Allow a form of /page/:id: à la express

[ColinFay]

Something that would allow to write :

ui <- function(request){
  brochure(
    page(
      href = "/profile/:id:",
      ui = tagList(
        h1("This is my first page"),
        h2(paste("Hello", {:id:}) 
      )
    )
  )
}

[ColinFay]

Idea:

• Add a page as /this/{id}/
• is turned in the name to /this/([^/])/
• is extracted by handlers and UI and server

How does express.JS does that under the hood? I feel like I'm missing something.

Basically the idea is to define profile/{id} inside the page() function, then have profile/colin and profile/matilda both root to that page, and the id is available to the ui & server.

[abelborges]

Hey, Colin! Great work here with this module.

On this issue, let me know what you think about the direction below.

This first part would be called once, as part of a "compilation" step:

compile_route <- function(route) {
  stopifnot(is.character(route) && length(route) == 1)

  params <- stringr::str_match_all(route, "\\{(\\w+)\\}")[[1]][,2]
  extractor <- stringr::str_replace_all(route, "\\{\\w+\\}", "([^//]+)")[[1]]

  list(
    template = route,
    parse = function(path) {
      parsed <- stringr::str_match_all(path, extractor)[[1]]
      if (!nrow(parsed)) return(NULL)
      setNames(parsed[1,-1], params)
    }
  )
}

route <- compile_route("/prefix/{arg1}/{arg2}-argsuffix/suffix")

And then in request time:

# NULL
route$parse("/blabla")
route$parse("/prefix")
route$parse("/prefix/1")
route$parse("/prefix/1/2-argsuffix")
route$parse("/prefix/1/almost/there-argsuffix/suffix")

# named vectors
route$parse("/prefix/1/2-argsuffix/suffix")
route$parse("/prefix/first/second with spaces-argsuffix/suffix")

Some timings, just for reference (8GB RAM, 2.7 GHz i7 CPU):

Unit: milliseconds
                                                             expr     min        lq
 route$parse("/prefix/first/second with spaces-argsuffix/suffix") 0.01958 0.0199325
        mean    median        uq      max neval
 0.020986522 0.0200675 0.0202895 0.117091  1000

Maybe this is missing some more validation in order to become user facing. I didn't test more weird inputs

[ColinFay]

Hey @abelborges,

Thanks a lot for this! Awesome.

I love the approach of returning a list with a function and all, smart.
Let me take a closer look into that and see how it could work inside brochure 🤔

[ColinFay]

Ok back to this.

Internally, express uses https://www.npmjs.com/package/path-to-regexp, so maybe we should have something in the same spirit, that turns path into regex, then does a grepl on the route table 🤔