add httpclient cookbook

data/cookbook/http-misc/00-cohttp.ml

@@ -0,0 +1,53 @@
+---
+packages:
+- name: "lwt"
+  tested_version: "5.7.0"
+  used_libraries:
+  - lwt
+  - lwt.unix
+- name: "lwt_ppx"
+  tested_version: "2.1.0"
+  used_libraries:
+  - lwt_ppx
+- name: "cohttp"
+  tested_version: "5.3.1"
+  used_libraries:
+  - cohttp
+- name: "cohttp-lwt-unix"
+  tested_version: "5.3.0"
+  used_libraries:
+  - cohttp-lwt-unix
+discussion: |
+  - **About `cohttp`:** The `cohttp` provides a client and a server implementation of HTTP(S)
+  - **Reference:** The `cohttp` package is documented on the [ocaml-cohttp page](https://github.com/mirage/ocaml-cohttp).
+---
+
+let url = "https://www.ocaml.org"
+
+(* The `get` function fetch the ressource. The status code is analysed, and if all is ok, return the body of the answer. If not, the reason of the failure *)
+
+let http_get url =
+  let%lwt (resp,body) = Cohttp_lwt_unix.Client.get
+                          (Uri.of_string url) in
+  let code = resp
+             |> Cohttp.Response.status
+             |> Cohttp.Code.code_of_status in
+  if Cohttp.Code.is_success code
+  then
+    let%lwt b = Cohttp_lwt.Body.to_string body in
+    Lwt.return (Ok b)
+  else
+    Lwt.return (Error (Cohttp.Code.reason_phrase_of_code code))
+
+(* Let's call the `http_get` function. *)
+let () =
+  Lwt_main.run @@
+    match%lwt http_get url with
+    | Error str ->
+       Printf.printf "%s:fail\n" url;
+       Printf.printf "Error: %s\n" str;
+       Lwt.return ()
+    | Ok result ->
+       Printf.printf "%s:succed\n" url;
+       print_string result;
+       Lwt.return ()

data/cookbook/tasks.yml

@@ -230,6 +230,8 @@ categories:
       slug: download-file-to-temporary-dir
     - title: Make a Partial Download with HTTP Range Header
       slug: make-partial-download-with-http-range-header
+    - title: Miscellaneous
+      slug: http-misc
   - title: Dealing with HTML
     tasks:
     - title: Render a HTML Template