NAME
WWW::Mechanize::Chrome::DOMops - Operations on the DOM loaded in Chrome
VERSION
Version 0.11
SYNOPSIS
This module provides a set of tools to operate on the DOM loaded onto the provided WWW::Mechanize::Chrome object after fetching a URL.
Operating on the DOM is powerful but there are security risks involved if the browser and profile you used for loading this DOM is your everyday browser and profile.
Please read "SECURITY WARNING" before continuing on to the main course.
Currently, WWW::Mechanize::Chrome::DOMops provides these tools:
domops_find()
: finds HTML elements,domops_zap()
: deletes HTML elements.
Both domops_find()
and domops_zap()
return some information from each match and its descendents (like tag
, id
etc.). This information can be tweaked by the caller. domops_find()
and domops_zap()
optionally execute javascript code on each match and its descendents and can return data back to the caller perl code.
The selection of the HTML elements in the DOM can be done in various ways:
by XPath selector,
by CSS selector,
by tag,
by class.
by id,
by name.
There is more information about this in section "ELEMENT SELECTORS".
Here are some usage scenaria:
use WWW::Mechanize::Chrome::DOMops qw/domops_zap domops_find domops_VERBOSITY/;
# adjust verbosity: 0, 1, 2, 3
$WWW::Mechanize::Chrome::domops_VERBOSITY = 3;
# First, create a mech object and load a URL on it
# Note: you need google-chrome binary installed in your system!
# See section CREATING THE MECH OBJECT for creating the mech
# and how to redirect its javascript console to perl's output
my $mechobj = WWW::Mechanize::Chrome->new();
# fetch a page which will setup a DOM on which to operate:
$mechobj->get('https://www.bbbbbbbbb.com');
# find elements in the DOM, select by CSS selector,
# XPath selector, id, tag or name:
my $ret = domops_find({
'mech-obj' => $mechobj,
# find elements whose class is in the provided
# scalar class name or array of class names
'element-class' => ['slanted-paragraph', 'class2', 'class3'],
# *OR* their tag is this:
'element-tag' => 'p',
# *OR* their name is this:
'element-name' => ['aname', 'name2'],
# *OR* their id is this:
'element-id' => ['id1', 'id2'],
# *OR* just provide a CSS selector
'element-cssselector' => 'a-css-selector',
# *OR* just provide a XPath selector
'element-xpathselector' => 'a-xpath-selector',
# specifies that we should use the union of the above sets
# hence the *OR* in above comment
'||' => 1,
# this says to find all elements whose class
# is such-and-such AND element tag is such-and-such
# '&&' => 1 means to calculate the INTERSECTION of all
# individual matches.
# build the information sent back from each match
'element-information-from-matched' => <<'EOJ',
// begin JS code to extract information from each match and return it
// back as a hash
const r = htmlElement.hasAttribute("role")
? htmlElement.getAttribute("role") : "<no role present>"
;
return {"tag" : htmlElement.tagName, "id" : htmlElement.id, "role" : r};
EOJ
# optionally run javascript code on all those elements matched
'find-cb-on-matched' => [
{
'code' =><<'EOJS',
// the element to operate on is 'htmlElement'
console.log("operating on this element "+htmlElement.tagName);
// this is returned back in the results of domops_find() under
// key "cb-results"->"find-cb-on-matched"
return 1;
EOJS
'name' => 'func1'
}, {...}
],
# optionally run javascript code on all those elements
# matched AND THEIR CHILDREN too!
'find-cb-on-matched-and-their-children' => [
{
'code' =><<'EOJS',
// the element to operate on is 'htmlElement'
console.log("operating on this element "+htmlElement.tagName);
// this is returned back in the results of domops_find() under
// key "cb-results"->"find-cb-on-matched" notice the complex data
return {"abc":"123",{"xyz":[1,2,3]}};
EOJS
'name' => 'func2'
}
],
# optionally ask it to create a valid id for any HTML
# element returned which does not have an id.
# The text provided will be postfixed with a unique
# incrementing counter value
'insert-id-if-none' => '_prefix_id',
# or ask it to randomise that id a bit to avoid collisions
'insert-id-if-none-random' => '_prefix_id',
# optionally, also output the javascript code to a file for debugging
'js-outfile' => 'output.js',
});
# Delete an element from the DOM
$ret = domops_zap({
'mech-obj' => $mechobj,
'element-id' => 'paragraph-123'
});
# Mass murder:
$ret = domops_zap({
'mech-obj' => $mechobj,
'element-tag' => ['div', 'span', 'p'],
'||' => 1, # the union of all those matched with above criteria
});
# error handling
if( $ret->{'status'} < 0 ){ die "error: ".$ret->{'message'} }
# status of -3 indicates parameter errors,
# -2 indicates that eval of javascript code inside the mech object
# has failed (syntax errors perhaps, which could have been introduced
# by user-specified callback
# -1 indicates that javascript code executed correctly but
# failed somewhere in its logic.
print "Found " . $ret->{'status'} . " matches which are: "
# ... results are in $ret->{'found'}->{'first-level'}
# ... and also in $ret->{'found'}->{'all-levels'}
# the latter contains a recursive list of those
# found AND ALL their children
# wait for page to load with catching the Page.loadEventFired
if( 0 == domops_wait_for_page_to_load() ){ print "page loaded\n" }
else { die "page did not load within the default timeout" }
domops_wait_for_page_to_load({
'timeout' => 50.5, # fractional seconds
'sleep' => 1.5, # fractional seconds to sleep between polling
});
# this waits for Page.loadEventFired AND for ALL
# DOM elements specified with the XPath selectors:
domops_wait_for_page_to_load({
'elements-must-be-present' => [
'div[@id="anid1"]',
'span[@id="anid2"]',
],
'elements-must-be-present-op' => '&&'
});
EXPORT
- the sub to find element(s) in the DOM
-
domops_find()
- the sub to delete element(s) from the DOM
-
domops_zap()
- the sub to read element selectors from a JSON string
-
domops_read_dom_element_selectors_from_JSON_string()
- the sub to read element selectors from a JSON file
-
domops_read_dom_element_selectors_from_JSON_file()
- the sub to wait for the DOM to load not only via detecting the
DOMContentLoaded
event but by also waiting for specific DOM elements, specified via selectors including CSS and XPath selectors, to appear -
domops_wait_for_page_to_load()
and the flag to denote verbosity (default is 0, no verbosity)
$WWW::Mechanize::Chrome::DOMops::domops_VERBOSITY
SUBROUTINES/METHODS
domops_find($params)
It finds HTML elements in the DOM currently loaded on the parameters-specified WWW::Mechanize::Chrome object. The parameters are:
mech-obj
: user must supply a WWW::Mechanize::Chrome object, this is required. See section "CREATING THE MECH OBJECT" for an example of creating the mech object with some parameters which work for me and javascript console output propagated on to perl's output.element-information-from-matched
: optional javascript code to be run on each HTML element matched in order to construct the information data whih is returned back. If none specified the following default will be used, which returns tagname and id:// the matched element is provided in htmlElement return {"tag" : htmlElement.tagName, "id" : htmlElement.id};
Basically the code is expected to be the body of a function which accepts one parameter:
htmlElement
(that is the element matched). That means it must not have the function preamble (function name, signature, etc.). Neither it must have the postamble, which is the end-block curly bracket. This piece of code must return a HASH. The code can throw exceptions which will be caught (because the code is run within a try-catch block) and the error message will be propagated to the perl code with status of -1.insert-id-if-none
: some HTML elements simply do not have an id (e.g.<p
>). If any of these elements is matched, its tag and its id (empty string) will be returned. By specifying this parameter (as a string, e.g._replacing_empty_ids
) all such elements matched will have their id set to_replacing_empty_ids_X
where X is an incrementing counter value starting from a random number. By runningdomops_find()
more than once on the same on the same DOM you are risking having the same ID. So provide a different prefix every time. Or useinsert-id-if-none-random
, see below.insert-id-if-none-random
: each timedomops_find()
is called a new random base id will be created formed by the specified prefix (as withinsert-id-if-none
) plus a long random string plus the incrementing counter, as above. This is supposed to be better at avoiding collisions but it can not guarantee it. If you are settingrand()
's seed to the same number before you calldomops_find()
then you are guaranteed to have collisions.find-cb-on-matched
: an array of user-specified javascript code to be run on each element matched in the order the elements are returned and in the order of the javascript code in the specified array. Each item of the array is a hash with keyscode
andname
. The former contains the code to be run assuming that the html element to operate on is namedhtmlElement
. The code must end with areturn
statement which will be recorded and returned back to perl code. The code can throw exceptions which will be caught (because the callback is run within a try-catch block) and the error message will be propagated to the perl code with status of -1. Basically the code is expected to be the body of a function which accepts one parameter:htmlElement
(that is the element matched). That means it must not have the function preamble (function name, signature, etc.). Neither it must have the postamble, which is the end-block curly bracket.Key
name
is just for making this process more descriptive and will be printed on log messages and returned back with the results.name
can contain any characters. Here is an example:'find-cb-on-matched' : [ { # this returns a complex data type 'code' => 'console.log("found id "+htmlElement.id); return {"a":"1","b":"2"};' 'name' => 'func1' }, { 'code' => 'console.log("second func: found id "+htmlElement.id); return 1;' 'name' => 'func2' }, ]
find-cb-on-matched-and-their-children
: exactly the same asfind-cb-on-matched
but it operates on all those HTML elements matched and also all their children and children of children etc.js-outfile
: optionally save the javascript code (which is evaluated within the mech object) to a file.element selectors
are covered in section "ELEMENT SELECTORS".
JAVASCRIPT HELPERS
There is one javascript function available to all user-specified callbacks:
getAllChildren(anHtmlElement)
: it returns back an array of HTML elements which are the children (at any depth) of the givenanHtmlElement
.
RETURN VALUE:
The returned value is a hashref with at least a status
key which is greater or equal to zero in case of success and denotes the number of matched HTML elements. Or it is -3, -2 or -1 in case of errors:
-3
: there is an error with the parameters passed to this sub.-2
: there is a syntax error in the javascript code to be evaluated by the mech object with something like$mech_obj-
eval()>. Most likely this syntax error is with user-specified callback code. Note that all the javascript code to be evaluated is dumped to stderr by increasing the verbosity. But also it can be saved to a local file for easier debugging by supplying thejs-outfile
parameter todomops_find()
ordomops_zap()
.-1
: there is a logical error while running the javascript code. For example a division by zero etc. This can be both in the callback code as well as in the internal javascript code for edge cases not covered by my tests. Please report these. Note that all the javascript code to be evaluated is dumped to stderr by increasing the verbosity. But also it can be saved to a local file for easier debugging by supplying thejs-outfile
parameter todomops_find()
ordomops_zap()
.
If status
is not negative, then this is success and its value denotes the number of matched HTML elements. Which can be zero or more. In this case the returned hash contains this
"found" => {
"first-level" => [
{
"tag" => "NAV",
"id" => "nav-id-1"
}
],
"all-levels" => [
{
"tag" => "NAV",
"id" => "nav-id-1"
},
{
"id" => "li-id-2",
"tag" => "LI"
},
]
}
Key first-level
contains those items matched directly while key all-levels
contains those matched directly as well as those matched because they are descendents (direct or indirect) of each matched element.
Each item representing a matched HTML element has two fields: tag
and id
. Beware of missing id
or use insert-id-if-none
or insert-id-if-none-random
to fill in the missing ids.
If find-cb-on-matched
or find-cb-on-matched-and-their-children
were specified, then the returned result contains this additional data:
"cb-results" => {
"find-cb-on-matched" => [
[
{
"name" => "func1",
"result" => {
"a" => 1,
"b" => 2
}
}
],
[
{
"result" => 1,
"name" => "func2"
}
]
],
"find-cb-on-matched-and-their-children" => ...
},
find-cb-on-matched
and/or find-cb-on-matched-and-their-children
will be present depending on whether corresponding value in the input parameters was specified or not. Each of these contain the return result for running the callback on each HTML element in the same order as returned under key found
.
HTML elements allows for missing id
. So field id
can be empty unless caller set the insert-id-if-none
input parameter which will create a unique id for each HTML element matched but with missing id. These changes will be saved in the DOM. When this parameter is specified, the returned HTML elements will be checked for duplicates because now all of them have an id field. Therefore, if you did not specify this parameter results may contain duplicate items and items with empty id field. If you did specify this parameter then some elements of the DOM (those matched by our selectors) will have their missing id created and saved in the DOM.
Another implication of using this parameter when running it twice or more with the same value is that you can get same ids. So, always supply a different value to this parameter if run more than once on the same DOM.
domops_zap($params)
It removes HTML element(s) from the DOM currently loaded on the parameters-specified WWW::Mechanize::Chrome object. The params are exactly the same as with "domops_find($params)" except that insert-id-if-none
is ignored.
domops_zap()
is implemented as a domops_find()
with an additional callback for all elements matched in the first level (not their children) as:
'find-cb-on-matched' => {
'code' => 'htmlElement.parentNode.removeChild(htmlElement); return 1;',
'name' => '_thezapper'
};
RETURN VALUE:
Return value is exactly the same as with "domops_find($params)"
domops_wait_for_page_to_load($params)
It waits for the page to load by detecting the Page.loadEventFired
event. However, because the DOM may be altered at any time, even if said event has been fired, there is provision to wait for specific DOM elements as well via the elements-must-be-present
input parameter. This can be a scalar or an ARRAY_REF containing XPath selectors for DOM elements to wait for their appearance on the page. If this contains more than one selectors (i.e. it is an ARRAY_REF), then input parameter elements-must-be-present-op
can be set to &&
or ||
, denoting the method to combine these. I.e. wait for all (&&
) or wait for any (||
).
INPUT PARAMETERS:
As a HASH_REF:
elements-must-be-present
: optionally specify XPath selector(s) either as a scalar or an ARRAY_REF to wait for their appearance.elements-must-be-present-op
: optionally specify how to combine the XPath selectors, specified viaelements-must-be-present
which in this case must be an ARRAY_REF, either as wait for all elements to appear (&&
) or for any element to appear (||
).document
: Checking for the appearance of specific DOM elements (viaelements-must-be-present
) is done for elements under the defaultdocument
's body. But, if frame elements are present (e.g.iframe
) then you can optionally search in theirdocument
. Javascript'sdocument.evaluate()
(which is an XPath query function) allows to use any other node. E.g. the frame's document. In this case setdocument
to Javascript code to return the element you want to search under it. For example, if you have an iframe and you want to search under it, then set 'document
' to this XPath selector: 'iframe[@id="myiframeid"]
'. Ifelements-must-be-present
is an ARRAY_REF then 'document
' can be a scalar or ARRAY_REF. In the former case, the document will apply for each item ofelements-must-be-present
. In the latter case, each item ofdocument
will apply to the corresponding item ofelements-must-be-present
.WARNING: accessing the document body of a frame element is most likely forbidden because of the weird CORS rules. In other words: an iframe is running on your browser but you are not allow to know what it does or how! Only watch the rendered results. Perfect! Note that test file
t/300-domops_wait_for_page_to_load-delayed-elements-inside-iframe.t.fails-because-of-cors
is renamed so that it does not run because it fails because of CORS which guards against, even, local pages.timeout
: fractional number of seconds to wait for the DOM loaded event and/or any DOM elements before returning, even without the conditions were satisfied and the page was most likely not loaded. The default value is 15 seconds.sleep
: fractional number of seconds to sleep between polling for the DOM elements, if any were specified. It does not apply when waiting for thePage.loadEventFired
I could not find a way to use a timeout with WWW::Mechanize::Chrome::_collectEvents, which is used internally. Default is 0.5 seconds of sleep between polling.
RETURN VALUE:
1
: denotes failure. For example if required input parameters are missing.0
: denotes absolute success meaning all events and DOM elements requested to wait for, have appeared and page is considered to be loaded and ready.2
: denotes partial success in that all code was run but events and/or DOM elements had not appeared within the current timeout. Which most likely means that the page is not ready yet. Increase the timeout and see. Or correct your DOM element selectors.
domops_read_dom_element_selectors_from_JSON_file($filename)
It reads DOM element selectors, in their various forms as documented at "ELEMENT SELECTORS", from specified filename and returns these as a Perl data structure which can then be passed on to "domops_find($params)" and "domops_zap($params)".
RETURN VALUE:
undef
: on failure, e.g. file not found or parsing errors.- a Perl data structure witht the selectors on success which can directly be passed on to "domops_find($params)" and "domops_zap($params)".
domops_read_dom_element_selectors_from_JSON_string($string)
It reads DOM element selectors, in their various forms as documented at "ELEMENT SELECTORS", from specified string and returns these as a Perl data structure which can then be passed on to "domops_find($params)" and "domops_zap($params)".
RETURN VALUE:
undef
: on failure, e.g. file not found or parsing errors.- a Perl data structure witht the selectors on success which can directly be passed on to "domops_find($params)" and "domops_zap($params)".
$WWW::Mechanize::Chrome::DOMops::domops_VERBOSITY
Set this upon loading the module to 0, 1, 2, 3
to adjust verbosity. 0
implies no verbosity.
ELEMENT SELECTORS
Element selectors
are how one selects HTML elements from the DOM. There are 5 ways to select HTML elements: by class (element-class
), tag (element-tag
), id (element-id
), name (element-name
), a CSS selector (element-cssselector
) or via an XPath selector (element-xpathselector
).
Multiple selectors can be specified by combining the various selector types, above. For example, one can select by element-class
and element-tag
(and ...). In this selection mode, the matched elements from each selector type (e.g. set A contains the HTML elements matched via element-class
and set B contains the HTML elements matched via element-tag
) must be combined by means of either the UNION (||
) or INTERSECTION (&&
) of the two sets A and B.
Each selector can take one or more values. If you want to select by just one class then provide that one class as a string scalar. If you want to select an HTML elements which may belong to two classes, then provide the two class names as an array.
These are the valid selectors:
element-class
: find DOM elements matching this class nameelement-tag
: find DOM elements matching this element tagelement-id
: find DOM element matching this element idelement-name
: find DOM element matching this element nameelement-cssselector
: find DOM element matching this CSS selectorelement-xpathselector
: find DOM element matching this XPath selector
And one of these two must be used to combine the results into a final list:
&&
: Intersection. When set to 1 the result is the intersection of all individual results. Meaning that an element will make it to the final list if it was matched by every selector specified. This is the default.||
: Union. When set to 1 the result is the union of all individual results. Meaning that an element will make it to the final list if it was matched by at least one of the selectors specified.As an example, the following selects all HTML elements which belong to class X AND class Y. It also selects all HTML elements of the
div
tag. And calculates the union of the two sets:{ 'element-class' => ['X', 'Y'], 'element-tag' => 'div', '&&' => 1, }
CREATING THE MECH OBJECT
The mech (WWW::Mechanize::Chrome) object must be supplied to the functions in this module. It must be created by the caller. This is how I do it:
use WWW::Mechanize::Chrome;
use Log::Log4perl qw(:easy);
Log::Log4perl->easy_init($ERROR);
my %default_mech_params = (
headless => 1,
# log => $mylogger,
launch_arg => [
'--window-size=600x800',
'--password-store=basic', # do not ask me for stupid chrome account password
# '--remote-debugging-port=9223',
# '--enable-logging', # see also log above
'--disable-gpu',
'--no-sandbox',
'--ignore-certificate-errors',
'--disable-background-networking',
'--disable-client-side-phishing-detection',
'--disable-component-update',
'--disable-hang-monitor',
'--disable-save-password-bubble',
'--disable-default-apps',
'--disable-infobars',
'--disable-popup-blocking',
],
);
my $mech_obj = eval {
WWW::Mechanize::Chrome->new(%default_mech_params)
};
die $@ if $@;
# This transfers all javascript code's console.log(...)
# messages to perl's warn()
# we need to keep $console var in scope!
my $console = $mech_obj->add_listener('Runtime.consoleAPICalled', sub {
warn
"js console: "
. join ", ",
map { $_->{value} // $_->{description} }
@{ $_[0]->{params}->{args} };
})
;
# and now fetch a page
my $URL = '...';
my $retmech = $mech_obj->get($URL);
die "failed to fetch $URL" unless defined $retmech;
$mech_obj->sleep(1); # let it settle
# now the mech object has loaded the URL and has a DOM hopefully.
# You can pass it on to domops_find() or domops_zap() to operate on the DOM.
SECURITY WARNING
WWW::Mechanize::Chrome invokes the google-chrome
executable on behalf of the current user. Headless or not, google-chrome
is invoked. Depending on the launch parameters, either a fresh, new browser session will be created or the session of the current user with their profile, data, cookies, passwords, history, etc. will be used. The latter case is very dangerous.
This behaviour is controlled by WWW::Mechanize::Chrome's constructor parameters which, in turn, are used for launching the google-chrome
executable. Specifically, see WWW::Mechanize::Chrome#separate_session, <WWW::Mechanize::Chrome#data_directory and WWW::Mechanize::Chrome#incognito.
Unless you really need to mechsurf with your current session, aim to launching the browser with a fresh new session. This is the safest option.
Do not rely on default behaviour as this may change over time. Be explicit.
Also, be warned that WWW::Mechanize::Chrome::DOMops executes javascript code on that google-chrome
instance. This is done nternally with javascript code hardcoded into the WWW::Mechanize::Chrome::DOMops's package files.
On top of that WWW::Mechanize::Chrome::DOMops allows for user-specified javascript code to be executed on that google-chrome
instance. For example the callbacks on each element found, etc.
This is an example of what can go wrong if you are not using a fresh google-chrome
session:
You have just used google-chrome
to access your yahoo webmail and you did not logout. So, there will be an access cookie in the google-chrome
when you later invoke it via WWW::Mechanize::Chrome (remember you have not told it to use a fresh session).
If you allow unchecked user-specified (or copy-pasted from ChatGPT) javascript code in WWW::Mechanize::Chrome::DOMops's domops_find()
, domops_zap()
, etc. then it is, theoretically, possible that this javascript code initiates an XHR to yahoo and fetch your emails and pass them on to your perl code.
But there is another problem, WWW::Mechanize::Chrome::DOMops's integrity of the embedded javascript code may have been compromised to exploit your current session.
This is very likely with a Windows installation which, being the security swiss cheese it is, it is possible for anyone to compromise your module's code. It is less likely in Linux, if your modules are installed by root and are read-only for normal users. But, still, it is possible to be compromised (by root).
Another issue is with the saved passwords and the browser's auto-fill when landing on a login form.
Therefore, for all these reasons, it is advised not to invoke (via WWW::Mechanize::Chrome) google-chrome
with your current/usual/everyday/email-access/bank-access identity so that it does not have access to your cookies, passwords, history etc.
It is better to create a fresh google-chrome
identity/profile and use that for your WWW::Mechanize::Chrome::DOMops
needs.
No matter what identity you use, you may want to erase the cookies and history of google-chrome
upon its exit. That's a good practice.
It is also advised to review the javascript code you provide via WWW::Mechanize::Chrome::DOMops callbacks if it is taken from 3rd-party, human or not, e.g. ChatGPT.
Additionally, make sure that the current installation of WWW::Mechanize::Chrome::DOMops in your system is not compromised with malicious javascript code injected into it. For this you can check its MD5 hash.
DEPENDENCIES
This module depends on WWW::Mechanize::Chrome which, in turn, depends on the google-chrome
executable be installed on the host computer. See WWW::Mechanize::Chrome::Install on how to install the executable.
Test scripts (which create there own mech object) will detect the absence of google-chrome
binary and exit gracefully, meaning the test passes. But with a STDERR message to the user. Who will hopefully notice it and proceed to google-chrome
installation. In any event, this module will be installed with or without google-chrome
.
AUTHOR
Andreas Hadjiprocopis, <bliako at cpan.org>
CODING CONDITIONS
This code was written under extreme climate conditions of 44 Celsius. Keep packaging those vegs in kilos of plastic wrappers, keep obsolidating our perfectly good hardware, keep inventing new consumer needs and brainwash them down our throats, in short Crack Deep the Roof Beam, Capitalism.
BUGS
Please report any bugs or feature requests to bug-www-mechanize-chrome-domops at rt.cpan.org
, or through the web interface at https://rt.cpan.org/NoAuth/ReportBug.html?Queue=WWW-Mechanize-Chrome-DOMops. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc WWW::Mechanize::Chrome::DOMops
You can also look for information at:
RT: CPAN's request tracker (report bugs here)
https://rt.cpan.org/NoAuth/Bugs.html?Dist=WWW-Mechanize-Chrome-DOMops
AnnoCPAN: Annotated CPAN documentation
Review this module at PerlMonks
Search CPAN
DEDICATIONS
Almaz
ACKNOWLEDGEMENTS
CORION for publishing WWW::Mechanize::Chrome and all its contributors.
LICENSE AND COPYRIGHT
Copyright 2019 Andreas Hadjiprocopis.
This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:
http://www.perlfoundation.org/artistic_license_2_0
Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.
If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.
This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.
This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.
Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.