/// <summary>
/// Executes a function in browser context
/// </summary>
/// <typeparam name="T">The type to deserialize the result to</typeparam>
/// <param name="script">Script to be evaluated in browser context</param>
/// <param name="args">Arguments to pass to script</param>
/// <remarks>
/// If the script, returns a Promise, then the method would wait for the promise to resolve and return its value.
/// <see cref="JSHandle"/> instances can be passed as arguments
/// </remarks>
/// <returns>Task which resolves to script return value</returns>
public Task <T> EvaluateFunctionAsync <T>(string script, params object[] args)
{
var list = new List <object>(args);
list.Insert(0, this);
return(ExecutionContext.EvaluateFunctionAsync <T>(script, list.ToArray()));
}
private async Task ScrollIntoViewIfNeededAsync()
{
var errorMessage = await ExecutionContext.EvaluateFunctionAsync <string>(@"async(element, pageJavascriptEnabled) => {
if (!element.isConnected)
return 'Node is detached from document';
if (element.nodeType !== Node.ELEMENT_NODE)
return 'Node is not of type HTMLElement';
// force-scroll if page's javascript is disabled.
if (!pageJavascriptEnabled) {
element.scrollIntoView({block: 'center', inline: 'center', behavior: 'instant'});
return false;
}
const visibleRatio = await new Promise(resolve => {
const observer = new IntersectionObserver(entries => {
resolve(entries[0].intersectionRatio);
observer.disconnect();
});
observer.observe(element);
});
if (visibleRatio !== 1.0)
element.scrollIntoView({block: 'center', inline: 'center', behavior: 'instant'});
return false;
}", this, Page.JavascriptEnabled).ConfigureAwait(false);
if (errorMessage != null)
{
throw new PuppeteerException(errorMessage);
}
}
/// <summary>
/// This method scrolls element into view if needed, and then uses <seealso cref="Page.ScreenshotBase64Async(ScreenshotOptions)"/> to take a screenshot of the element.
/// If the element is detached from DOM, the method throws an error.
/// </summary>
/// <returns>Task which resolves to a <see cref="string"/> containing the image data as base64.</returns>
/// <param name="options">Screenshot options.</param>
public async Task <string> ScreenshotBase64Async(ScreenshotOptions options)
{
var needsViewportReset = false;
var boundingBox = await BoundingBoxAsync().ConfigureAwait(false);
if (boundingBox == null)
{
throw new PuppeteerException("Node is either not visible or not an HTMLElement");
}
var viewport = Page.Viewport;
if (viewport != null && (boundingBox.Width > viewport.Width || boundingBox.Height > viewport.Height))
{
var newRawViewport = JObject.FromObject(viewport);
newRawViewport.Merge(new ViewPortOptions
{
Width = (int)Math.Max(viewport.Width, Math.Ceiling(boundingBox.Width)),
Height = (int)Math.Max(viewport.Height, Math.Ceiling(boundingBox.Height))
});
await Page.SetViewportAsync(newRawViewport.ToObject <ViewPortOptions>()).ConfigureAwait(false);
needsViewportReset = true;
}
await ExecutionContext.EvaluateFunctionAsync(@"function(element) {
element.scrollIntoView({ block: 'center', inline: 'center', behavior: 'instant'});
}", this).ConfigureAwait(false);
await ScrollIntoViewIfNeededAsync().ConfigureAwait(false);
boundingBox = await BoundingBoxAsync().ConfigureAwait(false);
if (boundingBox == null)
{
throw new PuppeteerException("Node is either not visible or not an HTMLElement");
}
var getLayoutMetricsResponse = await Client.SendAsync <GetLayoutMetricsResponse>("Page.getLayoutMetrics").ConfigureAwait(false);
var clip = boundingBox;
clip.X += getLayoutMetricsResponse.LayoutViewport.PageX;
clip.Y += getLayoutMetricsResponse.LayoutViewport.PageY;
options.Clip = boundingBox.ToClip();
var imageData = await Page.ScreenshotBase64Async(options).ConfigureAwait(false);
if (needsViewportReset)
{
await Page.SetViewportAsync(viewport).ConfigureAwait(false);
}
return(imageData);
}
/// <summary>
/// Evaluates if the element is visible in the current viewport.
/// </summary>
/// <returns>A task which resolves to true if the element is visible in the current viewport.</returns>
public Task <bool> IsIntersectingViewportAsync()
=> ExecutionContext.EvaluateFunctionAsync <bool>(@"async element =>
{
const visibleRatio = await new Promise(resolve =>
{
const observer = new IntersectionObserver(entries =>
{
resolve(entries[0].intersectionRatio);
observer.disconnect();
});
observer.observe(element);
});
return visibleRatio > 0;
}", this);
private async Task ScrollIntoViewIfNeededAsync()
{
var errorMessage = await ExecutionContext.EvaluateFunctionAsync <string>(@"element => {
if (!element.isConnected)
return 'Node is detached from document';
if (element.nodeType !== Node.ELEMENT_NODE)
return 'Node is not of type HTMLElement';
element.scrollIntoViewIfNeeded();
return null;
}", this);
if (errorMessage != null)
{
throw new PuppeteerException(errorMessage);
}
}
/// <summary>
/// This method scrolls element into view if needed, and then uses <seealso cref="Page.ScreenshotDataAsync(ScreenshotOptions)"/> to take a screenshot of the element.
/// If the element is detached from DOM, the method throws an error.
/// </summary>
/// <returns>Task which resolves to a <see cref="byte"/>[] containing the image data.</returns>
/// <param name="options">Screenshot options.</param>
public async Task <byte[]> ScreenshotDataAsync(ScreenshotOptions options)
{
var needsViewportReset = false;
var boundingBox = await AssertBoundingBoxAsync();
var viewport = Page.Viewport;
if (boundingBox.Width > viewport.Width || boundingBox.Height > viewport.Height)
{
var newRawViewport = JObject.FromObject(viewport);
newRawViewport.Merge(new ViewPortOptions
{
Width = (int)Math.Max(viewport.Width, Math.Ceiling(boundingBox.Width)),
Height = (int)Math.Max(viewport.Height, Math.Ceiling(boundingBox.Height))
});
await Page.SetViewportAsync(newRawViewport.ToObject <ViewPortOptions>());
needsViewportReset = true;
}
await ExecutionContext.EvaluateFunctionAsync(@"function(element) {
element.scrollIntoView({ block: 'center', inline: 'center', behavior: 'instant'});
}", this);
boundingBox = await AssertBoundingBoxAsync();
var getLayoutMetricsResponse = await Client.SendAsync <GetLayoutMetricsResponse>("Page.getLayoutMetrics");
var clip = boundingBox;
clip.X += getLayoutMetricsResponse.LayoutViewport.PageX;
clip.Y += getLayoutMetricsResponse.LayoutViewport.PageY;
options.Clip = boundingBox.ToClip();
var imageData = await Page.ScreenshotDataAsync(options);
if (needsViewportReset)
{
await Page.SetViewportAsync(viewport);
}
return(imageData);
}
/// <summary>
/// Calls <c>focus</c> <see cref="https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/focus"/> on the element.
/// </summary>
/// <returns>Task</returns>
public Task FocusAsync() => ExecutionContext.EvaluateFunctionAsync("element => element.focus()", this);
