[Caml-list] Using Uri with Google Distance Matrix API

[O Frolovs <ollie.frolovs.2012@my.bristol.ac.uk>]

Hello

I'm learning OCaml and currently trying to use it for my project at uni.

Specifically, i’m trying to use Uri [1] to create a Google Distance
Matrix request and i find it a bit awkward since the API uses pipe
character "|" for separating parameter values but Uri uses commas ","
and i could not find a way to override it:

utop # open Core.Std;;
utop # #require "uri";;

utop # let x = Uri.of_string "http://www.github.com/";;
val x : Uri.t = <abstr>

utop # let y = Uri.add_query_param x ("origins", ["Bristol";
"Cambridge"; "Plymouth"; "London"]);;
val y : Uri.t = <abstr>

utop # Uri.to_string y;;
- : string = "http://www.github.com/?origins=Bristol,Cambridge,Plymouth,London"

This is not what the API expects.

I also tried concatenating the origins values before passing it to Uri
but as you can see below, Uri performed character escape on pipe
characters. So besides not looking elegant, it did not work:

utop # String.concat ~sep:"|" ["Bristol"; "Cambridge"; "Plymouth"; "London"];;
- : string = "Bristol|Cambridge|Plymouth|London"

utop # let y = Uri.add_query_param x ("origins", [c]);;
val y : Uri.t = <abstr>

utop # Uri.to_string y;;
- : string = "http://www.github.com/?origins=Bristol%7CCambridge%7CPlymouth%7CLondon"

I am wondering

(a) if there is a way to make Uri do what i want, that is to use pipe
character to separate the origins values.

(b) why Uri does not have an optional ~sep parameter, like Jane
Street's Core.String.concat does?

Help?!

-- Ollie

[1] http://www.cl.cam.ac.uk/projects/ocamllabs/pkg/uri/1.3.8/index.html
[2] https://developers.google.com/maps/documentation/distancematrix/