dollar-ref

Introduction

If you have JSON/YAML configuration files that have grown huge and you would like to split them for better organization, then this package is definitely for you.

dollar-ref is both a command line tool and a Python library module that provides functionality to deal with JSON references.

For instance, if you are developing an API and maintain OpenAPI definition for it, the definition file may grow over time. At some point you might want to split different parts of the definition into separate files and reference them in the root document using JSON References. At that stage, you can use dollar-ref to merge them back into one single file for further usage, like feeding into API validators.

Installation

dollar-ref is a Python package, so the installation process is as easy as a single pip call:

$ pip install dollar-ref

Usage

As already mentioned, dollar-ref comes both with a library module and a command line tool. In the following sections we will discuss both in detail.

Command Line Tool

The command line tool is called dref. The name is both short for dollar-ref and dereference. To get started, just start but looking at the help message of the tool by running:

$ dref --help

As you may see from the help message, dref requires two positional arguments:

• input_uri - the root document URI containing JSON/YAML data. Any external references in this file will be recursively resolved and replaced with the contents of the referenced document. The URI may be an absolute or relative file path.
• output_file - the filename to write the resolved/merged output to. Depending on the provided filename extension, the output format will be different. When the extension is yaml or yml, the output format will be YAML, otherwise JSON:

$ dref input.json output.yaml

dref will print appropriate error messages if it detects any problems with provided information or data, otherwise a success message is shown. In case if you need to see more verbose information (e.g. for reporting a bug), you may append -v flag to the command invocation:

$ dref input.yaml output.json -v

Library Module

The dollar_ref module comes with the dollar-ref package and can be imported and used by other Python programs to deal with JSON references.

The main product of the dollar_ref module is the pluck function. You provide is with a Python dict and a key path in form of a sequence of strings. The return value is the object at the specified path with all the references inside it resolved.

Example Code

from dollar_ref import pluck


root_doc = {
    'we-do-not': 'need-this',
    'sub-document': {
        'target': {
            'awesome': 'data',
            'we': {
                '$ref': '#/we-do-not'
            }
        }
    }
}


target = pluck(root_doc, 'sub-document', 'target')

assert target == {
    'awesome': 'data',
    'we': 'need-this'
}

How to Contribute

If you would like to contribute to dollar-ref, then you are more than welcome!

You may start by looking at open issues, especially the ones labeled help wanted and good first issue. Feel free to join discussions in the comments and share any related ideas.

If you have identified any problems in dollar-ref that does not have any open issue associated, you should definitely create one, providing any relevant information that would help to fix it.

Finally, whenever you have a fix (doc, code, whatever!) do not hesitate to create a Pull Request!

License

See LICENSE.