Nothing
R/chromote_session.R
In chromote: Headless Chrome Web Browser Interface
Defines functions
create_session
#' ChromoteSession class
#'
#' @description
#' This represents one _session_ in a Chromote object. Note that in the Chrome
#' DevTools Protocol a session is a debugging session connected to a _target_,
#' which is a browser window/tab or an iframe.
#'
#' A single target can potentially have more than one session connected to it,
#' but this is not currently supported by chromote.
#'
#' @export
#' @param targetId
#' [Target](https://chromedevtools.github.io/devtools-protocol/tot/Target/)
#' ID of an existing target to attach to. When a `targetId` is provided, the
#' `width` and `height` arguments are ignored. If NULL (the default) a new
#' target is created and attached to, and the `width` and `height`
#' arguments determine its viewport size.
ChromoteSession <- R6Class(
"ChromoteSession",
lock_objects = FALSE,
cloneable = FALSE,
public = list(
#' @description Create a new `ChromoteSession` object.
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Create a ChromoteSession with a specific height,width
#' b <- ChromoteSession$new(height = 1080, width = 1920)
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # View current chromote session
#' if (interactive()) b$view()
#' ```
#'
#' @param parent [`Chromote`] object to use; defaults to
#' [default_chromote_object()]
#' @param width,height Width and height of the new window in integer pixel
#' values.
#' @param wait_ If `FALSE`, return a [promises::promise()] of a new
#' `ChromoteSession` object. Otherwise, block during initialization, and
#' return a `ChromoteSession` object directly.
#' @param mobile Whether to emulate mobile device. When `TRUE`, Chrome
#' updates settings to emulate browsing on a mobile phone; this includes
#' viewport meta tag, overlay scrollbars, text autosizing and more. The
#' default is `FALSE`.
#' @param auto_events If `NULL` (the default), use the `auto_events` setting
#' from the parent `Chromote` object. If `TRUE`, enable automatic
#' event enabling/disabling; if `FALSE`, disable automatic event
#' enabling/disabling.
#' @return A new `ChromoteSession` object.
initialize = function(
parent = default_chromote_object(),
width = 992,
height = 1323,
targetId = NULL,
wait_ = TRUE,
auto_events = NULL,
mobile = FALSE
) {
check_number_whole(width)
check_number_whole(height)
check_logical(auto_events, allow_null = TRUE)
check_logical(mobile)
check_logical(wait_)
self$parent <- parent
lockBinding("parent", self) # do not allow `$parent` to be set!
self$default_timeout <- parent$default_timeout
# Create a session from the Chromote. Basically the same code as
# new_session(), but this is synchronous.
if (is.null(targetId)) {
# In earlier versions of chromote (< 0.5.0), we set `width` and `height`
# in `Target.createTarget`. With legacy (old) headless mode, each new
# session was essentially a tab in a new window. With new headless mode,
# introduced with Chrome v128, new tabs are created in existing windows.
# For Chrome v128-v133, `width` and `height` in `Target.createTarget`
# were ignored completely, and for v134+ they only have an effect when
# creating a new window, i.e. for the first ChromoteSession. We now use
# `Emulation.setDeviceMetricsOverride` below to set the viewport
# dimensions, which works across all versions of Chrome/headless-shell
# regardless of the parent window size.
p <- parent$Target$createTarget("about:blank", wait_ = FALSE)$then(
function(value) {
private$target_id <- value$targetId
parent$Target$attachToTarget(
value$targetId,
flatten = TRUE,
wait_ = FALSE
)
}
)
} else {
private$target_id <- targetId
p <- parent$Target$attachToTarget(
targetId,
flatten = TRUE,
wait_ = FALSE
)
}
p <- p$then(function(value) {
private$session_id <- value$sessionId
self$parent$register_session(self)
})
# Whenever a command method (like x$Page$navigate()) is executed, it calls
# x$send_command(). This object's send_command() method calls the parent's
# send_command() method with a sessionId -- that is how the command is
# scoped to this session.
self$protocol <- protocol_reassign_envs(
parent$protocol,
env = self$.__enclos_env__
)
lockBinding("protocol", self)
# Graft the entries from self$protocol onto self
list2env(self$protocol, self)
private$auto_events <- auto_events
private$event_manager <- EventManager$new(self)
private$session_is_active <- TRUE
private$target_is_active <- TRUE
# Find pixelRatio for screenshots
p <- p$then(function(value) {
private$get_pixel_ratio()
})
if (is.null(targetId)) {
# `Emulation.setDeviceMetricsOverride` is equivalent to turning on
# responsive preview in developer tools and lets us adjust the size of
# the viewport for the active session. This avoids setting the size of
# the parent browser window and ensures that the viewport of the current
# tab has dimensions that exactly match the requested `width` and
# `height`.
p <- p$then(function(value) {
self$Emulation$setDeviceMetricsOverride(
width = width,
height = height,
deviceScaleFactor = private$pixel_ratio,
mobile = mobile,
wait_ = FALSE
)
})
}
# When a target crashes, raise a warning.
if (!is.null(self$Inspector$targetCrashed)) {
p <- p$then(function(value) {
self$Inspector$targetCrashed(
timeout_ = NULL,
wait_ = FALSE,
function(value) {
warning(
"Chromote has received a Inspector.targetCrashed event. This means that the ChromoteSession has probably crashed."
)
# Even if no targetId nor sessionId is returned by Inspector.targetCashed
# mark the session as closed. This will close all sessions..
self$mark_closed(TRUE)
}
)
})
}
if (wait_) {
self$wait_for(p)
} else {
# If wait_=FALSE, then we can't use the usual strategy of just
# returning p, because the call to ChromoteSession$new() always
# returns the new object. Instead, we'll store it as
# private$init_promise_, and the user can retrieve it with
# b$get_init_promise().
private$init_promise_ <- p$then(function(value) self)
}
},
#' @description Display the current session in the [`Chromote`] browser.
#'
#' If a [`Chrome`] browser is being used, this method will open a new tab
#' using your [`Chrome`] browser. When not using a [`Chrome`] browser, set
#' `options(browser=)` to change the default behavior of [`browseURL()`].
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # View current chromote session
#' if (interactive()) b$view()
#' ```
view = function() {
# A data frame of targets, one row per target.
info <- fromJSON(self$parent$url("/json"))
path <- info$devtoolsFrontendUrl[info$id == private$target_id]
if (length(path) == 0) {
stop("Target info not found.")
}
browse_url(path, self$parent)
},
#' @description Close the Chromote session.
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # Close current chromote session
#' b$close()
#' ```
#'
#' @param wait_ If `FALSE`, return a [promises::promise()] that will resolve
#' when the `ChromoteSession` is closed. Otherwise, block until the
#' `ChromoteSession` has closed.
close = function(wait_ = TRUE) {
if (!private$target_is_active) {
return(invisible())
}
# Even if this session calls Target.closeTarget, the response from
# the browser is sent without a sessionId. In order to wait for the
# correct browser response, we need to invoke this from the parent's
# browser-level methods.
p <- self$parent$protocol$Target$closeTarget(
private$target_id,
wait_ = FALSE
)
p <- p$then(function(value) {
if (isTRUE(value$success)) {
self$mark_closed(TRUE)
}
invisible(value$success)
})
if (wait_) {
self$wait_for(p)
} else {
p
}
},
#' @description Get the viewport size
#'
#' @param wait_ If `FALSE`, return a [promises::promise()] of a new
#' `ChromoteSession` object. Otherwise, block during initialization, and
#' return a `ChromoteSession` object directly.
#'
#' @return Returns a list with values `width`, `height`, `zoom`
#' and `mobile`. See `$set_viewport_size()` for more details.
get_viewport_size = function(wait_ = TRUE) {
check_bool(wait_)
p <- self$Page$getLayoutMetrics(wait_ = FALSE)$then(function(value) {
list(
width = value$cssVisualViewport$clientWidth,
height = value$cssVisualViewport$clientHeight
)
})$then(function(value) {
list(
width = value$width,
height = value$height,
zoom = private$pixel_ratio %||% 0,
mobile = private$is_mobile
)
})
if (wait_) self$wait_for(p) else p
},
#' @description Set the viewport size
#'
#' Each ChromoteSession is associated with a page that may be one page open
#' in a browser window among many. Each page can have its own viewport size,
#' that can be thought of like the window size for that page.
#'
#' This function uses the
#' [Emulation.setDeviceMetricsOverride](https://chromedevtools.github.io/devtools-protocol/tot/Emulation/#method-setDeviceMetricsOverride)
#' command to set the viewport size. If you need more granular control or
#' access to additional settings, use
#' `$Emulation$setDeviceMetricsOverride()`.
#'
#' @param width,height Width and height of the new window in integer pixel
#' values.
#' @param zoom The zoom level of displayed content on a device, where a
#' value of 1 indicates normal size, greater than 1 indicates zoomed in,
#' and less than 1 indicates zoomed out.
#' @param mobile Whether to emulate mobile device. When `TRUE`, Chrome
#' updates settings to emulate browsing on a mobile phone; this includes
#' viewport meta tag, overlay scrollbars, text autosizing and more. The
#' default is `FALSE`.
#' @param wait_ If `FALSE`, return a [promises::promise()] of a new
#' `ChromoteSession` object. Otherwise, block during initialization, and
#' return a `ChromoteSession` object directly.
#'
#' @return Invisibly returns the previous viewport dimensions so that you
#' can restore the viewport size, if desired.
set_viewport_size = function(
width,
height,
zoom = NULL,
mobile = NULL,
wait_ = TRUE
) {
check_number_whole(width)
check_number_whole(height)
check_number_decimal(zoom, allow_null = TRUE)
check_bool(mobile, allow_null = TRUE)
check_bool(wait_)
prev_bounds <- NULL
p <- self$get_viewport_size(wait_ = FALSE)$then(function(value) {
prev_bounds <<- value
self$Emulation$setDeviceMetricsOverride(
width = width,
height = height,
deviceScaleFactor = zoom %||% private$pixel_ratio %||% 0,
mobile = mobile %||% private$is_mobile %||% FALSE,
wait_ = FALSE
)
})$then(function(value) {
prev_bounds
})
if (wait_) invisible(self$wait_for(p)) else p
},
#' @description Take a PNG screenshot
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # Take screenshot
#' tmppngfile <- tempfile(fileext = ".png")
#' is_interactive <- interactive() # Display screenshot if interactive
#' b$screenshot(tmppngfile, show = is_interactive)
#'
#' # Show screenshot file info
#' unlist(file.info(tmppngfile))
#'
#'
#' # Take screenshot using a selector
#' sidebar_file <- tempfile(fileext = ".png")
#' b$screenshot(sidebar_file, selector = ".sidebar", show = is_interactive)
#'
#' # ----------------------------
#' # Take screenshots in parallel
#'
#' urls <- c(
#' "https://www.r-project.org/",
#' "https://github.com/",
#' "https://news.ycombinator.com/"
#' )
#' # Helper method that:
#' # 1. Navigates to the given URL
#' # 2. Waits for the page loaded event to fire
#' # 3. Takes a screenshot
#' # 4. Prints a message
#' # 5. Close the ChromoteSession
#' screenshot_p <- function(url, filename = NULL) {
#' if (is.null(filename)) {
#' filename <- gsub("^.*://", "", url)
#' filename <- gsub("/", "_", filename)
#' filename <- gsub("\\.", "_", filename)
#' filename <- sub("_$", "", filename)
#' filename <- paste0(filename, ".png")
#' }
#'
#' b2 <- b$new_session()
#' b2$Page$navigate(url, wait_ = FALSE)
#' b2$Page$loadEventFired(wait_ = FALSE)$
#' then(function(value) {
#' b2$screenshot(filename, wait_ = FALSE)
#' })$
#' then(function(value) {
#' message(filename)
#' })$
#' finally(function() {
#' b2$close()
#' })
#' }
#'
#' # Take multiple screenshots simultaneously
#' ps <- lapply(urls, screenshot_p)
#' pa <- promises::promise_all(.list = ps)$then(function(value) {
#' message("Done!")
#' })
#'
#' # Block the console until the screenshots finish (optional)
#' b$wait_for(pa)
#' #> www_r-project_org.png
#' #> github_com.png
#' #> news_ycombinator_com.png
#' #> Done!
#' ```
#'
#' @param filename File path of where to save the screenshot. The format of
#' the screenshot is inferred from the file extension; use
#' `options = list(format = "jpeg")` to manually choose the format. See
#' [`Page.captureScreenshot`](https://chromedevtools.github.io/devtools-protocol/tot/Page/#method-captureScreenshot)
#' for supported formats; at the time of this release the format options
#' were `"png"` (default), `"jpeg"`, or `"webp"`.
#' @param selector CSS selector to use for the screenshot.
#' @param cliprect An unnamed vector or list containing values for `top`,
#' `left`, `width`, and `height`, in that order. See
#' [`Page.Viewport`](https://chromedevtools.github.io/devtools-protocol/tot/Page/#type-Viewport)
#' for more information. If provided, `selector` and `expand` will be
#' ignored. To provide a scale, use the `scale` parameter.
#' @param region CSS region to use for the screenshot.
#' @param expand Extra pixels to expand the screenshot. May be a single
#' value or a numeric vector of top, right, bottom, left values.
#' @param scale Page scale factor
#' @param show If `TRUE`, the screenshot will be displayed in the viewer.
#' @param delay The number of seconds to wait before taking the screenshot
#' after resizing the page. For complicated pages, this may need to be
#' increased.
#' @param options Additional options passed to
#' [`Page.captureScreenshot`](https://chromedevtools.github.io/devtools-protocol/tot/Page/#method-captureScreenshot).
#' @param wait_ If `FALSE`, return a [promises::promise()] that will resolve
#' when the `ChromoteSession` has saved the screenshot. Otherwise, block
#' until the `ChromoteSession` has saved the screenshot.
screenshot = function(
filename = "screenshot.png",
selector = "html",
cliprect = NULL,
region = c("content", "padding", "border", "margin"),
expand = NULL,
scale = 1,
show = FALSE,
delay = 0.5,
options = list(),
wait_ = TRUE
) {
chromote_session_screenshot(
self,
private,
filename = filename,
selector = selector,
cliprect = cliprect,
region = region,
expand = expand,
scale = scale,
show = show,
delay = delay,
options = options,
wait_ = wait_
)
},
#' @description Take a PDF screenshot
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # Take screenshot
#' tmppdffile <- tempfile(fileext = ".pdf")
#' b$screenshot_pdf(tmppdffile)
#'
#' # Show PDF file info
#' unlist(file.info(tmppdffile))
#' ```
#'
#' @param filename File path of where to save the screenshot.
#' @param pagesize A single character value in the set `"letter"`,
#' `"legal"`, `"tabloid"`, `"ledger"` and `"a0"` through `"a1"`. Or a
#' numeric vector `c(width, height)` specifying the page size.
#' @param margins A numeric vector `c(top, right, bottom, left)` specifying
#' the page margins.
#' @param units Page and margin size units. Either `"in"` or `"cm"` for
#' inches and centimeters respectively.
#' @param landscape Paper orientation.
#' @param display_header_footer Display header and footer.
#' @param print_background Print background graphics.
#' @param scale Page scale factor.
#' @param wait_ If `FALSE`, return a [promises::promise()] that will resolve
#' when the `ChromoteSession` has saved the screenshot. Otherwise, block
#' until the `ChromoteSession` has saved the screnshot.
screenshot_pdf = function(
filename = "screenshot.pdf",
pagesize = "letter",
margins = 0.5,
units = c("in", "cm"),
landscape = FALSE,
display_header_footer = FALSE,
print_background = FALSE,
scale = 1,
wait_ = TRUE
) {
chromote_session_screenshot_pdf(
self,
private,
filename = filename,
pagesize = pagesize,
margins = margins,
units = units,
landscape = landscape,
display_header_footer = display_header_footer,
print_background = print_background,
scale = scale,
wait_ = wait_
)
},
#' @description Create a new tab / window
#'
#' ## Examples
#'
#' ```r
#' b1 <- ChromoteSession$new()
#' b1$Page$navigate("http://www.google.com")
#' b2 <- b1$new_session()
#' b2$Page$navigate("http://www.r-project.org/")
#' b1$Runtime$evaluate("window.location", returnByValue = TRUE)$result$value$href
#' #> [1] "https://www.google.com/"
#' b2$Runtime$evaluate("window.location", returnByValue = TRUE)$result$value$href
#' #> [1] "https://www.r-project.org/"
#' ```
#'
#' @param width,height Width and height of the new window.
#' @param wait_ If `FALSE`, return a [promises::promise()] that will resolve
#' when the `ChromoteSession` has created a new session. Otherwise, block
#' until the `ChromoteSession` has created a new session.
new_session = function(
width = 992,
height = 1323,
targetId = NULL,
wait_ = TRUE
) {
create_session(
chromote = self$parent,
width = width,
height = height,
targetId = targetId,
wait_ = wait_
)
},
#' @description
#' Retrieve the session id
get_session_id = function() {
private$session_id
},
#' @description
#' Create a new session that connects to the same target (i.e. page)
#' as this session. This is useful if the session has been closed but the target still
#' exists.
respawn = function() {
if (!private$target_is_active) {
stop("Can't respawn session; target has been closed.")
}
create_session(
chromote = self$parent,
targetId = private$target_id,
auto_events = private$auto_events
)
},
#' @description
#' Retrieve the target id
get_target_id = function() {
private$target_id
},
#' @description
#' Wait for a Chromote Session to finish. This method will block the R
#' session until the provided promise resolves. The loop from
#' `$get_child_loop()` will only advance just far enough for the promise to
#' resolve.
#'
#' ## Examples
#'
#' ```r
#' b <- ChromoteSession$new()
#'
#' # Async with promise
#' p <- b$Browser$getVersion(wait_ = FALSE)
#' p$then(str)
#'
#' # Async with callback
#' b$Browser$getVersion(wait_ = FALSE, callback_ = str)
#' ```
#'
#' @param p A promise to resolve.
wait_for = function(p) {
self$parent$wait_for(p)
},
#' @description
#' Send a debug log message to the parent [Chromote] object
#'
#' ## Examples
#'
#' ```r
#' b <- ChromoteSession$new()
#' b$parent$debug_messages(TRUE)
#' b$Page$navigate("https://www.r-project.org/")
#' #> SEND {"method":"Page.navigate","params":{"url":"https://www.r-project.org/"}| __truncated__}
#' # Turn off debug messages
#' b$parent$debug_messages(FALSE)
#' ```
#'
#' @param ... Arguments pasted together with `paste0(..., collapse = "")`.
debug_log = function(...) {
self$parent$debug_log(...)
},
#' @description
#' \pkg{later} loop.
#'
#' For expert async usage only.
get_child_loop = function() {
self$parent$get_child_loop()
},
#' @description
#' Send command through Chrome DevTools Protocol.
#'
#' For expert use only.
#' @param msg A JSON-serializable list containing `method`, and `params`.
#' @param callback Method to run when the command finishes successfully.
#' @param error Method to run if an error occurs.
#' @param timeout Number of milliseconds for Chrome DevTools Protocol
#' execute a method.
send_command = function(
msg,
callback = NULL,
error = NULL,
timeout = NULL
) {
self$check_active()
self$parent$send_command(
msg,
callback,
error,
timeout,
sessionId = private$session_id
)
},
#' @description
#' Resolved `auto_events` value.
#'
#' For internal use only.
get_auto_events = function() {
if (!is.null(private$auto_events)) {
private$auto_events
} else {
self$parent$get_auto_events()
}
},
#' @description
#' Set or retrieve the `enable` command arguments for a domain. These
#' arguments are used for the `enable` command that is called for a domain,
#' e.g. `Fetch$enable()`, when accessing an event method.
#'
#' @examples
#' if (interactive()) {
#' b <- ChromoteSession$new(
#' auto_events_enable_args = list(
#' Fetch = list(handleAuthRequests = TRUE)
#' )
#' )
#'
#' # Get current `Fetch.enable` args
#' b$auto_events_enable_args("Fetch")
#'
#' # Update the `Fetch.enable` args
#' b$auto_events_enable_args("Fetch", handleAuthRequests = FALSE)
#'
#' # Reset `Fetch.enable` args
#' b$auto_events_enable_args("Fetch", NULL)
#' }
#'
#' @param domain A command domain, e.g. `"Fetch"`.
#' @param ... Arguments to use for auto-events for the domain. If not
#' provided, returns the argument values currently in place for the
#' domain. Use `NULL` to clear the enable arguments for a domain.
auto_events_enable_args = function(domain, ...) {
dots <- dots_list(..., .named = TRUE)
if (length(dots) == 0) {
return(get_auto_events_enable_args(private, domain, self$parent))
}
set_auto_events_enable_args(self, private, domain, dots)
},
#' @description
#' Immediately call all event callback methods.
#'
#' For internal use only.
#' @param event A single event string
#' @param params A list of parameters to pass to the event callback methods.
invoke_event_callbacks = function(event, params) {
private$event_manager$invoke_event_callbacks(event, params)
},
#' @description Mark a session, and optionally, the underlying target,
#' as closed. For internal use only.
#' @param target_closed Has the underlying target been closed as well as the
#' active debugging session?
mark_closed = function(target_closed) {
private$session_is_active <- FALSE
private$target_is_active <- !target_closed
},
#' @description Retrieve active status
#' Once initialized, the value returned is `TRUE`. If `$close()` has been
#' called, this value will be `FALSE`.
is_active = function() {
private$session_is_active &&
private$target_is_active &&
self$parent$is_active()
},
#' @description Check that a session is active, erroring if not.
check_active = function() {
if (self$is_active()) {
return()
}
if (private$target_is_active) {
abort(
c(
"Session has been closed.",
i = "Call session$respawn() to create a new session that connects to the same target."
)
)
} else {
abort("Session and underlying target have been closed.")
}
},
#' @description Initial promise
#'
#' For internal use only.
get_init_promise = function() {
private$init_promise_
},
#' @description Summarise the current state of the object.
#' @param verbose The print method defaults to a brief summary
#' of the most important debugging info; use `verbose = TRUE` tp
#' see the complex R6 object.
#' @param ... Passed on to `format()` when `verbose` = TRUE
print = function(..., verbose = FALSE) {
if (verbose) {
cat(format(self, ...), sep = "\n")
} else {
if (self$is_active()) {
state <- "session + target active"
} else if (private$target_is_active) {
state <- "target active"
} else {
state <- "closed"
}
cat_line("<ChromoteSession> (", state, ")")
if (self$is_active()) cat_line(" Session ID: ", self$get_session_id())
if (private$target_is_active)
cat_line(" Target ID: ", self$get_target_id())
browser <- self$parent$get_browser()
if (browser$is_local()) {
cat_line(
" Parent PID: ",
self$parent$get_browser()$get_process()$get_pid()
)
} else {
cat_line(
" Remote Host: ",
sprintf("http://%s:%s", browser$get_host(), browser$get_port())
)
}
}
invisible(self)
},
#' @field parent [`Chromote`] object
parent = NULL,
#' @field default_timeout Default timeout in seconds for \pkg{chromote} to
#' wait for a Chrome DevTools Protocol response.
default_timeout = NULL,
#' @field protocol Dynamic protocol implementation. For expert use only!
protocol = NULL
),
private = list(
session_id = NULL,
target_id = NULL,
session_is_active = NULL,
target_is_active = NULL,
event_manager = NULL,
auto_events = NULL,
init_promise_ = NULL,
# Updated when `Emulation.setDeviceMetricsOverride` is called
is_mobile = NULL,
pixel_ratio = NULL,
get_pixel_ratio = function() {
if (!is.null(private$pixel_ratio)) {
promise_resolve(private$pixel_ratio)
} else {
self$Runtime$evaluate("window.devicePixelRatio", wait_ = FALSE)$then(
function(value) {
(private$pixel_ratio <- value$result$value)
}
)
}
},
register_event_listener = function(event, callback = NULL, timeout = NULL) {
self$check_active()
private$event_manager$register_event_listener(event, callback, timeout)
}
)
)
# Wrapper around ChromoteSession$new() that can return a promise
create_session <- function(
chromote = default_chromote_object(),
width = 992,
height = 1323,
targetId = NULL,
wait_ = TRUE,
auto_events = NULL
) {
session <- ChromoteSession$new(
parent = chromote,
width = width,
height = height,
targetId,
auto_events = auto_events,
wait_ = wait_
)
if (wait_) {
session
} else {
# ChromoteSession$new() must return a ChromoteSession object so we need a
# side-channel to return a promise
session$get_init_promise()
}
}
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Defines functions create_session
#' ChromoteSession class
#'
#' @description
#' This represents one _session_ in a Chromote object. Note that in the Chrome
#' DevTools Protocol a session is a debugging session connected to a _target_,
#' which is a browser window/tab or an iframe.
#'
#' A single target can potentially have more than one session connected to it,
#' but this is not currently supported by chromote.
#'
#' @export
#' @param targetId
#' [Target](https://chromedevtools.github.io/devtools-protocol/tot/Target/)
#' ID of an existing target to attach to. When a `targetId` is provided, the
#' `width` and `height` arguments are ignored. If NULL (the default) a new
#' target is created and attached to, and the `width` and `height`
#' arguments determine its viewport size.
ChromoteSession <- R6Class(
"ChromoteSession",
lock_objects = FALSE,
cloneable = FALSE,
public = list(
#' @description Create a new `ChromoteSession` object.
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Create a ChromoteSession with a specific height,width
#' b <- ChromoteSession$new(height = 1080, width = 1920)
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # View current chromote session
#' if (interactive()) b$view()
#' ```
#'
#' @param parent [`Chromote`] object to use; defaults to
#' [default_chromote_object()]
#' @param width,height Width and height of the new window in integer pixel
#' values.
#' @param wait_ If `FALSE`, return a [promises::promise()] of a new
#' `ChromoteSession` object. Otherwise, block during initialization, and
#' return a `ChromoteSession` object directly.
#' @param mobile Whether to emulate mobile device. When `TRUE`, Chrome
#' updates settings to emulate browsing on a mobile phone; this includes
#' viewport meta tag, overlay scrollbars, text autosizing and more. The
#' default is `FALSE`.
#' @param auto_events If `NULL` (the default), use the `auto_events` setting
#' from the parent `Chromote` object. If `TRUE`, enable automatic
#' event enabling/disabling; if `FALSE`, disable automatic event
#' enabling/disabling.
#' @return A new `ChromoteSession` object.
initialize = function(
parent = default_chromote_object(),
width = 992,
height = 1323,
targetId = NULL,
wait_ = TRUE,
auto_events = NULL,
mobile = FALSE
) {
check_number_whole(width)
check_number_whole(height)
check_logical(auto_events, allow_null = TRUE)
check_logical(mobile)
check_logical(wait_)
self$parent <- parent
lockBinding("parent", self) # do not allow `$parent` to be set!
self$default_timeout <- parent$default_timeout
# Create a session from the Chromote. Basically the same code as
# new_session(), but this is synchronous.
if (is.null(targetId)) {
# In earlier versions of chromote (< 0.5.0), we set `width` and `height`
# in `Target.createTarget`. With legacy (old) headless mode, each new
# session was essentially a tab in a new window. With new headless mode,
# introduced with Chrome v128, new tabs are created in existing windows.
# For Chrome v128-v133, `width` and `height` in `Target.createTarget`
# were ignored completely, and for v134+ they only have an effect when
# creating a new window, i.e. for the first ChromoteSession. We now use
# `Emulation.setDeviceMetricsOverride` below to set the viewport
# dimensions, which works across all versions of Chrome/headless-shell
# regardless of the parent window size.
p <- parent$Target$createTarget("about:blank", wait_ = FALSE)$then(
function(value) {
private$target_id <- value$targetId
parent$Target$attachToTarget(
value$targetId,
flatten = TRUE,
wait_ = FALSE
)
}
)
} else {
private$target_id <- targetId
p <- parent$Target$attachToTarget(
targetId,
flatten = TRUE,
wait_ = FALSE
)
}
p <- p$then(function(value) {
private$session_id <- value$sessionId
self$parent$register_session(self)
})
# Whenever a command method (like x$Page$navigate()) is executed, it calls
# x$send_command(). This object's send_command() method calls the parent's
# send_command() method with a sessionId -- that is how the command is
# scoped to this session.
self$protocol <- protocol_reassign_envs(
parent$protocol,
env = self$.__enclos_env__
)
lockBinding("protocol", self)
# Graft the entries from self$protocol onto self
list2env(self$protocol, self)
private$auto_events <- auto_events
private$event_manager <- EventManager$new(self)
private$session_is_active <- TRUE
private$target_is_active <- TRUE
# Find pixelRatio for screenshots
p <- p$then(function(value) {
private$get_pixel_ratio()
})
if (is.null(targetId)) {
# `Emulation.setDeviceMetricsOverride` is equivalent to turning on
# responsive preview in developer tools and lets us adjust the size of
# the viewport for the active session. This avoids setting the size of
# the parent browser window and ensures that the viewport of the current
# tab has dimensions that exactly match the requested `width` and
# `height`.
p <- p$then(function(value) {
self$Emulation$setDeviceMetricsOverride(
width = width,
height = height,
deviceScaleFactor = private$pixel_ratio,
mobile = mobile,
wait_ = FALSE
)
})
}
# When a target crashes, raise a warning.
if (!is.null(self$Inspector$targetCrashed)) {
p <- p$then(function(value) {
self$Inspector$targetCrashed(
timeout_ = NULL,
wait_ = FALSE,
function(value) {
warning(
"Chromote has received a Inspector.targetCrashed event. This means that the ChromoteSession has probably crashed."
)
# Even if no targetId nor sessionId is returned by Inspector.targetCashed
# mark the session as closed. This will close all sessions..
self$mark_closed(TRUE)
}
)
})
}
if (wait_) {
self$wait_for(p)
} else {
# If wait_=FALSE, then we can't use the usual strategy of just
# returning p, because the call to ChromoteSession$new() always
# returns the new object. Instead, we'll store it as
# private$init_promise_, and the user can retrieve it with
# b$get_init_promise().
private$init_promise_ <- p$then(function(value) self)
}
},
#' @description Display the current session in the [`Chromote`] browser.
#'
#' If a [`Chrome`] browser is being used, this method will open a new tab
#' using your [`Chrome`] browser. When not using a [`Chrome`] browser, set
#' `options(browser=)` to change the default behavior of [`browseURL()`].
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # View current chromote session
#' if (interactive()) b$view()
#' ```
view = function() {
# A data frame of targets, one row per target.
info <- fromJSON(self$parent$url("/json"))
path <- info$devtoolsFrontendUrl[info$id == private$target_id]
if (length(path) == 0) {
stop("Target info not found.")
}
browse_url(path, self$parent)
},
#' @description Close the Chromote session.
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # Close current chromote session
#' b$close()
#' ```
#'
#' @param wait_ If `FALSE`, return a [promises::promise()] that will resolve
#' when the `ChromoteSession` is closed. Otherwise, block until the
#' `ChromoteSession` has closed.
close = function(wait_ = TRUE) {
if (!private$target_is_active) {
return(invisible())
}
# Even if this session calls Target.closeTarget, the response from
# the browser is sent without a sessionId. In order to wait for the
# correct browser response, we need to invoke this from the parent's
# browser-level methods.
p <- self$parent$protocol$Target$closeTarget(
private$target_id,
wait_ = FALSE
)
p <- p$then(function(value) {
if (isTRUE(value$success)) {
self$mark_closed(TRUE)
}
invisible(value$success)
})
if (wait_) {
self$wait_for(p)
} else {
p
}
},
#' @description Get the viewport size
#'
#' @param wait_ If `FALSE`, return a [promises::promise()] of a new
#' `ChromoteSession` object. Otherwise, block during initialization, and
#' return a `ChromoteSession` object directly.
#'
#' @return Returns a list with values `width`, `height`, `zoom`
#' and `mobile`. See `$set_viewport_size()` for more details.
get_viewport_size = function(wait_ = TRUE) {
check_bool(wait_)
p <- self$Page$getLayoutMetrics(wait_ = FALSE)$then(function(value) {
list(
width = value$cssVisualViewport$clientWidth,
height = value$cssVisualViewport$clientHeight
)
})$then(function(value) {
list(
width = value$width,
height = value$height,
zoom = private$pixel_ratio %||% 0,
mobile = private$is_mobile
)
})
if (wait_) self$wait_for(p) else p
},
#' @description Set the viewport size
#'
#' Each ChromoteSession is associated with a page that may be one page open
#' in a browser window among many. Each page can have its own viewport size,
#' that can be thought of like the window size for that page.
#'
#' This function uses the
#' [Emulation.setDeviceMetricsOverride](https://chromedevtools.github.io/devtools-protocol/tot/Emulation/#method-setDeviceMetricsOverride)
#' command to set the viewport size. If you need more granular control or
#' access to additional settings, use
#' `$Emulation$setDeviceMetricsOverride()`.
#'
#' @param width,height Width and height of the new window in integer pixel
#' values.
#' @param zoom The zoom level of displayed content on a device, where a
#' value of 1 indicates normal size, greater than 1 indicates zoomed in,
#' and less than 1 indicates zoomed out.
#' @param mobile Whether to emulate mobile device. When `TRUE`, Chrome
#' updates settings to emulate browsing on a mobile phone; this includes
#' viewport meta tag, overlay scrollbars, text autosizing and more. The
#' default is `FALSE`.
#' @param wait_ If `FALSE`, return a [promises::promise()] of a new
#' `ChromoteSession` object. Otherwise, block during initialization, and
#' return a `ChromoteSession` object directly.
#'
#' @return Invisibly returns the previous viewport dimensions so that you
#' can restore the viewport size, if desired.
set_viewport_size = function(
width,
height,
zoom = NULL,
mobile = NULL,
wait_ = TRUE
) {
check_number_whole(width)
check_number_whole(height)
check_number_decimal(zoom, allow_null = TRUE)
check_bool(mobile, allow_null = TRUE)
check_bool(wait_)
prev_bounds <- NULL
p <- self$get_viewport_size(wait_ = FALSE)$then(function(value) {
prev_bounds <<- value
self$Emulation$setDeviceMetricsOverride(
width = width,
height = height,
deviceScaleFactor = zoom %||% private$pixel_ratio %||% 0,
mobile = mobile %||% private$is_mobile %||% FALSE,
wait_ = FALSE
)
})$then(function(value) {
prev_bounds
})
if (wait_) invisible(self$wait_for(p)) else p
},
#' @description Take a PNG screenshot
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # Take screenshot
#' tmppngfile <- tempfile(fileext = ".png")
#' is_interactive <- interactive() # Display screenshot if interactive
#' b$screenshot(tmppngfile, show = is_interactive)
#'
#' # Show screenshot file info
#' unlist(file.info(tmppngfile))
#'
#'
#' # Take screenshot using a selector
#' sidebar_file <- tempfile(fileext = ".png")
#' b$screenshot(sidebar_file, selector = ".sidebar", show = is_interactive)
#'
#' # ----------------------------
#' # Take screenshots in parallel
#'
#' urls <- c(
#' "https://www.r-project.org/",
#' "https://github.com/",
#' "https://news.ycombinator.com/"
#' )
#' # Helper method that:
#' # 1. Navigates to the given URL
#' # 2. Waits for the page loaded event to fire
#' # 3. Takes a screenshot
#' # 4. Prints a message
#' # 5. Close the ChromoteSession
#' screenshot_p <- function(url, filename = NULL) {
#' if (is.null(filename)) {
#' filename <- gsub("^.*://", "", url)
#' filename <- gsub("/", "_", filename)
#' filename <- gsub("\\.", "_", filename)
#' filename <- sub("_$", "", filename)
#' filename <- paste0(filename, ".png")
#' }
#'
#' b2 <- b$new_session()
#' b2$Page$navigate(url, wait_ = FALSE)
#' b2$Page$loadEventFired(wait_ = FALSE)$
#' then(function(value) {
#' b2$screenshot(filename, wait_ = FALSE)
#' })$
#' then(function(value) {
#' message(filename)
#' })$
#' finally(function() {
#' b2$close()
#' })
#' }
#'
#' # Take multiple screenshots simultaneously
#' ps <- lapply(urls, screenshot_p)
#' pa <- promises::promise_all(.list = ps)$then(function(value) {
#' message("Done!")
#' })
#'
#' # Block the console until the screenshots finish (optional)
#' b$wait_for(pa)
#' #> www_r-project_org.png
#' #> github_com.png
#' #> news_ycombinator_com.png
#' #> Done!
#' ```
#'
#' @param filename File path of where to save the screenshot. The format of
#' the screenshot is inferred from the file extension; use
#' `options = list(format = "jpeg")` to manually choose the format. See
#' [`Page.captureScreenshot`](https://chromedevtools.github.io/devtools-protocol/tot/Page/#method-captureScreenshot)
#' for supported formats; at the time of this release the format options
#' were `"png"` (default), `"jpeg"`, or `"webp"`.
#' @param selector CSS selector to use for the screenshot.
#' @param cliprect An unnamed vector or list containing values for `top`,
#' `left`, `width`, and `height`, in that order. See
#' [`Page.Viewport`](https://chromedevtools.github.io/devtools-protocol/tot/Page/#type-Viewport)
#' for more information. If provided, `selector` and `expand` will be
#' ignored. To provide a scale, use the `scale` parameter.
#' @param region CSS region to use for the screenshot.
#' @param expand Extra pixels to expand the screenshot. May be a single
#' value or a numeric vector of top, right, bottom, left values.
#' @param scale Page scale factor
#' @param show If `TRUE`, the screenshot will be displayed in the viewer.
#' @param delay The number of seconds to wait before taking the screenshot
#' after resizing the page. For complicated pages, this may need to be
#' increased.
#' @param options Additional options passed to
#' [`Page.captureScreenshot`](https://chromedevtools.github.io/devtools-protocol/tot/Page/#method-captureScreenshot).
#' @param wait_ If `FALSE`, return a [promises::promise()] that will resolve
#' when the `ChromoteSession` has saved the screenshot. Otherwise, block
#' until the `ChromoteSession` has saved the screenshot.
screenshot = function(
filename = "screenshot.png",
selector = "html",
cliprect = NULL,
region = c("content", "padding", "border", "margin"),
expand = NULL,
scale = 1,
show = FALSE,
delay = 0.5,
options = list(),
wait_ = TRUE
) {
chromote_session_screenshot(
self,
private,
filename = filename,
selector = selector,
cliprect = cliprect,
region = region,
expand = expand,
scale = scale,
show = show,
delay = delay,
options = options,
wait_ = wait_
)
},
#' @description Take a PDF screenshot
#'
#' ## Examples
#'
#' ```r
#' # Create a new `ChromoteSession` object.
#' b <- ChromoteSession$new()
#'
#' # Navigate to page
#' b$Page$navigate("http://www.r-project.org/")
#'
#' # Take screenshot
#' tmppdffile <- tempfile(fileext = ".pdf")
#' b$screenshot_pdf(tmppdffile)
#'
#' # Show PDF file info
#' unlist(file.info(tmppdffile))
#' ```
#'
#' @param filename File path of where to save the screenshot.
#' @param pagesize A single character value in the set `"letter"`,
#' `"legal"`, `"tabloid"`, `"ledger"` and `"a0"` through `"a1"`. Or a
#' numeric vector `c(width, height)` specifying the page size.
#' @param margins A numeric vector `c(top, right, bottom, left)` specifying
#' the page margins.
#' @param units Page and margin size units. Either `"in"` or `"cm"` for
#' inches and centimeters respectively.
#' @param landscape Paper orientation.
#' @param display_header_footer Display header and footer.
#' @param print_background Print background graphics.
#' @param scale Page scale factor.
#' @param wait_ If `FALSE`, return a [promises::promise()] that will resolve
#' when the `ChromoteSession` has saved the screenshot. Otherwise, block
#' until the `ChromoteSession` has saved the screnshot.
screenshot_pdf = function(
filename = "screenshot.pdf",
pagesize = "letter",
margins = 0.5,
units = c("in", "cm"),
landscape = FALSE,
display_header_footer = FALSE,
print_background = FALSE,
scale = 1,
wait_ = TRUE
) {
chromote_session_screenshot_pdf(
self,
private,
filename = filename,
pagesize = pagesize,
margins = margins,
units = units,
landscape = landscape,
display_header_footer = display_header_footer,
print_background = print_background,
scale = scale,
wait_ = wait_
)
},
#' @description Create a new tab / window
#'
#' ## Examples
#'
#' ```r
#' b1 <- ChromoteSession$new()
#' b1$Page$navigate("http://www.google.com")
#' b2 <- b1$new_session()
#' b2$Page$navigate("http://www.r-project.org/")
#' b1$Runtime$evaluate("window.location", returnByValue = TRUE)$result$value$href
#' #> [1] "https://www.google.com/"
#' b2$Runtime$evaluate("window.location", returnByValue = TRUE)$result$value$href
#' #> [1] "https://www.r-project.org/"
#' ```
#'
#' @param width,height Width and height of the new window.
#' @param wait_ If `FALSE`, return a [promises::promise()] that will resolve
#' when the `ChromoteSession` has created a new session. Otherwise, block
#' until the `ChromoteSession` has created a new session.
new_session = function(
width = 992,
height = 1323,
targetId = NULL,
wait_ = TRUE
) {
create_session(
chromote = self$parent,
width = width,
height = height,
targetId = targetId,
wait_ = wait_
)
},
#' @description
#' Retrieve the session id
get_session_id = function() {
private$session_id
},
#' @description
#' Create a new session that connects to the same target (i.e. page)
#' as this session. This is useful if the session has been closed but the target still
#' exists.
respawn = function() {
if (!private$target_is_active) {
stop("Can't respawn session; target has been closed.")
}
create_session(
chromote = self$parent,
targetId = private$target_id,
auto_events = private$auto_events
)
},
#' @description
#' Retrieve the target id
get_target_id = function() {
private$target_id
},
#' @description
#' Wait for a Chromote Session to finish. This method will block the R
#' session until the provided promise resolves. The loop from
#' `$get_child_loop()` will only advance just far enough for the promise to
#' resolve.
#'
#' ## Examples
#'
#' ```r
#' b <- ChromoteSession$new()
#'
#' # Async with promise
#' p <- b$Browser$getVersion(wait_ = FALSE)
#' p$then(str)
#'
#' # Async with callback
#' b$Browser$getVersion(wait_ = FALSE, callback_ = str)
#' ```
#'
#' @param p A promise to resolve.
wait_for = function(p) {
self$parent$wait_for(p)
},
#' @description
#' Send a debug log message to the parent [Chromote] object
#'
#' ## Examples
#'
#' ```r
#' b <- ChromoteSession$new()
#' b$parent$debug_messages(TRUE)
#' b$Page$navigate("https://www.r-project.org/")
#' #> SEND {"method":"Page.navigate","params":{"url":"https://www.r-project.org/"}| __truncated__}
#' # Turn off debug messages
#' b$parent$debug_messages(FALSE)
#' ```
#'
#' @param ... Arguments pasted together with `paste0(..., collapse = "")`.
debug_log = function(...) {
self$parent$debug_log(...)
},
#' @description
#' \pkg{later} loop.
#'
#' For expert async usage only.
get_child_loop = function() {
self$parent$get_child_loop()
},
#' @description
#' Send command through Chrome DevTools Protocol.
#'
#' For expert use only.
#' @param msg A JSON-serializable list containing `method`, and `params`.
#' @param callback Method to run when the command finishes successfully.
#' @param error Method to run if an error occurs.
#' @param timeout Number of milliseconds for Chrome DevTools Protocol
#' execute a method.
send_command = function(
msg,
callback = NULL,
error = NULL,
timeout = NULL
) {
self$check_active()
self$parent$send_command(
msg,
callback,
error,
timeout,
sessionId = private$session_id
)
},
#' @description
#' Resolved `auto_events` value.
#'
#' For internal use only.
get_auto_events = function() {
if (!is.null(private$auto_events)) {
private$auto_events
} else {
self$parent$get_auto_events()
}
},
#' @description
#' Set or retrieve the `enable` command arguments for a domain. These
#' arguments are used for the `enable` command that is called for a domain,
#' e.g. `Fetch$enable()`, when accessing an event method.
#'
#' @examples
#' if (interactive()) {
#' b <- ChromoteSession$new(
#' auto_events_enable_args = list(
#' Fetch = list(handleAuthRequests = TRUE)
#' )
#' )
#'
#' # Get current `Fetch.enable` args
#' b$auto_events_enable_args("Fetch")
#'
#' # Update the `Fetch.enable` args
#' b$auto_events_enable_args("Fetch", handleAuthRequests = FALSE)
#'
#' # Reset `Fetch.enable` args
#' b$auto_events_enable_args("Fetch", NULL)
#' }
#'
#' @param domain A command domain, e.g. `"Fetch"`.
#' @param ... Arguments to use for auto-events for the domain. If not
#' provided, returns the argument values currently in place for the
#' domain. Use `NULL` to clear the enable arguments for a domain.
auto_events_enable_args = function(domain, ...) {
dots <- dots_list(..., .named = TRUE)
if (length(dots) == 0) {
return(get_auto_events_enable_args(private, domain, self$parent))
}
set_auto_events_enable_args(self, private, domain, dots)
},
#' @description
#' Immediately call all event callback methods.
#'
#' For internal use only.
#' @param event A single event string
#' @param params A list of parameters to pass to the event callback methods.
invoke_event_callbacks = function(event, params) {
private$event_manager$invoke_event_callbacks(event, params)
},
#' @description Mark a session, and optionally, the underlying target,
#' as closed. For internal use only.
#' @param target_closed Has the underlying target been closed as well as the
#' active debugging session?
mark_closed = function(target_closed) {
private$session_is_active <- FALSE
private$target_is_active <- !target_closed
},
#' @description Retrieve active status
#' Once initialized, the value returned is `TRUE`. If `$close()` has been
#' called, this value will be `FALSE`.
is_active = function() {
private$session_is_active &&
private$target_is_active &&
self$parent$is_active()
},
#' @description Check that a session is active, erroring if not.
check_active = function() {
if (self$is_active()) {
return()
}
if (private$target_is_active) {
abort(
c(
"Session has been closed.",
i = "Call session$respawn() to create a new session that connects to the same target."
)
)
} else {
abort("Session and underlying target have been closed.")
}
},
#' @description Initial promise
#'
#' For internal use only.
get_init_promise = function() {
private$init_promise_
},
#' @description Summarise the current state of the object.
#' @param verbose The print method defaults to a brief summary
#' of the most important debugging info; use `verbose = TRUE` tp
#' see the complex R6 object.
#' @param ... Passed on to `format()` when `verbose` = TRUE
print = function(..., verbose = FALSE) {
if (verbose) {
cat(format(self, ...), sep = "\n")
} else {
if (self$is_active()) {
state <- "session + target active"
} else if (private$target_is_active) {
state <- "target active"
} else {
state <- "closed"
}
cat_line("<ChromoteSession> (", state, ")")
if (self$is_active()) cat_line(" Session ID: ", self$get_session_id())
if (private$target_is_active)
cat_line(" Target ID: ", self$get_target_id())
browser <- self$parent$get_browser()
if (browser$is_local()) {
cat_line(
" Parent PID: ",
self$parent$get_browser()$get_process()$get_pid()
)
} else {
cat_line(
" Remote Host: ",
sprintf("http://%s:%s", browser$get_host(), browser$get_port())
)
}
}
invisible(self)
},
#' @field parent [`Chromote`] object
parent = NULL,
#' @field default_timeout Default timeout in seconds for \pkg{chromote} to
#' wait for a Chrome DevTools Protocol response.
default_timeout = NULL,
#' @field protocol Dynamic protocol implementation. For expert use only!
protocol = NULL
),
private = list(
session_id = NULL,
target_id = NULL,
session_is_active = NULL,
target_is_active = NULL,
event_manager = NULL,
auto_events = NULL,
init_promise_ = NULL,
# Updated when `Emulation.setDeviceMetricsOverride` is called
is_mobile = NULL,
pixel_ratio = NULL,
get_pixel_ratio = function() {
if (!is.null(private$pixel_ratio)) {
promise_resolve(private$pixel_ratio)
} else {
self$Runtime$evaluate("window.devicePixelRatio", wait_ = FALSE)$then(
function(value) {
(private$pixel_ratio <- value$result$value)
}
)
}
},
register_event_listener = function(event, callback = NULL, timeout = NULL) {
self$check_active()
private$event_manager$register_event_listener(event, callback, timeout)
}
)
)
# Wrapper around ChromoteSession$new() that can return a promise
create_session <- function(
chromote = default_chromote_object(),
width = 992,
height = 1323,
targetId = NULL,
wait_ = TRUE,
auto_events = NULL
) {
session <- ChromoteSession$new(
parent = chromote,
width = width,
height = height,
targetId,
auto_events = auto_events,
wait_ = wait_
)
if (wait_) {
session
} else {
# ChromoteSession$new() must return a ChromoteSession object so we need a
# side-channel to return a promise
session$get_init_promise()
}
}
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