lwp::useragent.3

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

Returns the default agent identifier.  This is a string of the form
\&\*(L"libwww\-perl/#.##\*(R", where \*(L"#.##\*(R" is substituted with the version number
of this library.
.ie n .IP "$ua\->from" 4
.el .IP "\f(CW$ua\fR\->from" 4
.IX Item "$ua->from"
.PD 0
.ie n .IP "$ua\fR\->from( \f(CW$email_address )" 4
.el .IP "\f(CW$ua\fR\->from( \f(CW$email_address\fR )" 4
.IX Item "$ua->from( $email_address )"
.PD
Get/set the e\-mail address for the human user who controls
the requesting user agent.  The address should be machine-usable, as
defined in \s-1RFC\s0 822.  The \f(CW\*(C`from\*(C'\fR value is send as the \*(L"From\*(R" header in
the requests.  Example:
.Sp
.Vb 1
\&  $ua\->from(\*([e-mail]\*(Aq);
.Ve
.Sp
The default is to not send a \*(L"From\*(R" header.  See the \fIdefault_headers()\fR
method for the more general interface that allow any header to be defaulted.
.ie n .IP "$ua\->cookie_jar" 4
.el .IP "\f(CW$ua\fR\->cookie_jar" 4
.IX Item "$ua->cookie_jar"
.PD 0
.ie n .IP "$ua\fR\->cookie_jar( \f(CW$cookie_jar_obj )" 4
.el .IP "\f(CW$ua\fR\->cookie_jar( \f(CW$cookie_jar_obj\fR )" 4
.IX Item "$ua->cookie_jar( $cookie_jar_obj )"
.PD
Get/set the cookie jar object to use.  The only requirement is that
the cookie jar object must implement the extract_cookies($request) and
add_cookie_header($response) methods.  These methods will then be
invoked by the user agent as requests are sent and responses are
received.  Normally this will be a \f(CW\*(C`HTTP::Cookies\*(C'\fR object or some
subclass.
.Sp
The default is to have no cookie_jar, i.e. never automatically add
\&\*(L"Cookie\*(R" headers to the requests.
.Sp
Shortcut: If a reference to a plain hash is passed in as the
\&\f(CW$cookie_jar_object\fR, then it is replaced with an instance of
\&\f(CW\*(C`HTTP::Cookies\*(C'\fR that is initialized based on the hash.  This form also
automatically loads the \f(CW\*(C`HTTP::Cookies\*(C'\fR module.  It means that:
.Sp
.Vb 1
\&  $ua\->cookie_jar({ file => "$ENV{HOME}/.cookies.txt" });
.Ve
.Sp
is really just a shortcut for:
.Sp
.Vb 2
\&  require HTTP::Cookies;
\&  $ua\->cookie_jar(HTTP::Cookies\->new(file => "$ENV{HOME}/.cookies.txt"));
.Ve
.ie n .IP "$ua\->default_headers" 4
.el .IP "\f(CW$ua\fR\->default_headers" 4
.IX Item "$ua->default_headers"
.PD 0
.ie n .IP "$ua\fR\->default_headers( \f(CW$headers_obj )" 4
.el .IP "\f(CW$ua\fR\->default_headers( \f(CW$headers_obj\fR )" 4
.IX Item "$ua->default_headers( $headers_obj )"
.PD
Get/set the headers object that will provide default header values for
any requests sent.  By default this will be an empty \f(CW\*(C`HTTP::Headers\*(C'\fR
object.  Example:
.Sp
.Vb 1
\&  $ua\->default_headers\->push_header(\*(AqAccept\-Language\*(Aq => "no, en");
.Ve
.ie n .IP "$ua\fR\->default_header( \f(CW$field )" 4
.el .IP "\f(CW$ua\fR\->default_header( \f(CW$field\fR )" 4
.IX Item "$ua->default_header( $field )"
.PD 0
.ie n .IP "$ua\fR\->default_header( \f(CW$field\fR => \f(CW$value )" 4
.el .IP "\f(CW$ua\fR\->default_header( \f(CW$field\fR => \f(CW$value\fR )" 4
.IX Item "$ua->default_header( $field => $value )"
.PD
This is just a short-cut for \f(CW$ua\fR\->default_headers\->header( \f(CW$field\fR =>
\&\f(CW$value\fR ). Example:
.Sp
.Vb 1
\&  $ua\->default_header(\*(AqAccept\-Language\*(Aq => "no, en");
.Ve
.ie n .IP "$ua\->conn_cache" 4
.el .IP "\f(CW$ua\fR\->conn_cache" 4
.IX Item "$ua->conn_cache"
.PD 0
.ie n .IP "$ua\fR\->conn_cache( \f(CW$cache_obj )" 4
.el .IP "\f(CW$ua\fR\->conn_cache( \f(CW$cache_obj\fR )" 4
.IX Item "$ua->conn_cache( $cache_obj )"
.PD
Get/set the \f(CW\*(C`LWP::ConnCache\*(C'\fR object to use.  See LWP::ConnCache
for details.
.ie n .IP "$ua\fR\->credentials( \f(CW$netloc\fR, \f(CW$realm\fR, \f(CW$uname\fR, \f(CW$pass )" 4
.el .IP "\f(CW$ua\fR\->credentials( \f(CW$netloc\fR, \f(CW$realm\fR, \f(CW$uname\fR, \f(CW$pass\fR )" 4
.IX Item "$ua->credentials( $netloc, $realm, $uname, $pass )"
Set the user name and password to be used for a realm.  It is often more
useful to specialize the \fIget_basic_credentials()\fR method instead.
.ie n .IP "$ua\->max_size" 4
.el .IP "\f(CW$ua\fR\->max_size" 4
.IX Item "$ua->max_size"
.PD 0
.ie n .IP "$ua\fR\->max_size( \f(CW$bytes )" 4
.el .IP "\f(CW$ua\fR\->max_size( \f(CW$bytes\fR )" 4
.IX Item "$ua->max_size( $bytes )"
.PD
Get/set the size limit for response content.  The default is \f(CW\*(C`undef\*(C'\fR,
which means that there is no limit.  If the returned response content
is only partial, because the size limit was exceeded, then a
\&\*(L"Client-Aborted\*(R" header will be added to the response.  The content
might end up longer than \f(CW\*(C`max_size\*(C'\fR as we abort once appending a
chunk of data makes the length exceed the limit.  The \*(L"Content-Length\*(R"
header, if present, will indicate the length of the full content and
will normally not be the same as \f(CW\*(C`length($res\->content)\*(C'\fR.
.ie n .IP "$ua\->max_redirect" 4
.el .IP "\f(CW$ua\fR\->max_redirect" 4
.IX Item "$ua->max_redirect"
.PD 0
.ie n .IP "$ua\fR\->max_redirect( \f(CW$n )" 4
.el .IP "\f(CW$ua\fR\->max_redirect( \f(CW$n\fR )" 4
.IX Item "$ua->max_redirect( $n )"
.PD
This reads or sets the object's limit of how many times it will obey
redirection responses in a given request cycle.
.Sp
By default, the value is 7. This means that if you call \fIrequest()\fR
method and the response is a redirect elsewhere which is in turn a
redirect, and so on seven times, then \s-1LWP\s0 gives up after that seventh
request.
.ie n .IP "$ua\->parse_head" 4
.el .IP "\f(CW$ua\fR\->parse_head" 4
.IX Item "$ua->parse_head"
.PD 0
.ie n .IP "$ua\fR\->parse_head( \f(CW$boolean )" 4
.el .IP "\f(CW$ua\fR\->parse_head( \f(CW$boolean\fR )" 4
.IX Item "$ua->parse_head( $boolean )"
.PD
Get/set a value indicating whether we should initialize response
headers from the <head> section of \s-1HTML\s0 documents. The default is
\&\s-1TRUE\s0.  Do not turn this off, unless you know what you are doing.
.ie n .IP "$ua\->protocols_allowed" 4
.el .IP "\f(CW$ua\fR\->protocols_allowed" 4
.IX Item "$ua->protocols_allowed"
.PD 0
.ie n .IP "$ua\->protocols_allowed( \e@protocols )" 4
.el .IP "\f(CW$ua\fR\->protocols_allowed( \e@protocols )" 4
.IX Item "$ua->protocols_allowed( @protocols )"
.PD
This reads (or sets) this user agent's list of protocols that the
request methods will exclusively allow.  The protocol names are case
insensitive.
.Sp
For example: \f(CW\*(C`$ua\->protocols_allowed( [ \*(Aqhttp\*(Aq, \*(Aqhttps\*(Aq] );\*(C'\fR
means that this user agent will \fIallow only\fR those protocols,
and attempts to use this user agent to access URLs with any other
schemes (like \*(L"ftp://...\*(R") will result in a 500 error.
.Sp
To delete the list, call: \f(CW\*(C`$ua\->protocols_allowed(undef)\*(C'\fR
.Sp
By default, an object has neither a \f(CW\*(C`protocols_allowed\*(C'\fR list, nor a
\&\f(CW\*(C`protocols_forbidden\*(C'\fR list.
.Sp
Note that having a \f(CW\*(C`protocols_allowed\*(C'\fR list causes any
\&\f(CW\*(C`protocols_forbidden\*(C'\fR list to be ignored.
.ie n .IP "$ua\->protocols_forbidden" 4
.el .IP "\f(CW$ua\fR\->protocols_forbidden" 4
.IX Item "$ua->protocols_forbidden"
.PD 0
.ie n .IP "$ua\->protocols_forbidden( \e@protocols )" 4
.el .IP "\f(CW$ua\fR\->protocols_forbidden( \e@protocols )" 4
.IX Item "$ua->protocols_forbidden( @protocols )"
.PD
This reads (or sets) this user agent's list of protocols that the
request method will \fInot\fR allow. The protocol names are case
insensitive.
.Sp
For example: \f(CW\*(C`$ua\->protocols_forbidden( [ \*(Aqfile\*(Aq, \*(Aqmailto\*(Aq] );\*(C'\fR
means that this user agent will \fInot\fR allow those protocols, and
attempts to use this user agent to access URLs with those schemes
will result in a 500 error.
.Sp
To delete the list, call: \f(CW\*(C`$ua\->protocols_forbidden(undef)\*(C'\fR
.ie n .IP "$ua\->requests_redirectable" 4
.el .IP "\f(CW$ua\fR\->requests_redirectable" 4
.IX Item "$ua->requests_redirectable"
.PD 0
.ie n .IP "$ua\->requests_redirectable( \e@requests )" 4
.el .IP "\f(CW$ua\fR\->requests_redirectable( \e@requests )" 4
.IX Item "$ua->requests_redirectable( @requests )"
.PD
This reads or sets the object's list of request names that
\&\f(CW\*(C`$ua\->redirect_ok(...)\*(C'\fR will allow redirection for.  By
default, this is \f(CW\*(C`[\*(AqGET\*(Aq, \*(AqHEAD\*(Aq]\*(C'\fR, as per \s-1RFC\s0 2616.  To
change to include '\s-1POST\s0', consider:
.Sp
.Vb 1
\&   push @{ $ua\->requests_redirectable }, \*(AqPOST\*(Aq;
.Ve
.ie n .IP "$ua\->timeout" 4
.el .IP "\f(CW$ua\fR\->timeout" 4
.IX Item "$ua->timeout"
.PD 0
.ie n .IP "$ua\fR\->timeout( \f(CW$secs )" 4
.el .IP "\f(CW$ua\fR\->timeout( \f(CW$secs\fR )" 4
.IX Item "$ua->timeout( $secs )"
.PD
Get/set the timeout value in seconds. The default \fItimeout()\fR value is
180 seconds, i.e. 3 minutes.
.Sp
The requests is aborted if no activity on the connection to the server
is observed for \f(CW\*(C`timeout\*(C'\fR seconds.  This means that the time it takes
for the complete transaction and the \fIrequest()\fR method to actually
return might be longer.
.Sh "Proxy attributes"
.IX Subsection "Proxy attributes"
The following methods set up when requests should be passed via a
proxy server.
.ie n .IP "$ua\fR\->proxy(\e@schemes, \f(CW$proxy_url)" 4
.el .IP "\f(CW$ua\fR\->proxy(\e@schemes, \f(CW$proxy_url\fR)" 4
.IX Item "$ua->proxy(@schemes, $proxy_url)"
.PD 0
.ie n .IP "$ua\fR\->proxy($scheme, \f(CW$proxy_url)" 4
.el .IP "\f(CW$ua\fR\->proxy($scheme, \f(CW$proxy_url\fR)" 4
.IX Item "$ua->proxy($scheme, $proxy_url)"
.PD
Set/retrieve proxy \s-1URL\s0 for a scheme:
.Sp
.Vb 2
\& $ua\->proxy([\*(Aqhttp\*(Aq, \*(Aqftp\*(Aq], \*(Aqhttp://proxy.sn.no:8001/\*(Aq);
\& $ua\->proxy(\*(Aqgopher\*(Aq, \*(Aqhttp://proxy.sn.no:8001/\*(Aq);
.Ve
.Sp
The first form specifies that the \s-1URL\s0 is to be used for proxying of
access methods listed in the list in the first method argument,
i.e. 'http' and 'ftp'.
.Sp
The second form shows a shorthand form for specifying
proxy \s-1URL\s0 for a single access scheme.
.ie n .IP "$ua\fR\->no_proxy( \f(CW$domain, ... )" 4
.el .IP "\f(CW$ua\fR\->no_proxy( \f(CW$domain\fR, ... )" 4
.IX Item "$ua->no_proxy( $domain, ... )"
Do not proxy requests to the given domains.  Calling no_proxy without
any domains clears the list of domains. Eg:
.Sp
.Vb 1
\& $ua\->no_proxy(\*(Aqlocalhost\*(Aq, \*(Aqno\*(Aq, ...);
.Ve
.ie n .IP "$ua\->env_proxy" 4
.el .IP "\f(CW$ua\fR\->env_proxy" 4
.IX Item "$ua->env_proxy"
Load proxy settings from *_proxy environment variables.  You might
specify proxies like this (sh-syntax):
.Sp
.Vb 4
\&  gopher_proxy=http://proxy.my.place/