bump to 0.3.0, add persistent browser examples

Author: rgarcia

templates/python/browser-use/pyproject.toml

@@ -6,7 +6,7 @@ readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
     "browser-use>=0.1.46",
-    "kernel==0.2.0",
+    "kernel==0.3.0",
     "langchain-openai>=0.3.11",
     "pydantic>=2.10.6",
 ]

templates/python/persistent-browser/.gitignore

@@ -0,0 +1,66 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# Virtual Environment
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+activate/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+.project
+.pydevproject
+.settings/
+
+# Testing
+.coverage
+htmlcov/
+.pytest_cache/
+.tox/
+.nox/
+coverage.xml
+*.cover
+.hypothesis/
+
+# Logs
+*.log
+logs/
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Misc
+.cache/
+.pytest_cache/
+.mypy_cache/
+.ruff_cache/
+.temp/
+.tmp/ 

templates/python/persistent-browser/README.md

@@ -0,0 +1,5 @@
+# Kernel Python Persistent Browser Example
+
+This is a simple Kernel application that shows how to use a persistent browser.
+
+The action reuses the same browser across invocations of the action, which lets it optimize for the case where the browser is already open and at the page of interest.

templates/python/persistent-browser/main.py

@@ -0,0 +1,73 @@
+import kernel
+from kernel import Kernel
+from playwright.async_api import async_playwright
+from typing import TypedDict
+from urllib.parse import urlparse
+from datetime import datetime
+
+client = Kernel()
+
+# Create a new Kernel app
+app = kernel.App("python-persistent-browser")
+
+class PageTitleInput(TypedDict):
+    url: str
+
+class PageTitleOutput(TypedDict):
+    title: str
+    elapsed_ms: float
+
+@app.action("get-page-title")
+async def get_page_title(ctx: kernel.KernelContext, input_data: PageTitleInput) -> PageTitleOutput:
+    """
+    A function that extracts the title of a webpage
+    
+    Args:
+        ctx: Kernel context containing invocation information
+        input_data: An object with a URL property
+        
+    Returns:
+        A dictionary containing the page title
+    """
+    url = input_data.get("url")
+    if not url or not isinstance(url, str):
+        raise ValueError("URL is required and must be a string")
+
+    # Add https:// if no protocol is present
+    if not url.startswith(('http://', 'https://')):
+        url = f"https://{url}"
+
+    # Validate the URL
+    try:
+        urlparse(url)
+    except Exception:
+        raise ValueError(f"Invalid URL: {url}")
+
+    # Create a browser instance using the context's invocation_id and a persistent id
+    kernel_browser = client.browsers.create(
+        invocation_id=ctx.invocation_id, 
+        persistence={"id": "my-awesome-persistent-browser-2"}
+    )
+    print("Kernel browser live view url: ", kernel_browser.browser_live_view_url)
+    
+    async with async_playwright() as playwright:
+        browser = await playwright.chromium.connect_over_cdp(kernel_browser.cdp_ws_url)
+        try:
+            now = datetime.now()
+            context = len(browser.contexts) > 0 and browser.contexts[0] or await browser.new_context()
+            page = len(context.pages) > 0 and context.pages[0] or await context.new_page()
+            current_url = page.url
+            print("Current url: ", current_url)
+            if current_url != url:
+                print("Not at url, navigating to it")
+                await page.goto(url)
+            else:
+                print("Already at url, skipping navigation")
+                # for some reason going straight to page.title() leads to an error: Page.title: Execution context was destroyed, most likely because of a navigation
+                # calling bring_to_front() seems to fix it :shrug:
+                await page.bring_to_front() 
+            title = await page.title()
+            elapsedMilliseconds = (datetime.now() - now).total_seconds() * 1000
+            return {"title": title, "elapsed_ms": elapsedMilliseconds}
+        finally:
+            await browser.close()

templates/python/persistent-browser/pyproject.toml

@@ -0,0 +1,10 @@
+[project]
+name = "persistent-browser"
+version = "0.1.0"
+description = "Basic Kernel application that demonstrates the use of persistent browsers"
+readme = "README.md"
+requires-python = ">=3.11"
+dependencies = ["kernel==0.3.0", "playwright>=1.52.0"]
+
+[dependency-groups]
+dev = ["mypy>=1.15.0"]

templates/python/persistent-browser/uv.lock

@@ -4,7 +4,7 @@ version = "0.1.0"
 description = "Kernel application template - Python"
 readme = "README.md"
 requires-python = ">=3.11"
-dependencies = ["kernel==0.2.0", "playwright>=1.52.0"]
+dependencies = ["kernel==0.3.0", "playwright>=1.52.0"]
 
 [dependency-groups]
 dev = ["mypy>=1.15.0"]

templates/python/sample-app/pyproject.toml

@@ -0,0 +1,39 @@
+# Dependencies
+node_modules/
+package-lock.json
+
+# TypeScript
+*.tsbuildinfo
+dist/
+build/
+
+# Environment
+.env
+.env.local
+.env.*.local
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+logs/
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Testing
+coverage/
+.nyc_output/
+
+# Misc
+.cache/
+.temp/
+.tmp/ 

templates/typescript/persistent-browser/.gitignore

@@ -0,0 +1,5 @@
+# Kernel Typscript Persistent Browser Example
+
+This is a simple Kernel application that extracts the title from a webpage, but uses a persistent browser to avoid navigations on subsequent invocations.
+
+See the [docs](https://docs.onkernel.com/quickstart) for information.

templates/typescript/persistent-browser/README.md

@@ -0,0 +1,80 @@
+import { Kernel, type KernelContext } from "@onkernel/sdk";
+import { chromium, type BrowserContext, type Page } from "playwright";
+
+const kernel = new Kernel();
+
+const app = kernel.app("ts-persistent-browser");
+
+interface PageTitleInput {
+  url: string;
+}
+
+interface PageTitleOutput {
+  title: string;
+  elapsed_ms: number;
+}
+
+app.action<PageTitleInput, PageTitleOutput>(
+  "get-page-title",
+  async (
+    ctx: KernelContext,
+    payload?: PageTitleInput
+  ): Promise<PageTitleOutput> => {
+    // A function that extracts the title of a webpage
+
+    // Args:
+    //     ctx: Kernel context containing invocation information
+    //     payload: An object with a URL property
+
+    // Returns:
+    //     A dictionary containing the page title
+    if (!payload?.url) {
+      throw new Error("URL is required");
+    }
+
+    if (
+      !payload.url.startsWith("http://") &&
+      !payload.url.startsWith("https://")
+    ) {
+      payload.url = `https://${payload.url}`;
+    }
+
+    // Validate the URL
+    try {
+      new URL(payload.url);
+    } catch {
+      throw new Error(`Invalid URL: ${payload.url}`);
+    }
+
+    const kernelBrowser = await kernel.browsers.create({
+      invocation_id: ctx.invocation_id,
+      persistence: {
+        id: "ts-persistent-browser",
+      },
+    });
+
+    console.log(
+      "Kernel browser live view url: ",
+      kernelBrowser.browser_live_view_url
+    );
+
+    const browser = await chromium.connectOverCDP(kernelBrowser.cdp_ws_url);
+    try {
+      const now = Date.now();
+      const contexts = await browser.contexts();
+      let context: BrowserContext = contexts[0] ?? (await browser.newContext());
+      let page: Page = context.pages()[0] ?? (await context.newPage());
+      if (page.url() !== payload.url) {
+        console.log("navigating to", payload.url);
+        await page.goto(payload.url);
+      } else {
+        console.log("page already loaded, skipping navigation");
+        await page.bringToFront();
+      }
+      const title = await page.title();
+      return { title, elapsed_ms: Date.now() - now };
+    } finally {
+      await browser.close();
+    }
+  }
+);