OpenAPI JSON Schema Generator

Auto generate a client sdk from your openapi 3.0.0-3.1.0 document using Openapi JSON Schema Generator. This project is a code generator that focuses on supporting all openapi and json schema features.

Overview

OpenAPI JSON Schema Generator allows auto-generation of API client libraries (SDK generation) given an OpenAPI document (3.0.0-3.1.0* are supported). This project focuses on making the output 100% compliant with openapi + JSON schema specs. The goal is to fully support everything defined in openapi + the included JSON schema specs so developers can use all of those features.

Currently, the following languages/frameworks are supported:

Reasons To Use the Generators

• Openapi spec support for v3.0.0-3.1.0
  • thorough tests run in CI using json schema test suite, see 3_0_0 and 3_1_0 sample clients
• Static analysis:
  • Python: mypy run in CI against python petstore sample
  • Java: checker framework run w/ NullnessChecker, ensures no null pointer exceptions
• Format support for: int32, int64, float, double, binary, date, datetime, uuid
• Invalid (in language) property names supported like from, 1var, hi-there etc in
  • schema property names
  • endpoint parameter names
• Openapi document inline schemas supported at any depth in any location
• Generated Code: Class + method inputs are typed
• Generated Code: Static type checking done in static languages using builder inputs and class property access
• Generated Code: run-time type checking done in all generators (a payload can be validated against n schemas)
• Generated Code re-use built in from the ground up
  • components/schemas/headers etc are generated as separate classes and imported when used via $ref
• Payload values are not coerced when validated, so a date/date-time value can pass other validations that describe the payload only as type string
• String transmission of numbers supported with type: string, format: number, value can be accessed as a Decimal with schemas.as_decimal(inst)
• Multiple content types supported for request and response bodies
• Endpoint response always also includes the raw response
• Interfaces kept consistent across generated languages

Join Our Community

We use a Discord server as a place to ask questions and help each other. It offers functionality very similar to Slack. You can join us here: https://discord.gg/mHB8WEQuYQ

Can I build here?

Yes; contributions are welcome! Submit a PR if you want to add a new server scaffold, client sdk, or documentation generator in any language.

Table of contents

• OpenAPI JSON Schema Generator
• Overview
• Table of Contents
• Installation
  • Compatibility
  • Build Projects
  • Docker
• Getting Started
• Usage
  • Customization
  • Workflow Integration
  • License Information
• Companies/Projects using OpenAPI JSON Schema Generator
• About Us
  • History of OpenAPI JSON Schema Generator
• License

Installation

Compatibility

The OpenAPI Specification has undergone 3 revisions since initial creation in 2010. The openapi-json-schema-generator project has the following compatibilities with the OpenAPI Specification:

OpenAPI v3.1.0 support

OpenAPI v3.1.0 specification support includes these new/updated 2020-12 json schema keywords:

1. const: only string values are working because of bugs in swagger parser
2. contains
3. dependentRequired
4. dependentSchemas
5. else
6. if
7. maxContains
8. minContains
9. patternProperties
10. prefixItems
11. propertyNames
12. then
13. type (array of types supported in addition to one non-array value)
14. unevaluatedItems
15. unevaluatedProperties

Note: these features can also be seen in the generator documentation schema features

Build Projects

To build from source, you need the following installed and available in your $PATH:

• Java 11

• Apache Maven 3.9.3 or greater

After cloning the project, you can build it from source with this command:

mvn clean install

The default build contains minimal static analysis (via CheckStyle). To run your build with PMD and Spotbugs, use the static-analysis profile:

mvn -Pstatic-analysis clean install

Docker

Public Pre-built Docker images

• https://hub.docker.com/r/openapijsonschematools/openapi-json-schema-generator-cli/ (official CLI)

OpenAPI JSON Schema Generator CLI Docker Image

The docker image acts as a standalone executable. It can be used as an alternative to installing via homebrew, or for developers who are unable to install Java or upgrade the installed version.

To generate code with this image, you'll need to mount a local location as a volume.

Example:

docker run --rm -v "${PWD}:/local" openapijsonschematools/openapi-json-schema-generator-cli generate \
    -i https://raw.githubusercontent.com/openapi-json-schema-tools/openapi-json-schema-generator/master/src/test/resources/3_0/petstore.yaml \
    -g python \
    -o /local/out/python

The generated code will be located under ./out/python in the current directory.

Development in docker

You can use bin/run-in-docker.sh to do all development. This script maps your local repository to /gen in the docker container. It also maps ~/.m2/repository to the appropriate container location.

To execute mvn package:

git clone https://github.com/openapi-json-schema-tools/openapi-json-schema-generator
cd openapi-json-schema-generator
./bin/run-in-docker.sh mvn package

Build artifacts are now accessible in your working directory.

Once built, run-in-docker.sh will act as an executable for openapi-json-schema-generator-cli. To generate code, you'll need to output to a directory under /gen (e.g. /gen/out). For example:

./bin/run-in-docker.sh help # Executes 'help' command for openapi-json-schema-generator-cli
./bin/run-in-docker.sh list # Executes 'list' command for openapi-json-schema-generator-cli
./bin/run-in-docker.sh /gen/bin/python-petstore.sh  # Builds the Python client
./bin/run-in-docker.sh generate -i src/test/resources/3_0/petstore.yaml \
    -g go -o /gen/out/python-petstore -p packageName=petstore_api # generates python client, outputs locally to ./out/python-petstore

Troubleshooting

If an error like this occurs, just execute the mvn clean install -U command:

org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.19.1:test (default-test) on project openapi-json-schema-generator: A type incompatibility occurred while executing org.apache.maven.plugins:maven-surefire-plugin:2.19.1:test: java.lang.ExceptionInInitializerError cannot be cast to java.io.IOException

./run-in-docker.sh mvn clean install -U

Failed to execute goal org.fortasoft:gradle-maven-plugin:1.0.8:invoke (default) on project openapi-json-schema-generator-gradle-plugin-mvn-wrapper: org.gradle.tooling.BuildException: Could not execute build using Gradle distribution 'https://services.gradle.org/distributions/gradle-4.7-bin.zip'

Right now: no solution for this one :|

Getting Started

To generate a python client for petstore.yaml, please run the following

git clone https://github.com/openapi-json-schema-tools/openapi-json-schema-generator
cd openapi-json-schema-generator
mvn clean package
java -jar target/openapi-json-schema-generator-cli.jar generate \
   -i https://raw.githubusercontent.com/openapi-json-schema-tools/openapi-json-schema-generator/master/src/test/resources/3_0/petstore.yaml \
   -g python \
   -o /var/tmp/python_api_client

(if you're on Windows, replace the last command with java -jar target\openapi-json-schema-generator-cli.jar generate -i https://raw.githubusercontent.com/openapi-json-schema-tools/openapi-json-schema-generator/master/src/test/resources/3_0/petstore.yaml -g python -o c:\temp\python_api_client)

To get a list of general options available, please run java -jar target/openapi-json-schema-generator-cli.jar help generate

To get a list of python specified options (which can be passed to the generator with a config file via the -c option), please run java -jar target/openapi-json-schema-generator-cli.jar config-help -g python

Usage

To generate a sample client library

You can build a client against the Petstore API as follows:

./bin/generate-samples.sh ./bin/generate_samples_configs/python.yaml

(On Windows, please install GIT Bash for Windows to run the command above)

This script will run the generator with this command:

java -jar target/openapi-json-schema-generator-cli.jar generate \
  -i https://raw.githubusercontent.com/openapijsonschematools/openapi-json-schema-generator/master/src/test/resources/3_0/petstore.yaml \
  -g python \
  -t src/main/resources/python \
  --additional-properties packageName=petstore_api \
  -o samples/client/petstore/python

with a number of options. The python options are documented here.

You can also get the options with the help generate command (below only shows partial results):

NAME
        openapi-json-schema-generator-cli generate - Generate code with the specified
        generator.

SYNOPSIS
        openapi-json-schema-generator-cli generate
                [(-a <authorization> | --auth <authorization>)]
                [--api-name-suffix <api name suffix>] [--api-package <api package>]
                [--artifact-id <artifact id>] [--artifact-version <artifact version>]
                [(-c <configuration file> | --config <configuration file>)] [--dry-run]
                [(-e <templating engine> | --engine <templating engine>)]
                [--enable-post-process-file]
                [(-g <generator name> | --generator-name <generator name>)]
                [--git-host <git host>] [--git-repo-id <git repo id>]
                [--git-user-id <git user id>] [--global-property <global properties>...]
                [--group-id <group id>] [--hide-generation-timestamp]
                [--http-user-agent <http user agent>]
                [(-i <spec file> | --input-spec <spec file>)]
                [--ignore-file-override <ignore file override location>]
                [--ints-allowed-for-float-double-formats]
                [--invoker-package <invoker package>] [--minimal-update]
                [--model-name-prefix <model name prefix>]
                [--model-name-suffix <model name suffix>]
                [(-o <output directory> | --output <output directory>)] [(-p <additional properties> | --additional-properties <additional properties>)...]
                [--package-name <package name>] [--release-note <release note>]
                [--remove-enum-value-prefix] [--remove-operation-id-prefix]
                [(-s | --skip-overwrite)] [--skip-operation-example]
                [--skip-validate-spec] [--strict-spec <true/false strict behavior>]
                [(-t <template directory> | --template-dir <template directory>)]
                [(-v | --verbose)]