feat: const effect for decoding consts in the metadata (#347)

codegen.ts

@@ -31,7 +31,7 @@ await codegen({
 
 async function getMetadata(src: string): Promise<M.Metadata> {
   if (src.startsWith("ws")) {
-    const client = U.throwIfError(await proxyClient(new Config(() => src, undefined!)));
+    const client = U.throwIfError(await proxyClient(new Config(() => src)));
     const metadata = U.throwIfError(await client.call("state_getMetadata", []));
     U.throwIfError(await client.close());
     if (metadata.error) fail();

config/mod.ts

@@ -1,10 +1,7 @@
 export class Config<DiscoveryValue = any> {
   #discoveryValue?: DiscoveryValue | Promise<DiscoveryValue>;
 
-  constructor(
-    readonly initDiscoveryValue: () => DiscoveryValue | Promise<DiscoveryValue>,
-    readonly addressPrefix: number,
-  ) {}
+  constructor(readonly initDiscoveryValue: () => DiscoveryValue | Promise<DiscoveryValue>) {}
 
   get discoveryValue() {
     if (!this.#discoveryValue) {

effects/const.ts

@@ -0,0 +1,32 @@
+import { Config } from "../config/mod.ts";
+import * as Z from "../deps/zones.ts";
+import * as U from "../util/mod.ts";
+import { codec } from "./core/codec.ts";
+import { decoded } from "./core/decoded.ts";
+import { deriveCodec } from "./core/deriveCodec.ts";
+import { constMetadata, metadata, palletMetadata } from "./metadata.ts";
+
+function const_<
+  PalletName extends Z.$<string>,
+  ConstName extends Z.$<string>,
+  Rest extends [blockHash?: Z.$<U.HexHash | undefined>],
+>(
+  config: Config,
+  palletName: PalletName,
+  constName: ConstName,
+  ...[blockHash]: [...Rest]
+) {
+  const metadata_ = metadata(config, blockHash);
+  const deriveCodec_ = deriveCodec(metadata_);
+  const palletMetadata_ = palletMetadata(metadata_, palletName);
+  const constMetadata_ = constMetadata(palletMetadata_, constName);
+  const entryValueTypeI = constMetadata_.access("ty").access("id");
+  const constValue = constMetadata_.access("value");
+  const $const = codec(deriveCodec_, entryValueTypeI);
+  return decoded($const, constValue, "value");
+}
+Object.defineProperty(const_, "name", {
+  value: "const",
+  writable: false,
+});
+export { const_ as const };

effects/core/decoded.ts

@@ -1,10 +1,9 @@
 import * as $ from "../../deps/scale.ts";
 import * as Z from "../../deps/zones.ts";
-import * as U from "../../util/mod.ts";
 
 export function decoded<
   Codec extends Z.$<$.Codec<unknown>>,
-  Encoded extends Z.$<U.Hex>,
+  Encoded extends Z.$<Uint8Array>,
   Key extends Z.$<string>,
 >(
   codec: Codec,
@@ -14,7 +13,7 @@ export function decoded<
   return Z.call(
     Z.ls(codec, encoded, key),
     function decodedImpl([codec, encoded, key]): Record<Z.T<Key>, any> {
-      return { [key]: codec.decode(U.hex.decode(encoded)) } as any;
+      return { [key]: codec.decode(encoded) } as any;
     },
   );
 }

effects/entryRead.ts

@@ -5,6 +5,7 @@ import { $storageKey } from "./core/$storageKey.ts";
 import { codec } from "./core/codec.ts";
 import { decoded } from "./core/decoded.ts";
 import { deriveCodec } from "./core/deriveCodec.ts";
+import { hexDecode } from "./core/hex.ts";
 import { storageKey } from "./core/storageKey.ts";
 import { entryMetadata, metadata, palletMetadata } from "./metadata.ts";
 import { rpcCall } from "./rpcCall.ts";
@@ -30,6 +31,6 @@ export function entryRead<
   const storageCall = rpcCall(config, "state_getStorage", [storageKey_, blockHash]);
   const entryValueTypeI = entryMetadata_.access("value");
   const $entry = codec(deriveCodec_, entryValueTypeI);
-  const resultHex = storageCall.access("result");
-  return decoded($entry, resultHex, "value");
+  const result = storageCall.access("result");
+  return decoded($entry, hexDecode(result), "value");
 }

effects/extrinsic.ts

@@ -6,6 +6,7 @@ import { Config } from "../mod.ts";
 import { NotifMessage } from "../rpc/mod.ts";
 import * as ss58 from "../ss58/mod.ts";
 import * as U from "../util/mod.ts";
+import { const as const_ } from "./const.ts";
 import { $extrinsic } from "./core/$extrinsic.ts";
 import { deriveCodec } from "./core/deriveCodec.ts";
 import { hexDecode } from "./core/hex.ts";
@@ -49,21 +50,27 @@ export class SignedExtrinsic<
     const props = props_ as Z.Rec$Access<Props>;
     const metadata_ = metadata(config);
     const deriveCodec_ = deriveCodec(metadata_);
-    const $extrinsic_ = $extrinsic(deriveCodec_, metadata_, this.sign, config.addressPrefix);
+    const addrPrefix = const_(config, "System", "SS58Prefix")
+      .access("value")
+      .as<number>();
+    const $extrinsic_ = $extrinsic(deriveCodec_, metadata_, this.sign, addrPrefix);
     const runtimeVersion = rpcCall(config, "state_getRuntimeVersion", []);
-    const senderSs58 = Z.call(props.sender, function senderSs58(sender) {
-      return ((): string => {
-        switch (sender.type) {
-          case "Id": {
-            return ss58.encode(config.addressPrefix, sender.value);
+    const senderSs58 = Z.call(
+      Z.ls(addrPrefix, props.sender),
+      function senderSs58([addrPrefix, sender]) {
+        return ((): string => {
+          switch (sender.type) {
+            case "Id": {
+              return ss58.encode(addrPrefix, sender.value);
+            }
+            // TODO: other types
+            default: {
+              unimplemented();
+            }
           }
-          // TODO: other types
-          default: {
-            unimplemented();
-          }
-        }
-      })();
-    });
+        })();
+      },
+    );
     const accountNextIndex = rpcCall(config, "system_accountNextIndex", [senderSs58]);
     const genesisHash = hexDecode(rpcCall(config, "chain_getBlockHash", [0]).access("result"));
     const checkpointHash = props.checkpoint

effects/metadata.ts

@@ -45,6 +45,21 @@ export function entryMetadata<PalletMetadata extends Z.$<M.Pallet>, EntryName ex
   );
 }
 
+export function constMetadata<
+  PalletMetadata extends Z.$<M.Pallet>,
+  ConstName extends Z.$<string>,
+>(
+  palletMetadata: PalletMetadata,
+  constName: ConstName,
+) {
+  return Z.call(
+    Z.ls(palletMetadata, constName),
+    function constMetadataImpl([palletMetadata, constName]) {
+      return M.getConst(palletMetadata, constName);
+    },
+  );
+}
+
 export function mapMetadata<PalletMetadata extends Z.$<M.Pallet>, EntryName extends Z.$<string>>(
   palletMetadata: PalletMetadata,
   entryName: EntryName,

effects/mod.ts

@@ -1,5 +1,6 @@
 export * from "./blockRead.ts";
 export * from "./blockWatch.ts";
+export * from "./const.ts";
 export * from "./entryRead.ts";
 export * from "./entryWatch.ts";
 export * from "./extrinsic.ts";

frame_metadata/Metadata.ts

@@ -159,6 +159,11 @@ export function getEntry(pallet: Pallet, name: string): StorageEntry | EntryNotF
 }
 export class EntryNotFoundError extends U.ErrorCtor("EntryNotFound") {}
 
+export function getConst(pallet: Pallet, name: string): Constant | ConstNotFoundError {
+  return pallet.constants?.find((constant) => constant.name === name) || new ConstNotFoundError();
+}
+export class ConstNotFoundError extends U.ErrorCtor("ConstNotFound") {}
+
 export function getPalletAndEntry(
   metadata: Metadata,
   palletName: string,

known/configs.ts

@@ -2,17 +2,11 @@
 
 import { Config } from "../config/mod.ts";
 
-export const polkadot = new Config(() => "wss://rpc.polkadot.io", 0);
-export const kusama = new Config(() => "wss://kusama-rpc.polkadot.io", 2);
-export const acala = new Config(() => "wss://acala-polkadot.api.onfinality.io/public-ws", 10);
-export const rococo = new Config(
-  () => "wss://rococo-contracts-rpc.polkadot.io",
-  undefined!, /* TODO */
-);
-export const moonbeam = new Config(() => "wss://wss.api.moonbeam.network", 1284);
-export const statemint = new Config(
-  () => "wss://statemint-rpc.polkadot.io",
-  undefined!, /* TODO */
-);
-export const subsocial = new Config(() => "wss://para.subsocial.network", 28);
-export const westend = new Config(() => "wss://westend-rpc.polkadot.io", 42);
+export const polkadot = new Config(() => "wss://rpc.polkadot.io");
+export const kusama = new Config(() => "wss://kusama-rpc.polkadot.io");
+export const acala = new Config(() => "wss://acala-polkadot.api.onfinality.io/public-ws");
+export const rococo = new Config(() => "wss://rococo-contracts-rpc.polkadot.io");
+export const moonbeam = new Config(() => "wss://wss.api.moonbeam.network");
+export const statemint = new Config(() => "wss://statemint-rpc.polkadot.io");
+export const subsocial = new Config(() => "wss://para.subsocial.network");
+export const westend = new Config(() => "wss://westend-rpc.polkadot.io");

test_util/config.ts

@@ -2,31 +2,23 @@ import { Config } from "../config/mod.ts";
 
 export class TestConfig extends Config<string> {
   constructor(readonly runtimeName: TestConfigRuntime.Name) {
-    super(
-      async () => {
-        const hostname = Deno.env.get("TEST_CTX_HOSTNAME");
-        const portRaw = Deno.env.get("TEST_CTX_PORT");
-        if (!hostname || !portRaw) await testCtx();
-        const conn = await Deno.connect({
-          hostname,
-          port: parseInt(portRaw!),
-        });
-        conn.write(new Uint8Array([TestConfigRuntime.CODES[runtimeName]]));
-        const port = await (async () => {
-          for await (const x of conn.readable) {
-            return new DataView(x.buffer).getUint16(0);
-          }
-          return undefined!;
-        })();
-        return `ws://127.0.0.1:${port}`;
-      },
-      {
-        kusama: 2,
-        rococo: undefined!, // TODO
-        westend: 0,
-        polkadot: 0,
-      }[runtimeName],
-    );
+    super(async () => {
+      const hostname = Deno.env.get("TEST_CTX_HOSTNAME");
+      const portRaw = Deno.env.get("TEST_CTX_PORT");
+      if (!hostname || !portRaw) await testCtx();
+      const conn = await Deno.connect({
+        hostname,
+        port: parseInt(portRaw!),
+      });
+      conn.write(new Uint8Array([TestConfigRuntime.CODES[runtimeName]]));
+      const port = await (async () => {
+        for await (const x of conn.readable) {
+          return new DataView(x.buffer).getUint16(0);
+        }
+        return undefined!;
+      })();
+      return `ws://127.0.0.1:${port}`;
+    });
   }
 }