/// <summary>
/// Executes a script in browser context
/// </summary>
/// <param name="pageFunction">Script to be evaluated in browser context</param>
/// <param name="args">Function arguments</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 <JSHandle> EvaluateFunctionHandleAsync(string pageFunction, params object[] args)
{
var list = new List <object>(args);
list.Insert(0, this);
return(ExecutionContext.EvaluateFunctionHandleAsync(pageFunction, list.ToArray()));
}
/// <summary>
/// Runs <c>element.querySelectorAll</c> within the page. If no elements match the selector, the return value resolve to <see cref="Array.Empty{T}"/>.
/// </summary>
/// <param name="selector">A selector to query element for</param>
/// <returns>Task which resolves to ElementHandles pointing to the frame elements</returns>
public async Task <ElementHandle[]> QuerySelectorAllAsync(string selector)
{
var arrayHandle = await ExecutionContext.EvaluateFunctionHandleAsync(
"(element, selector) => element.querySelectorAll(selector)",
this, selector);
var properties = await arrayHandle.GetPropertiesAsync();
await arrayHandle.DisposeAsync();
return(properties.Values.OfType <ElementHandle>().ToArray());
}
/// <summary>
/// The method runs <c>element.querySelector</c> within the page. If no element matches the selector, the return value resolve to <c>null</c>.
/// </summary>
/// <param name="selector">A selector to query element for</param>
/// <returns>Task which resolves to <see cref="ElementHandle"/> pointing to the frame element</returns>
public async Task <ElementHandle> QuerySelectorAsync(string selector)
{
var handle = await ExecutionContext.EvaluateFunctionHandleAsync(
"(element, selector) => element.querySelector(selector)",
this, selector);
if (handle is ElementHandle element)
{
return(element);
}
await handle.DisposeAsync();
return(null);
}
/// <summary>
/// Fetches a single property from the referenced object
/// </summary>
/// <param name="propertyName">property to get</param>
/// <returns>Task of <see cref="JSHandle"/></returns>
public async Task <JSHandle> GetPropertyAsync(string propertyName)
{
var objectHandle = await ExecutionContext.EvaluateFunctionHandleAsync(@"(object, propertyName) => {
const result = { __proto__: null};
result[propertyName] = object[propertyName];
return result;
}", this, propertyName);
var properties = await objectHandle.GetPropertiesAsync();
properties.TryGetValue(propertyName, out var result);
await objectHandle.DisposeAsync();
return(result);
}
internal async Task <ElementHandle> GetElementAsync(string selector)
{
var handle = await ExecutionContext.EvaluateFunctionHandleAsync(
"(element, selector) => element.querySelector(selector)",
this, selector);
var element = handle.AsElement();
if (element != null)
{
return(element);
}
await handle.Dispose();
return(null);
}
/// <summary>
/// Evaluates the XPath expression relative to the elementHandle. If there's no such element, the method will resolve to <c>null</c>.
/// </summary>
/// <param name="expression">Expression to evaluate <see cref="https://developer.mozilla.org/en-US/docs/Web/API/Document/evaluate"/></param>
/// <returns>Task which resolves to an array of <see cref="ElementHandle"/></returns>
public async Task <ElementHandle[]> XPathAsync(string expression)
{
var arrayHandle = await ExecutionContext.EvaluateFunctionHandleAsync(
@"(element, expression) => {
const document = element.ownerDocument || element;
const iterator = document.evaluate(expression, element, null, XPathResult.ORDERED_NODE_ITERATOR_TYPE);
const array = [];
let item;
while ((item = iterator.iterateNext()))
array.push(item);
return array;
}",
this, expression
);
var properties = await arrayHandle.GetPropertiesAsync();
await arrayHandle.DisposeAsync();
return(properties.Values.OfType <ElementHandle>().ToArray());
}
/// <summary>
/// A utility function to be used with <see cref="Extensions.EvaluateFunctionAsync{T}(Task{JSHandle}, string, object[])"/>
/// </summary>
/// <param name="selector">A selector to query element for</param>
/// <returns>Task which resolves to a <see cref="JSHandle"/> of <c>document.querySelectorAll</c> result</returns>
public Task <JSHandle> QuerySelectorAllHandleAsync(string selector)
=> ExecutionContext.EvaluateFunctionHandleAsync(
"(element, selector) => Array.from(element.querySelectorAll(selector))", this, selector);