Mounted routers should require a slash for route location

[blairj09]

On MacOS 10.14.16 with R 3.6.1 and Plumber 0.4.6, mounted routers are inaccessible. Consider the following example:

library(plumber)

root <- plumber$new()

# Mount first
first <- plumber$new()
first$handle("GET", "/echo", function(msg = "") {
  list(msg = paste0("The message is '", msg, "'"))
})
root$mount("first", first)

# Mount second
second <- plumber$new()
second$handle("GET", "/add", function(x, y) {
  as.numeric(x) + as.numeric(y)
})
root$mount("second", second)

root
#> # Plumber router with 0 endpoints, 4 filters, and 2 sub-routers.
#> # Call run() on this object to start the API.
#> ├──[queryString]
#> ├──[postBody]
#> ├──[cookieParser]
#> ├──[sharedSecret]
#> ├──/first
#> │  │ # Plumber router with 1 endpoint, 4 filters, and 0 sub-routers.
#> │  ├──[queryString]
#> │  ├──[postBody]
#> │  ├──[cookieParser]
#> │  ├──[sharedSecret]
#> │  └──/echo (GET)
#> ├──/second
#> │  │ # Plumber router with 1 endpoint, 4 filters, and 0 sub-routers.
#> │  ├──[queryString]
#> │  ├──[postBody]
#> │  ├──[cookieParser]
#> │  ├──[sharedSecret]
#> │  └──/add (GET)

This seems to indicate that echo would be available at /first/echo and add would be available at /second/add. However, when trying to access either of those endpoints, a 404 error is returned:

curl -X GET 'http://localhost:5762/first/echo?msg=hi'
{"error":["404 - Resource Not Found"]}

curl -X GET 'http://localhost:5762/second/add?x=1&y=9'
{"error":["404 - Resource Not Found"]}

[schloerke]

The code below works.

library(plumber)

root <- plumber$new()

# Mount first
first <- plumber$new()
first$handle("GET", "/echo", function(msg = "") {
  list(msg = paste0("The message is '", msg, "'"))
})
root$mount("/first", first)

root$run(port = 7400)

---

Maybe add a starting slash to all endpoints / mounts if it is missing?

[schloerke]

@sravangottipaty Can you phrase your question in a different way? I don't fully understand it. Thank you!

The error above was caused by calling root$mount("first"). When $mount should require that the route starts with a slash (/), ex: root$mount("/first"). I'd like for plumber to produce an error when mounting path does not start with a slash.