[FEAT] added check when retrieving a key, but also specifying a seque…

…nce (new feature), that the key matched. If not, null is returned as the sequence is not referencing the expected key.

[FIX] conversion from stored message captured the key as provided by the client, and returned an entry with the said key.

nats-base-client/kv.ts

@@ -312,10 +312,10 @@ export class Bucket implements KV, KvRemove {
     return data.length;
   }
 
-  smToEntry(key: string, sm: StoredMsg): KvEntry {
+  smToEntry(sm: StoredMsg): KvEntry {
     return {
       bucket: this.bucket,
-      key: key,
+      key: sm.subject.substring(this.prefixLen),
       value: sm.data,
       delta: 0,
       created: sm.time,
@@ -325,7 +325,7 @@ export class Bucket implements KV, KvRemove {
     };
   }
 
-  jmToEntry(_k: string, jm: JsMsg): KvEntry {
+  jmToEntry(jm: JsMsg): KvEntry {
     const key = this.decodeKey(jm.subject.substring(this.prefixLen));
     return {
       bucket: this.bucket,
@@ -370,19 +370,23 @@ export class Bucket implements KV, KvRemove {
 
   async get(
     k: string,
-    opts: { revision: number } = { revision: 0 },
+    opts?: { revision: number },
   ): Promise<KvEntry | null> {
     const ek = this.encodeKey(k);
     this.validateKey(ek);
 
     let arg: MsgRequest = { last_by_subj: this.fullKeyName(ek) };
-    if (opts.revision !== 0) {
+    if (opts && opts.revision > 0) {
       arg = { seq: opts.revision };
     }
 
     try {
       const sm = await this.jsm.streams.getMessage(this.bucketName(), arg);
-      return this.smToEntry(k, sm);
+      const ke = this.smToEntry(sm);
+      if (ke.key !== ek) {
+        return null;
+      }
+      return ke;
     } catch (err) {
       if (err.message === "no message found") {
         return null;
@@ -476,7 +480,7 @@ export class Bucket implements KV, KvRemove {
         return;
       }
       if (jm) {
-        const e = this.jmToEntry(k, jm);
+        const e = this.jmToEntry(jm);
         qi.push(e);
         qi.received++;
         //@ts-ignore - function will be removed
@@ -553,7 +557,7 @@ export class Bucket implements KV, KvRemove {
         return;
       }
       if (jm) {
-        const e = this.jmToEntry(k, jm);
+        const e = this.jmToEntry(jm);
         qi.push(e);
         qi.received++;
 

tests/kv_test.ts

@@ -1279,27 +1279,31 @@ Deno.test("kv - get revision", async () => {
   const js = nc.jetstream();
   const sc = StringCodec();
 
-  const b = await js.views.kv("a", { history: 3 }) as Bucket;
-  await b.put("A", sc.encode("a"));
-  await b.put("A", sc.encode("b"));
-  await b.put("A", sc.encode("c"));
+  const b = await js.views.kv(nuid.next(), { history: 3 }) as Bucket;
 
-  async function check(value: string | null, revision = 0) {
-    const e = await b.get("A", { revision });
+  async function check(key: string, value: string | null, revision = 0) {
+    const e = await b.get(key, { revision });
     if (value === null) {
       assertEquals(e, null);
     } else {
       assertEquals(sc.decode(e!.value), value);
     }
   }
 
-  await check("c");
-  await check("a", 1);
-  await check("b", 2);
+  await b.put("A", sc.encode("a"));
+  await b.put("A", sc.encode("b"));
+  await b.put("A", sc.encode("c"));
+
+  // expect null, as sequence 1, holds "A"
+  await check("B", null, 1);
+
+  await check("A", "c");
+  await check("A", "a", 1);
+  await check("A", "b", 2);
 
   await b.put("A", sc.encode("d"));
-  await check("d");
-  await check(null, 1);
+  await check("A", "d");
+  await check("A", null, 1);
 
   await cleanup(ns, nc);
 });