Add contract interface

src/stacks-rpc-api/smart-contracts/index.ts

@@ -2,8 +2,11 @@ import { mapEntry } from "./map-entry.js";
 export type * as MapEntry from "./map-entry.js";
 import { readOnly } from "./read-only.js";
 export type * as ReadOnly from "./read-only.js";
+import { contractInterface } from "./interface.js";
+export type * as ContractInterface from "./interface.js";
 
 export const smartContracts = {
+  contractInterface,
   mapEntry,
   readOnly,
 };

src/stacks-rpc-api/smart-contracts/interface.ts

@@ -0,0 +1,53 @@
+import type { ClarityAbi } from "@stacks/transactions";
+import type { ApiRequestOptions, ProofAndTip } from "../../stacks-api/types.js";
+import { error, safePromise, success, type Result } from "../../utils/safe.js";
+
+export type Args = {
+  contractAddress: string;
+  contractName: string;
+} & ApiRequestOptions &
+  ProofAndTip;
+
+export type InterfaceResponse = ClarityAbi;
+
+export async function contractInterface(
+  args: Args,
+): Promise<Result<InterfaceResponse>> {
+  const search = new URLSearchParams();
+  if (args.proof === 0) search.append("proof", "0");
+  if (args.tip) search.append("tip", args.tip);
+
+  const init: RequestInit = {};
+  if (args.apiKeyConfig) {
+    init.headers = {
+      [args.apiKeyConfig.header]: args.apiKeyConfig.key,
+    };
+  }
+
+  const endpoint = `${args.baseUrl}/v2/contracts/interface/${args.contractAddress}/${args.contractName}`;
+  const res = await fetch(endpoint, init);
+  if (!res.ok) {
+    return error({
+      name: "FetcContractInterfaceError",
+      message: "Failed to fetch contract interface.",
+      data: {
+        init,
+        status: res.status,
+        statusText: res.statusText,
+        endpoint,
+        bodyText: await safePromise(res.text()),
+      },
+    });
+  }
+
+  const [jsonError, data] = await safePromise(res.json());
+  if (jsonError) {
+    return error({
+      name: "ParseBodyError",
+      message: "Failed to parse response body as JSON.",
+      data: jsonError,
+    });
+  }
+
+  return success(data as InterfaceResponse);
+}