Protocol

Description

The PHPMQ message protocol

Installation

composer require php-mq/protocol

Usage

---

Message headers

Each message sent from a client to the endpoint must have a leading header line which defines:

• A flag that identifies the line as message header
• A number that identifies the version of the message protocol
• The type of the message (see message types) (3 bytes)
• The number of the following packages (see packet types)

Example:

H0100102

means:

PACKET-ID | VERSION | MSG-TYPE | PACKAGE COUNT
        H |      01 |      001 |            02 

So a header always has a length of 8 byte.

Message types

• 001 - Client sends a message (client to server)
• 002 - Client wants to consume messages (consume request)
• 003 - Server dispatches a message (server to client)
• 004 - Client acknowledges a message (acknowledgement)
• 005 - Client wants to re-queue a message (pop from queue, append to queue)
• 006 - Client sends a dead letter for a message (remove message from queue)

Packet headers

Each data package in a message is preceded by a package header with defines:

• A flag that identifies the line as package header
• A number that identifies the package type
• The length of the following package content

Example:

P01000000000000000000000000000000256

means:

PACKET-ID | PKG-TYPE | CONTENT-LENGTH (as int)
        P |       01 |                     256

So a package header always has a length of 32 byte.

Please note: The content length has a length of 32 bytes and is filled up with zeros.

Packet types

All

PKG-Type	Meaning
01	Queue name
02	Message content
03	Message ID
04	Count of message for consumption
05	Time to live of message (TTL)

---

For messages from client to endpoint

• 01 - Queue name
• 02 - Message content
• 05 - Message TTL

For messages from endpoint to client

• 01 - Queue name
• 02 - Message content
• 03 - Message ID
• 05 - Message TTL

For Consumption

• 01 - Queue name
• 04 - Count of messages the client wants to consume from the queue

For message acknowledgment

• 01 - Queue name
• 03 - Message ID

For message re-queue

• 01 - Queue name
• 03 - Message ID
• 05 - Message TTL

For dead letter

• 01 - Queue name
• 03 - Message ID

---

Full message examples

Send a message

Client sends a new message with content "Hello World" for queue "Foo" to server with a TTL of 3600 seconds.

H0100103
P0100000000000000000000000000003
Foo
P0200000000000000000000000000011
Hello World
P0500000000000000000000000000004
3600

Consume messages

Client wants to consume 5 messages from queue "Foo".

H0100202
P0100000000000000000000000000003
Foo
P0400000000000000000000000000001
5

Dispatch a message

Server sends the message above to the client 300 seconds later.

H0100304
P0100000000000000000000000000003
Foo
P0200000000000000000000000000011
Hello World
P0300000000000000000000000000032
d7e7f68761d34838494b233148b5486c
P0500000000000000000000000000004
3300

Note: TTL was reduced to 3300 seconds.

Acknowledge a message

Client acknowledges the consumed message with ID d7e7f68761d34838494b233148b5486c.

H0100402
P0100000000000000000000000000003
Foo
P0300000000000000000000000000032
d7e7f68761d34838494b233148b5486c

Re-queue a message

Client wants the message to be re-queued at the end of the queue, with a new TTL of 3600 seconds.

H0100503
P0100000000000000000000000000003
Foo
P0300000000000000000000000000032
d7e7f68761d34838494b233148b5486c
P0500000000000000000000000000004
3600

Send a dead letter

Client wants the message to be removed from queue, regardless its TTL

H0100602
P0100000000000000000000000000003
Foo
P0300000000000000000000000000032
d7e7f68761d34838494b233148b5486c

---

Contributing

Contributions are welcome and will be fully credited. Please see the contribution guide for details.