this repo has no description
x-ocaml: auto-discover worker URL from findlib_index compiler field
When a findlib_index.json contains a "compiler" field with version
and content_hash, x-ocaml now constructs the worker URL automatically.
This means .mld files only need @x-ocaml.universe — no separate
@x-ocaml.worker tag is required. The explicit x-ocaml-worker meta
tag still takes priority when present.
Uses a synchronous XHR pre-fetch of the findlib_index.json (~200 bytes)
before creating the worker, with browser JSON.parse for extraction.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+68
-11
+68
-11
src/x_ocaml.ml
+68
-11
src/x_ocaml.ml
···
13
13
| None -> "builtin"
14
14
| Some name -> Jstr.to_string name
15
15
16
-
let worker_url =
17
-
match current_attribute "src-worker" with
18
-
| None ->
19
-
if backend_name = "builtin" then
20
-
failwith "x-ocaml script missing src-worker attribute"
21
-
else ""
22
-
| Some url -> Jstr.to_string url
23
-
24
16
let read_meta name =
25
17
let doc = Brr.Document.to_jv Brr.G.document in
26
18
let selector = Jstr.of_string ("meta[name=\"" ^ name ^ "\"]") in
···
39
31
(List.map String.trim (String.split_on_char ',' s)) in
40
32
if pkgs = [] then None else Some pkgs
41
33
42
-
let findlib_index =
34
+
let resolve_url relative =
35
+
let url_ctor = Jv.get Jv.global "URL" in
36
+
let loc = Jv.get (Jv.get Jv.global "window") "location" in
37
+
let href = Jv.to_string (Jv.get loc "href") in
38
+
let url_obj = Jv.new' url_ctor [| Jv.of_string relative; Jv.of_string href |] in
39
+
Jv.to_string (Jv.get url_obj "href")
40
+
41
+
let findlib_index_url =
43
42
match read_meta "x-ocaml-universe" with
44
43
| None -> None
45
44
| Some base ->
46
45
let base = if String.length base > 0 && base.[String.length base - 1] = '/'
47
46
then base else base ^ "/" in
48
-
Some (base ^ "findlib_index.json")
47
+
Some (resolve_url (base ^ "findlib_index.json"))
48
+
49
+
(** Synchronous XHR fetch of a small text resource.
50
+
Used only for the findlib_index.json pre-fetch (~200 bytes)
51
+
to extract compiler info before creating the worker. *)
52
+
let sync_fetch_text url =
53
+
let xhr = Jv.new' (Jv.get Jv.global "XMLHttpRequest") [||] in
54
+
Jv.call xhr "open" [| Jv.of_string "GET"; Jv.of_string url; Jv.of_bool false |] |> ignore;
55
+
(try Jv.call xhr "send" [||] |> ignore with _ -> ());
56
+
let status = Jv.to_int (Jv.get xhr "status") in
57
+
if status = 200 then Some (Jv.to_string (Jv.get xhr "responseText"))
58
+
else None
59
+
60
+
(** Extract compiler version and content_hash from a findlib_index.json.
61
+
Uses browser JSON.parse — no OCaml JSON library needed. *)
62
+
let compiler_from_findlib_index =
63
+
match findlib_index_url with
64
+
| None -> None
65
+
| Some url ->
66
+
match sync_fetch_text url with
67
+
| None -> None
68
+
| Some text ->
69
+
(try
70
+
let json = Jv.call (Jv.get Jv.global "JSON") "parse" [| Jv.of_string text |] in
71
+
let compiler = Jv.get json "compiler" in
72
+
if Jv.is_none compiler || Jv.is_undefined compiler then None
73
+
else
74
+
let version = Jv.to_string (Jv.get compiler "version") in
75
+
let content_hash = Jv.to_string (Jv.get compiler "content_hash") in
76
+
Some (version, content_hash)
77
+
with _ -> None)
78
+
79
+
let worker_url =
80
+
(* Priority: 1) explicit x-ocaml-worker meta tag,
81
+
2) compiler field from findlib_index.json,
82
+
3) src-worker script attribute *)
83
+
match read_meta "x-ocaml-worker" with
84
+
| Some url -> url
85
+
| None ->
86
+
match compiler_from_findlib_index with
87
+
| Some (version, content_hash) ->
88
+
(* Construct worker URL relative to the findlib_index's directory.
89
+
findlib_index is at e.g. .../p/yojson/3.0.0/findlib_index.json
90
+
We need .../compiler/<ver>/<hash>/worker.js
91
+
Relative from the findlib_index dir: ../../../compiler/... *)
92
+
let fi_url = Option.get findlib_index_url in
93
+
let base_dir = match String.rindex_opt fi_url '/' with
94
+
| Some i -> String.sub fi_url 0 (i + 1)
95
+
| None -> fi_url
96
+
in
97
+
base_dir ^ "../../../compiler/" ^ version ^ "/" ^ content_hash ^ "/worker.js"
98
+
| None ->
99
+
match current_attribute "src-worker" with
100
+
| None ->
101
+
if backend_name = "builtin" then
102
+
failwith "x-ocaml script missing src-worker attribute"
103
+
else ""
104
+
| Some url -> Jstr.to_string url
49
105
50
-
let backend = Backend.make ~backend:backend_name ?extra_load ?findlib_requires ?findlib_index worker_url
106
+
let backend = Backend.make ~backend:backend_name ?extra_load ?findlib_requires
107
+
?findlib_index:findlib_index_url worker_url
51
108
52
109
let format_config =
53
110
match current_attribute "x-ocamlformat" with