1 files changed, 352 insertions, 0 deletions
diff --git a/lib/activitypub/decode.ml b/lib/activitypub/decode.ml
new file mode 100644
index 0000000..4074e68
--- /dev/null
+++ b/lib/activitypub/decode.ml
@@ -0,0 +1,352 @@
+open Containers
+open Common
+
+let decode_string enc vl = D.decode_string enc vl |> Result.map_err D.string_of_error
+
+let id = D.(one_of ["string", string; "id", field "id" string])
+
+let ordered_collection_page obj =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"Expected OrderedCollectionPage (received %s)" "OrderedCollectionPage"
+  and* id = field "id" string
+  and* next = field_opt "next" id
+  and* prev = field_opt "prev" id
+  and* part_of = field_opt "partOf" string
+  and* total_items = field_opt "totalItems" int
+  and* (is_ordered, items) = items obj in
+  succeed ({id; next; prev; part_of; total_items; is_ordered; items}: _ Types.ordered_collection_page)
+
+let ordered_collection obj =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"Expected OrderedCollection (received %s)" "OrderedCollection"
+  and* id = field_opt "id" string
+  and* total_items = field "totalItems" int
+  and* contents =
+    one_of [
+      "items", map (fun v -> `Items v) (items obj);
+      "first", map (fun v -> `First v) (field "first" (ordered_collection_page obj))
+    ] in
+  succeed ({id; total_items; contents}: _ Types.ordered_collection)
+
+let mention =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Mention (received %s)" "Mention"
+  and* href = field "href" string
+  and* name = field "name" string in
+  succeed ({ty=`Mention; href;name} : Types.tag)
+
+let hashtag =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Hashtag (received %s)" "Hashtag"
+  and* href = field "href" string
+  and* name = field "name" string in
+  succeed ({ty=`Hashtag; href;name}: Types.tag)
+
+let tag =
+  let open D in
+  let* ty = field "type" string in
+  match ty with
+  | "Mention" -> mention
+  | "Hashtag" -> hashtag
+  | _ -> fail (Printf.sprintf "unknown tag %s" ty)
+
+let undo obj =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Undo (received %s)" "Undo"
+  and* id = field "id" string
+  and* actor = field "actor" id
+  and* published = field_opt "published" timestamp
+  and* obj = field "object" obj
+  and* raw = value in
+  succeed ({id;published;actor;obj;raw}: _ Types.undo)
+
+let like =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Like (received %s)" "Like"
+  and* id = field "id" string
+  and* actor = field "actor" id
+  and* published = field_opt "published" timestamp
+  and* obj = field "object" id
+  and* raw = value in
+  succeed ({id; actor; published; obj; raw}: Types.like)
+
+let tombstone =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Tombstone (received %s)" "Tombstone"
+  and* id = field "id" string in
+  succeed id
+
+let delete obj =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Delete (received %s)" "Delete"
+  and* id = field "id" string
+  and* actor = field "actor" id
+  and* published = field_opt "published" timestamp
+  and* obj = field "object" obj
+  and* raw = value in
+  succeed ({id;published;actor;obj;raw}: _ Types.delete)
+
+let block =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Block (received %s)" "Block"
+  and* id = field "id" string
+  and* obj = field "object" string
+  and* published = field_opt "published" timestamp
+  and* actor = field "actor" id
+  and* raw = value in
+  succeed ({id;published;obj;actor;raw}: Types.block)
+
+let accept obj =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Accept (received %s)" "Accept"
+  and* id = field "id" string
+  and* actor = field "actor" id
+  and* published = field_opt "published" timestamp
+  and* obj = field "object" obj
+  and* raw = value in
+  succeed ({id;published;actor;obj;raw}: _ Types.accept)
+
+let public_key =
+  let open D in
+  let* id = field "id" string
+  and* owner = field "owner" string
+  and* pem = field "publicKeyPem" string in
+  succeed ({id;owner;pem}: Types.public_key)
+
+let attachment =
+  let open D in
+  let* media_type = field_opt "mediaType" string
+  and* name = field_opt "name" string
+  and* type_ = field_opt "type" string
+  and* url = field "url" string in
+  succeed ({media_type;name;type_;url}: Types.attachment)
+
+
+let person =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Person (received %s)" "Person"
+  and* id = field "id" string
+  and* name = field_opt "name" string
+  and* url = field_or_default "url" (nullable string) None
+  and* preferred_username = field_opt "preferredUsername" string
+  and* inbox = field "inbox" string
+  and* outbox = field "outbox" string
+  and* summary = field_opt "summary" string
+  and* public_key = field "publicKey" public_key
+  and* manually_approves_followers =
+    field_or_default "manuallyApprovesFollowers" bool false
+  and* discoverable = field_or_default "discoverable" bool false
+  and* followers = field_opt "followers" string
+  and* following = field_opt "following" string
+  and* icon = maybe (at ["icon";"url"] string)
+  and* raw = value in
+  succeed ({
+    id;
+    name;
+    url;
+
+    preferred_username;
+
+    inbox;
+    outbox;
+
+    summary;
+
+    public_key;
+
+    manually_approves_followers;
+
+    discoverable;
+    followers;
+    following;
+    icon;
+    raw;
+  }: Types.person)
+
+let note = 
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected Note (received %s)" "Note"
+  and* id = field "id" string
+  and* actor = one_of ["actor", field "actor" id; "attributed_to", field "attributedTo" id]
+  and* attachment = field_or_default "attachment" (singleton_or_list attachment) []
+  and* to_ = field "to" (singleton_or_list string)
+  and* in_reply_to = field_or_default "inReplyTo" (nullable string) None
+  and* cc = field_or_default "cc" (singleton_or_list string) []
+  and* content = field "content" string
+  and* source = field_opt "source"
+                  (one_of ["string", string; "multi-encode", field "content" string])
+  and* summary = field_or_default "summary" (nullable string) None
+  and* sensitive = field_or_default "sensitive" (nullable bool) None
+  and* published = field_opt "published" timestamp
+  and* tags = field_or_default "tag" (lossy_list_of tag) []
+  and* raw = value in
+  succeed ({ id; actor; attachment; in_reply_to; to_; cc;
+             sensitive=Option.value ~default:false sensitive;
+             content; source; summary; tags; published; raw }: Types.note)
+
+let follow =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected create object (received %s)" "Follow"
+  and* actor = field "actor" id
+  and* cc = field_or_default "cc" (singleton_or_list string) []
+  and* to_ = field_or_default "to" (singleton_or_list string) []
+  and* id = field "id" string
+  and* object_ = field "object" id
+  and* state = field_opt "state" (string >>= function "pending" -> succeed `Pending
+                                                    | "cancelled" -> succeed `Cancelled
+                                                    | _ -> fail "unknown status")
+  and* raw = value in
+  succeed ({actor; cc; to_; id; object_; state; raw}: Types.follow)
+
+let announce obj =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected create object (received %s)" "Announce"
+  and* actor = field "actor" id
+  and* id = field "id" string
+  and* published = field_opt "published" timestamp
+  and* to_ = field "to" (singleton_or_list string)
+  and* cc = field_or_default "cc" (singleton_or_list string) []
+  and* obj = field "object" obj
+  and* raw = value in
+  succeed ({id; published; actor; to_; cc; obj; raw}: _ Types.announce)
+
+let create obj =
+  let open D in
+  let* () = field "type" @@ constant ~msg:"expected create object (received %s)" "Create"
+  and* id = field "id" string
+  and* actor = field "actor" id
+  and* direct_message = field_or_default "direct" bool false
+  and* published = field_opt "published" timestamp
+  and* to_ = field_or_default "to" (singleton_or_list string) []
+  and* cc = field_or_default "cc" (singleton_or_list string) []
+  and* obj = field "object" obj
+  and* raw = value in
+
+  succeed ({
+    id; actor; published;
+    to_; cc;
+    direct_message;
+    obj;
+    raw;
+  }: _ Types.create)
+
+let core_obj () =
+  let open D in
+  let* ty = field_opt "type" string in
+  match ty with
+  | Some "Person" -> person >|= fun v -> `Person v
+  | Some "Follow" -> follow >|= fun v -> `Follow v
+  | Some "Note" -> note >|= fun v -> `Note v
+  | Some "Block" -> block >|= fun v -> `Block v
+  | Some "Like" -> like >|= fun v -> `Like v
+  | None -> string >|= fun v -> `Link v
+  | Some ev -> fail ("unsupported event" ^ ev)
+
+let core_obj = core_obj ()
+
+let event (enc: Types.core_obj D.decoder) : Types.obj D.decoder =
+  let open D in
+  let* ty = field "type" string in
+  match ty with
+  | "Create" -> create enc >|= fun v -> `Create v
+  | "Accept" -> accept enc >|= fun v -> `Accept v
+  | "Undo" -> undo enc >|= fun v -> `Undo v
+  | "Delete" -> delete enc >|= fun v -> `Delete v
+  | "Announce" -> announce enc >|= fun v -> `Announce v
+  | _ -> fail "unsupported event"
+
+let obj : Types.obj D.decoder =
+  D.one_of [
+    "core_obj", core_obj;
+    "core_obj event", (event core_obj)
+  ]
+
+module Webfinger = struct
+
+  let ty =
+    let open D in
+    string >>= function
+    | str when String.prefix ~pre:Constants.ContentType.html str ->
+      succeed `Html
+    | str when String.prefix ~pre:Constants.ContentType.plain_json str ->
+      succeed `Json
+    | str when String.prefix ~pre:Constants.ContentType.activity_json str ->
+      succeed `ActivityJson
+    | str when String.prefix ~pre:Constants.ContentType.ld_json_activity_streams str ->
+      succeed `ActivityJsonLd
+    | _ ->
+      fail "unsupported self link type"
+
+  let self =
+    let open D in
+    let* ty = field "type" ty
+    and* href = field "href" string in
+    succeed @@ Types.Webfinger.Self (ty, href)
+
+  let profile_page =
+    let open D in
+    let* ty = field "type" ty
+    and* href = field "href" string in
+    succeed @@ Types.Webfinger.ProfilePage (ty, href)
+
+  let ostatus_subscribe =
+    let open D in
+    let* template = field "template" string in
+    succeed @@ Types.Webfinger.OStatusSubscribe template
+
+  let link =
+    let open D in
+    let* rel = field "rel" string in
+    match rel with
+    | "self" -> self
+    | str when String.equal str Constants.Webfinger.ostatus_rel ->
+      ostatus_subscribe
+    | str when String.equal str Constants.Webfinger.profile_page ->
+      profile_page
+    | _ -> fail "unsupported link relation"
+
+  let query_result =
+    let open D in
+    let* subject = field "subject" string
+    and* aliases = field "aliases" (list string)
+    and* links = field "links" (list_ignoring_unknown link) in
+
+    succeed Types.Webfinger.{subject;aliases;links}
+
+end
+
+module Nodeinfo = struct
+
+  let software =
+    let open D in
+    let* name = field "name" string
+    and* version = field "version" string in
+    succeed @@ Types.Nodeinfo.{name;version}
+
+  let usage_users =
+    let open D in
+    let* total = field_or_default "total" int 0
+    and* active_month = field_or_default "activeMonth" int 0
+    and* active_half_year = field_or_default "activeHalfyear" int 0 in
+    succeed @@ Types.Nodeinfo.{total; active_month; active_half_year}
+
+  let usage =
+    let open D in
+    let* users = field "users" usage_users 
+    and* local_posts = field_or_default "localPosts" int 0 in
+    succeed @@ Types.Nodeinfo.{users; local_posts}
+
+  let t =
+    let open D in
+    let* software = field "software" software
+    and* protocols = field_or_default "protocols" (list string) []
+    and* inbound_services = field_or_default "services" (field_or_default "inbound" (list string) []) []
+    and* outbound_services = field_or_default "services" (field_or_default "outbound" (list string) []) []
+    and* usage = field "usage" usage
+    and* open_registrations = field_or_default "openRegistrations" bool false 
+    and* metadata = field_opt "metadata" value
+    and* raw = value in
+    succeed @@ Types.Nodeinfo.{software;protocols;inbound_services;outbound_services;usage;open_registrations;metadata;raw}
+
+
+end