+                expect(
+                    await client.hmget(key, [field1, nonExistingField, field2])
+                ).toEqual([value, null, value]);
+                expect(
+                    await client.hmget(nonExistingKey, [field1, field2])
+                ).toEqual([null, null]);
+            });
+        },
+        config.timeout
+    );
 }
 
 export function runCommonTests<Context>(config: {
diff --git a/node/tests/TestUtilities.ts b/node/tests/TestUtilities.ts
index 26e65127e9..97b4b26173 100644
--- a/node/tests/TestUtilities.ts
+++ b/node/tests/TestUtilities.ts
@@ -67,5 +67,17 @@ export function transactionTest(
     baseTransaction.hset(key4, { [field]: value });
     baseTransaction.hget(key4, field);
     baseTransaction.hdel(key4, [field]);
-    return ["OK", null, ["bar", "baz"], "OK", ["bar", "baz"], 1, 1, value, 1];
+    baseTransaction.hmget(key4, [field]);
+    return [
+        "OK",
+        null,
+        ["bar", "baz"],
+        "OK",
+        ["bar", "baz"],
+        1,
+        1,
+        value,
+        1,
+        [null],
+    ];
 }