Why is the last slash removed from the downstream URL in versions 23.x.x?

[willsbctm]

The / is not being propagated downstream.

Expected Behavior

Using version Ocelot 22.x.x with the following setup:

{
    "Routes": [
        {
            "DownstreamScheme": "http",
            "UpstreamPathTemplate": "/api/v1/endpoint-slash",
            "UpstreamHttpMethod": [
                "Get"
            ],
            "DownstreamPathTemplate": "/v1/endpoint-slash/",
            "AuthenticationOptions": {
                "AuthenticationProviderKey": "Jwt-IDM"
            },
            "DownstreamHostAndPorts": [
                {
                    "Host": "localhost",
                    "Port": 8885
                }
            ]
        }
    ]
}

We got the slash at the end of the downtream applied path:

Actual Behavior

Using version Ocelot 23.x.x with the following setup:

{
    "Routes": [
        {
            "DownstreamScheme": "http",
            "UpstreamPathTemplate": "/api/v1/endpoint-slash",
            "UpstreamHttpMethod": [
                "Get"
            ],
            "DownstreamPathTemplate": "/v1/endpoint-slash/",
            "AuthenticationOptions": {
                "AuthenticationProviderKey": "Jwt-IDM"
            },
            "DownstreamHostAndPorts": [
                {
                    "Host": "localhost",
                    "Port": 8885
                }
            ]
        }
    ]
}

We didn't get the slash at the end of the downtream applied path:

Is that a problem or is that an expected behaviour?

Thanks!

[raman-m]

Hello, Will!

That is not a problem at all. It is expected behavior because Ocelot clears up the last slash.
Additionally, Ocelot has many features related to path manipulation and slash workarounds.
Have you read these documents 👉 Routing Empty Placeholders ❔
If you want to keep the last slash, just define a Catch-All route and your slash will be preserved. Also, send URLs to upstream with the slash.

            "UpstreamPathTemplate": "/api/v1/endpoint-slash/{everything}",
            "DownstreamPathTemplate": "/v1/endpoint-slash/{everything}",

or with Catch All route:

            "UpstreamPathTemplate": "/api/{catchAll}",
            "DownstreamPathTemplate": "/{catchAll}",

Hope it helps!

[willsbctm]

Thanks for your answer, @raman-m .

Is there a way to propagate slash without change the UpstreamPathTemplate?

            "UpstreamPathTemplate": "/api/v1/endpoint-slash",
            "DownstreamPathTemplate": "/v1/endpoint-slash/{everything}",

I tried:

{
    "Routes": [
        {
            "DownstreamScheme": "http",
            "UpstreamPathTemplate": "/api/v1/endpoint-slash",
            "UpstreamHttpMethod": [
                "Get"
            ],
            "DownstreamPathTemplate": "/v1/endpoint-slash/{everything}",
            "AuthenticationOptions": {
                "AuthenticationProviderKey": "Jwt-IDM"
            },
            "DownstreamHostAndPorts": [
                {
                    "Host": "localhost",
                    "Port": 8885
                }
            ]
        }
    ]
}

Result:

[raman-m]

Are you fixing a deployed Ocelot app in production?
If you don't want to change current routing paths to upstream in ocelot.json, but you want to change or tune your downstream paths on the fly then you have 2 options:

• Develop custom Delegating Handler which will transform a downstream URL to acceptable value.
• Override PreQueryStringBuilderMiddleware and attach your custom middleware to process downstream URLs 👉 Check it out how: Middleware Injection

P.S. I'm just curious... Why do you waste your time with this last slash? Is downstream service failing without the slash and producing errors? Really wonder...

[willsbctm]

That's because we have an old app that redirects requests that don't include a trailing slash (to an url with slash).
This app is our downstream.

When the frontends call the route without a trailing slash (since the upstream has none), they receive a 307 redirect, which causes them to break

We didn’t encounter this issue in version 22.x.x.

So we downgraded to version 22.x.x.

[raman-m]

Please continue using the version that suits your needs.
Over the past two years, numerous bugs have fixed and new features added to the Routing feature, including Empty Placeholders.
If you or your team decide to migrate to a new/latest Ocelot version, you will need to develop a workaround/patch to address the issue with the old service, as explained here.
Good luck!

[raman-m]

Related topic

• How to utilize Catch All, Empty Placeholders, Priority routing features correctly since v23+? #2136