Update metadata script for types-support

scripts/metadata-get.mjs

@@ -17,47 +17,70 @@ const CMD = {
 const META_VERSION_HEX = '0x0f000000';
 const META_VERSION = 15;
 
-let requestId = 0;
-
 /**
+ * Small CLI parser.
+ *
+ * This script accepts `--url` to specify the endpoint to query the metadata from.
  *
- * @param {'rpc_methods' | 'state_getMetadata' | 'state_getRuntimeVersion' | 'state_call'} method
- * @param {string[]} params
- * @returns {Promise<any>}
+ * @returns {string}
  */
-async function get (method, params = []) {
-  const res = await fetch('http://127.0.0.1:9944', {
-    body: JSON.stringify({
-      id: ++requestId,
-      jsonrpc: '2.0',
-      method,
-      params
-    }),
-    headers: {
-      Accept: 'application/json',
-      'Content-Type': 'application/json'
-    },
-    method: 'POST'
-  });
-  const body = await res.json();
-
-  return body.result;
-}
-
-/** @type {[string[], string, { specName: 'polkadot' | 'kusama' | 'node'; specVersion: string; }]} */
-const [methods, metadata, version] = await Promise.all([
-  get('rpc_methods'),
-  get('state_call', ['Metadata_metadata_at_version', META_VERSION_HEX]),
-  get('state_getRuntimeVersion')
-]);
-const chain = version.specName === 'node'
-  ? 'substrate'
-  : version.specName;
-const metaVer = parseInt(metadata.substring(10, 12), 16);
-const path = `packages/types-support/src/metadata/v${META_VERSION}/${chain}`;
-
-fs.writeFileSync(`${path}-hex.ts`, `${CMD[chain]} '${metadata}';\n`);
-fs.writeFileSync(`${path}-rpc.ts`, `${CMD[chain]} ${JSON.stringify(methods, null, 2)};\n`);
-fs.writeFileSync(`${path}-ver.ts`, `${CMD[chain]} ${JSON.stringify(version, null, 2)};\n`);
-
-console.log(`Retrieved ${chain}/${version.specVersion}, metadata v${metaVer}`);
+const getUrl = () => {
+  const [,, command, ...args] = process.argv;
+
+  if (command === '--url') {
+    return args.join(' ');
+  }
+
+  return 'http://127.0.0.1:9944';
+};
+
+const main = async () => {
+  let requestId = 0;
+
+  const chainUrl = getUrl();
+
+  /**
+   *
+   * @param {'rpc_methods' | 'state_getMetadata' | 'state_getRuntimeVersion' | 'state_call'} method
+   * @param {string[]} params
+   * @returns {Promise<any>}
+   */
+  async function get (method, params = []) {
+    const res = await fetch(chainUrl, {
+      body: JSON.stringify({
+        id: ++requestId,
+        jsonrpc: '2.0',
+        method,
+        params
+      }),
+      headers: {
+        Accept: 'application/json',
+        'Content-Type': 'application/json'
+      },
+      method: 'POST'
+    });
+    const body = await res.json();
+
+    return body.result;
+  }
+
+  /** @type {[string[], string, { specName: 'polkadot' | 'kusama' | 'node'; specVersion: string; }]} */
+  const [methods, metadata, version] = await Promise.all([
+    get('rpc_methods'),
+    get('state_call', ['Metadata_metadata_at_version', META_VERSION_HEX]),
+    get('state_getRuntimeVersion')
+  ]);
+  const chain = version.specName === 'node'
+    ? 'substrate'
+    : version.specName;
+  const metaVer = parseInt(metadata.substring(10, 12), 16);
+  const path = `packages/types-support/src/metadata/v${META_VERSION}/${chain}`;
+
+  fs.writeFileSync(`${path}-hex.ts`, `${CMD[chain]} '${metadata}';\n`);
+  fs.writeFileSync(`${path}-rpc.ts`, `${CMD[chain]} ${JSON.stringify(methods, null, 2)};\n`);
+  fs.writeFileSync(`${path}-ver.ts`, `${CMD[chain]} ${JSON.stringify(version, null, 2)};\n`);
+
+  console.log(`Retrieved ${chain}/${version.specVersion}, metadata v${metaVer}`);
+};
+
+main().catch((err) => console.error(err)).finally(() => process.exit());