feat: add variable interpolation support for WebSocket requests (#6064)

* feat: add variable interpolation support for WebSocket requests

- Add WebSocket body interpolation in interpolateVars function
- Interpolate URL, headers, and all messages in request.body.ws array with full variable context
- Refactor sendWsRequest to use main process preparation (removes duplication)
- Add mode property to wsRequest object for proper request type detection
- Ensure consistent variable precedence matching HTTP/gRPC requests
- Centralize all interpolation logic in main process via prepareWsRequest

* Add Playwright tests for WebSocket variable interpolation

- Add tests for URL interpolation (wss://echo.{{url}}.org)
- Add tests for message content interpolation ({"test": "{{data}}"})
- Update test fixtures to use wss://echo.websocket.org echo server
- Add WEBSOCKET_FLOWS.md documentation
- Refactor queueWsMessage to handle variable interpolation in main process

* removed ws flow documentation

* chore: updated the network/index.js file to reduce merge conflicts by moving around code

* fix: added collection and item to WsQueryUrl Editor to fix available variable highlight

* chore: remove unnecessary whitespace in WebSocket event handlers

---------

Co-authored-by: Sid <siddharth@usebruno.com>

tests/websockets/variable-interpolation/fixtures/collection/bruno.json

@@ -0,0 +1,10 @@
+{
+  "version": "1",
+  "name": "variable-interpolation",
+  "type": "collection",
+  "ignore": [
+    "node_modules",
+    ".git"
+  ]
+}
+

tests/websockets/variable-interpolation/fixtures/collection/environments/Test.bru

@@ -0,0 +1,5 @@
+vars {
+  url: websocket
+  data: test-data
+}
+

tests/websockets/variable-interpolation/fixtures/collection/ws-interpolation-test.bru

@@ -0,0 +1,20 @@
+meta {
+  name: ws-interpolation-test
+  type: ws
+  seq: 1
+}
+
+ws {
+  url: wss://echo.{{url}}.org
+  auth: inherit
+}
+
+body:ws {
+  name: message 1
+  content: '''
+    {
+      "test": "{{data}}"
+    }
+  '''
+}
+

tests/websockets/variable-interpolation/init-user-data/preferences.json

@@ -0,0 +1,10 @@
+{
+  "maximized": false,
+  "lastOpenedCollections": [
+    "{{projectRoot}}/tests/websockets/variable-interpolation/fixtures/collection"
+  ],
+  "beta": {
+    "websocket": true
+  }
+}
+

tests/websockets/variable-interpolation/variable-interpolation.spec.ts

@@ -0,0 +1,109 @@
+import { test, expect } from '../../../playwright';
+import { buildWebsocketCommonLocators } from '../../utils/page/locators';
+import { closeAllCollections, openCollectionAndAcceptSandbox } from '../../utils/page';
+
+const BRU_REQ_NAME = /^ws-interpolation-test$/;
+const MAX_CONNECTION_TIME = 10000; // Increased timeout for external server
+
+test.describe.serial('WebSocket Variable Interpolation', () => {
+  test.afterAll(async ({ pageWithUserData: page }) => {
+    await closeAllCollections(page);
+  });
+
+  test('interpolates variables in WebSocket URL', async ({ pageWithUserData: page, restartApp }) => {
+    const locators = buildWebsocketCommonLocators(page);
+
+    // Open the collection and accept sandbox modal if it appears
+    await openCollectionAndAcceptSandbox(page, 'variable-interpolation', 'safe');
+
+    // Open the request
+    await expect(page.getByTitle(BRU_REQ_NAME)).toBeVisible();
+    await page.getByTitle(BRU_REQ_NAME).click();
+
+    // Select the test environment (which has url: websocket)
+    await page.locator('div.current-environment').click();
+    await expect(page.locator('.dropdown-item').filter({ hasText: 'Test' })).toBeVisible();
+    await page.locator('.dropdown-item').filter({ hasText: 'Test' }).click();
+    await expect(page.locator('.current-environment').filter({ hasText: /Test/ })).toBeVisible();
+
+    // Wait a bit for environment to be applied
+    await page.waitForTimeout(200);
+
+    // Connect WebSocket
+    await locators.connectionControls.connect().click();
+
+    // Wait for connection to establish
+    await expect(locators.connectionControls.disconnect()).toBeAttached({
+      timeout: MAX_CONNECTION_TIME
+    });
+
+    // Verify the connection message shows interpolated URL
+    // The URL should be wss://echo.websocket.org (not wss://echo.{{url}}.org)
+    await expect(locators.messages().first().getByText(/Connected to wss:\/\/echo\.websocket\.org/)).toBeAttached({
+      timeout: 2000
+    });
+  });
+
+  test('interpolates variables in WebSocket message content', async ({ pageWithUserData: page, restartApp }) => {
+    const locators = buildWebsocketCommonLocators(page);
+
+    // Wait for collection to be visible (it should auto-load from preferences)
+    await expect(page.locator('#sidebar-collection-name').filter({ hasText: 'variable-interpolation' })).toBeVisible({ timeout: 5000 });
+
+    // Check if sandbox modal is present and handle it
+    const sandboxModal = page.locator('.bruno-modal-card').filter({ has: page.locator('.bruno-modal-header-title', { hasText: 'JavaScript Sandbox' }) });
+    const isModalVisible = await sandboxModal.isVisible().catch(() => false);
+
+    if (isModalVisible) {
+      // Accept sandbox modal
+      await sandboxModal.getByLabel('Safe Mode').check();
+      await sandboxModal.locator('.bruno-modal-footer .submit').click();
+      await sandboxModal.waitFor({ state: 'detached' });
+    } else {
+      // Collection might already be open, just ensure it's clicked
+      await page.locator('#sidebar-collection-name').filter({ hasText: 'variable-interpolation' }).click();
+    }
+
+    // Wait a bit for any modals to fully close
+    await page.waitForTimeout(300);
+
+    // Open the request
+    await expect(page.getByTitle(BRU_REQ_NAME)).toBeVisible();
+    await page.getByTitle(BRU_REQ_NAME).click();
+
+    // Select the test environment (which has data: test-data)
+    await page.locator('div.current-environment').click();
+    await page.locator('.dropdown-item').filter({ hasText: 'Test' }).click();
+
+    // Clear any previous messages
+    await locators.toolbar.clearResponse().click();
+
+    // Send the request (connect + send messages)
+    await locators.runner().click();
+
+    // Wait for connection
+    await expect(locators.connectionControls.disconnect()).toBeAttached({
+      timeout: MAX_CONNECTION_TIME
+    });
+
+    // Wait a bit for messages to be sent and received (echo server echoes back)
+    await page.waitForTimeout(1000);
+
+    // Verify the sent message contains interpolated value
+    // Should send {"test": "test-data"} (not {"test": "{{data}}"})
+    const messages = locators.messages();
+
+    // Find the outgoing message with interpolated content
+    // The echo server will echo back the same message, so we should see it twice
+    const sentMessage = messages.filter({ hasText: 'test-data' }).first();
+    await expect(sentMessage).toBeAttached({ timeout: 2000 });
+
+    // Verify the message content shows interpolated value, not literal variable
+    const messageText = await sentMessage.locator('.text-ellipsis').textContent();
+    expect(messageText).toContain('test-data');
+    expect(messageText).not.toContain('{{data}}');
+
+    // Verify JSON structure is correct
+    expect(messageText).toMatch(/\{[\s\S]*"test"[\s\S]*"test-data"[\s\S]*\}/);
+  });
+});