playwright/docs/src/api/class-cdpsession.md

class: CDPSession

• since: v1.8
• extends: [EventEmitter]

The CDPSession instances are used to talk raw Chrome Devtools Protocol:

• protocol methods can be called with session.send method.
• protocol events can be subscribed to with session.on method.

Useful links:

• Documentation on DevTools Protocol can be found here: DevTools Protocol Viewer.
• Getting Started with DevTools Protocol: https://github.com/aslushnikov/getting-started-with-cdp/blob/master/README.md

const client = await page.context().newCDPSession(page);
await client.send('Animation.enable');
client.on('Animation.animationCreated', () => console.log('Animation created!'));
const response = await client.send('Animation.getPlaybackRate');
console.log('playback rate is ' + response.playbackRate);
await client.send('Animation.setPlaybackRate', {
  playbackRate: response.playbackRate / 2
});

client = await page.context.new_cdp_session(page)
await client.send("Animation.enable")
client.on("Animation.animationCreated", lambda: print("animation created!"))
response = await client.send("Animation.getPlaybackRate")
print("playback rate is " + str(response["playbackRate"]))
await client.send("Animation.setPlaybackRate", {
    "playbackRate": response["playbackRate"] / 2
})

client = page.context.new_cdp_session(page)
client.send("Animation.enable")
client.on("Animation.animationCreated", lambda: print("animation created!"))
response = client.send("Animation.getPlaybackRate")
print("playback rate is " + str(response["playbackRate"]))
client.send("Animation.setPlaybackRate", {
    "playbackRate": response["playbackRate"] / 2
})

var client = await Page.Context.NewCDPSessionAsync(Page);
await client.SendAsync("Runtime.enable");
client.Event("Animation.animationCreated").OnEvent += (_, _) => Console.WriteLine("Animation created!");
var response = await client.SendAsync("Animation.getPlaybackRate");
var playbackRate = response.Value.GetProperty("playbackRate").GetDouble();
Console.WriteLine("playback rate is " + playbackRate);
await client.SendAsync("Animation.setPlaybackRate", new() { { "playbackRate", playbackRate / 2 } });

CDPSession client = page.context().newCDPSession(page);
client.send("Runtime.enable");

client.on("Animation.animationCreated", (event) -> System.out.println("Animation created!"));

JsonObject response = client.send("Animation.getPlaybackRate");
double playbackRate = response.get("playbackRate").getAsDouble();
System.out.println("playback rate is " + playbackRate);

JsonObject params = new JsonObject();
params.addProperty("playbackRate", playbackRate / 2);
client.send("Animation.setPlaybackRate", params);

async method: CDPSession.detach

• since: v1.8

Detaches the CDPSession from the target. Once detached, the CDPSession object won't emit any events and can't be used to send messages.

async method: CDPSession.send

• since: v1.8

• returns: <[Object]>

async method: CDPSession.send

• since: v1.30
• langs: csharp

• returns: <[JsonElement?]>

async method: CDPSession.send

• since: v1.37
• langs: java

• returns: <[JsonObject]>

param: CDPSession.send.method

• since: v1.8

• method <[string]>

Protocol method name.

param: CDPSession.send.params

• since: v1.8
• langs: js, python

• params ?<[Object]>

Optional method parameters.

param: CDPSession.send.params

• since: v1.30
• langs: csharp
  • alias-csharp: args

• params ?<[Map<string, Object>]>

Optional method parameters.

param: CDPSession.send.params

• since: v1.37
• langs: java
  • alias-java: args

• params ?<[JsonObject]>

Optional method parameters.

method: CDPSession.event

• since: v.1.30
• langs: csharp

• returns: <[CDPSessionEvent]>

Returns an event emitter for the given CDP event name.

param: CDPSession.event.eventName

• since: v1.30
• langs: csharp

• eventName <[string]>

CDP event name.

method: CDPSession.on

• since: v1.37
• langs: java

Register an event handler for events with the specified event name. The given handler will be called for every event with the given name.

param: CDPSession.on.eventName

• since: v1.37

• eventName <[string]>

CDP event name.

param: CDPSession.on.handler

• since: v1.37

• handler <[function]([JsonObject])>

Event handler.

method: CDPSession.off

• since: v1.37
• langs: java

Unregister an event handler for events with the specified event name. The given handler will not be called anymore for events with the given name.

param: CDPSession.off.eventName

• since: v1.37

• eventName <[string]>

CDP event name.

param: CDPSession.off.handler

• since: v1.37

• handler <[function]([JsonObject])>

Event handler.