Add support for querying protocol state by state hash or height

graphql_schema.json

@@ -15375,7 +15375,7 @@
             {
               "name": "protocolState",
               "description":
-                "Get the current protocol state, optionally encoded in Base64",
+                "Get the protocol state for a given block, optionally encoded in Base64",
               "args": [
                 {
                   "name": "encoding",
@@ -15386,6 +15386,23 @@
                     "ofType": null
                   },
                   "defaultValue": null
+                },
+                {
+                  "name": "height",
+                  "description":
+                    "The height of the desired block in the best chain",
+                  "type": { "kind": "SCALAR", "name": "Int", "ofType": null },
+                  "defaultValue": null
+                },
+                {
+                  "name": "stateHash",
+                  "description": "The state hash of the desired block",
+                  "type": {
+                    "kind": "SCALAR",
+                    "name": "String",
+                    "ofType": null
+                  },
+                  "defaultValue": null
                 }
               ],
               "type": {

src/lib/mina_graphql/mina_graphql.ml

@@ -2598,39 +2598,62 @@ struct
 
   let protocol_state =
     io_field "protocolState"
-      ~doc:"Get the current protocol state, optionally encoded in Base64"
+      ~doc:
+        "Get the protocol state for a given block, optionally encoded in Base64"
       ~typ:(non_null string)
       ~args:
         Arg.
-          [ arg "encoding" ~doc:"Encoding format (JSON or BASE64)"
+          [ arg "stateHash" ~doc:"The state hash of the desired block"
+              ~typ:string
+          ; arg "height"
+              ~doc:"The height of the desired block in the best chain" ~typ:int
+          ; arg "encoding" ~doc:"Encoding format (JSON or BASE64)"
               ~typ:
                 (enum "Encoding"
                    ~values:
                      [ enum_value "JSON" ~value:`JSON
                      ; enum_value "BASE64" ~value:`BASE64
                      ] )
           ]
-      ~resolve:(fun { ctx = mina; _ } () encoding_opt ->
-        match Mina_lib.best_tip mina with
-        | `Active best_tip ->
-            let protocol_state =
-              Transition_frontier.Breadcrumb.protocol_state best_tip
-            in
-            let encoded =
-              match encoding_opt with
-              | Some `BASE64 ->
-                  Bin_prot.Writer.to_string
-                    Mina_state.Protocol_state.Value.Stable.V2.bin_t.writer
-                    protocol_state
-                  |> Base64.encode_exn
-              | Some `JSON | None ->
-                  (* Default to JSON if no encoding is specified *)
-                  Mina_state.Protocol_state.value_to_yojson protocol_state
-                  |> Yojson.Safe.to_string
-            in
-            return (Ok encoded)
-        | `Bootstrapping ->
-            return (Error "Node is bootstrapping") )
+      ~resolve:(fun { ctx = mina; _ } () state_hash_base58_opt height_opt
+                    encoding_opt ->
+        let open Deferred.Result.Let_syntax in
+        let%map breadcrumb =
+          match (state_hash_base58_opt, height_opt) with
+          | None, None -> (
+              match Mina_lib.best_tip mina with
+              | `Active best_tip ->
+                  Deferred.Result.return best_tip
+              | `Bootstrapping ->
+                  Deferred.Result.fail "Node is bootstrapping" )
+          | Some state_hash_base58, None ->
+              let%bind state_hash =
+                Deferred.return (State_hash.of_base58_check state_hash_base58)
+                |> Deferred.Result.map_error ~f:Error.to_string_hum
+              in
+              Deferred.return
+                (Mina_lib.best_chain_block_by_state_hash mina state_hash)
+          | None, Some height ->
+              let height_uint32 = Unsigned.UInt32.of_int height in
+              Deferred.return
+                (Mina_lib.best_chain_block_by_height mina height_uint32)
+          | Some _, Some _ ->
+              Deferred.Result.fail
+                "Must provide exactly one of state hash, height"
+        in
+        let protocol_state =
+          Transition_frontier.Breadcrumb.protocol_state breadcrumb
+        in
+        match encoding_opt with
+        | Some `BASE64 ->
+            Bin_prot.Writer.to_string
+              Mina_state.Protocol_state.Value.Stable.V2.bin_t.writer
+              protocol_state
+            |> Base64.encode_exn
+        | Some `JSON | None ->
+            (* Default to JSON if no encoding is specified *)
+            Mina_state.Protocol_state.value_to_yojson protocol_state
+            |> Yojson.Safe.to_string )
 
   let commands =
     [ sync_status