Direct Message Multiple Values

[scottf]

Overview

Because of the way the server stacks values during republishes, the last value for each header field is the correct value for direct messages

Nats-Subject
Nats-Sequence
Nats-Last-Sequence
Nats-Time-Stamp
Nats-Stream

Clients and Tools

• Go @piotrpio
• Java @scottf [FIX] Direct Message Subject Header May Contain Multiple Subjects nats.java#1016 and Message Info always use last value in the headers. nats.java#1099
• JavaScript @aricart KV get fails to get republished value (message) with multiple headers nats.deno#586
• .Net @scottf https://github.com/nats-io/nats.net/pull/830 and https://github.com/nats-io/nats.net/pull/879
• C @levb
• Python @wallyqs
• Ruby @wallyqs
• Rust @Jarema @caspervonb
• .Net V2 @mtmk Direct Message Header May Contain Multiple Subjects nats.net#512

Example Unit Test

1. Create a stream with configuration:

name: "sbname"
subjects: "sub.>"
republish 
    src: ">" 
    dest: "$KV.sbname.>"

2. Create a Key Value bucket with bucket name matching the stream name

name: "sbname"

3. Publish 3 different ways for coverage

Connection Publish: Subject: "sub.1", Payload: "A"
JetStream Publish: Subject: "sub.2", Payload: "B"
Key Value Put to Bucket: Key: "sub.3", Value: "C"

4. Retrieve values from the bucket.

KeyValueEntry kve1 = kv.get(publishSubject1);
assertEquals("sbname", kve1.getBucket());
assertEquals("sub.1", kve1.getKey());
assertEquals("A", kve1.getValueAsString());

KeyValueEntry kve2 = kv.get(publishSubject2);
assertEquals("sbname", kve2.getBucket());
assertEquals("sub.2", kve2.getKey());
assertEquals("B", kve2.getValueAsString());

KeyValueEntry kve3 = kv.get(publishSubject3);
assertEquals("sbname", kve3.getBucket());
assertEquals("sub.3", kve3.getKey());
assertEquals("C", kve3.getValueAsString());

Other Tasks

• docs.nats.io updated @bruth
• Update ADR to Implemented
• Update client features spreadsheet

Client authors please update with your progress. If you open issues in your own repositories as a result of this request, please link them to this one by pasting the issue URL in a comment or main issue description.