Not Supported

Ocelot does not support…

  • Chunked Encoding - Ocelot will always get the body size and return Content-Length header. Sorry if this doesn’t work for your use case!
  • Fowarding a host header - The host header that you send to Ocelot will not be forwarded to the downstream service. Obviously this would break everything :(
  • Swagger - I have looked multiple times at building swagger.json out of the Ocelot ocelot.json but it doesnt fit into the vision

I have for Ocelot. If you would like to have Swagger in Ocelot then you must roll your own swagger.json and do the following in your Startup.cs or Program.cs. The code sample below registers a piece of middleware that loads your hand rolled swagger.json and returns it on /swagger/v1/swagger.json. It then registers the SwaggerUI middleware from Swashbuckle.AspNetCore

app.Map("/swagger/v1/swagger.json", b =>
{
    b.Run(async x => {
        var json = File.ReadAllText("swagger.json");
        await x.Response.WriteAsync(json);
    });
});
app.UseSwaggerUI(c =>
{
    c.SwaggerEndpoint("/swagger/v1/swagger.json", "Ocelot");
});

app.UseOcelot().Wait();

The main reasons why I don’t think Swagger makes sense is we already hand roll our definition in ocelot.json. If we want people developing against Ocelot to be able to see what routes are available then either share the ocelot.json with them (This should be as easy as granting access to a repo etc) or use the Ocelot administration API so that they can query Ocelot for the configuration.

In addition to this many people will configure Ocelot to proxy all traffic like /products/{everything} to there product service and you would not be describing what is actually available if you parsed this and turned it into a Swagger path. Also Ocelot has no concept of the models that the downstream services can return and linking to the above problem the same endpoint can return multiple models. Ocelot does not know what models might be used in POST, PUT etc so it all gets a bit messy and finally the Swashbuckle package doesnt reload swagger.json if it changes during runtime. Ocelot’s configuration can change during runtime so the Swagger and Ocelot information would not match. Unless I rolled my own Swagger implementation.

If the user wants something to easily test against the Ocelot API then I suggest using Postman as a simple way to do this. It might even be possible to write something that maps ocelot.json to the postman json spec. However I don’t intend to do this.