How to write custom code to convert parameter?

[DaleyKD]

Expected Behavior / New Feature

Is it possible to execute some kind of class or code to do some logic to tweak an Upstream parameter so that it is different for a Downstream parameter? For example, someone consuming my API may call in to the gateway with an accountID, but my downstream path may actually need to use an accountName. The code would hook into my database service to resolve the ID to the name, and then that could be used to route for the downstream.

        {
            "DownstreamPathTemplate": "/{accountName}/api/{everything}",
            "DownstreamScheme": "http",
            "ServiceName": "my-test-service",
            "UpstreamPathTemplate": "/{accountID}/api/{everything}",
            "UpstreamHttpMethod": [],
            "AuthenticationOptions": {
                "AuthenticationProviderKey": "IdentityApiKey",
                "AllowedScopes": []
            }
        }

[DaleyKD]

Bump?

[ks1990cn]

Hi @DaleyKD!
I think it will be really wrong approach to introduce database call in API Gateway to map parameters. We should optimize our gateway so we can have approx realtime communication between upstream and downstream. Introducing database call will adversely impact performance and when system increases with users it will be too slow and cost unnecessary for hitting DB everytime.

What are your thoughts on it? @DaleyKD @raman-m

[raman-m]

@DaleyKD Kyle,
Are you still with Ocelot?

Ocelot doesn't transforms URL placeholder values. Path Placeholder is substituted as-is. so there is no conversions.
If you have a time to research Ocelot, use these features:

• Delegating Handlers
• Inject PreQueryStringBuilderMiddleware of the Middleware Injection

I guess, the 2nd option is the best

[DaleyKD]

Hey @raman-m ,
Thanks for the reply!
We still use Ocelot for a project at work that is currently sleeping. We've had to move over to other priorities, and hope to get back to this project next year.

We haven't touched the code in almost 2 years. It's still on .NET 5 and using Ocelot v17.0.0.

[raman-m]

Yeah, it is time to migrate to .NET 7 (and .NET 8 soon) and latest Ocelot version.

[DaleyKD]

Yup! Just not sure when we'll have time.

[RaynaldM]

migrate to 6, 7 or 8 is very simple.
don't increase your technical debt!

[raman-m]

Release: 21.0.0
NuGet: 21.0.0

It should be easy to migrate because Ocelot NuGet packs support multi-planforms: net6.0 + net7.0 + net8.0