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LWP::UserAgent(3)     User Contributed Perl Documentation    LWP::UserAgent(3)




NAME

       LWP::UserAgent - Web user agent class


SYNOPSIS

        use strict;
        use warnings;
        use LWP::UserAgent ();

        my $ua = LWP::UserAgent->new;
        $ua->timeout(10);
        $ua->env_proxy;

        my $response = $ua->get('http://search.cpan.org/');

        if ($response->is_success) {
            print $response->decoded_content;  # or whatever
        }
        else {
            die $response->status_line;
        }


DESCRIPTION

       The LWP::UserAgent is a class implementing a web user agent.
       LWP::UserAgent objects can be used to dispatch web requests.

       In normal use the application creates an LWP::UserAgent object, and
       then configures it with values for timeouts, proxies, name, etc. It
       then creates an instance of HTTP::Request for the request that needs to
       be performed. This request is then passed to one of the request method
       the UserAgent, which dispatches it using the relevant protocol, and
       returns a HTTP::Response object.  There are convenience methods for
       sending the most common request types: "get" in LWP::UserAgent, "head"
       in LWP::UserAgent, "post" in LWP::UserAgent, "put" in LWP::UserAgent
       and "delete" in LWP::UserAgent.  When using these methods, the creation
       of the request object is hidden as shown in the synopsis above.

       The basic approach of the library is to use HTTP-style communication
       for all protocol schemes.  This means that you will construct
       HTTP::Request objects and receive HTTP::Response objects even for non-
       HTTP resources like gopher and ftp.  In order to achieve even more
       similarity to HTTP-style communications, gopher menus and file
       directories are converted to HTML documents.


CONSTRUCTOR METHODS

       The following constructor methods are available:

   clone
           my $ua2 = $ua->clone;

       Returns a copy of the LWP::UserAgent object.

       CAVEAT: Please be aware that the clone method does not copy or clone
       your "cookie_jar" attribute. Due to the limited restrictions on what
       can be used for your cookie jar, there is no way to clone the
       attribute. The "cookie_jar" attribute will be "undef" in the new object
       instance.

   new
           my $ua = LWP::UserAgent->new( %options )

       This method constructs a new LWP::UserAgent object and returns it.
       Key/value pair arguments may be provided to set up the initial state.
       The following options correspond to attribute methods described below:

          KEY                     DEFAULT
          -----------             --------------------
          agent                   "libwww-perl/#.###"
          from                    undef
          conn_cache              undef
          cookie_jar              undef
          default_headers         HTTP::Headers->new
          local_address           undef
          ssl_opts                { verify_hostname => 1 }
          max_size                undef
          max_redirect            7
          parse_head              1
          protocols_allowed       undef
          protocols_forbidden     undef
          requests_redirectable   ['GET', 'HEAD']
          timeout                 180
          proxy                   undef
          no_proxy                []

       The following additional options are also accepted: If the "env_proxy"
       option is passed in with a true value, then proxy settings are read
       from environment variables (see "env_proxy" in LWP::UserAgent). If
       "env_proxy" isn't provided, the "PERL_LWP_ENV_PROXY" environment
       variable controls if "env_proxy" in LWP::UserAgent is called during
       initialization.  If the "keep_alive" option is passed in, then a
       "LWP::ConnCache" is set up (see "conn_cache" in LWP::UserAgent).  The
       "keep_alive" value is passed on as the "total_capacity" for the
       connection cache.

       "proxy" must be set as an arrayref of key/value pairs. "no_proxy" takes
       an arrayref of domains.


ATTRIBUTES

       The settings of the configuration attributes modify the behaviour of
       the LWP::UserAgent when it dispatches requests.  Most of these can also
       be initialized by options passed to the constructor method.

       The following attribute methods are provided.  The attribute value is
       left unchanged if no argument is given.  The return value from each
       method is the old attribute value.

   agent
           my $agent = $ua->agent;
           $ua->agent('Checkbot/0.4 ');    # append the default to the end
           $ua->agent('Mozilla/5.0');
           $ua->agent("");                 # don't identify

       Get/set the product token that is used to identify the user agent on
       the network. The agent value is sent as the "User-Agent" header in the
       requests.

       The default is a string of the form "libwww-perl/#.###", where "#.###"
       is substituted with the version number of this library.

       If the provided string ends with space, the default "libwww-perl/#.###"
       string is appended to it.

       The user agent string should be one or more simple product identifiers
       with an optional version number separated by the "/" character.

   conn_cache
           my $cache_obj = $ua->conn_cache;
           $ua->conn_cache( $cache_obj );

       Get/set the LWP::ConnCache object to use.  See LWP::ConnCache for
       details.

   cookie_jar
           my $jar = $ua->cookie_jar;
           $ua->cookie_jar( $cookie_jar_obj );

       Get/set the cookie jar object to use.  The only requirement is that the
       cookie jar object must implement the "extract_cookies($response)" and
       "add_cookie_header($request)" methods.  These methods will then be
       invoked by the user agent as requests are sent and responses are
       received.  Normally this will be a HTTP::Cookies object or some
       subclass.

       The default is to have no cookie jar, i.e. never automatically add
       "Cookie" headers to the requests.

       Shortcut: If a reference to a plain hash is passed in, it is replaced
       with an instance of HTTP::Cookies that is initialized based on the
       hash. This form also automatically loads the HTTP::Cookies module.  It
       means that:

         $ua->cookie_jar({ file => "$ENV{HOME}/.cookies.txt" });

       is really just a shortcut for:

         require HTTP::Cookies;
         $ua->cookie_jar(HTTP::Cookies->new(file => "$ENV{HOME}/.cookies.txt"));

   credentials
           my $creds = $ua->credentials();
           $ua->credentials( $netloc, $realm );
           $ua->credentials( $netloc, $realm, $uname, $pass );
           $ua->credentials("www.example.com:80", "Some Realm", "foo", "secret");

       Get/set the user name and password to be used for a realm.

       The $netloc is a string of the form "<host>:<port>".  The username and
       password will only be passed to this server.

   default_header
           $ua->default_header( $field );
           $ua->default_header( $field => $value );
           $ua->default_header('Accept-Encoding' => scalar HTTP::Message::decodable());
           $ua->default_header('Accept-Language' => "no, en");

       This is just a shortcut for "$ua->default_headers->header( $field =>
       $value )".

   default_headers
           my $headers = $ua->default_headers;
           $ua->default_headers( $headers_obj );

       Get/set the headers object that will provide default header values for
       any requests sent.  By default this will be an empty HTTP::Headers
       object.

   from
           my $from = $ua->from;
           $ua->from('foo@bar.com');

       Get/set the email address for the human user who controls the
       requesting user agent.  The address should be machine-usable, as
       defined in RFC2822 <https://tools.ietf.org/html/rfc2822>. The "from"
       value is sent as the "From" header in the requests.

       The default is to not send a "From" header.  See "default_headers" in
       LWP::UserAgent for the more general interface that allow any header to
       be defaulted.

   local_address
           my $address = $ua->local_address;
           $ua->local_address( $address );

       Get/set the local interface to bind to for network connections.  The
       interface can be specified as a hostname or an IP address.  This value
       is passed as the "LocalAddr" argument to IO::Socket::INET.

   max_redirect
           my $max = $ua->max_redirect;
           $ua->max_redirect( $n );

       This reads or sets the object's limit of how many times it will obey
       redirection responses in a given request cycle.

       By default, the value is 7. This means that if you call "request" in
       LWP::UserAgent and the response is a redirect elsewhere which is in
       turn a redirect, and so on seven times, then LWP gives up after that
       seventh request.

   max_size
           my $size = $ua->max_size;
           $ua->max_size( $bytes );

       Get/set the size limit for response content.  The default is "undef",
       which means that there is no limit.  If the returned response content
       is only partial, because the size limit was exceeded, then a
       "Client-Aborted" header will be added to the response.  The content
       might end up longer than "max_size" as we abort once appending a chunk
       of data makes the length exceed the limit.  The "Content-Length"
       header, if present, will indicate the length of the full content and
       will normally not be the same as "length($res->content)".

   parse_head
           my $bool = $ua->parse_head;
           $ua->parse_head( $boolean );

       Get/set a value indicating whether we should initialize response
       headers from the <head> section of HTML documents. The default is true.
       Do not turn this off unless you know what you are doing.

   protocols_allowed
           my $aref = $ua->protocols_allowed;      # get allowed protocols
           $ua->protocols_allowed( \@protocols );  # allow ONLY these
           $ua->protocols_allowed(undef);          # delete the list
           $ua->protocols_allowed(['http',]);      # ONLY allow http

       By default, an object has neither a "protocols_allowed" list, nor a
       "protocols_forbidden" in LWP::UserAgent list.

       This reads (or sets) this user agent's list of protocols that the
       request methods will exclusively allow.  The protocol names are case
       insensitive.

       For example: "$ua->protocols_allowed( [ 'http', 'https'] );" means that
       this user agent will allow only those protocols, and attempts to use
       this user agent to access URLs with any other schemes (like
       "ftp://...") will result in a 500 error.

       Note that having a "protocols_allowed" list causes any
       "protocols_forbidden" in LWP::UserAgent list to be ignored.

   protocols_forbidden
           my $aref = $ua->protocols_forbidden;    # get the forbidden list
           $ua->protocols_forbidden(\@protocols);  # do not allow these
           $ua->protocols_forbidden(['http',]);    # All http reqs get a 500
           $ua->protocols_forbidden(undef);        # delete the list

       This reads (or sets) this user agent's list of protocols that the
       request method will not allow. The protocol names are case insensitive.

       For example: "$ua->protocols_forbidden( [ 'file', 'mailto'] );" means
       that this user agent will not allow those protocols, and attempts to
       use this user agent to access URLs with those schemes will result in a
       500 error.

   requests_redirectable
           my $aref = $ua->requests_redirectable;
           $ua->requests_redirectable( \@requests );
           $ua->requests_redirectable(['GET', 'HEAD',]); # the default

       This reads or sets the object's list of request names that
       "redirect_ok" in LWP::UserAgent will allow redirection for. By default,
       this is "['GET', 'HEAD']", as per RFC 2616
       <https://tools.ietf.org/html/rfc2616>.  To change to include "POST",
       consider:

          push @{ $ua->requests_redirectable }, 'POST';

   send_te
           my $bool = $ua->send_te;
           $ua->send_te( $boolean );

       If true, will send a "TE" header along with the request. The default is
       true. Set it to false to disable the "TE" header for systems who can't
       handle it.

   show_progress
           my $bool = $ua->show_progress;
           $ua->show_progress( $boolean );

       Get/set a value indicating whether a progress bar should be displayed
       on the terminal as requests are processed. The default is false.

   ssl_opts
           my @keys = $ua->ssl_opts;
           my $val = $ua->ssl_opts( $key );
           $ua->ssl_opts( $key => $value );

       Get/set the options for SSL connections.  Without argument return the
       list of options keys currently set.  With a single argument return the
       current value for the given option.  With 2 arguments set the option
       value and return the old.  Setting an option to the value "undef"
       removes this option.

       The options that LWP relates to are:

       "verify_hostname" => $bool
           When TRUE LWP will for secure protocol schemes ensure it connects
           to servers that have a valid certificate matching the expected
           hostname.  If FALSE no checks are made and you can't be sure that
           you communicate with the expected peer.  The no checks behaviour
           was the default for libwww-perl-5.837 and earlier releases.

           This option is initialized from the "PERL_LWP_SSL_VERIFY_HOSTNAME"
           environment variable.  If this environment variable isn't set; then
           "verify_hostname" defaults to 1.

       "SSL_ca_file" => $path
           The path to a file containing Certificate Authority certificates.
           A default setting for this option is provided by checking the
           environment variables "PERL_LWP_SSL_CA_FILE" and "HTTPS_CA_FILE" in
           order.

       "SSL_ca_path" => $path
           The path to a directory containing files containing Certificate
           Authority certificates.  A default setting for this option is
           provided by checking the environment variables
           "PERL_LWP_SSL_CA_PATH" and "HTTPS_CA_DIR" in order.

       Other options can be set and are processed directly by the SSL Socket
       implementation in use.  See IO::Socket::SSL or Net::SSL for details.

       The libwww-perl core no longer bundles protocol plugins for SSL.  You
       will need to install LWP::Protocol::https separately to enable support
       for processing https-URLs.

   timeout
           my $secs = $ua->timeout;
           $ua->timeout( $secs );

       Get/set the timeout value in seconds. The default value is 180 seconds,
       i.e. 3 minutes.

       The request is aborted if no activity on the connection to the server
       is observed for "timeout" seconds.  This means that the time it takes
       for the complete transaction and the "request" in LWP::UserAgent method
       to actually return might be longer.

       When a request times out, a response object is still returned.  The
       response will have a standard HTTP Status Code (500).  This response
       will have the "Client-Warning" header set to the value of "Internal
       response".  See the "get" in LWP::UserAgent method description below
       for further details.


PROXY ATTRIBUTES

       The following methods set up when requests should be passed via a proxy
       server.

   env_proxy
           $ua->env_proxy;

       Load proxy settings from *_proxy environment variables.  You might
       specify proxies like this (sh-syntax):

         gopher_proxy=http://proxy.my.place/
         wais_proxy=http://proxy.my.place/
         no_proxy="localhost,example.com"
         export gopher_proxy wais_proxy no_proxy

       csh or tcsh users should use the "setenv" command to define these
       environment variables.

       On systems with case insensitive environment variables there exists a
       name clash between the CGI environment variables and the "HTTP_PROXY"
       environment variable normally picked up by "env_proxy".  Because of
       this "HTTP_PROXY" is not honored for CGI scripts.  The "CGI_HTTP_PROXY"
       environment variable can be used instead.

   no_proxy
           $ua->no_proxy( @domains );
           $ua->no_proxy('localhost', 'example.com');
           $ua->no_proxy(); # clear the list

       Do not proxy requests to the given domains.  Calling "no_proxy" without
       any domains clears the list of domains.

   proxy
           $ua->proxy(\@schemes, $proxy_url)
           $ua->proxy(['http', 'ftp'], 'http://proxy.sn.no:8001/');

           # For a single scheme:
           $ua->proxy($scheme, $proxy_url)
           $ua->proxy('gopher', 'http://proxy.sn.no:8001/');

           # To set multiple proxies at once:
           $ua->proxy([
               ftp => 'http://ftp.example.com:8001/',
               [ 'http', 'https' ] => 'http://http.example.com:8001/',
           ]);

       Set/retrieve proxy URL for a scheme.

       The first form specifies that the URL is to be used as a proxy for
       access methods listed in the list in the first method argument, i.e.
       "http" and "ftp".

       The second form shows a shorthand form for specifying proxy URL for a
       single access scheme.

       The third form demonstrates setting multiple proxies at once. This is
       also the only form accepted by the constructor.


HANDLERS

       Handlers are code that injected at various phases during the processing
       of requests.  The following methods are provided to manage the active
       handlers:

   add_handler
           $ua->add_handler( $phase => \&cb, %matchspec )

       Add handler to be invoked in the given processing phase.  For how to
       specify %matchspec see "Matching" in HTTP::Config.

       The possible values $phase and the corresponding callback signatures
       are:

       response_data => sub { my($response, $ua, $h, $data) = @_; ... }
           This handler is called for each chunk of data received for the
           response.  The handler might croak to abort the request.

           This handler needs to return a TRUE value to be called again for
           subsequent chunks for the same request.

       response_done => sub { my($response, $ua, $h) = @_; ... }
           The handler is called after the response has been fully received,
           but before any redirect handling is attempted.  The handler can be
           used to extract information or modify the response.

       response_header => sub { my($response, $ua, $h) = @_; ... }
           This handler is called right after the response headers have been
           received, but before any content data.  The handler might set up
           handlers for data and might croak to abort the request.

           The handler might set the $response->{default_add_content} value to
           control if any received data should be added to the response object
           directly.  This will initially be false if the $ua->request()
           method was called with a $content_file or $content_cb argument;
           otherwise true.

       request_prepare => sub { my($request, $ua, $h) = @_; ... }
           The handler is called before the request is sent and can modify the
           request any way it see fit.  This can for instance be used to add
           certain headers to specific requests.

           The method can assign a new request object to $_[0] to replace the
           request that is sent fully.

           The return value from the callback is ignored.  If an exception is
           raised it will abort the request and make the request method return
           a "400 Bad request" response.

       request_preprepare => sub { my($request, $ua, $h) = @_; ... }
           The handler is called before the "request_prepare" and other
           standard initialization of the request.  This can be used to set up
           headers and attributes that the "request_prepare" handler depends
           on.  Proxy initialization should take place here; but in general
           don't register handlers for this phase.

       request_send => sub { my($request, $ua, $h) = @_; ... }
           This handler gets a chance of handling requests before they're sent
           to the protocol handlers.  It should return an HTTP::Response
           object if it wishes to terminate the processing; otherwise it
           should return nothing.

           The "response_header" and "response_data" handlers will not be
           invoked for this response, but the "response_done" will be.

       response_redirect => sub { my($response, $ua, $h) = @_; ... }
           The handler is called in $ua->request after "response_done".  If
           the handler returns an HTTP::Request object we'll start over with
           processing this request instead.

   get_my_handler
           $ua->get_my_handler( $phase, %matchspec );
           $ua->get_my_handler( $phase, %matchspec, $init );

       Will retrieve the matching handler as hash ref.

       If $init is passed as a true value, create and add the handler if it's
       not found.  If $init is a subroutine reference, then it's called with
       the created handler hash as argument.  This sub might populate the hash
       with extra fields; especially the callback.  If $init is a hash
       reference, merge the hashes.

   handlers
           $ua->handlers( $phase, $request )
           $ua->handlers( $phase, $response )

       Returns the handlers that apply to the given request or response at the
       given processing phase.

   remove_handler
           $ua->remove_handler( undef, %matchspec );
           $ua->remove_handler( $phase, %matchspec );
           $ua->remove_handlers(); # REMOVE ALL HANDLERS IN ALL PHASES

       Remove handlers that match the given %matchspec.  If $phase is not
       provided, remove handlers from all phases.

       Be careful as calling this function with %matchspec that is not
       specific enough can remove handlers not owned by you.  It's probably
       better to use the "set_my_handler" in LWP::UserAgent method instead.

       The removed handlers are returned.

   set_my_handler
           $ua->set_my_handler( $phase, $cb, %matchspec );
           $ua->set_my_handler($phase, undef); # remove handler for phase

       Set handlers private to the executing subroutine.  Works by defaulting
       an "owner" field to the %matchspec that holds the name of the called
       subroutine.  You might pass an explicit "owner" to override this.

       If $cb is passed as "undef", remove the handler.


REQUEST METHODS

       The methods described in this section are used to dispatch requests via
       the user agent.  The following request methods are provided:

   delete
           my $res = $ua->delete( $url );
           my $res = $ua->delete( $url, $field_name => $value, ... );

       This method will dispatch a "DELETE" request on the given URL.
       Additional headers and content options are the same as for the "get" in
       LWP::UserAgent method.

       This method will use the DELETE() function from HTTP::Request::Common
       to build the request.  See HTTP::Request::Common for a details on how
       to pass form content and other advanced features.

   get
           my $res = $ua->get( $url );
           my $res = $ua->get( $url , $field_name => $value, ... );

       This method will dispatch a "GET" request on the given URL.  Further
       arguments can be given to initialize the headers of the request. These
       are given as separate name/value pairs.  The return value is a response
       object.  See HTTP::Response for a description of the interface it
       provides.

       There will still be a response object returned when LWP can't connect
       to the server specified in the URL or when other failures in protocol
       handlers occur.  These internal responses use the standard HTTP status
       codes, so the responses can't be differentiated by testing the response
       status code alone.  Error responses that LWP generates internally will
       have the "Client-Warning" header set to the value "Internal response".
       If you need to differentiate these internal responses from responses
       that a remote server actually generates, you need to test this header
       value.

       Fields names that start with ":" are special.  These will not
       initialize headers of the request but will determine how the response
       content is treated.  The following special field names are recognized:

           :content_file   => $filename
           :content_cb     => \&callback
           :read_size_hint => $bytes

       If a $filename is provided with the ":content_file" option, then the
       response content will be saved here instead of in the response object.
       If a callback is provided with the ":content_cb" option then this
       function will be called for each chunk of the response content as it is
       received from the server.  If neither of these options are given, then
       the response content will accumulate in the response object itself.
       This might not be suitable for very large response bodies.  Only one of
       ":content_file" or ":content_cb" can be specified.  The content of
       unsuccessful responses will always accumulate in the response object
       itself, regardless of the ":content_file" or ":content_cb" options
       passed in.  Note that errors writing to the content file (for example
       due to permission denied or the filesystem being full) will be reported
       via the "Client-Aborted" or "X-Died" response headers, and not the
       "is_success" method.

       The ":read_size_hint" option is passed to the protocol module which
       will try to read data from the server in chunks of this size.  A
       smaller value for the ":read_size_hint" will result in a higher number
       of callback invocations.

       The callback function is called with 3 arguments: a chunk of data, a
       reference to the response object, and a reference to the protocol
       object.  The callback can abort the request by invoking die().  The
       exception message will show up as the "X-Died" header field in the
       response returned by the get() function.

   head
           my $res = $ua->head( $url );
           my $res = $ua->head( $url , $field_name => $value, ... );

       This method will dispatch a "HEAD" request on the given URL.  Otherwise
       it works like the "get" in LWP::UserAgent method described above.

   is_protocol_supported
           my $bool = $ua->is_protocol_supported( $scheme );

       You can use this method to test whether this user agent object supports
       the specified "scheme".  (The "scheme" might be a string (like "http"
       or "ftp") or it might be an URI object reference.)

       Whether a scheme is supported is determined by the user agent's
       "protocols_allowed" or "protocols_forbidden" lists (if any), and by the
       capabilities of LWP.  I.e., this will return true only if LWP supports
       this protocol and it's permitted for this particular object.

   is_online
           my $bool = $ua->is_online;

       Tries to determine if you have access to the Internet. Returns 1 (true)
       if the built-in heuristics determine that the user agent is able to
       access the Internet (over HTTP) or 0 (false).

       See also LWP::Online.

   mirror
           my $res = $ua->mirror( $url, $filename );

       This method will get the document identified by URL and store it in
       file called $filename.  If the file already exists, then the request
       will contain an "If-Modified-Since" header matching the modification
       time of the file.  If the document on the server has not changed since
       this time, then nothing happens.  If the document has been updated, it
       will be downloaded again.  The modification time of the file will be
       forced to match that of the server.

       The return value is an HTTP::Response object.

   post
           my $res = $ua->post( $url, \%form );
           my $res = $ua->post( $url, \@form );
           my $res = $ua->post( $url, \%form, $field_name => $value, ... );
           my $res = $ua->post( $url, $field_name => $value, Content => \%form );
           my $res = $ua->post( $url, $field_name => $value, Content => \@form );
           my $res = $ua->post( $url, $field_name => $value, Content => $content );

       This method will dispatch a "POST" request on the given URL, with %form
       or @form providing the key/value pairs for the fill-in form content.
       Additional headers and content options are the same as for the "get" in
       LWP::UserAgent method.

       This method will use the "POST" function from HTTP::Request::Common to
       build the request.  See HTTP::Request::Common for a details on how to
       pass form content and other advanced features.

   put
           # Any version of HTTP::Message works with this form:
           my $res = $ua->put( $url, $field_name => $value, Content => $content );

           # Using hash or array references requires HTTP::Message >= 6.07
           use HTTP::Request 6.07;
           my $res = $ua->put( $url, \%form );
           my $res = $ua->put( $url, \@form );
           my $res = $ua->put( $url, \%form, $field_name => $value, ... );
           my $res = $ua->put( $url, $field_name => $value, Content => \%form );
           my $res = $ua->put( $url, $field_name => $value, Content => \@form );

       This method will dispatch a "PUT" request on the given URL, with %form
       or @form providing the key/value pairs for the fill-in form content.
       Additional headers and content options are the same as for the "get" in
       LWP::UserAgent method.

       CAVEAT:

       This method can only accept content that is in key-value pairs when
       using HTTP::Request::Common prior to version 6.07. Any use of hash or
       array references will result in an error prior to version 6.07.

       This method will use the "PUT" function from HTTP::Request::Common to
       build the request.  See HTTP::Request::Common for a details on how to
       pass form content and other advanced features.

   request
           my $res = $ua->request( $request );
           my $res = $ua->request( $request, $content_file );
           my $res = $ua->request( $request, $content_cb );
           my $res = $ua->request( $request, $content_cb, $read_size_hint );

       This method will dispatch the given $request object. Normally this will
       be an instance of the HTTP::Request class, but any object with a
       similar interface will do. The return value is an HTTP::Response
       object.

       The "request" method will process redirects and authentication
       responses transparently. This means that it may actually send several
       simple requests via the "simple_request" in LWP::UserAgent method
       described below.

       The request methods described above; "get" in LWP::UserAgent, "head" in
       LWP::UserAgent, "post" in LWP::UserAgent and "mirror" in LWP::UserAgent
       will all dispatch the request they build via this method. They are
       convenience methods that simply hide the creation of the request object
       for you.

       The $content_file, $content_cb and $read_size_hint all correspond to
       options described with the "get" in LWP::UserAgent method above. Note
       that errors writing to the content file (for example due to permission
       denied or the filesystem being full) will be reported via the
       "Client-Aborted" or "X-Died" response headers, and not the "is_success"
       method.

       You are allowed to use a CODE reference as "content" in the request
       object passed in.  The "content" function should return the content
       when called.  The content can be returned in chunks.  The content
       function will be invoked repeatedly until it return an empty string to
       signal that there is no more content.

   simple_request
           my $request = HTTP::Request->new( ... );
           my $res = $ua->simple_request( $request );
           my $res = $ua->simple_request( $request, $content_file );
           my $res = $ua->simple_request( $request, $content_cb );
           my $res = $ua->simple_request( $request, $content_cb, $read_size_hint );

       This method dispatches a single request and returns the response
       received.  Arguments are the same as for the "request" in
       LWP::UserAgent described above.

       The difference from "request" in LWP::UserAgent is that
       "simple_request" will not try to handle redirects or authentication
       responses.  The "request" in LWP::UserAgent method will, in fact,
       invoke this method for each simple request it sends.


CALLBACK METHODS

       The following methods will be invoked as requests are processed. These
       methods are documented here because subclasses of LWP::UserAgent might
       want to override their behaviour.

   get_basic_credentials
           # This checks wantarray and can either return an array:
           my ($user, $pass) = $ua->get_basic_credentials( $realm, $uri, $isproxy );
           # or a string that looks like "user:pass"
           my $creds = $ua->get_basic_credentials($realm, $uri, $isproxy);

       This is called by "request" in LWP::UserAgent to retrieve credentials
       for documents protected by Basic or Digest Authentication.  The
       arguments passed in is the $realm provided by the server, the $uri
       requested and a "boolean flag" to indicate if this is authentication
       against a proxy server.

       The method should return a username and password.  It should return an
       empty list to abort the authentication resolution attempt.  Subclasses
       can override this method to prompt the user for the information. An
       example of this can be found in "lwp-request" program distributed with
       this library.

       The base implementation simply checks a set of pre-stored member
       variables, set up with the "credentials" in LWP::UserAgent method.

   prepare_request
           $request = $ua->prepare_request( $request );

       This method is invoked by "simple_request" in LWP::UserAgent. Its task
       is to modify the given $request object by setting up various headers
       based on the attributes of the user agent. The return value should
       normally be the $request object passed in.  If a different request
       object is returned it will be the one actually processed.

       The headers affected by the base implementation are; "User-Agent",
       "From", "Range" and "Cookie".

   progress
           my $prog = $ua->progress( $status, $request_or_response );

       This is called frequently as the response is received regardless of how
       the content is processed.  The method is called with $status "begin" at
       the start of processing the request and with $state "end" before the
       request method returns.  In between these $status will be the fraction
       of the response currently received or the string "tick" if the fraction
       can't be calculated.

       When $status is "begin" the second argument is the HTTP::Request
       object, otherwise it is the HTTP::Response object.

   redirect_ok
           my $bool = $ua->redirect_ok( $prospective_request, $response );

       This method is called by "request" in LWP::UserAgent before it tries to
       follow a redirection to the request in $response.  This should return a
       true value if this redirection is permissible.  The
       $prospective_request will be the request to be sent if this method
       returns true.

       The base implementation will return false unless the method is in the
       object's "requests_redirectable" list, false if the proposed
       redirection is to a "file://..."  URL, and true otherwise.


SEE ALSO

       See LWP for a complete overview of libwww-perl5.  See lwpcook and the
       scripts lwp-request and lwp-download for examples of usage.

       See HTTP::Request(3) and HTTP::Response(3) for a description of the 
       message objects dispatched and received.  See HTTP::Request::Common(3)
       and HTML::Form(3) for other ways to build request objects.

       See WWW::Mechanize(3) and WWW::Search(3) for examples of more 
       specialized user agents based on "LWP::UserAgent".


COPYRIGHT AND LICENSE

       Copyright 1995-2009 Gisle Aas.

       This library is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.



perl v5.26.2                      2018-06-05                 LWP::UserAgent(3)

libwww-perl 6.340.0 - Generated Thu Jun 7 16:21:49 CDT 2018
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