Swagger-codegen: Add a "Validate" option to Swagger Codegen

[wing328]

Description

Currently Swagger Codegen supports the following options:

swagger-codegen|master ⇒ swagger-codegen help
usage: swagger-codegen-cli <command> [<args>]

The most commonly used swagger-codegen-cli commands are:
    config-help   Config help for chosen lang
    generate      Generate code with chosen lang
    help          Display help information
    langs         Shows available langs
    meta          MetaGenerator. Generator for creating a new template set and configuration for Codegen.  The output will be based on the language you specify, and includes default templates to include.
    version       Show version information

See 'swagger-codegen-cli help <command>' for more information on a specific
command.

We want to add another option "validate" to validate the Swagger/OpenAPI spec and show human-readable result.

Ref: https://github.com/swagger-api/swagger-parser/issues/46#issuecomment-150605901

Swagger-codegen version

Latest master

Suggest a Fix

If anyone from the community wants to contribute this enhancement, please let us know. https://github.com/swagger-api/swagger-parser/issues/46#issuecomment-150605901 is a good starting point.

[taxpon]

@wing328 I am interested in working on this issue. Please wait for while before sending PR.

[wing328]

@taxpon thanks for the PR 👍

@kenjones-cisco please pull the latest master to give it a try.

[kenjones-cisco]

@wing328 The validate option works as expected.
There are some other issues in master currently. But they are unrelated to this change.

Great job! @taxpon Thanks!

[wing328]

There are some other issues in master currently.

Can you please elaborate on that?

[kenjones-cisco]

I am making note as I go through all the latest changes.

[kkms]

I see this issue in io.swagger.codegen.v3 version 3.0.20, Generated API class don't have @Validated