Unhelpful error message when providing a non-existent output directory

JSON Schema for Humans

Quickly generate a beautiful static HTML or Markdown page documenting a JSON schema

Features

Support for JSON Schema Draft-07
Since the result is static, it is easier to host and faster to load
HTML and Markdown output support
Different templates to choose from. More details: HTML version - Markdown version
Anchor links, allow to send a user to a specific section of the documentation
Support for references (even circular!)

Installation

pip install json-schema-for-humans

Usage

Options for generation of the doc are documented using the library itself: HTML version - Markdown version

They can be supplied in various ways:

Using a JSON or YAML configuration file with the CLI option --config-file
Using the CLI option --config
Using the ConfigurationOption object from code

More details are available in the appropriate sections below.

From CLI

generate-schema-doc [OPTIONS] SCHEMA_FILES_OR_DIR [RESULT_FILE_OR_DIR]

SCHEMA_FILES_OR_DIR can be:

a path to a single schema file;
a path to a directory, in this case all files with extensions json, yaml, or yml will be used;
a glob pattern (starts from the current working directory); or
a comma-separated list of the above

All schemas provided must be a valid JSON Schema (in JSON or YAML format)

Examples:

my_schema.json
my_folder
my_folder/my_schema.yaml,another_schema.json
**/*.yaml.*

The default value for RESULT_FILE_OR_DIR depends on the context:

the current working directory if more than one schema as been provided as input
schema_doc.html if rendering a single schema as HTML
schema_doc.md if rendering a single schema as Markdown

In a case where more than one schema is provided as input, RESULT_FILE_OR_DIR must be a directory. The output documentation will have the same name as the input schema, but with a different extension (html or md).

Choosing a template

To choose a template on the CLI, use --config template_name=[TEMPLATE_NAME]. For example --config template_name=js (HTML) or --config template_name=md (Markdown). The list of available templates is documented here

CLI options

--config

Supply generation config parameters. The parameters are documented in the JSON schema config_schema.json at the root of the repo or see the generated doc: HTML version - Markdown version.

Each parameter is in the format --config parameter_name=parameter_value. Example: --config expand_buttons=true. The parameter value must be valid JSON.

For flags, you can also omit the value for true or prefix the parameter name with no_ for false. Example: --config expand_buttons or --config no_expand_buttons.

--config-file

Path to a JSON or YAML configuration file respecting the schema config_schema.json.

Example: --config-file jsfh-conf.yaml where jsfh-conf.yaml is in the current directory and contains the following:

description_is_markdown: false
expand_buttons: true
copy_js: false

From code

The following methods are available to import from json_schema_for_humans.generate

Method Name	Schema input	Output	CSS and JS copied?
generate_from_schema	`schema_file` as str or `pathlib.Path`	Rendered doc as a str	No
generate_from_filename	`schema_file_name` as str or `pathlib.Path`	Rendered doc written to the file at path `result_file_name`	Yes
generate_from_file_object	`schema_file` as an open file object (read mode)	Rendered doc written to the file at `result_file`, which must be an open file object (in write mode)	Yes

Notes:

When using file objects, it is assumed that files are opened with encoding "utf-8"
CSS and JS files are copied to the current working directory with names "schema_doc.css" and "schema_doc.min.js" respectively, if necessary
Other parameters of these methods are analogous to the CLI parameters documented above.

The GenerationConfiguration object

To reduce the number of parameters to pass from function to function in the code, there is a GenerationConfiguration object that should be used for providing options.

Example:

from json_schema_for_humans.generate import generate_from_filename
from json_schema_for_humans.generation_configuration import GenerationConfiguration

config = GenerationConfiguration(copy_css=False, expand_buttons=True)

generate_from_filename("my_schema.json", "schema_doc.html", config=config)

# Your doc is now in a file named "schema_doc.html". Next to it, "schema_doc.min.js" was copied, but not "schema_doc.css"
# Your doc will contain a "Expand all" and a "Collapse all" button at the top

Pre-load schemas

generate_from_schema has a loaded_schemas parameter that can be used to pre-load schemas. This must be a dict with the key being the real path of the schema file and the value being the result of loading the schema (with json.load or yaml.safe_load, for example).

This should not be necessary in normal scenarios.

What's supported

See the excellent Understanding JSON Schema to understand what are those checks

The following are supported:

Types
Regular expressions
String length
String format
Numeric types multiples and range
Constant and enumerated values
Required properties
Pattern properties
Default values
Array minItems, maxItems, uniqueItems, items, prefixItems, additionalItems, and contains
Combining schema with oneOf, allOf, anyOf, and not
Examples
Conditional subschemas

These are not supported at the moment (PRs welcome!):

Property names and size
Property dependencies
Media

References

References are supported:

To another part of the schema, e.g. { $ref: "#/definitions/something" }
To a local file, {"$ref": "references.json"}, {"$ref": "references.json#/definitions/something"}, {"$ref": "file:references.json"}, {"$ref": "file:references.json#/definitions/something}
To a URL, {"$ref": "http://example.com/schema.json"}, {"$ref": "http://example.com/schema.json#/definitions/something"}

You can have a description next to a $ref, it will be displayed in priority to the description from the referenced element.

If you have several attributes using the same definition, the definition will only be rendered once. All other usages of the same definition will be replaced with an anchor link to the first render of the definition. This can be turned off using --config no_link_to_reused_ref. See With references in the examples.

Templates

Templates control the style of the generated documentation.

js

This is the default template. It uses Bootstrap along with minimal Javascript to allow for the following:

Properties are in expandable dynamic sections. You can include a button to expand or collapse all. (See doc: HTML version - Markdown version)
Conditional subschemas (anyOf, oneOf, allOf) are in tabbed sections
Anchor links will scroll to, expand, and animate the target section
Long descriptions are collapsed by default

When using this template, you need to include the Javascript file (schema_doc.min.js) that is automatically copied next to the output HTML file (schema_doc.html by default).

js_offline

This schema is identical to the js template, but all CSS and JavaScript resources are bundled so that the generated documentation can be used in an offline setting.

flat

Note: This template is a work in progress

It is sometimes not possible or desirable to include custom Javascript in documentation. This template addresses this issue by removing interactive elements in favor of simpler HTML.

At the moment, this means the whole documentation is generated without any collapsible sections, which may make it hard to understand the schema structure. Contributions are welcomed to improve it!