NAME
AnyEvent::WebDriver - control browsers using the W3C WebDriver protocol
SYNOPSIS
# start geckodriver(chromedriver or any other webdriver via the shell
$ geckodriver -b myfirefox/firefox --log trace --port 4444
# chromedriver --port=4444
# then use it
use AnyEvent::WebDriver;
# create a new webdriver object
my $wd = new AnyEvent::WebDriver;
# create a new session with default capabilities.
$wd->new_session ({});
$wd->navigate_to ("https://duckduckgo.com/html");
my $searchbox = $wd->find_element (css => 'input[type="text"]');
$wd->element_send_keys ($searchbox => "free software");
$wd->element_click ($wd->find_element (css => 'input[type="submit"]'));
# session gets autodeleted by default, so wait a bit
sleep 10;
# this is an example of an action sequence
$wd->actions
->move ($wd->find_element (...), 40, 5)
->click
->type ("some text")
->key ("{Enter}")
->perform;
DESCRIPTION
This module aims to implement the W3C WebDriver
specification which is the
standardised equivalent to the Selenium WebDriver API, which in turn
aims at remotely controlling web browsers such as Firefox or Chromium.
One of the design goals of this module was to stay very close to the
language and words used in the WebDriver specification itself, so to
make most of this module, or, in fact, to make any reasonable use of
this module, you would need to refer to the W3C WebDriver
recommendation, which can be found here
:
https://www.w3.org/TR/webdriver1/
Mozilla's "geckodriver" has had webdriver support for a long time, while
"chromedriver" only has basic and mostly undocumented webdriver support
as of release 77.
In Debian GNU/Linux, you can install the chromedriver for chromium via
the "chromium-driver" package. Unfortunately, there is no (working)
package for geckodriver, but you can download it from github
.
CONVENTIONS
Unless otherwise stated, all delays and time differences in this module
are represented as an integer number of milliseconds, which is perhaps
surprising to users of my other modules but is what the WebDriver spec
uses.
WEBDRIVER OBJECTS
new AnyEvent::WebDriver key => value...
Create a new WebDriver object. Example for a remote WebDriver
connection (the only type supported at the moment):
my $wd = new AnyEvent::WebDriver endpoint => "http://localhost:4444";
Supported keys are:
endpoint => $string
For remote connections, the endpoint to connect to (defaults to
"http://localhost:4444").
proxy => $proxyspec
The proxy to use (same as the "proxy" argument used by
AnyEvent::HTTP). The default is "undef", which disables proxies.
To use the system-provided proxy (e.g. "http_proxy" environment
variable), specify the string "default".
autodelete => $boolean
If true (the default), then automatically execute
"delete_session" when the WebDriver object is destroyed with an
active session. If set to a false value, then the session will
continue to exist.
Note that due to bugs in perl that are unlikely to get fixed,
"autodelete" is likely ineffective during global destruction and
might even crash your process, so you should ensure objects go
out of scope before that, or explicitly call "delete_session",
if you want the session to be cleaned up.
timeout => $seconds
The HTTP timeout, in (fractional) seconds (default: 300). This
timeout is reset on any activity, so it is not an overall
request timeout. Also, individual requests might extend this
timeout if they are known to take longer.
persistent => 1 | "undef"
If true (the default) then persistent connections will be used
for all requests, which assumes you have a reasonably stable
connection (such as to "localhost" :) and that the WebDriver has
a persistent timeout much higher than what AnyEvent::HTTP uses.
You can force connections to be closed for non-idempotent
requests (the safe default of AnyEvent::HTTP) by setting this to
"undef".
$al = $wd->actions
Creates an action list associated with this WebDriver. See ACTION
LISTS, below, for full details.
$sessionstring = $wd->save_session
Save the current session in a string so it can be restored load with
"load_session". Note that only the session data itself is stored
(currently the session id and capabilities), not the endpoint
information itself.
The main use of this function is in conjunction with disabled
"autodelete", to save a session to e.g., and restore it later. It
could presumably used for other applications, such as using the same
session from multiple processes and so on.
$wd->load_session ($sessionstring)
$wd->set_session ($sessionid, $capabilities)
Starts using the given session, as identified by $sessionid.
$capabilities should be the original session capabilities, although
the current version of this module does not make any use of it.
The $sessionid is stored in "$wd->{sid}" (and could be fetched form
there for later use), while the capabilities are stored in
"$wd->{capabilities}".
SIMPLIFIED API
This section documents the simplified API, which is really just a very
thin wrapper around the WebDriver protocol commands. They all block the
caller until the result is available (using AnyEvent condvars), so must
not be called from an event loop callback - see "EVENT BASED API" for an
alternative.
The method names are pretty much taken directly from the W3C WebDriver
specification, e.g. the request documented in the "Get All Cookies"
section is implemented via the "get_all_cookies" method.
The order is the same as in the WebDriver draft at the time of this
writing, and only minimal massaging is done to request parameters and
results.
SESSIONS
$wd->new_session ({ key => value... })
Try to connect to the WebDriver and initialize a new session with a
"new session" command, passing the given key-value pairs as value
(e.g. "capabilities").
No session-dependent methods must be called before this function
returns successfully, and only one session can be created per
WebDriver object.
On success, "$wd->{sid}" is set to the session ID, and
"$wd->{capabilities}" is set to the returned capabilities.
Simple example of creating a WebDriver object and a new session:
my $wd = new AnyEvent::WebDriver endpoint => "http://localhost:4444";
$wd->new_session ({});
Real-world example with capability negotiation:
$wd->new_session ({
capabilities => {
alwaysMatch => {
pageLoadStrategy => "eager",
unhandledPromptBehavior => "dismiss",
# proxy => { proxyType => "manual", httpProxy => "1.2.3.4:56", sslProxy => "1.2.3.4:56" },
},
firstMatch => [
{
browserName => "firefox",
"moz:firefoxOptions" => {
binary => "firefox/firefox",
args => ["-devtools", "-headless"],
prefs => {
"dom.webnotifications.enabled" => \0,
"dom.push.enabled" => \0,
"dom.disable_beforeunload" => \1,
"browser.link.open_newwindow" => 3,
"browser.link.open_newwindow.restrictions" => 0,
"dom.popup_allowed_events" => "",
"dom.disable_open_during_load" => \1,
},
},
},
{
browserName => "chrome",
"goog:chromeOptions" => {
binary => "/bin/chromium",
args => ["--no-sandbox", "--headless"],
prefs => {
# ...
},
},
},
{
# generic fallback
},
],
},
});
Firefox-specific capability documentation can be found on MDN
, Chrome-specific capability documentation might be found here
, but the latest
release at the time of this writing (chromedriver 77) has
essentially no documentation about webdriver capabilities (even MDN
has better documentation about chromwedriver!)
If you have URLs for Safari/IE/Edge etc. capabilities, feel free to
tell me about them.
$wd->delete_session
Deletes the session - the WebDriver object must not be used after
this call (except for calling this method).
This method is always safe to call and will not do anything if there
is no active session.
$timeouts = $wd->get_timeouts
Get the current timeouts, e.g.:
my $timeouts = $wd->get_timeouts;
=> { implicit => 0, pageLoad => 300000, script => 30000 }
$wd->set_timeouts ($timeouts)
Sets one or more timeouts, e.g.:
$wd->set_timeouts ({ script => 60000 });
NAVIGATION
$wd->navigate_to ($url)
Navigates to the specified URL.
$url = $wd->get_current_url
Queries the current page URL as set by "navigate_to".
$wd->back
The equivalent of pressing "back" in the browser.
$wd->forward
The equivalent of pressing "forward" in the browser.
$wd->refresh
The equivalent of pressing "refresh" in the browser.
$title = $wd->get_title
Returns the current document title.
COMMAND CONTEXTS
$handle = $wd->get_window_handle
Returns the current window handle.
$wd->close_window
Closes the current browsing context.
$wd->switch_to_window ($handle)
Changes the current browsing context to the given window.
$handles = $wd->get_window_handles
Return the current window handles as an array-ref of handle IDs.
$handles = $wd->switch_to_frame ($frame)
Switch to the given frame identified by $frame, which must be either
"undef" to go back to the top-level browsing context, an integer to
select the nth subframe, or an element object.
$handles = $wd->switch_to_parent_frame
Switch to the parent frame.
$rect = $wd->get_window_rect
Return the current window rect(angle), e.g.:
$rect = $wd->get_window_rect
=> { height => 1040, width => 540, x => 0, y => 0 }
$wd->set_window_rect ($rect)
Sets the window rect(angle), e.g.:
$wd->set_window_rect ({ width => 780, height => 560 });
$wd->set_window_rect ({ x => 0, y => 0, width => 780, height => 560 });
$wd->maximize_window
$wd->minimize_window
$wd->fullscreen_window
Changes the window size by either maximising, minimising or making
it fullscreen. In my experience, this will timeout if no window
manager is running.
ELEMENT RETRIEVAL
To reduce typing and memory strain, the element finding functions accept
some shorter and hopefully easier to remember aliases for the standard
locator strategy values, as follows:
Alias Locator Strategy
css css selector
link link text
substr partial link text
tag tag name
$element = $wd->find_element ($locator_strategy, $selector)
Finds the first element specified by the given selector and returns
its element object. Raises an error when no element was found.
Examples showing all standard locator strategies:
$element = $wd->find_element ("css selector" => "body a");
$element = $wd->find_element ("link text" => "Click Here For Porn");
$element = $wd->find_element ("partial link text" => "orn");
$element = $wd->find_element ("tag name" => "input");
$element = $wd->find_element ("xpath" => '//input[@type="text"]');
=> e.g. { "element-6066-11e4-a52e-4f735466cecf" => "decddca8-5986-4e1d-8c93-efe952505a5f" }
Same examples using aliases provided by this module:
$element = $wd->find_element (css => "body a");
$element = $wd->find_element (link => "Click Here For Porn");
$element = $wd->find_element (substr => "orn");
$element = $wd->find_element (tag => "input");
$elements = $wd->find_elements ($locator_strategy, $selector)
As above, but returns an arrayref of all found element objects.
$element = $wd->find_element_from_element ($element, $locator_strategy,
$selector)
Like "find_element", but looks only inside the specified $element.
$elements = $wd->find_elements_from_element ($element,
$locator_strategy, $selector)
Like "find_elements", but looks only inside the specified $element.
my $head = $wd->find_element ("tag name" => "head");
my $links = $wd->find_elements_from_element ($head, "tag name", "link");
$element = $wd->get_active_element
Returns the active element.
ELEMENT STATE
$bool = $wd->is_element_selected
Returns whether the given input or option element is selected or
not.
$string = $wd->get_element_attribute ($element, $name)
Returns the value of the given attribute.
$string = $wd->get_element_property ($element, $name)
Returns the value of the given property.
$string = $wd->get_element_css_value ($element, $name)
Returns the value of the given CSS value.
$string = $wd->get_element_text ($element)
Returns the (rendered) text content of the given element.
$string = $wd->get_element_tag_name ($element)
Returns the tag of the given element.
$rect = $wd->get_element_rect ($element)
Returns the element rect(angle) of the given element.
$bool = $wd->is_element_enabled
Returns whether the element is enabled or not.
ELEMENT INTERACTION
$wd->element_click ($element)
Clicks the given element.
$wd->element_clear ($element)
Clear the contents of the given element.
$wd->element_send_keys ($element, $text)
Sends the given text as key events to the given element. Key input
state can be cleared by embedding "\x{e000}" in $text. Presumably,
you can embed modifiers using their unicode codepoints, but the
specification is less than clear to mein this area.
DOCUMENT HANDLING
$source = $wd->get_page_source
Returns the (HTML/XML) page source of the current document.
$results = $wd->execute_script ($javascript, $args)
Synchronously execute the given script with given arguments and
return its results ($args can be "undef" if no arguments are
wanted/needed).
$ten = $wd->execute_script ("return arguments[0]+arguments[1]", [3, 7]);
$results = $wd->execute_async_script ($javascript, $args)
Similar to "execute_script", but doesn't wait for script to return,
but instead waits for the script to call its last argument, which is
added to $args automatically.
$twenty = $wd->execute_async_script ("arguments[0](20)", undef);
COOKIES
$cookies = $wd->get_all_cookies
Returns all cookies, as an arrayref of hashrefs.
# google surely sets a lot of cookies without my consent
$wd->navigate_to ("http://google.com");
use Data::Dump;
ddx $wd->get_all_cookies;
$cookie = $wd->get_named_cookie ($name)
Returns a single cookie as a hashref.
$wd->add_cookie ($cookie)
Adds the given cookie hashref.
$wd->delete_cookie ($name)
Delete the named cookie.
$wd->delete_all_cookies
Delete all cookies.
ACTIONS
$wd->perform_actions ($actions)
Perform the given actions (an arrayref of action specifications
simulating user activity, or an "AnyEvent::WebDriver::Actions"
object). For further details, read the spec or the section "ACTION
LISTS", below.
An example to get you started (see the next example for a mostly
equivalent example using the "AnyEvent::WebDriver::Actions" helper
API):
$wd->navigate_to ("https://duckduckgo.com/html");
my $input = $wd->find_element ("css selector", 'input[type="text"]');
$wd->perform_actions ([
{
id => "myfatfinger",
type => "pointer",
pointerType => "touch",
actions => [
{ type => "pointerMove", duration => 100, origin => $input, x => 40, y => 5 },
{ type => "pointerDown", button => 0 },
{ type => "pause", duration => 40 },
{ type => "pointerUp", button => 0 },
],
},
{
id => "mykeyboard",
type => "key",
actions => [
{ type => "pause" },
{ type => "pause" },
{ type => "pause" },
{ type => "pause" },
{ type => "keyDown", value => "a" },
{ type => "pause", duration => 100 },
{ type => "keyUp", value => "a" },
{ type => "pause", duration => 100 },
{ type => "keyDown", value => "b" },
{ type => "pause", duration => 100 },
{ type => "keyUp", value => "b" },
{ type => "pause", duration => 2000 },
{ type => "keyDown", value => "\x{E007}" }, # enter
{ type => "pause", duration => 100 },
{ type => "keyUp", value => "\x{E007}" }, # enter
{ type => "pause", duration => 5000 },
],
},
]);
And here is essentially the same (except for fewer pauses) example
as above, using the much simpler "AnyEvent::WebDriver::Actions" API:
$wd->navigate_to ("https://duckduckgo.com/html");
my $input = $wd->find_element ("css selector", 'input[type="text"]');
$wd->actions
->move ($input, 40, 5, "touch1")
->click
->key ("a")
->key ("b")
->pause (2000) # so you can watch leisurely
->key ("{Enter}")
->pause (5000) # so you can see the result
->perform;
$wd->release_actions
Release all keys and pointer buttons currently depressed.
USER PROMPTS
$wd->dismiss_alert
Dismiss a simple dialog, if present.
$wd->accept_alert
Accept a simple dialog, if present.
$text = $wd->get_alert_text
Returns the text of any simple dialog.
$text = $wd->send_alert_text
Fills in the user prompt with the given text.
SCREEN CAPTURE
$wd->take_screenshot
Create a screenshot, returning it as a PNG image. To decode and
save, you could do something like:
use MIME::Base64 ();
my $screenshot = $wd->take_screenshot;
open my $fh, ">", "screenshot.png" or die "screenshot.png: $!\n";
syswrite $fh, MIME::Base64::decode_base64 $screenshot;
$wd->take_element_screenshot ($element)
Similar to "take_screenshot", but only takes a screenshot of the
bounding box of a single element.
Compatibility note: As of chrome version 80, I found that the
screenshot scaling is often wrong (the screenshot is much smaller
than the element normally displays) unless chrome runs in headless
mode. The spec does allow for any form of scaling, so this is not
strictly a bug in chrome, but of course it diminishes trhe
screenshot functionality.
PRINT
$wd->print_page (key => value...)
Create a printed version of the document, returning it as a PDF
document encoded as base64. See "take_screenshot" for an example on
how to decode and save such a string.
This command takes a lot of optional parameters, see the print
section of the WebDriver
specification for details.
This command is taken from a draft document, so it might change in
the future.
ACTION LISTS
Action lists can be quite complicated. Or at least it took a while for
me to twist my head around them. Basically, an action list consists of a
number of sources representing devices (such as a finger, a mouse, a pen
or a keyboard) and a list of actions for each source, in a timeline.
An action can be a key press, a pointer move or a pause (time delay).
While you can provide these action lists manually, it is (hopefully)
less cumbersome to use the API described in this section to create them.
The basic process of creating and performing actions is to create a new
action list, adding action sources, followed by adding actions. Finally
you would "perform" those actions on the WebDriver.
Most methods here are designed to chain, i.e. they return the web
actions object, to simplify multiple calls.
Also, while actions from different sources can happen "at the same time"
in the WebDriver protocol, this class by default ensures that actions
will execute in the order specified.
For example, to simulate a mouse click to an input element, followed by
entering some text and pressing enter, you can use this:
$wd->actions
->click (0, 100)
->type ("some text")
->key ("{Enter}")
->perform;
By default, "keyboard" and "mouse" input sources are provided and used.
You can create your own sources and use them when adding events. The
above example could be more verbosely written like this:
$wd->actions
->source ("mouse", "pointer", pointerType => "mouse")
->source ("kbd", "key")
->click (0, 100, "mouse")
->type ("some text", "kbd")
->key ("{Enter}", "kbd")
->perform;
When you specify the event source explicitly it will switch the current
"focus" for this class of device (all keyboards are in one class, all
pointer-like devices such as mice/fingers/pens are in one class), so you
don't have to specify the source for subsequent actions that are on the
same class.
When you use the sources "keyboard", "mouse", "touch1".."touch3", "pen"
without defining them, then a suitable default source will be created
for them.
$al = new AnyEvent::WebDriver::Actions
Create a new empty action list object. More often you would use the
"$wd->action_list" method to create one that is already associated
with a given web driver.
$al = $al->source ($id, $type, key => value...)
The first time you call this with a given ID, this defines the event
source using the extra parameters. Subsequent calls merely switch
the current source for its event class.
It's not an error to define built-in sources (such as "keyboard" or
"touch1") differently then the defaults.
Example: define a new touch device called "fatfinger".
$al->source (fatfinger => "pointer", pointerType => "touch");
Example: define a new touch device called "fatfinger".
$al->source (fatfinger => "pointer", pointerType => "touch");
Example: switch default keyboard source to "kbd1", assuming it is of
"key" class.
$al->source ("kbd1");
$al = $al->pause ($duration)
Creates a pause with the given duration. Makes sure that time
progresses in any case, even when $duration is 0.
$al = $al->pointer_down ($button, $source)
$al = $al->pointer_up ($button, $source)
Press or release the given button. $button defaults to 0.
$al = $al->click ($button, $source)
Convenience function that creates a button press and release action
without any delay between them. $button defaults to 0.
$al = $al->doubleclick ($button, $source)
Convenience function that creates two button press and release
action pairs in a row, with no unnecessary delay between them.
$button defaults to 0.
$al = $al->move ($origin, $x, $y, $duration, $source)
Moves a pointer to the given position, relative to origin (either
"viewport", "pointer" or an element object. The coordinates will be
truncated to integer values.
$al = $al->cancel ($source)
Executes a pointer cancel action.
$al = $al->key_down ($key, $source)
$al = $al->key_up ($key, $source)
Press or release the given key.
$al = $al->key ($key, $source)
Peess and release the given key in one go, without unnecessary
delay.
A special syntax, "{keyname}" can be used for special keys - all the
special key names from the second table in section 17.4.2
of the
WebDriver recommendation can be used - prefix with "Shift-Space". to
get the shifted version, as in "Shift-"
Example: press and release "a".
$al->key ("a");
Example: press and release the "Enter" key:
$al->key ("\x{e007}");
Example: press and release the "enter" key using the special key
name syntax:
$al->key ("{Enter}");
$al = $al->type ($string, $source)
Convenience method to simulate a series of key press and release
events for the keys in $string, one pair per extended unicode
grapheme cluster. There is no syntax for special keys, everything
will be typed "as-is" if possible.
$al->perform ($wd)
Finalises and compiles the list, if not done yet, and calls
"$wd->perform" with it.
If $wd is undef, and the action list was created using the
"$wd->actions" method, then perform it against that WebDriver
object.
There is no underscore variant - call the "perform_actions_" method
with the action object instead.
$al->perform_release ($wd)
Exactly like "perform", but additionally call "release_actions"
afterwards.
($actions, $duration) = $al->compile
Finalises and compiles the list, if not done yet, and returns an
actions object suitable for calls to "$wd->perform_actions". When
called in list context, additionally returns the total duration of
the action list.
Since building large action lists can take nontrivial amounts of
time, it can make sense to build an action list only once and then
perform it multiple times.
No additional actions must be added after compiling an action list.
EVENT BASED API
This module wouldn't be a good AnyEvent citizen if it didn't have a true
event-based API.
In fact, the simplified API, as documented above, is emulated via the
event-based API and an "AUTOLOAD" function that automatically provides
blocking wrappers around the callback-based API.
Every method documented in the "SIMPLIFIED API" section has an
equivalent event-based method that is formed by appending a underscore
("_") to the method name, and appending a callback to the argument list
(mnemonic: the underscore indicates the "the action is not yet finished"
after the call returns).
For example, instead of a blocking calls to "new_session", "navigate_to"
and "back", you can make a callback-based ones:
my $cv = AE::cv;
$wd->new_session ({}, sub {
my ($status, $value) = @_,
die "error $value->{error}" if $status ne "200";
$wd->navigate_to_ ("http://www.nethype.de", sub {
$wd->back_ (sub {
print "all done\n";
$cv->send;
});
});
});
$cv->recv;
While the blocking methods "croak" on errors, the callback-based ones
all pass two values to the callback, $status and $res, where $status is
the HTTP status code (200 for successful requests, typically 4xx or 5xx
for errors), and $res is the value of the "value" key in the JSON
response object.
Other than that, the underscore variants and the blocking variants are
identical.
LOW LEVEL API
All the simplified API methods are very thin wrappers around WebDriver
commands of the same name. They are all implemented in terms of the
low-level methods ("req", "get", "post" and "delete"), which exist in
blocking and callback-based variants ("req_", "get_", "post_" and
"delete_").
Examples are after the function descriptions.
$wd->req_ ($method, $uri, $body, $cb->($status, $value))
$value = $wd->req ($method, $uri, $body)
Appends the $uri to the "endpoint/session/{sessionid}/" URL and
makes a HTTP $method request ("GET", "POST" etc.). "POST" requests
can provide a UTF-8-encoded JSON text as HTTP request body, or the
empty string to indicate no body is used.
For the callback version, the callback gets passed the HTTP status
code (200 for every successful request), and the value of the
"value" key in the JSON response object as second argument.
$wd->get_ ($uri, $cb->($status, $value))
$value = $wd->get ($uri)
Simply a call to "req_" with $method set to "GET" and an empty body.
$wd->post_ ($uri, $data, $cb->($status, $value))
$value = $wd->post ($uri, $data)
Simply a call to "req_" with $method set to "POST" - if $body is
"undef", then an empty object is send, otherwise, $data must be a
valid request object, which gets encoded into JSON for you.
$wd->delete_ ($uri, $cb->($status, $value))
$value = $wd->delete ($uri)
Simply a call to "req_" with $method set to "DELETE" and an empty
body.
Example: implement "get_all_cookies", which is a simple "GET" request
without any parameters:
$cookies = $wd->get ("cookie");
Example: implement "execute_script", which needs some parameters:
$results = $wd->post ("execute/sync" => { script => "$javascript", args => [] });
Example: call "find_elements" to find all "IMG" elements:
$elems = $wd->post (elements => { using => "css selector", value => "img" });
HISTORY
This module was unintentionally created (it started inside some quickly
hacked-together script) simply because I couldn't get the existing
"Selenium::Remote::Driver" module to work reliably, ever, despite
multiple attempts over the years and trying to report multiple bugs,
which have been completely ignored. It's also not event-based, so,
yeah...
AUTHOR
Marc Lehmann
http://anyevent.schmorp.de