Request URI is wrong when using API Gateway in some common cases

[iliana]

Without using a custom domain mapping in API Gateway, the URI looks like:

https://1234567890.execute-api.us-east-1.amazonaws.com/prod/a/b/c

where prod is the deployment stage. Currently lambda_http doesn't include the stage in the URL (but it looks like it's available in the event).

I tested it and it works fine with an empty custom domain mapping, but a non-empty custom domain mapping might also not work; I didn't test that, and I'm not sure if the domain mapping is present in the event.

(I'm running into this because I'm writing request validation for a Twilio endpoint, which involves concatenating key/value pairs onto the URL Twilio knows. So I'm relying on Request::uri().to_string().)

[bernardobelchior]

This is due to this portion of code:

let mut builder = HttpRequest::builder();
        builder.method(http_method);
        builder.uri({
            format!(
                "{}://{}{}",
                headers
                    .get("X-Forwarded-Proto")
                    .map(|val| val.to_str().unwrap_or_else(|_| "https"))
                    .unwrap_or_else(|| "https"),
                headers
                    .get(HOST)
                    .map(|val| val.to_str().unwrap_or_default())
                    .unwrap_or_default(),
                path
            )
        });

You can see that not only are stage variables not available, but the query string is also being ignored.
I have run into the same problems, as I am using Uri::parse to obtain values from the query string.

[saks]

Hey @bernardobelchior! I'm not 100% sure that this exactly what you need, but I'd suggest to take a look at RequestExt trait. It provides few methods for accessing url and path params.

[bernardobelchior]

Thanks, @saks! That was the solution!
Nevertheless, this still seems like a bug

[softprops]

I can take a closer look at this

[GREsau]

I'm having a similar issue with the stage missing from the path, which breaks absolute paths from the webserver e.g. in the Location header of 302 responses.

I'm able to arbitrarily modify the incoming request, so I could just get the stage from the request context and prepend it to the path - but I think that would then break custom domain mappings, as they don't include the stage in the path.

I assume the most reliable way of getting the original "real" path (i.e. what the end-user would have in their browser's address bar) would be to use the request context's path property, but that's not included in the RequestContext::ApiGateway struct - in fact, it's explicitly commented out, any idea why?

aws-lambda-rust-runtime/lambda-http/src/request.rs

Line 63 in 0ac259a

//pub path: String,

[maxcountryman]

I assume the most reliable way of getting the original "real" path (i.e. what the end-user would have in their browser's address bar) would be to use the request context's path property, but that's not included in the RequestContext::ApiGateway struct - in fact, it's explicitly commented out, any idea why?

aws-lambda-rust-runtime/lambda-http/src/request.rs

Line 63 in 0ac259a

//pub path: String,

I'm also curious about this--when I first encountered this issue my instinct was to use the path, but unfortunately it's not available, as you point out.

[duaneking]

There is no legitimate reason for this path not to be included and correct.

[duaneking]

@softprops May I ask the status of this? I normally don't like pinging people directly but you stated above you were working on this.. and this is core to the typical usage of rust and lambda.