ZeroMQ Messages

Sent by Client

parse

Description

Asks the server to parse a string of Alda code.

Options include as, which can be one of lisp or map, indicating whether the score should be parsed into alda.lisp code or the final map of score data. When omitted, the default behavior is to parse as lisp code.

Example

{
  "command": "parse",
  "body": "piano: c8 d e f g2",
  "options": {
    "as": "map"
  }
}

---

ping

Description

Pings the server to see if it's up.

Example

{"command": "ping"}

---

play

Description

Asks the server to play a string of Alda code.

Options include from and to strings, representing minute/second markings or score marker names directing the server where in the score to start/end. (When omitted, the score will default to the beginning and end of the score.)

Example

{
  "command": "play",
  "body": "piano: c8 d e f g2",
  "options": {
    "from": "chorus",
    "to": "5:55"
  }
}

---

play-status

Description

Asks a worker for its current status, e.g. parsing a score, playing a score, done.

Note that this message is sent not to the server, but to a specific worker. To do this, you add an extra frame with the worker's address. For more details, see ZeroMQ Architecture#Message Structure.

Example

{"command": "play-status"}

---

stop-server

Description

Tells the server to shut down.

Example

{"command": "stop-server"}

---

status

Description

Asks the server for its current status.

The response from the server is a string like Server up (2/2 workers available).

Example

{"command": "status"}

---

version

Description

Asks the server for its Alda version number.

Example

{"command": "version"}

Sent by Server

The server sends 3 kinds of messages:

• Messages forwarded to/from clients and workers.
• One-frame worker control messages like KILL and HEARTBEAT.
• Direct JSON responses to client requests that don't need to be handled by workers.

Only the last type is covered here.

Example Response

{"success": true, "body": "1.0.0-rc42", "noWorker": true}

Sent by Worker

Example Response

{"success": true, "pending": false, "body": "playing"}

See Also

• ZeroMQ Architecture