[RFC] feat: Middlewares addition

src/near-bindgen.ts

@@ -89,6 +89,50 @@ export function call({
   };
 }
 
+/**
+ * The interface that a middleware has to implement in order to be used as a middleware function/class.
+ */
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+interface Middleware<Arguments extends Array<any>> {
+  /**
+   * The method that gets called with the same arguments that are passed to the function it is wrapping.
+   *
+   * @param args - Arguments that will be passed to the function - immutable.
+   */
+  call(...args: Arguments): void;
+}
+
+/**
+ * Tells the SDK to apply an array of passed in middleware to the function execution.
+ *
+ * @param middlewares - The middlewares to be executed.
+ */
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export function middleware<Arguments extends Array<any>>(
+  ...middlewares: Middleware<Arguments>[]
+): DecoratorFunction {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return function <AnyFunction extends (...args: Arguments) => any>(
+    _target: object,
+    _key: string | symbol,
+    descriptor: TypedPropertyDescriptor<AnyFunction>
+  ): void {
+    const originalMethod = descriptor.value;
+
+    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+    // @ts-ignore
+    descriptor.value = function (...args: Arguments): ReturnType<AnyFunction> {
+      try {
+        middlewares.forEach((middleware) => middleware.call(...args));
+      } catch (error) {
+        throw new Error(error);
+      }
+
+      return originalMethod.apply(this, args);
+    };
+  };
+}
+
 /**
  * Extends this class with the methods needed to make the contract storable/serializable and readable/deserializable to and from the blockchain.
  * Also tells the SDK to capture and expose all view, call and initialize functions.

tests/__tests__/test-middlewares.ava.js

@@ -0,0 +1,84 @@
+import { Worker } from "near-workspaces";
+import test from "ava";
+
+test.beforeEach(async (t) => {
+  // Init the worker and start a Sandbox server
+  const worker = await Worker.init();
+
+  // Prepare sandbox for tests, create accounts, deploy contracts, etx.
+  const root = worker.rootAccount;
+
+  // Deploy the contract.
+  const middlewares = await root.devDeploy("build/middlewares.wasm");
+
+  // Create the init args.
+  const args = JSON.stringify({ randomData: "anything" });
+  // Capture the result of the init function call.
+  const result = await middlewares.callRaw(middlewares, "init", args);
+
+  // Extract the logs.
+  const { logs } = result.result.receipts_outcome[0].outcome;
+  // Create the expected logs.
+  const expectedLogs = [`Log from middleware: ${args}`];
+
+  // Check for correct logs.
+  t.deepEqual(logs, expectedLogs);
+
+  // Create test users
+  const ali = await root.createSubAccount("ali");
+
+  // Save state for test runs
+  t.context.worker = worker;
+  t.context.accounts = { root, middlewares, ali };
+});
+
+test.afterEach.always(async (t) => {
+  await t.context.worker.tearDown().catch((error) => {
+    console.log("Failed to tear down the worker:", error);
+  });
+});
+
+test("The middleware logs with call functions", async (t) => {
+  const { ali, middlewares } = t.context.accounts;
+
+  // Create the arguments which will be passed to the function.
+  const args = JSON.stringify({ id: "1", text: "hello" });
+  // Call the function.
+  const result = await ali.callRaw(middlewares, "add", args);
+  // Extract the logs.
+  const { logs } = result.result.receipts_outcome[0].outcome;
+  // Create the expected logs.
+  const expectedLogs = [`Log from middleware: ${args}`];
+
+  t.deepEqual(logs, expectedLogs);
+});
+
+test("The middleware logs with view functions", async (t) => {
+  const { ali, middlewares } = t.context.accounts;
+
+  // Create the arguments which will be passed to the function.
+  const args = JSON.stringify({ id: "1", accountId: "hello" });
+  // Call the function.
+  const result = await ali.callRaw(middlewares, "get", args);
+  // Extract the logs.
+  const { logs } = result.result.receipts_outcome[0].outcome;
+  // Create the expected logs.
+  const expectedLogs = [`Log from middleware: ${args}`];
+
+  t.deepEqual(logs, expectedLogs);
+});
+
+test("The middleware logs with private functions", async (t) => {
+  const { ali, middlewares } = t.context.accounts;
+
+  // Create the arguments which will be passed to the function.
+  const args = { id: "test", accountId: "tset" };
+  // Call the function.
+  const result = await ali.callRaw(middlewares, "get_private", "");
+  // Extract the logs.
+  const { logs } = result.result.receipts_outcome[0].outcome;
+  // Create the expected logs.
+  const expectedLogs = [`Log from middleware: ${args}`];
+
+  t.deepEqual(logs, expectedLogs);
+});

tests/package.json

@@ -28,6 +28,7 @@
     "build:private": "near-sdk-js build src/decorators/private.ts build/private.wasm",
     "build:bigint-serialization": "near-sdk-js build src/bigint-serialization.ts build/bigint-serialization.wasm",
     "build:date-serialization": "near-sdk-js build src/date-serialization.ts build/date-serialization.wasm",
+    "build:middlewares": "near-sdk-js build src/middlewares.ts build/middlewares.wasm",
     "test": "ava",
     "test:context-api": "ava __tests__/test_context_api.ava.js",
     "test:math-api": "ava __tests__/test_math_api.ava.js",
@@ -49,7 +50,8 @@
     "test:private": "ava __tests__/decorators/private.ava.js",
     "test:bigint-serialization": "ava __tests__/test-bigint-serialization.ava.js",
     "test:date-serialization": "ava __tests__/test-date-serialization.ava.js",
-    "test:serialization": "ava __tests__/test-serialization.ava.js"
+    "test:serialization": "ava __tests__/test-serialization.ava.js",
+    "test:middlewares": "ava __tests__/test-middlewares.ava.js"
   },
   "author": "Near Inc <hello@nearprotocol.com>",
   "license": "Apache-2.0",

tests/src/middlewares.ts

@@ -0,0 +1,45 @@
+import { NearBindgen, near, call, view } from "near-sdk-js";
+import { initialize, middleware } from "../../lib/near-bindgen";
+
+@NearBindgen({ requireInit: true })
+export class Contract {
+  @initialize({})
+  @middleware({
+    call: (args) => near.log(`Log from middleware: ${args}`),
+  })
+  // eslint-disable-next-line @typescript-eslint/no-empty-function
+  init({ randomData: _ }: { randomData: string }) {}
+
+  @call({})
+  @middleware({
+    call: (args) => near.log(`Log from middleware: ${args}`),
+  })
+  // eslint-disable-next-line @typescript-eslint/no-empty-function
+  add({ id: _, text: _t }: { id: string; text: string }) {}
+
+  @view({})
+  @middleware({
+    call: (args) => near.log(`Log from middleware: ${args}`),
+  })
+  get({ id, accountId }: { id: string; accountId: string }): {
+    id: string;
+    accountId: string;
+  } {
+    return { id: accountId, accountId: id };
+  }
+
+  @view({})
+  get_private(): { id: string; accountId: string } {
+    return this.getFromPrivate({ id: "test", accountId: "tset" });
+  }
+
+  @middleware({
+    call: (args) => near.log(`Log from middleware: ${args}`),
+  })
+  getFromPrivate({ id, accountId }: { id: string; accountId: string }): {
+    id: string;
+    accountId: string;
+  } {
+    return { id, accountId };
+  }
+}