playwright/docs-src/network.md

# Network

Playwright provides APIs to **monitor** and **modify** network traffic, both HTTP and HTTPS.
Any requests that page does, including [XHRs](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest) and
[fetch](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API) requests, can be tracked, modified and handled.

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## HTTP Authentication

```js
const context = await browser.newContext({
  httpCredentials: {
    username: 'bill',
    password: 'pa55w0rd',
  },
});
const page = await context.newPage();
await page.goto('https://example.com');
```

#### API reference

- [`method: Browser.newContext`]

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## Handle file downloads

```js
const [ download ] = await Promise.all([
  page.waitForEvent('download'), // <-- start waiting for the download
  page.click('button#delayed-download') // <-- perform the action that directly or indirectly initiates it.
]);
const path = await download.path();
```

For every attachment downloaded by the page, [`event: Page.download`] event is emitted. If you create a browser context with the `acceptDownloads: true`, all these attachments are going to be downloaded into a temporary folder. You can obtain the download url, file system path and payload stream using the [Download] object from the event.

#### Variations

If you have no idea what initiates the download, you can still handle the event:

```js
page.on('download', download => download.path().then(console.log));
```

Note that handling the event forks the control flow and makes script harder to follow. Your scenario might end while you are downloading a file since your main control flow is not awaiting for this operation to resolve.

#### API reference

- [Download]
- [`event: Page.download`]
- [`method: Page.waitForEvent`]

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## Network events

You can monitor all the requests and responses:

```js
const { chromium, webkit, firefox } = require('playwright');

(async () => {
  const browser = await chromium.launch();
  const page = await browser.newPage();

  // Subscribe to 'request' and 'response' events.
  page.on('request', request =>
      console.log('>>', request.method(), request.url()));
  page.on('response', response =>
      console.log('<<', response.status(), response.url()));
  await page.goto('https://example.com');

  await browser.close();
})();
```

Or wait for a network response after the button click:

```js
// Use a glob URL pattern
const [response] = await Promise.all([
  page.waitForResponse('**/api/fetch_data'),
  page.click('button#update'),
]);
```

#### Variations

```js
// Use a RegExp
const [response] = await Promise.all([
  page.waitForResponse(/\.jpeg$/),
  page.click('button#update'),
]);

// Use a predicate taking a Response object
const [response] = await Promise.all([
  page.waitForResponse(response => response.url().includes(token)),
  page.click('button#update'),
]);
```

#### API reference

- [Request]
- [Response]
- [`event: Page.request`]
- [`event: Page.response`]
- [`method: Page.waitForRequest`]
- [`method: Page.waitForResponse`]

<br/>

## Handle requests

```js
await page.route('**/api/fetch_data', route => route.fulfill({
  status: 200,
  body: testData,
}));
await page.goto('https://example.com');
```

You can mock API endpoints via handling the network quests in your Playwright script.

#### Variations

```js
// Set up route on the entire browser context.
// It will apply to popup windows and opened links.

await browserContext.route('**/api/login', route => route.fulfill({
  status: 200,
  body: 'accept',
}));
await page.goto('https://example.com');
```

#### API reference

- [`method: BrowserContext.route`]
- [`method: BrowserContext.unroute`]
- [`method: Page.route`]
- [`method: Page.unroute`]
- [Route]

<br/>

## Modify requests

```js
// Delete header
await page.route('**/*', route => {
  const headers = route.request().headers();
  delete headers['X-Secret'];
  route.continue({headers});
});

// Continue requests as POST.
await page.route('**/*', route => route.continue({method: 'POST'}));
```

You can continue requests with modifications. Example above removes an HTTP header from the outgoing requests.

## Abort requests

```js
await page.route('**/*.{png,jpg,jpeg}', route => route.abort());

// Abort based on the request type
await page.route('**/*', route => {
  return route.request().resourceType() === 'image' ?
      route.abort() : route.continue();
});
```

#### API reference

- [`method: Page.route`]
- [`method: BrowserContext.route`]
- [`method: Route.abort`]

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