Configurable download behavior

[inancgumus]

What?

Add support to make download behavior configurable:

• Downloading can be turned on or off.
• Downloads are turned on by default in local runs.
• Downloads are turned off in remote runs for security reasons.
• User can set where to download files.
• Create temporary directories if the download path is unset.

Why?

Turning off is required because some scripts hang when the file choosers open.

Turning on is required when users want to download files and see where the files are.

How?

Turning On and Off Downloads

We can control the download behavior using the existing BrowserContext.acceptDownloads option:

const context = await browser.newContext({
    acceptDownloads: false,
});

However, although we have the option implemented (set to false by default), we don't use it in the module code. So, the module's current behavior is always to accept downloads and open file choosers.

The goal of this issue is to use this option to control download behavior.

Other tools set this option to true by default. One advantage of keeping it false is that it lets us learn about user behavior. The disadvantage is that users would need to explicitly set it to true to make downloading in their scripts work. We'll set the option to true by default to match the general industry.

Setting the download path

We can let users where to save files using the downloadsPath option:

const context = await browser.newContext({
    acceptDownloads: true,
    downloadsPath: '/my/directory',
});

When set, files are downloaded into the directory. Otherwise, they're saved in a temporary directory.

CDP API

action := cdpbrowser.
	SetDownloadBehavior(/* configurable */).
	WithDownloadPath(/* configurable */).
	WithBrowserContextID(...)

Explanation:

• SetDownloadBehaviorBehaviorDefault: Opens a file chooser by default. This is the browser module's current behavior even without calling SetDownloadBehavior.
• SetDownloadBehaviorBehaviorAllow: Automatically downloads files to a user-specified folder. Other tools randomly pick a directory name if not specified. We'll follow suit.
• SetDownloadBehaviorBehaviorDeny: Denies downloads. We'll set this based on the user's request or if the test run is on the cloud.

Tasks

Tasks

Preview Give feedback

1. Add browserContext.downloadsPath xk6-browser#1496
   feature +1
   
2. PR: Add acceptDownloads to newContext and newPage
3. PR: Set acceptDownloads to true by default
4. PR: Activate acceptDownloads CDP calls
5. PR: Turn off acceptDownloads for remote runs
6. Add a JavaScript example
7. Docs PR
8. Update the k6 release notes for each PR and tasks

Related PR(s)/Issue(s)

#4233

[ankur22]

I like this new proposal where we're working with an existing field on browserContext 🙏

const context = await browser.newContext({
    acceptDownloads: false,
});