Question

我希望使用 OCaml 来访问Yahoo Finance API。从本质上讲，它只是一堆HTTP请求来获取雅虎财经的报价。

我应该使用哪个模块？

我希望有异步HTTP请求。

Answer 1

有使用lwt的可能性：

ocsigen有一个非常完整且有点复杂的实现
cohttp稍微简单但缺少一些有用的部分

使用opam安装：

$ opam install ocsigenserver cohttp

例如在一个顶层：

try Topdirs.dir_directory (Sys.getenv "OCAML_TOPLEVEL_PATH") with _ -> ();;
#use "topfind";;
#thread;;
#require "ocsigenserver";;
open Lwt

(* a simple function to access the content of the response *)
let content = function
  | { Ocsigen_http_frame.frame_content = Some v } ->
      Ocsigen_stream.string_of_stream 100000 (Ocsigen_stream.get v)
  | _ -> return ""

(* launch both requests in parallel *)
let t = Lwt_list.map_p Ocsigen_http_client.get_url
  [ "http://ocsigen.org/";
    "http://stackoverflow.com/" ]

(* maps the result through the content function *)
let t2 = t >>= Lwt_list.map_p content

(* launch the event loop *)
let result = Lwt_main.run t2

并使用cohttp：

try Topdirs.dir_directory (Sys.getenv "OCAML_TOPLEVEL_PATH") with _ -> ();;
#use "topfind";;
#require "cohttp.lwt";;
open Lwt

(* a simple function to access the content of the response *)
let content = function
  | Some (_, body) -> Cohttp_lwt_unix.Body.string_of_body body
  | _ -> return ""

(* launch both requests in parallel *)
let t = Lwt_list.map_p Cohttp_lwt_unix.Client.get
  (List.map Uri.of_string
     [ "http://example.org/";
       "http://example2.org/" ])

(* maps the result through the content function *)
let t2 = t >>= Lwt_list.map_p content

(* launch the event loop *)
let v = Lwt_main.run t2

请注意，jane street异步库的cohttp实现也可用

Answer 2

仅供记录，还有ocurl with curl multi API support。

OCaml中Http请求的最佳模块是什么

2 个答案: