Converting a Swagger YAML file to JSON from the co

Question

I'd like to convert a Swagger YAML file to JSON from the command line. The plan is to use this command line during a CI job. I've searched on google and found many solutions, but most of them use Python or Ruby, which I'd prefer not to use. For example: http://www.commandlinefu.com/commands/view/12218/convert-yaml-to-json

I'd like to do this without using Python or Ruby, and I'd also like to be able to control the leading whitespace when formatting the JSON to match exactly the JSON that is output from Swagger's editor.swagger.io editor, when you choose File -> Download JSON

All this means is that I'd like the whitespace padding to be four spaces, like so:

{
    "swagger": "2.0",
    "info": {
        "title": "API TITLE",

I haven't tried the Python method in the link above, but the Ruby method uses two space whitespace padding. Perhaps there is a way to control that, but I don't want to use Ruby or Python in this solution anyway.

I'm sure that there are many "correct" answers to this question. I am looking for the solution that is most elegant with the least number of dependencies. Ideally, a diff of the resulting JSON file against a JSON file generated by the editor.swagger.io should be empty.

Answer 1

swagger-codegen cli interface

As Liel has already pointed out, you can run

swagger-codegen generate -i swagger.yaml -l swagger

Docker

If you use Docker, then I suggest you try swaggerapi/swagger-codegen-cli.

You can generate a json file using docker with the following command:

docker run -v ./docs:/docs swaggerapi/swagger-codegen-cli generate -i /docs/swagger.yaml -l swagger -o /docs

I like to setup a docker-compose.yml to "alias" this command for easy reuse:

version: "2"
services:
  gen-swagger:
    volumes:
      - ./docs:/docs
    image: swaggerapi/swagger-codegen-cli
    command: generate -i /docs/swagger.yaml -l swagger -o /docs

And now I can just run docker-compose run gen-swagger

Answer 2

I think that you are looking for the swagger-codegen functionality:

Running

swagger-codegen generate -i swagger.yaml -l swagger

will out put a swagger.json in the same location.

Update For CI: If you can install it on your build machine- good for you. If you can't - the github page has a link to a docker image with a nodejs server is available (to convert using a curl command as suggested in a different answer).

Answer 3

You can use the online swagger codegen project to do this:

curl -X POST --header "Content-Type: application/json" --header "Accept: application/json" -d "{
  \"spec\": {}
}" "https://generator.swagger.io/api/gen/clients/swagger-yaml"

Put the value of your swagger definition in the spec object. You'll get a link to download the converted & validated spec, in yaml format.

For options, take a look here:

http://generator.swagger.io/

Answer 4

Using yamljs:

yaml2json swagger.yaml -p -i4

The output from this command diff'd against the JSON output from editor.swagger.io produces an empty diff.

This is indeed what I'm looking for, but it brings in a huge dependency (node). I'm hoping for something even lighter, yet equally as elegant as this.

Answer 5

For version swagger-codegen 3.0.4

Use

swagger-codegen generate -i my_yaml.yaml -l openapi

to get a .json.