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Damien Cassou 422606a7bf Merge branch 'optional-tcp-started-callback' into 'master' 4 months ago
test Add initial unit-tests 5 months ago
.gitignore Initial release 5 months ago
.gitlab-ci.yml Initial release 5 months ago
COPYING Initial release 5 months ago
Makefile Add initial unit-tests 5 months ago Add melpa badges 5 months ago
json-process-client.el Stop forcing a tcp-started-callback 4 months ago



MELPA Stable


pipeline status



The package json-process-client is an Emacs library to facilitate communicating with servers that read and write JSON. The library is responsible for starting the server and connecting with TCP. It is also responsible for converting to and from JSON.

The library was written by Nicolas Petton in the context of Indium and later generalized by Damien Cassou who needed something similar to integrate basecamp within Emacs.


Get json-process-client from melpa or melpa stable. You can also clone the git repository.


There are two entry points to the API: json-process-client-start and ~json-process-client-start-with-id~. They both launch an executable passed as parameter wait for it to be ready, and connect to it using TCP. They both return an "application" that must be passed as parameter to all other functions of the API.

Because everything is asynchronous, the server can send responses in a different order than the messages the client sent. The server can also send messages which are not responses to a former message. There must be a way to map responses to the initial message when there was one. The two functions json-process-client-start and ~json-process-client-start-with-id~ differs in the way they map responses to their corresponding message. The later function is the simplest but requires that the server reads ids from the messages and writes the ids back in its responses. The former function let the API user implement the mapping.

There are three other public methods in the API:

  • json-process-client-stop terminates the TCP connection and the
  • server.
  • json-process-client-process-live-p returns non-nil if the server
  • is still listening.
  • json-process-client-send sends a message to the server and
  • executes a given callback upon reception.


See COPYING. Copyright (c) 2019 Nicolas Petton and Damien Cassou.