WWW::Mechanize - Handy web browsing in a Perl object

Version 1.12

CWWWW::Mechanize, or Mech for short, helps you automate interaction with a website. It supports performing a sequence of page fetches including following links and submitting forms. Each fetched page is parsed and its links and forms are extracted. A link or a form can be selected, form fields can be filled and the next page can be fetched. Mech also stores a history of the URLs you've visited, which can be queried and revisited.

    use WWW::Mechanize;
    my $mech = WWW::Mechanize->new();

    $mech->get( $url );

    $mech->follow_link( n => 3 );
    $mech->follow_link( text_regex => qr/download this/i );
    $mech->follow_link( url => 'http://host.com/index.html' );

    $mech->submit_form(
        form_number => 3,
        fields      => {
            username    => 'mungo',
            password    => 'lost-and-alone',
        }
    );

    $mech->submit_form(
        form_name => 'search',
        fields    => { query  => 'pot of gold', },
        button    => 'Search Now'
    );

Mech is well suited for use in testing web applications. If you use one of the Test::*, like Test::HTML::Lint modules, you can check the fetched content and use that as input to a test call.

    use Test::More;
    like( $mech->content(), qr/$expected/, "Got expected content" );

Each page fetch stores its URL in a history stack which you can traverse.

    $mech->back();

If you want finer control over over your page fetching, you can use these methods. CWfollow_link and CWsubmit_form are just high level wrappers around them.

    $mech->follow( $link );
    $mech->find_link( n => $number );
    $mech->form_number( $number );
    $mech->form_name( $name );
    $mech->field( $name, $value );
    $mech->set_fields( %field_values );
    $mech->set_visible( @criteria );
    $mech->click( $button );

WWW::Mechanize is a proper subclass of LWP::UserAgent and you can also use any of LWP::UserAgent's methods.

    $mech->add_header($name => $value);

* <http://search.cpan.org/dist/WWW-Mechanize/>

The CPAN documentation page for Mechanize.

* <http://rt.cpan.org/NoAuth/Bugs.html?Dist=WWW-Mechanize>

The RT queue for bugs & enhancements in Mechanize. Click the Report bug link if your bug isn't already reported.

Creates and returns a new WWW::Mechanize object, hereafter referred to as the 'agent'.

    my $mech = WWW::Mechanize->new()

The constructor for WWW::Mechanize overrides two of the parms to the LWP::UserAgent constructor:

    agent => "WWW-Mechanize/#.##"
    cookie_jar => {}    # an empty, memory-only HTTP::Cookies object

You can override these overrides by passing parms to the constructor, as in:

    my $mech = WWW::Mechanize->new( agent=>"wonderbot 1.01" );

If you want none of the overhead of a cookie jar, or don't want your bot accepting cookies, you have to explicitly disallow it, like so:

    my $mech = WWW::Mechanize->new( cookie_jar => undef );

Here are the parms that WWW::Mechanize recognizes. These do not include parms that LWP::UserAgent recognizes. Checks each request made to see if it was successful. This saves you the trouble of manually checking yourself. Any errors found are errors, not warnings. Default is off. Reference to a CWwarn-compatible function, such as CWCarp::carp, that is called when a warning needs to be shown. If this is set to CWundef, no warnings will ever be shown. However, it's probably better to use the CWquiet method to control that behavior. If this value is not passed, Mech uses CWCarp::carp if Carp is installed, or CWCORE::warn if not. Reference to a CWdie-compatible function, such as CWCarp::croak, that is called when there's a fatal error. If this is set to CWundef, no errors will ever be shown. If this value is not passed, Mech uses CWCarp::croak if Carp is installed, or CWCORE::die if not. Don't complain on warnings. Setting CWquiet => 1 is the same as calling CW$agent->quiet(1). Default is off. Sets the depth of the page stack that keeps tracks of all the downloaded pages. Default is 0 (infinite). If the stack is eating up your memory, then set it to 1. Sets the user agent string to the expanded version from a table of actual user strings. $alias can be one of the following:

* Windows IE 6

* Windows Mozilla

* Mac Safari

* Mac Mozilla

* Linux Mozilla

* Linux Konqueror

then it will be replaced with a more interesting one. For instance,

    $mech->agent_alias( 'Windows IE 6' );

sets your User-Agent to

    Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)

The list of valid aliases can be returned from CWknown_agent_aliases().

Returns a list of all the agent aliases that Mech knows about.

Given a URL/URI, fetches it. Returns an HTTP::Response object. $url can be a well-formed URL string, a URI object, or a WWW::Mechanize::Link object.

The results are stored internally in the agent object, but you don't know that. Just use the accessors listed below. Poking at the internals is deprecated and subject to change in the future.

CWget() is a well-behaved overloaded version of the method in LWP::UserAgent. This lets you do things like

    $mech->get( $url, ":content_file"=>$tempfile );

and you can rest assured that the parms will get filtered down appropriately.

Acts like the reload button in a browser: repeats the current request. The history (as per the back method) is not altered.

Returns the HTTP::Response object from the reload, or CWundef if there's no current request.

The equivalent of hitting the back button in a browser. Returns to the previous page. Won't go back past the first page. (Really, what would it do if it could?)

Returns a boolean telling whether the last request was successful. If there hasn't been an operation yet, returns false.

This is a convenience function that wraps CW$mech->res->is_success.

Returns the current URI. Return the current response as an HTTP::Response object.

Synonym for CW$mech->response()

Returns the HTTP status code of the response.

Returns the content type of the response.

Returns the base URI for the current response

When called in a list context, returns a list of the forms found in the last fetched page. In a scalar context, returns a reference to an array with those forms. The forms returned are all HTML::Form objects.

Returns the current form as an HTML::Form object. I'd call this CWform() except that CWCIform()CW already exists and sets the current_form.

When called in a list context, returns a list of the links found in the last fetched page. In a scalar context it returns a reference to an array with those links. Each link is a WWW::Mechanize::Link object.

Returns true/false on whether our content is HTML, according to the HTTP headers.

Returns the contents of the CW<TITLE> tag, as parsed by HTML::HeadParser. Returns undef if the content is not HTML.

Returns the content that the mech uses internally for the last page fetched. Ordinarily this is the same as CW$mech->response()->content(), but this may differ for HTML documents if update_html is overloaded (in which case the value passed to the base-class implementation of same will be returned), and/or extra named arguments are passed to content(): Returns a text-only version of the page, with all HTML markup stripped. This feature requires HTML::TreeBuilder to be installed, or a fatal error will be thrown.

$mech->content( base_href => [$base_href|undef] )

Returns the HTML document, modified to contain a CW<base href="$base_href"> mark-up in the header. $base_href is CW$mech->base() if not specified. This is handy to pass the HTML to e.g. HTML::Display.

Passing arguments to CWcontent() if the current document is not HTML has no effect now (i.e. the return value is the same as CW$self->response()->content(). This may change in the future, but will likely be backwards-compatible when it does.

Lists all the links on the current page. Each link is a WWW::Mechanize::Link object. In list context, returns a list of all links. In scalar context, returns an array reference of all links.

Follows a specified link on the page. You specify the match to be found using the same parms that CWCIfind_link()CW uses.

Here some examples:

    $mech->follow_link( text => "download", n => 3 );

    $mech->follow_link( url_regex => qr/download/i );

    $mech->follow_link( url_regex => qr/(?i:download)/ );

* 3rd link on the page

    $mech->follow_link( n => 3 );

Returns the result of the GET method (an HTTP::Response object) if a link was found. If the page has no links, or the specified link couldn't be found, returns undef.

This method is meant to replace CW$mech->follow() which should not be used in future development.

Finds a link in the currently fetched page. It returns a WWW::Mechanize::Link object which describes the link. (You'll probably be most interested in the CWurl() property.) If it fails to find a link it returns undef.

You can take the URL part and pass it to the CWget() method. If that's your plan, you might as well use the CWfollow_link() method directly, since it does the CWget() for you automatically.

Note that CW<FRAME SRC="..."> tags are parsed out of the the HTML and treated as links so this method works with them.

You can select which link to find by passing in one or more of these key/value pairs: CWtext matches the text of the link against string, which must be an exact match. To select a link with text that is exactly download, use

    $mech->find_link( text => "download" );

    $mech->find_link( text_regex => qr/download/i );

    $mech->find_link( tag_regex => qr/^(a|frame)$/ );

If CWn is not specified, it defaults to 1. Therefore, if you don't specify any parms, this method defaults to finding the first link on the page.

Note that you can specify multiple text or URL parameters, which will be ANDed together. For example, to find the first link with text of News and with cnn.com in the URL, use:

    $mech->find_link( text => "News", url_regex => qr/cnn\.com/ );

The return value is a reference to an array containing a WWW::Mechanize::Link object for every link in CW$self->content.

The links come from the following:

Returns all the links on the current page that match the criteria. The method for specifying link criteria is the same as in CWCIfind_link()CW. Each of the links returned is a WWW::Mechanize::Link object.

In list context, CWfind_all_links() returns a list of the links. Otherwise, it returns a reference to the list of links.

CWfind_all_links() with no parameters returns all links in the page.

Lists all the images on the current page. Each image is a WWW::Mechanize::Image object. In list context, returns a list of all images. In scalar context, returns an array reference of all images.

Finds an image in the current page. It returns a WWW::Mechanize::Image object which describes the image. If it fails to find an image it returns undef.

You can select which link to find by passing in one or more of these key/value pairs: CWalt matches the ALT attribute of the image against string, which must be an exact match. To select a image with an ALT tag that is exactly download, use

    $mech->find_image( alt  => "download" );

    $mech->find_image( alt_regex => qr/download/i );

    $mech->find_image( tag_regex => qr/^(img|input)$/ );

If CWn is not specified, it defaults to 1. Therefore, if you don't specify any parms, this method defaults to finding the first image on the page.

Note that you can specify multiple ALT or URL parameters, which will be ANDed together. For example, to find the first image with ALT text of News and with cnn.com in the URL, use:

    $mech->find_image( image => "News", url_regex => qr/cnn\.com/ );

The return value is a reference to an array containing a WWW::Mechanize::Image object for every image in CW$self->content.

Returns all the images on the current page that match the criteria. The method for specifying image criteria is the same as in CWCIfind_image()CW. Each of the images returned is a WWW::Mechanize::Image object.

In list context, CWfind_all_images() returns a list of the images. Otherwise, it returns a reference to the list of images.

CWfind_all_images() with no parameters returns all images in the page.

Lists all the forms on the current page. Each form is an HTML::Form object. In list context, returns a list of all forms. In scalar context, returns an array reference of all forms.

Selects the numberth form on the page as the target for subsequent calls to CWCIfield()CW and CWCIclick()CW. Also returns the form that was selected. Emits a warning and returns undef if there is no such form. Forms are indexed from 1, so the first form is number 1, not zero.

Selects a form by name. If there is more than one form on the page with that name, then the first one is used, and a warning is generated. Also returns the form itself, or undef if it's not found.

Note that this functionality requires libwww-perl 5.69 or higher. Given the name of a field, set its value to the value specified. This applies to the current form (as set by the CWCIform()CW method or defaulting to the first form on the page).

The optional $number parameter is used to distinguish between two fields with the same name. The fields are numbered from 1.

Given the name of a CWselect field, set its value to the value specified. If the field is not <select multiple> and the CW$value is an array, only the first value will be set. [Note: the documentation previously claimed that only the last value would be set, but this was incorrect.] Passing CW$value as a hash with an CWn key selects an item by number (e.g. CW{n = 3> or CW{n = [2,4]}>). The numbering starts at 1. This applies to the current form (as set by the CWCIform()CW method or defaulting to the first form on the page).

Returns 1 on successfully setting the value. On failure, returns undef and calls CW$self-warn()> with an error message. This method sets multiple fields of the current form. It takes a list of field name and value pairs. If there is more than one field with the same name, the first one found is set. If you want to select which of the duplicate field to set, use a value which is an anonymous array which has the field value and its number as the 2 elements.

        # set the second foo field
        $mech->set_fields( $name => [ 'foo', 2 ] ) ;

The fields are numbered from 1.

This applies to the current form (as set by the CWCIform()CW method or defaulting to the first form on the page). This method sets fields of the current form without having to know their names. So if you have a login screen that wants a username and password, you do not have to fetch the form and inspect the source (or use the mech-dump utility, installed with WWW::Mechanize) to see what the field names are; you can just say

    $mech->set_visible( $username, $password ) ;

and the first and second fields will be set accordingly. The method is called set_visible because it acts only on visible fields; hidden form inputs are not considered. The order of the fields is the order in which they appear in the HTML source which is nearly always the order anyone viewing the page would think they are in, but some creative work with tables could change that; caveat user.

Each element in CW@criteria is either a field value or a field specifier. A field value is a scalar. A field specifier allows you to specify the type of input field you want to set and is denoted with an arrayref containing two elements. So you could specify the first radio button with

    $mech->set_visible( [ radio => "KCRW" ] ) ;

Field values and specifiers can be intermixed, hence

    $mech->set_visible( "fred", "secret", [ option => "Checking" ] ) ;

would set the first two fields to fred and secret, and the next CWOPTION menu field to Checking.

The possible field specifier types are: text, password, hidden, textarea, file, image, submit, radio, checkbox and option. 'Ticks' the first checkbox that has both the name and value assoicated with it on the current form. Dies if there is no named check box for that value. Passing in a false value as the third optional argument will cause the checkbox to be unticked. Causes the checkbox to be unticked. Shorthand for CWtick($name,$value,undef) Given the name of a field, return its value. This applies to the current form (as set by the CWform() method or defaulting to the first form on the page).

The option $number parameter is used to distinguish between two fields with the same name. The fields are numbered from 1.

If the field is of type file (file upload field), the value is always cleared to prevent remote sites from downloading your local files. To upload a file, specify its file name explicitly. Has the effect of clicking a button on the current form. The first argument is the name of the button to be clicked. The second and third arguments (optional) allow you to specify the (x,y) coordinates of the click.

If there is only one button on the form, CW$mech->click() with no arguments simply clicks that one button.

Returns an HTTP::Response object.

Has the effect of clicking a button on the current form by specifying its name, value, or index. Its arguments are a list of key/value pairs. Only one of name, number, input or value must be specified in the keys.

* name => name

Clicks the button named name in the current form.

* number => n

Clicks the nth button in the current form. Numbering starts at 1.

* value => value

Clicks the button with the value value in the current form. Clicks on the button referenced by CW$inputobject, an instance of HTML::Form::SubmitInput obtained e.g. from

  $mech->current_form()->find_input(undef, "submit")

$inputobject must belong to the current form.

* x => x =item * y => y

These arguments (optional) allow you to specify the (x,y) coordinates of the click.

Submits the page, without specifying a button to click. Actually, no button is clicked at all.

This used to be a synonym for CW$mech->click("submit"), but is no longer so.

This method lets you select a form from the previously fetched page, fill in its fields, and submit it. It combines the form_number/form_name, set_fields and click methods into one higher level call. Its arguments are a list of key/value pairs, all of which are optional.

* form_number => n

Selects the nth form (calls CWCIform_number()CW). If this parm is not specified, the currently-selected form is used.

* form_name => name

Selects the form named name (calls CWCIform_name()CW)

* fields => fields

Sets the field values from the fields hashref (calls CWCIset_fields()CW)

* button => button

Clicks on button button (calls CWCIclick()CW)

* x => x, y => y

Sets the x or y values for CWCIclick()CW

If no form is selected, the first form found is used.

If button is not passed, then the CWCIsubmit()CW method is used instead.

Returns an HTTP::Response object.

Sets HTTP headers for the agent to add or remove from the HTTP request.

    $mech->add_header( Encoding => 'text/klingon' );

If a value is CWundef, then that header will be removed from any future requests. For example, to never send a Referer header:

    $mech->add_header( Referer => undef );

If you want to delete a header, use CWdelete_header.

Returns the number of name/value pairs added.

NOTE: This method was very different in WWW::Mechanize before 1.00. Back then, the headers were stored in a package hash, not as a member of the object instance. Calling CWadd_header() would modify the headers for every WWW::Mechanize object, even after your object no longer existed.

Removes HTTP headers from the agent's list of special headers. For instance, you might need to do something like:

    # Don't send a Referer for this URL
    $mech->add_header( Referer => undef );

    # Get the URL
    $mech->get( $url );

    # Back to the default behavior
    $mech->delete_header( 'Referer' );

Allows you to suppress warnings to the screen.

    $mech->quiet(0); # turns on warnings (the default)
    $mech->quiet(1); # turns off warnings
    $mech->quiet();  # returns the current quietness status

Get or set the page stack depth. Older pages are discarded first.

A value of 0 means keep all the pages. Dumps the contents of CW$mech->content into $filename. $filename will be overwritten.

An overloaded version of CWredirect_ok() in LWP::UserAgent. This method is used to determine whether a redirection in the request should be followed. Overloaded version of CWrequest() in LWP::UserAgent. Performs the actual request. Normally, if you're using WWW::Mechanize, it's because you don't want to deal with this level of stuff anyway.

Note that CW$request will be modified.

Returns an HTTP::Response object. Allows you to replace the HTML that the mech has found. Updates the forms and links parse-trees that the mech uses internally.

Say you have a page that you know has malformed output, and you want to update it so the links come out correctly:

    my $html = $mech->content;
    $html =~ s[</option>.{0,3}</td>][</option></select></td>]isg;
    $mech->update_html( $html );

This method is also used internally by the mech itself to update its own HTML content when loading a page. This means that if you would like to systematically perform the above HTML substitution, you would overload update_html in a subclass thusly:

   package MyMech;
   use base 'WWW::Mechanize';

   sub update_html {
       my ($self, $html) = @_;
       $html =~ s[</option>.{0,3}</td>][</option></select></td>]isg;
       $self->WWW::Mechanize::update_html( $html );
   }

If you do this, then the mech will use the tidied-up HTML instead of the original both when parsing for its own needs, and for returning to you through content.

Overloading this method is also the recommended way of implementing extra validation steps (e.g. link checkers) for every HTML page received. warn and die would then come in handy to signal validation errors.

This methods have been replaced by more flexible and precise methods. Please use them instead.

DEPRECATED in favor of CWCIfollow_link()CW, which provides more flexibility.

Follow a link. If you provide a string, the first link whose text matches that string will be followed. If you provide a number, it will be the $numth link on the page. Note that the links are 0-based.

Returns true if the link was found on the page or undef otherwise.

DEPRECATED in favor of CWCIform_name()CW or CWCIform_number()CW.

Selects a form by number or name, depending on if it gets passed an all-numeric string or not. This means that if you have a form name that's all digits, this method will not do the right thing.

These methods are only used internally. You probably don't need to know about them. Updates all internal variables in CW$mech as if CW$request was just performed, and returns CW$response. The page stack is not altered by this method, it is up to caller (e.g. request) to do that. Modifies the request according to all the internal header mangling.

Convenience method to make it easier for subclasses like WWW::Mechanize::Cached to intercept the request.

Resets the internal fields that track page parsed stuff.

Extracts links from the content of a webpage, and populates the CW{links} property with WWW::Mechanize::Link objects. The agent keeps a stack of visited pages, which it can pop when it needs to go BACK and so on.

The current page needs to be pushed onto the stack before we get a new page, and the stack needs to be popped when BACK occurs.

Neither of these take any arguments, they just operate on the CW$mech object. Centralized warning method, for diagnostics and non-fatal problems. Defaults to calling CWCORE::warn, but may be overridden by setting CWonwarn in the construcotr. Centralized error method. Defaults to calling CWCORE::die, but may be overridden by setting CWonerror in the constructor.

Mech is hosted by the kind generosity of Ask and Robert, maintainers of perl.org. The Subversion repository is at <http://svn.perl.org/modules/www-mechanize>.

Spidering Hacks from O'Reilly (<http://www.oreilly.com/catalog/spiderhks/>) is a great book for anyone wanting to know more about screen-scraping and spidering.

There are six hacks that use Mech or a Mech derivative:

#21 WWW::Mechanize 101

#22 Scraping with WWW::Mechanize

#36 Downloading Images from Webshots

#44 Archiving Yahoo! Groups Messages with WWW::Yahoo::Groups

#64 Super Author Searching

#73 Scraping TV Listings

The book was also positively reviewed on Slashdot: <http://books.slashdot.org/article.pl?sid=03/12/11/2126256>

* WWW::Mechanize Development mailing list

Hosted at Sourceforge, this is where the contributors to Mech discuss things. <http://sourceforge.net/mail/?group_id=83309>

* LWP mailing list

The LWP mailing list is at <http://lists.perl.org/showlist.cgi?name=libwww>, and is more user-oriented and well-populated than the WWW::Mechanize Development list. This is a good list for Mech users, since LWP is the basis for Mech.

* WWW::Mechanize::Examples

A random array of examples submitted by users, included with the Mechanize distribution.

* <http://www.oreilly.com/catalog/googlehks2/chapter/hack84.pdf>

Leland Johnson's hack #84 in Google Hacks, 2nd Edition is an example of a production script that uses WWW::Mechanize and HTML::TableContentParser. It takes in keywords and returns the estimated price of these keywords on Google's AdWords program.

* <http://www.perl.com/pub/a/2004/06/04/recorder.html>

Linda Julien writes about using HTTP::Recorder to create WWW::Mechanize scripts.

* <http://www.developer.com/lang/other/article.php/3454041>

Jason Gilmore's article on using WWW::Mechanize for scraping sales information from Amazon and eBay.

* <http://www.perl.com/pub/a/2003/01/22/mechanize.html>

Chris Ball's article about using WWW::Mechanize for scraping TV listings.

* <http://www.stonehenge.com/merlyn/LinuxMag/col47.html>

Randal Schwartz's article on scraping Yahoo News for images. It's already out of date: He manually walks the list of links hunting for matches, which wouldn't have been necessary if the CWfind_link() method existed at press time.

* <http://www.perladvent.org/2002/16th/>

WWW::Mechanize on the Perl Advent Calendar, by Mark Fowler.

* <http://www.linux-magazin.de/Artikel/ausgabe/2004/03/perl/perl.html>

Michael Schilli's article on Mech and WWW::Mechanize::Shell for the German magazine Linux Magazin.

Here are modules that use or subclass Mechanize. Let me know of any others:

* Finance::Bank::LloydsTSB

* HTTP::Recorder

Acts as a proxy for web interaction, and then generates WWW::Mechanize scripts.

* Win32::IE::Mechanize

Just like Mech, but using Microsoft Internet Explorer to do the work.

* WWW::Bugzilla

* WWW::Google::Groups

* WWW::Hotmail

* WWW::Mechanize::Cached

* WWW::Mechanize::FormFiller

* WWW::Mechanize::Shell

* WWW::Mechanize::Sleepy

* WWW::Mechanize::SpamCop

* WWW::Mechanize::Timed

* WWW::SourceForge

* WWW::Yahoo::Groups

Please report any requests, suggestions or (gasp!) bugs via the excellent RT bug-tracking system at http://rt.cpan.org/, or email to bug-WWW-Mechanize@rt.cpan.org. This makes it much easier for me to track things.

<http://rt.cpan.org/NoAuth/Bugs.html?Dist=WWW-Mechanize> is the RT queue for Mechanize. Please check to see if your bug has already been reported.

Thanks to the numerous people who have helped out on WWW::Mechanize in one way or another, including Kirrily Robert for the orignal CWWWW::Automate, Mike O'Regan, Mark Stosberg, Uri Guttman, Peter Scott, Phillipe Bruhat, Ian Langworth, John Beppu, Gavin Estey, Jim Brandt, Ask Bjoern Hansen, Greg Davies, Ed Silva, Mark-Jason Dominus, Autrijus Tang, Mark Fowler, Stuart Children, Max Maischein, Meng Wong, Prakash Kailasa, Abigail, Jan Pazdziora, Dominique Quatravaux, Scott Lanning, Rob Casey, Leland Johnson, Joshua Gatcomb, Julien Beasley, Abe Timmerman, and the late great Iain Truskett.

Copyright (c) 2005 Andy Lester. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.