OpenAPI2JsonSchema 2.0.0

OpenApi2JsonSchema

A library to create Json-Schemas from OpenAPI-specifications giving the possibility to include FluentValdiation rules in JsonSchemas.

Getting Started

Create OpenAPI-specifiation

First you will need to create an OpenAPI-specification, which you'll be translating to Json-Schema later.

Example

If you use Swashbuckle this might look something like this:

Register services in Program.cs

builder.Services.AddSwaggerGen(c =>
      {
        c.SwaggerDoc("v1", new OpenApiInfo {Title = "MyApplication", Version = "v1"});
        var xmlFile = $"{Assembly.GetExecutingAssembly().GetName().Name}.xml";
        var xmlPath = Path.Combine(AppContext.BaseDirectory, xmlFile);
        c.IncludeXmlComments(xmlPath);
        c.AddFluentValidationRules();
      });

In this example, an OpenAPI-specification is created. In order to keep Data Annotations out of its model, this examples uses FluentValidationRules, that can be added easily using the last line in the example above from Swashbuckle.FluentValidation.

Enable middleware in Program.cs

app.UseSwagger();

if (app.Environment.IsDevelopment())
{
    app.UseSwaggerUI(c => { c.SwaggerEndpoint("/swagger/v1/swagger.json", "MyApplication v1"); });
}

Installation

Install the library using NuGet-Package Manager:

Install-Package OpenAPI2JsonSchema

Dependency Injection

First import the following Package in Startup.cs:

using OpenApi2JsonSchema.DependencyInjection;
using OpenApi2JsonSchema.Configuration;

Now, in order to be able to use the library, simply add the following line to the ConfigureServices()-method in Startup.cs:

services.AddJsonSchemaGenerator(new JsonSchemaGeneratorConfiguration
            {
                OpenApiFileDownloadPath = "swagger.json",
                OpenApiUrl = "http://localhost:61306/swagger/v1/swagger.json"
            });

The JsonSchemaGeneratorConfiguration allows to specify the following optional properties:

• OpenApiFileDownloadPath → Path where to save the downloaded file (ignored if caching is disabled)
• OpenApiUrl → URL to the OpenAPI-specification
• CachingDisabled → Specify wheter or not caching should be disabled. Default is false.

Note that if you don't specify an URL for the OpenAPI-specification here in ConfigureServices()-method, you will need to specify it whenever you use the JsonSchemaGenerator-instance.

Usage

You can generate a JsonSchema for any type using:

var schema = JsonSchemaGenerator.GetSchemaWithOpenApi<T>("<url-to-openapi-file>");

If not specified in Startup.cs, just replace <url-to-openapi-file> with the URL that points to your OpenAPI-JSON-file, otherwise pass no parameter.

Configuration

Delete OpenAPI-file on Startup

Since the library downloads the specified OpenAPI-file and caches it for further usage, you can optionally delete the downloaded file on Startup by adding the following lines to the Configure()-method in Startup.cs:

app.UseOpenApi2JsonSchemaGenerator(new JsonSchemaGeneratorConfiguration
{
    OpenApiFileDownloadPath = "swagger.json"
});

Note that the if you did not set the DownloadPath to the OpenAPI-file in ConfigureServices()-method, you don't need to pass a parameter.