Add Sturdy_ref.with_cap and with_cap_exn convenience functions

README.md

@@ -440,8 +440,7 @@ let () =
     Fmt.pr "Connecting to echo service at: %a@." Uri.pp_hum uri;
     let client_vat = Capnp_rpc_unix.client_only_vat () in
     let sr = Capnp_rpc_unix.Vat.import_exn client_vat uri in
-    Sturdy_ref.connect_exn sr >>= fun proxy_to_service ->
-    run_client proxy_to_service
+    Sturdy_ref.with_cap_exn sr run_client
   end
 ```
 
@@ -522,8 +521,8 @@ In `start_server`:
 #### The client side
 
 After starting the server and getting the sturdy URI, we create a client vat and connect to the sturdy ref.
-The result, `proxy_to_service`, is a proxy to the remote service via the network
-that can be used in exactly the same way as the direct reference we used before.
+The result is a proxy to the remote service via the network that can be used in
+exactly the same way as the direct reference we used before.
 
 #### Separate processes
 
@@ -605,8 +604,7 @@ let connect uri =
     Fmt.pr "Connecting to echo service at: %a@." Uri.pp_hum uri;
     let client_vat = Capnp_rpc_unix.client_only_vat () in
     let sr = Capnp_rpc_unix.Vat.import_exn client_vat uri in
-    Sturdy_ref.connect_exn sr >>= fun proxy_to_service ->
-    run_client proxy_to_service
+    Sturdy_ref.with_cap_exn sr run_client
   end
 
 open Cmdliner
@@ -1291,7 +1289,7 @@ The calculator example can also be run across two Unix processes.
 Start the server with:
 
 ```
-$ dune exec -- ./test-bin/calc.bc serve \
+$ dune exec -- ./test-bin/calc.exe serve \
     --capnp-listen-address unix:/tmp/calc.socket \
     --capnp-secret-key-file=key.pem
 Waiting for incoming connections at:
@@ -1303,7 +1301,7 @@ Note that `key.pem` does not need to exist. A new key will be generated and save
 In another terminal, run the client and connect to the address displayed by the server:
 
 ```
-dune exec -- ./test-bin/calc.bc connect capnp://sha-256:LPp-7l74zqvGcRgcP8b7-kdSpwwzxlA555lYC8W8prc@/tmp/calc.socket/
+dune exec -- ./test-bin/calc.exe connect capnp://sha-256:LPp-7l74zqvGcRgcP8b7-kdSpwwzxlA555lYC8W8prc@/tmp/calc.socket/
 ```
 
 You can also use `--capnp-disable-tls` if you prefer to run without encryption

capnp-rpc-lwt/capnp_rpc_lwt.mli

@@ -182,6 +182,17 @@ module Sturdy_ref : sig
   val connect_exn : 'a t -> 'a Capability.t Lwt.t
   (** [connect_exn] is a wrapper for [connect] that returns a failed Lwt thread on error. *)
 
+  val with_cap :
+    'a t ->
+    ('a Capability.t -> ('b, [> `Capnp of Capnp_rpc.Exception.t] as 'e) Lwt_result.t) ->
+    ('b, 'e) Lwt_result.t
+  (** [with_cap t f] uses [connect t] to get a live-ref [x],
+      then does [Capability.with_ref x f]. *)
+
+  val with_cap_exn : 'a t -> ('a Capability.t -> 'b Lwt.t) -> 'b Lwt.t
+  (** [with_cap_exn t f] uses [connect_exn t] to get a live-ref [x],
+      then does [Capability.with_ref x f]. *)
+
   val reader :
     ('a StructStorage.reader_t -> Capnp.MessageSig.ro Slice.t option) ->
     'a StructStorage.reader_t -> Uri.t

capnp-rpc-lwt/sturdy_ref.ml

@@ -16,3 +16,12 @@ let builder fn (s : 'a Capnp.BytesMessage.StructStorage.builder_t) (sr : 'a t) =
   sr#to_uri_with_secrets |> Uri.to_string |> Schema.BuilderOps.write_string (fn s)
 
 let cast t = t
+
+let with_cap t f =
+  connect t >>= function
+  | Ok x -> Capability.with_ref x f
+  | Error e -> Lwt_result.fail (`Capnp e)
+
+let with_cap_exn t f =
+  connect_exn t >>= fun x ->
+  Capability.with_ref x f

test-bin/calc.ml

@@ -45,7 +45,7 @@ let connect addr =
   Lwt_main.run begin
     let vat = Capnp_rpc_unix.client_only_vat () in
     let sr = Vat.import_exn vat addr in
-    Capnp_rpc_lwt.Sturdy_ref.connect_exn sr >>= fun calc ->
+    Capnp_rpc_lwt.Sturdy_ref.with_cap_exn sr @@ fun calc ->
     Logs.info (fun f -> f "Evaluating expression...");
     let remote_add = Calc.getOperator calc `Add in
     let result = Calc.evaluate calc Calc.Expr.(Call (remote_add, [Float 40.0; Float 2.0])) in

test-bin/echo/echo_bench.ml

@@ -39,6 +39,5 @@ let () =
     Fmt.pr "Connecting to echo service at: %a@." Uri.pp_hum uri;
     let client_vat = Capnp_rpc_unix.client_only_vat () in
     let sr = Capnp_rpc_unix.Vat.import_exn client_vat uri in
-    Sturdy_ref.connect_exn sr >>= fun proxy -> 
-    run_client proxy
+    Sturdy_ref.with_ref_exn sr run_client
   end

test-lwt/test_lwt.ml

@@ -608,7 +608,7 @@ let test_store switch =
   (* Set up client *)
   let client = Capnp_rpc_unix.client_only_vat ~tags:Test_utils.client_tags ~switch () in
   let sr = Capnp_rpc_unix.Vat.import_exn client store_uri in
-  Sturdy_ref.connect_exn sr >>= fun store ->
+  Sturdy_ref.with_cap_exn sr @@ fun store ->
   (* Try creating a file *)
   let file = Store.create_file store in
   Store.File.set file "Hello" >>= fun () ->
@@ -623,12 +623,9 @@ let test_store switch =
   (* Restart server *)
   start_server ~switch () >>= fun _server ->
   (* Reconnect client *)
-  Sturdy_ref.connect_exn file_sr >>= fun file ->
+  Sturdy_ref.with_cap_exn file_sr @@ fun file ->
   Store.File.get file >>= fun data ->
   Alcotest.(check string) "Read file" "Hello" data;
-  (* Clean up *)
-  Capability.dec_ref file;
-  Capability.dec_ref store;
   Lwt.return_unit
 
 let run name fn = Alcotest_lwt.test_case_sync name `Quick fn