Network and Web Libraries

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2023-12-01

Ruby provides two levels of access to network services. At a low level, you can access the basic socket support in the underlying operating system, which allows you to implement clients and servers for both connection-oriented and connectionless protocols. These are documented in the next section.
Ruby also has libraries that provide higher-level access to specific application-level network protocols, such as FTP, HTTP, and so on. These are documented starting on page 482.
Finally, theCGI libraries, documented beginning on page 497, provide server-side developers with a convenient interface for developing Web applications.

Socket-Level Access

Sockets are the endpoints of a bidirectional communications channel. Sockets may communicate within a process, between processes on the same machine, or between processes on different continents. Sockets may be implemented over a number of different channel types: Unix domain sockets, TCP, UDP, and so on. The socket library provides specific classes for handling the common transports as well as a generic interface for handling the rest. All functionality in the socket library is accessible through a single extension library. Access it using

require 'socket'

Sockets have their own vocabulary:

domain

The family of protocols that will be used as the transport mechanism. These values are constants such asPF_INET,PF_UNIX,PF_X25, and so on.

type

The type of communications between the two endpoints, typicallySOCK_STREAM for connection-oriented protocols andSOCK_DGRAM for connectionless protocols.

protocol

Typically zero, this may be used to identify a variant of a protocol within a domain and type.

hostName

The identifier of a network interface:

a string, which can be a host name, a dotted-quad address, or an IPV6 address in colon (and possibly dot) notation,
the string ``<broadcast>'', which specifies anINADDR_BROADCAST address,
a zero-length string, which specifiesINADDR_ANY, or
anInteger, interpreted as a binary address in host byte order.

port

(sometimes calledservice) Each server listens for clients calling on one or more ports. A port may be aFixnum port number, a string containing a port number, or the name of a service.

Sockets are children of classIO. Once a socket has been successfully opened, the conventional I/O methods may be used. However, greater efficiency is sometimes obtained by using socket-specific methods. As with other I/O classes, socket I/O blocks by default. The hierarchy of the socket classes is shown in Figure 26.1 on page 471.
For more information on the use of sockets, see your operating system documentation. You'll also find a comprehensive treatment in W. Richard Stevens,Unix Network Programming, Volumes 1 and 2 .

class BasicSocket
Parent:
IO
Version:
1.6

Index:

do_not_reverse_lookup do_not_reverse_lookup= lookup_order lookup_order=close_readclose_writegetpeernamegetsocknamegetsockoptrecvsendsetsockoptshutdown

BasicSocket is an abstract base class for all other socket classes.
This class and its subclasses often manipulate addresses using something called astruct sockaddr, which is effectively an opaque binary string.[In reality, it maps onto the underlying C-languagestruct sockaddr set of structures, documented in the man pages and in the books by Stevens.]

class methods
do_not_reverse_lookup
BasicSocket.do_not_reverse_lookup ->true orfalse
Returns the value of the global reverse lookup flag. If set totrue, queries on remote addresses will return the numeric address but not the host name.

do_not_reverse_lookup=
BasicSocket.do_not_reverse_lookup =true orfalse
Sets the global reverse lookup flag.

lookup_order
BasicSocket.lookup_order ->aFixnum
Returns the global address lookup order, one of:

Order
Families Searched
LOOKUP_UNSP
AF_UNSPEC
LOOKUP_INET
AF_INET,AF_INET6,AF_UNSPEC
LOOKUP_INET6
AF_INET6,AF_INET,AF_UNSPEC
lookup_order=
BasicSocket.lookup_order =aFixnum
Sets the global address lookup order.

instance methods
close_read
aSession.close_read ->nil
Closes the readable connection on this socket.

close_write
aSession.close_write ->nil
Closes the writable connection on this socket.

getpeername
aSession.getpeername ->aString
Returns thestruct sockaddr structure associated with the other end of this socket connection.

getsockname
aSession.getsockname ->aString
Returns thestruct sockaddr structure associated withaSession.

getsockopt
aSession.getsockopt(level,optname ) ->aString
Returns the value of the specified option.

recv
aSession.recv(len,[,flags] ) ->aString
Receives up tolen bytes fromaSession.

send
aSession.send(aString,flags,[,to] ) ->aFixnum
SendsaString overaSession. If specified,to is astruct sockaddr specifying the recipient address.flags are the sum or one or more of theMSG_ options (listed on page 478). Returns the number of characters sent.

setsockopt
aSession.setsockopt(level,optname,optval ) -> 0
Sets a socket option.level is one of the socket-level options (listed on page 478).optname andoptval are protocol specific---see your system documentation for details.

shutdown
aSession.shutdown(how=2 ) -> 0
Shuts down the receive (how == 0), or send (how == 1), or both (how == 2), parts of this socket.

class IPSocket
Parent:
BasicSocket
Version:
1.6

Index:

getaddressaddrpeeraddr

ClassIPSocket is a base class for sockets using IP as their transport.TCPSocket andUDPSocket are based on this class.

class methods
getaddress
IPSocket.getaddress(hostName ) ->aString
Returns the dotted-quad IP address ofhostName.

a = IPSocket.getaddress('www.ruby-lang.org')
a
»
"210.251.121.214"

instance methods
addr
aSession.addr ->anArray
Returns the domain, port, name, and IP address ofaSession as a four-element array. The name will be returned as an address if thedo_not_reverse_lookup flag istrue.

u = UDPSocket.new
u.bind('localhost', 8765)
u.addr
»
["AF_INET", 8765, "localhost", "127.0.0.1"]
BasicSocket.do_not_reverse_lookup = true
u.addr
»
["AF_INET", 8765, "127.0.0.1", "127.0.0.1"]

peeraddr
aSession.peeraddr ->anArray
Returns the domain, port, name, and IP address of the peer.

class TCPSocket
Parent:
IPSocket
Version:
1.6

Index:

gethostbyname new openrecvfrom

t = TCPSocket.new('localhost', 'ftp')
t.gets
»
"220 zip.local.thomases.com FTP server (Version 6.5/OpenBSD, linux port 0.3.2) ready.\r\n"
t.close
»
nil

class methods
gethostbyname
TCPSocket.gethostbyname(hostName ) ->anArray
Looks uphostName and returns its canonical name, an array containing any aliases, the address type (AF_INET), and the dotted-quad IP address.

a = TCPSocket.gethostbyname('ns.pragprog.com')
a
»
["pragprog.com", [], 2, "216.87.136.211"]

new
TCPSocket.new(hostName,port ) ->aSession
Opens a TCP connection tohostName on theport.

open
TCPSocket.open(hostName,port ) ->aSession
Synonym forTCPSocket.new.

instance methods
recvfrom
aSession.recvfrom(len[,flags] ) ->anArray
Receives up tolen bytes on the connection.flags is zero or more of theMSG_ options (listed on page 478). Returns a two-element array. The first element is the received data, the second is an array containing information about the peer.

t = TCPSocket.new('localhost', 'ftp')

data = t.recvfrom(30)

data

class SOCKSSocket
Parent:
TCPSocket
Version:
1.6

Index:

new openclose

ClassSOCKSSocket supports connections based on the SOCKS protocol.
class methods
new
SOCKSSocket.new(hostName,port ) ->aSession
Opens a SOCKS connection toport onhostName.

open
SOCKSSocket.open(hostName,port ) ->aSession
Synonym forSOCKSSocket.new.

instance methods
close
aSession.close ->nil
Closes this SOCKS connection.

class TCPServer
Parent:
TCPSocket
Version:
1.6

Index:

new openaccept

ATCPServer accepts incoming TCP connections. Here is a Web server that listens on a given port and returns the time.

require 'socket'

port = (ARGV[0] || 80).to_i

server = TCPServer.new('localhost', port)

while (session = server.accept)

  puts "Request: #{session.gets}"

  session.print "HTTP/1.1 200/OK\r\nContent-type: text/html\r\n\r\n"

  session.print "<html><body><h1>#{Time.now}</h1></body></html>\r\n"

  session.close

end

class methods
new
TCPServer.new([hostName,]port ) ->aSession
Creates a new socket on the given interface (identified byhostName and port). IfhostName is omitted, the server will listen on all interfaces on the current host (equivalent to an address of 0.0.0.0).

open
TCPServer.open([hostName,]port ) ->aSession
Synonym forTCPServer.new.

instance methods
accept
aSession.accept ->aTCPSocket
Waits for a connection onaSession, and returns a newTCPSocket connected to the caller. See the example on page 474.

class UDPSocket
Parent:
IPSocket
Version:
1.6

Index:

new openbindconnectrecvfromsend

UDP sockets send and receive datagrams. In order to receive data, a socket must be bound to a particular port. You have two choices when sending data: you can connect to a remote UDP socket and thereafter send datagrams to that port, or you can specify a host and port for use with every packet you send. This example is a UDP server that prints the message it receives. It is called by both connectionless and connection-based clients.

require 'socket'

$port = 4321

sThread = Thread.start do # run server in a thread
server = UDPSocket.open
server.bind(nil, $port)
2.times { p server.recvfrom(64) }
end

# Ad-hoc client
UDPSocket.open.send("ad hoc", 0, 'localhost', $port)

# Connection based client
sock = UDPSocket.open
sock.connect('localhost', $port)
sock.send("connection-based", 0)
sThread.join
produces:

["ad hoc", ["AF_INET", 33224, "localhost", "127.0.0.1"]]

["connection-based", ["AF_INET", 33225, "localhost", "127.0.0.1"]]

class methods
new
UDPSocket.new(family =AF_INET ) ->aSession
Creates an endpoint for UDP communications, optionally specifying the address family.

open
UDPSocket.open(family =AF_INET ) ->aSession
Synonym forUDPSocket.new.

instance methods
bind
aSession.bind(hostName,port ) -> 0
Associates the local end of the UDP connection with a givenhostName andport. Must be used by servers to establish an accessible endpoint.

connect
aSession.connect(hostName,port ) -> 0
Creates a connection to the givenhostName andport. SubsequentUDPSocket#send requests that don't override the recipient will use this connection. Multipleconnect requests may be issued onaSession: the most recent will be used bysend.

recvfrom
aSession.recvfrom(len[,flags] ) ->anArray
Receives up tolen bytes fromaSession.flags is zero or more of theMSG_ options (listed on page 478). The result is a two-element array containing the received data and information on the sender. See the example on page 475.

send
aSession.send(aString,flags ) ->aFixnum
aSession.send(aString,flags,hostName,port ) ->aFixnum
The two-parameter form sendsaString on an existing connection. The four-parameter form sendsaString toport onhostName.

class UNIXSocket
Parent:
BasicSocket
Version:
1.6

Index:

new openaddrpathpeeraddrrecvfrom

ClassUNIXSocket supports interprocess communications using the Unix domain protocol. Although the underlying protocol supports both datagram and stream connections, the Ruby library provides only a stream-based connection.

require 'socket'

$path = "/tmp/sample"

sThread = Thread.start do # run server in a thread
sock = UNIXServer.open($path)
s1 = sock.accept
p s1.recvfrom(124)
end

client = UNIXSocket.open($path)
client.send("hello", 0)
client.close

sThread.join
produces:

["hello", ["AF_UNIX", ""]]

class methods
new
UNIXSocket.new(path ) ->aSession
Opens a new domain socket onpath, which must be a pathname.

open
UNIXSocket.open(path ) ->aSession
Synonym forUNIXSocket.new.

instance methods
addr
aSession.addr ->anArray
Returns the address family and path of this socket.

path
aSession.path ->aString
Returns the path of this domain socket.

peeraddr
aSession.peeraddr ->anArray
Returns the address family and path of the server end of the connection.

recvfrom
aSession.recvfrom(len[,flags] ) ->anArray
Receives up tolen bytes fromaSession.flags is zero or more of theMSG_ options (listed on page 478). The first element of the returned array is the received data, and the second contains (minimal) information on the sender.

class UNIXServer
Parent:
UNIXSocket
Version:
1.6

Index:

new openaccept

ClassUNIXServer provides a simple Unix domain socket server. SeeUNIXSocket for example code.

class methods
new
UNIXServer.new(path ) ->aSession
Creates a server on the givenpath. The corresponding file must not exist at the time of the call.

open
UNIXServer.open(path ) ->aSession
Synonym forUNIXServer.new.

instance methods
accept
aSession.accept ->aUnixSocket
Waits for a connection on the server socket and returns a new socket object for that connection. See the example forUNIXSocket on page 476.

class Socket
Parent:
BasicSocket
Version:
1.6

Index:

for_fd getaddrinfo gethostbyaddr gethostbyname gethostname getnameinfo getservbyname new open pair socketpairacceptbindconnectlistenrecvfrom

ClassSocket provides access to the underlying operating system socket implementation. It can be used to provide more operating system-specific functionality than the protocol-specific socket classes, but at the expense of greater complexity. In particular, the class handles addresses usingstruct sockaddr structures packed into Ruby strings, which can be a joy to manipulate.

constants
ClassSocket defines constants for use throughout the socket library. Individual constants are available only on architectures that support the related facility.

Types:

SOCK_DGRAM,SOCK_PACKET,SOCK_RAW,SOCK_RDM,SOCK_SEQPACKET,SOCK_STREAM.

Protocol families:

PF_APPLETALK,PF_AX25,PF_INET6,PF_INET,PF_IPX,PF_UNIX,PF_UNSPEC.

Address families:

AF_APPLETALK,AF_AX25,AF_INET6,AF_INET,AF_IPX,AF_UNIX,AF_UNSPEC.

Lookup-order options:

LOOKUP_INET6,LOOKUP_INET,LOOKUP_UNSPEC.

Send/receive options:

MSG_DONTROUTE,MSG_OOB,MSG_PEEK.

Socket-level options:

SOL_ATALK,SOL_AX25,SOL_IPX,SOL_IP,SOL_SOCKET,SOL_TCP,SOL_UDP.

Socket options:

SO_BROADCAST,SO_DEBUG,SO_DONTROUTE,SO_ERROR,SO_KEEPALIVE,SO_LINGER,SO_NO_CHECK,SO_OOBINLINE,SO_PRIORITY,SO_RCVBUF,SO_REUSEADDR,SO_SNDBUF,SO_TYPE.

QOS options:

SOPRI_BACKGROUND,SOPRI_INTERACTIVE,SOPRI_NORMAL.

Multicast options:

IP_ADD_MEMBERSHIP,IP_DEFAULT_MULTICAST_LOOP,IP_DEFAULT_MULTICAST_TTL,IP_MAX_MEMBERSHIPS,IP_MULTICAST_IF,IP_MULTICAST_LOOP,IP_MULTICAST_TTL.

TCP options:

TCP_MAXSEG,TCP_NODELAY.

getaddrinfo error codes:

EAI_ADDRFAMILY,EAI_AGAIN,EAI_BADFLAGS,EAI_BADHINTS,EAI_FAIL,EAI_FAMILY,EAI_MAX,EAI_MEMORY,EAI_NODATA,EAI_NONAME,EAI_PROTOCOL,EAI_SERVICE,EAI_SOCKTYPE,EAI_SYSTEM.

ai_flags values:

AI_ALL,AI_CANONNAME,AI_MASK,AI_NUMERICHOST,AI_PASSIVE,AI_V4MAPPED_CFG.

class methods
for_fd
Socket.for_fd(anFD ) ->aSession
Wraps an already open file descriptor into a socket object.

getaddrinfo
Socket.getaddrinfo(hostName,port,
[family[socktype[protocol[flags]]]] ) ->anArray
Returns an array of arrays describing the given host and port (optionally qualified as shown). Each subarray contains the address family, port number, host name, host IP address, protocol family, socket type, and protocol.

for line in Socket.getaddrinfo('www.microsoft.com', 'http')

  puts line.join(", ")

end

produces:

AF_INET, 80, microsoft.net, 207.46.130.149, 2, 1, 6

AF_INET, 80, microsoft.net, 207.46.131.137, 2, 1, 6

AF_INET, 80, microsoft.com, 207.46.230.218, 2, 1, 6

AF_INET, 80, microsoft.com, 207.46.230.219, 2, 1, 6

AF_INET, 80, microsoft.net, 207.46.130.14, 2, 1, 6

gethostbyaddr
Socket.gethostbyaddr(addr,type=AF_INET ) ->anArray
Returns the host name, address family, andsockaddr component for the given address.

a = Socket.gethostbyname("216.87.136.211")
res = Socket.gethostbyaddr(a[3], a[2])
res.join(', ')
»
"pragprog.com, , 2, \330W\210\323"

gethostbyname
Socket.gethostbyname(hostName ) ->anArray
Returns a four-element array containing the canonical host name, a subarray of host aliases, the address family, and the address portion of thesockaddr structure.

a = Socket.gethostbyname("216.87.136.211")
a.join(', ')
»
"pragprog.com, , 2, \330W\210\323"

gethostname
aSession.gethostname ->aString
Returns the name of the current host.

getnameinfo
Socket.getnameinfo(addr[,flags] ) ->anArray
Looks up the given address, which may be either a string containing a sockaddr or a three- or four-element array. Ifsockaddr is an array, it should contain the string address family, the port (or nil), and the host name or IP address. If a fourth element is present and notnil, it will be used as the host name. Returns a canonical hostname (or address) and port number as an array.

a = Socket.getnameinfo(["AF_INET", '23', 'www.ruby-lang.org'])
a
»
["helium.ruby-lang.org", "telnet"]

getservbyname
Socket.getservbyname(service,proto='tcp' ) ->aFixnum
Returns the port corresponding to the given service and protocol.

Socket.getservbyname("telnet")
»
23

new
Socket.new(domain,type,protocol ) ->aSession
Creates a socket using the given parameters.

open
Socket.open(domain,type,protocol ) ->aSession
Synonym forSocket.new.

pair
Socket.pair(domain,type,protocol ) ->anArray
Returns a pair of connected, anonymous sockets of the given domain, type, and protocol.

socketpair
Socket.socketpair(domain,type,protocol ) ->anArray
Synonym forSocket.pair.

instance methods
accept
aSession.accept ->anArray
Accepts an incoming connection returning an array containing a newSocket object and a string holding thestruct sockaddr information about the caller.

bind
aSession.bind(sockaddr ) -> 0
Binds to the givenstruct sockaddr, contained in a string.

connect
aSession.connect(sockaddr ) -> 0
Connects to the givenstruct sockaddr, contained in a string.

listen
aSession.listen(aFixnum ) -> 0
Listens for connections, using the specifiedaFixnum as the backlog.

recvfrom
aSession.recvfrom(len[,flags] ) ->anArray
Receives up tolen bytes fromaSession.flags is zero or more of theMSG_ options. The first element of the result is the data received. The second element contains protocol-specific information on the sender.

Higher-Level Access

Ruby provides a set of classes to facilitate writing clients for:

File Transfer Protocol (FTP)
HyperText Transfer Protocol (HTTP)
Post Office Protocol (POP)
Simple Mail Transfer Protocol (SMTP)
Telnet

HTTP, POP, and SMTP are layered on top of a helper class,lib/net/protocol. Although we don't document theProtocol class here, you should probably study it if you are considering writing your own network client.

class Net::FTP
Parent:
Object
Version:
1.6

Index:

new openServer commandscloseclosed?connectdebug_modedebug_mode=dirgetbinaryfilegettextfilelastresplistloginlsmtimepassivepassive=putbinaryfileputtextfileresumeresume=retrbinaryretrlinesreturn_codestorbinarystorlineswelcome

require 'net/ftp'

ftp = Net::FTP.new('ftp.netlab.co.jp')
ftp.login
files = ftp.chdir('pub/lang/ruby/contrib')
files = ftp.list('n*')
ftp.getbinaryfile('nif.rb-0.91.gz', 'nif.gz', 1024)
ftp.close

Thenet/ftp library implements a File Transfer Protocol (FTP) client.

constants
FTP_PORT
Default port for FTP connections (21).

class methods
new
FTP.new(host=nil,user=nil,passwd=nil,acct=nil) ->aSession
Creates and returns a newFTP object. If the host parameter is notnil, a connection is made to that host. Additionally, if theuser parameter is notnil, the given user name, password, and (optionally) account are used to log in. See the description ofFTP#login on page 484.

open
FTP.open(host,user=nil,passwd=nil,acct=nil) ->aSession
A synonym forFTP.new, but with a mandatoryhost parameter.

instance methods
Server commands
aSession.acct(account )
aSession.chdir(dir )
aSession.delete(remoteFile )
aSession.mdtm(remoteFile ) ->aString
aSession.mkdir(dir )
aSession.nlst(dir=nil ) ->anArray
aSession.rename(fromname,toname )
aSession.rmdir(dir )
aSession.pwd ->aString
aSession.size(remoteFile ) ->anInteger
aSession.status ->aString
aSession.system ->aString
Issues the corresponding server command and returns the result.

close
aSession.close
Closes the current connection.

closed?
aSession.closed? ->true orfalse
Returnstrue if the current connection is closed.

connect
aSession.connect(host,port=FTP_PORT )
Establishes an FTP connection tohost, optionally overriding the default port. If the environment variableSOCKS_SERVER is set, sets up the connection through a SOCKS proxy. Raises an exception (typicallyErrno::ECONNREFUSED) if the connection cannot be established.

debug_mode
aSession.debug_mode ->true orfalse
Returns the current debug mode.

debug_mode=
aSession.debug_mode =true orfalse
If the debug mode istrue, all traffic to and from the server is written to$stdout.

dir
aSession.dir([pattern]^*) ->anArray
aSession.dir([pattern]^*) {| line | block }

Synonym forFTP#list.

getbinaryfile
aSession.getbinaryfile(remotefile,localfile,blocksize,callback=nil)
aSession.getbinaryfile(remotefile,localfile,blocksize ) {| data | block }

Retrievesremotefile in binary mode, storing the result inlocalfile. Ifcallback or an associated block is supplied, calls it, passing in the retrieved data inblocksize chunks.

gettextfile
aSession.gettextfile(remotefile,localfile,callback=nil)
aSession.gettextfile(remotefile,localfile ) {| data | block }

Retrievesremotefile in ASCII (text) mode, storing the result inlocalfile. Ifcallback or an associated block is supplied, calls it, passing in the retrieved data one line at a time.

lastresp
aSession.lastresp ->aString
Returns the host's last response.

list
aSession.list([pattern]^*) ->anArray
aSession.list([pattern]^*) {| line | block }

Fetches a directory listing of files matching the given pattern(s). If a block is associated with the call, invokes it with each line of the result. Otherwise, returns the result as an array of strings.

login
aSession.login(user="anonymous",passwd=nil,acct=nil ) -> aString
Logs into the remote host.aSession must have been previously connected. Ifuser is the string ``anonymous'' and the password isnil, a password ofuser@host is synthesized. If theacct parameter is notnil, an FTPACCT command is sent following the successful login. Raises an exception on error (typicallyNet::FTPPermError).

ls
aSession.ls([pattern]^*) ->anArray
aSession.ls([pattern]^*) {| line | block }

Synonym forFTP#list.

mtime
aSession.mtime(remoteFile,local=false ) ->aTime
Returns the last-modified time ofremoteFile, interpreting the server's response as a GMT time iflocal isfalse, or as a local time otherwise.

passive
aSession.passive ->true orfalse
Returns the state of thepassive flag.

passive=
aSession.passive =true orfalse
Puts the connection into passive mode iftrue.

putbinaryfile
aSession.putbinaryfile(localfile,remotefile,blocksize,callback=nil)
aSession.putbinaryfile(localfile,remotefile,blocksize ) {| data | block }

Transferslocalfile to the server in binary mode, storing the result inremotefile. Ifcallback or an associated block is supplied, calls it, passing in the transmitted data inblocksize chunks.

puttextfile
aSession.puttextfile(localfile,remotefile,callback=nil)
aSession.puttextfile(localfile,remotefile,blocksize ) {| data | block }

Transferslocalfile to the server in ASCII (text) mode, storing the result inremotefile. Ifcallback or an associated block is supplied, calls it, passing in the transmitted data one line at a time.

resume
aSession.resume ->true orfalse
Returns the status of theresume flag (seeFTP#resume=). Default isfalse.

resume=
aSession.resume=aBoolean
Sets the status of theresume flag. Whenresume istrue, partially received files will resume where they left off, instead of starting from the beginning again. This is done by sending aREST command (RESTart incomplete transfer) to the server.

retrbinary
aSession.retrbinary(cmd,blocksize ) {| data | block }

Puts the connection into binary (image) mode, issues the given command, and fetches the data returned, passing it to the associated block in chunks ofblocksize characters. Note thatcmd is a server command (such as ``RETR myfile'').

retrlines
aSession.retrlines(cmd) {| line | block }

Puts the connection into ASCII (text) mode, issues the given command, and passes the resulting data, one line at a time, to the associated block. If no block is given, prints the lines. Note thatcmd is a server command (such as ``RETR myfile'').

return_code
aSession.return_code ->aFixnum
Returns the return code from the last operation.

storbinary
aSession.storbinary(cmd,fileName,blocksize,callback=nil)
aSession.storbinary(cmd,fileName,blocksize ) {| data | block }

Puts the connection into binary (image) mode, issues the given server-side command (such as ``STOR myfile''), and sends the contents of the file namedfileName to the server. If the optional block is given, or if thecallBack parameter is aProc, also passes it the data, in chunks ofblocksize characters.

storlines
aSession.storlines(cmd,fileName,callback=nil)
aSession.storlines(cmd,fileName ) {| data | block }

Puts the connection into ASCII (text) mode, issues the given server-side command (such as ``STOR myfile''), and sends the contents of the file namedfileName to the server, one line at a time. If the optional block is given, or if thecallBack parameter is aProc, also passes it the lines.

welcome
aSession.welcome ->aString
Returns the host's welcome message.

class Net::HTTP
Parent:
Net::Protocol
Version:
1.6

Index:

new port startgetheadpoststart

require 'net/http'

h = Net::HTTP.new('www.pragmaticprogrammer.com', 80)
resp, data = h.get('/index.html', nil )
puts "Code = #{resp.code}"
puts "Message = #{resp.message}"
resp.each {|key, val| printf "%-14s = %-40.40s\n", key, val }
p data[0..55]
produces:

Code = 200

Message = OK

last-modified  = Wed, 29 May 2002 11:08:01 GMT

connection     = close

content-type   = text/html

etag           = "804d98-255c-3cf4b691"

date           = Sun, 09 Jun 2002 05:15:10 GMT

server         = Rapidsite/Apa/1.3.20 (Unix) FrontPage/4.

content-length = 9564

accept-ranges  = bytes

"<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional"

Thenet/http library provides a simple client to fetch headers and Web page contents using the HTTP protocol.
Theget,post, andhead requests raise exceptions on any error, including some HTTP status responses that would normally be considered recoverable. There are two ways of handling these.

Each method has a corresponding versionget2,post2, orhead2 that does not raise an exception. These versions are documented in the source.
Recoverable errors raise aNet::ProtoRetriableError exception. This exception contains adata attribute containing the response returned by the server.

The code below illustrates the handling of an HTTP status 301, a redirect. It uses Tomoyuki Kosimizu's URI package, available in the RAA.

h = Net::HTTP.new(ARGV[0] || 'www.ruby-lang.org', 80)

url = ARGV[1] || '/'

begin
resp, data = h.get(url, nil) { |a| }
rescue Net::ProtoRetriableError => detail
head = detail.data

if head.code == "301"
uri = URI.create(head['location'])

host = uri['host']
url = uri['path']
port = uri['port']

h.finish
h = Net::HTTP.new(host, port)

retry
end
end

class methods
new
Net::HTTP.new(host='localhost',port=80,proxy=nil,proxy_port=nil ) ->aSession
Creates and returns a newHTTP object. No connection is made untilHTTP#start is called.

port
Net::HTTP.port ->aFixnum
Returns the default HTTP port (80).

start
Net::HTTP.start(host=nil,port=80 )
Net::HTTP.start(host=nil,port=80 ) {|aSession | block }

Equivalent toNet::HTTP.new(host,port).start.

instance methods
get
aSession.get(path,headers=nil,dest="" ) ->anArray
aSession.get(path,headers=nil) {| result | block }
->anArray
Retrieves headers and content from the specifiedpath on the host specified whenaSession was created. If specified, theheaders parameter is aHash containing additional header names and values to be sent with the request. The method returns a two-element array. The first element is anHTTPResponse object (documented in the next section). The second element is the page's content. The page's content is also passed to the<< method of thedest parameter, or to the block if specified. This result is built network block by network block, not line by line. An exception is raised if an error is encountered. Multipleget calls may be made onaSession. UnlessProtocol#finish is explicitly called, the connection will use the HTTP/1.1 keep-alive protocol, and will not close between requests.

head
aSession.head(path,headers=nil ) ->aHash
Retrieves headers from the specifiedpath on the host specified whenaSession was created. If specified, theheaders parameter is a hash containing additional header names and values to be sent with the request. The method returns a hash of received headers. An exception is raised if an error is encountered. Multiplehead calls may be made onaSession.

post
aSession.post(path,data,headers=nil,dest="" ) ->anArray
aSession.post(path,data,headers=nil ) {| result | block } ->anArray
Sendsdata topath using an HTTP POST request.headers is a hash containing additional headers. Assigns the result todata or to the block, as forNet_HTTP#get. Returns a two-element array containing an HTTPResponse object and the reply body.

start
aSession.start
aSession.start {|aSession | block }

Establishes a connection to the host associated withaSession. (start is actually a method inNet::Protocol, but its use is required in HTTP objects.) In the block form, closes the session at the end of the block.

class Net::HTTPResponse
Parent:
Version:
1.6

Index:

[ ][ ]=codeeachkey?message

Represents an HTTP response to a GET or POST request.

instance methods
[ ]
aSession[aKey ] ->aString
Returns the header corresponding to the case-insensitive key. For example, a key of ``Content-type'' might return ``text/html''.

[ ]=
aSession[aKey ] =aString
Sets the header corresponding to the case-insensitive key.

code
aSession.code ->aString
Returns the result code from the request (for example, ``404'').

each
aSession.each {| key, val | block }

Iterates over all the header key-value pairs.

key?
aSession.key?(aKey ) ->true orfalse
Returnstrue only if a header with the given key exists.

message
aSession.message ->aString
Returns the result message from the request (for example, ``Not found'').

class Net::POP
Parent:
Net::Protocol
Version:
1.6

Index:

neweachfinishmailsstart

require 'net/pop'

pop = Net::POP3.new('server.ruby-stuff.com')

pop.start('user', 'secret') do |pop|

  msg = pop.mails[0]

# Print the 'From:' header line
puts msg.header.split("\r\n").grep(/^From: /)

# Put message to $stdout (by calling <<)
puts "\nFull message:\n"
msg.all($stdout)
end
produces:

From: dummy msg for Andy

Full message:
From: dummy msg for Andy
looks-better: on dave's box

That's all folks!

Thenet/pop library provides a simple client to fetch and delete mail on a Post Office Protocol (POP) server.
The classNet::POP3 is used to access a POP server, returning a list ofNet::POPMail objects, one per message stored on the server. ThesePOPMail objects are then used to fetch and/or delete individual messages. The library also provides an alternative to thePOP3 class that performsAPOP authentication.

class methods
new
HTTP.new(host='localhost',port=110 ) ->aSession
Creates and returns a newPOP3 object. No connection is made untilPOP3#start is called.

instance methods
each
aSession.each {| popmail | block }

Calls the associated block once for each e-mail stored on the server, passing in the correspondingPOPMail object.

finish
aSession.finish ->true orfalse
Closes the pop connection. Some servers require that a connection is closed before they honor actions such as deleting mail. Returnsfalse if the connection was never used.

mails
aSession.mails ->anArray
Returns an array ofPOPMail objects, where each object corresponds to an e-mail message stored on the server.

start
aSession.start(user,password )
aSession.start(user,password ) {| pop | block }

Establishes a connection to the pop server, using the supplied username and password. Fetches a list of mail held on the server, which may be accessed using thePOP3#mails andPOP3#each methods. In block form, passesaSession to the block, and closes the connection usingfinish when the block terminates.

class Net::APOP
Parent:
Net::POP3
Version:
1.6

Index:

start

instance methods
start
aSession.start(user,password )
Establishes a connection to the APOP server.

class Net::POPMail
Parent:
Object
Version:
1.6

Index:

alldeletedelete!headersizetopuidl

instance methods
all
aSession.all ->aString
aSession.all(dest )
aSession.all {| aString | block }

Fetches the corresponding e-mail from the server. With no argument or associated block, returns the e-mail as a string. With an argument but no block, appends the e-mail todest by invokingdest<< for each line in the e-mail. With an associated block, invokes the block once for each line in the e-mail.

delete
aSession.delete
Deletes the e-mail from the server.

delete!
aSession.delete!
Synonym forPOPMail#delete.

header
aSession.header ->aString
Returns the header lines for the corresponding e-mail message.

size
aSession.size ->aFixnum
Returns the size in bytes of the corresponding e-mail.

top
aSession.top(lines ) ->aString
Returns the header lines, pluslines message lines for the corresponding e-mail message.

uidl
aSession.uidl ->aString
Returns the server-specific unique identifier for the corresponding e-mail.

class Net::SMTP
Parent:
Net::Protocol
Version:
1.6

Index:

new startreadysendmailstart

require 'net/smtp'

# --- Send using class methods
msg = [ "Subject: Test\n", "\n", "Now is the time\n" ]
Net::SMTP.start do |smtp|
smtp.sendmail( msg, 'dave@localhost', ['dave'] )
end

# --- Send using SMTP object and an adaptor
smtp = Net::SMTP.new
smtp.start('pragprog.com')
smtp.ready('dave@localhost', 'dave') do |a|
a.write "Subject: Test1\r\n"
a.write "\r\n"
a.write "And so is this"
end

Thenet/smtp library provides a simple client to send electronic mail using the Simple Mail Transfer Protocol (SMTP).
class methods
new
Net::SMTP.new(server='localhost',port=25 ) ->aSession
Returns a newSMTP object connected to the given server and port.

start
Net::SMTP.start(server='localhost',port=25,domain=ENV['HOSTNAME'],acct=nil,passwd=nil,authtype=:cram_md5 ) ->aSession
Net::SMTP.start(server='localhost',port=25,domain=ENV['HOSTNAME'],acct=nil,passwd=nil,authtype=:cram_md5 ) {| smtp | block }

Equivalent toNet::SMTP.new(server,port).start(...). For an explanation of the remainder of the parameters, see the instance methodNet_SMTP#start. Creates a newSMTP object. Thedomain parameter will be used in the initialHELO orEHLO transaction with the SMTP server. In the block form, thesmtp object is passed into the block. When the block terminates, the session is closed.

instance methods
ready
aSession.ready(from,to ) {| anAdaptor | block }

Equivalent tosendmail(from, to) { ...}. Sends header and body lines to the sendmail server. Thefrom parameter is used as the sender's name in theMAIL FROM: command, and theto is either a string or an array of strings containing the recipients for theRCPT TO: command. The block is passed an adaptor object. Lines are sent to the server by calling the adaptor'swrite method. The terminating '.' andQUIT are sent automatically.

sendmail
aSession.sendmail(src,from,to )
Sends header and body lines to the sendmail server. Thefrom parameter is used as the sender's name in theMAIL FROM: command, andto is either a string or an array of strings containing the recipients for theRCPT TO: command. Lines to be sent are fetched by invokingsrc.each. The terminating '.' andQUIT are sent automatically.

start
aSession.start(domain=ENV['HOSTNAME'],acct=nil,passwd=nil,authtype=:cram_md5 ) ->true orfalse
aSession.start(domain=ENV['HOSTNAME'],acct=nil,passwd=nil,authtype=:cram_md5 ) {| smtp | block } ->true orfalse
Starts an SMTP session by connecting to the given domain (host). Ifacct andpasswd are given, authentication will be attempted using the given authentication type (:plain or:cram_md5). If a block is supplied, it will be invoked withaSession as a parameter. The connection will be closed when the block terminates.

class Net::Telnet
Parent:
[Socket]
Version:
1.6

Index:

newbinmodebinmode=cmdloginprinttelnetmodetelnetmode=waitforwrite

Connect to alocalhost, run the ``date'' command, and disconnect.

require 'net/telnet'

tn = Net::Telnet.new({})
tn.login "guest", "secret"
tn.cmd "date"
»
"date\r\nSun Jun 9 00:15:20 CDT 2002\n\r> "

Monitor output as it occurs. We associate a block with each of the library calls; this block is called whenever data becomes available from the host.

require 'net/telnet'

tn = Net::Telnet.new({}) { |str| print str }
tn.login("guest", "secret") { |str| print str }
tn.cmd("date") { |str| print str }
produces:

Trying localhost...

Connected to localhost.

Welcome to SuSE Linux 7.1 (i386) - Kernel 2.4.0-64GB-SMP (8).

zip login: guest
Password:
Last login: Sun Jun 9 00:15:19 from localhost
/etc/zshrc: setopt: no such option: histexpiredupsfirst [31]
> date
Sun Jun 9 00:15:20 CDT 2002
>

Get the time from an NTP server.

require 'net/telnet'

tn = Net::Telnet.new('Host'       => 'time.nonexistent.org',

                     'Port'       => 'time',

                     'Timeout'    => 60,

                     'Telnetmode' => false)

atomicTime = tn.recv(4).unpack('N')[0]

puts "Atomic time: " + Time.at(atomicTime - 2208988800).to_s

puts "Local time:  " + Time.now.to_s

produces:

Atomic time: Sun Jun 09 00:15:12 CDT 2002

Local time:  Sun Jun 09 00:15:20 CDT 2002

Thenet/telnet library provides a complete implementation of a telnet client and includes features that make it a convenient mechanism for interacting with non-telnet services.
Although the class description that follows indicates thatNet::Telnet is a subclass of classSocket, this is a lie. In reality, the class delegates toSocket. The net effect is the same: the methods ofSocket and its parent, classIO, are available throughNet::Telnet objects.
The methodsnew,cmd,login, andwaitfor take an optional block. If present, the block is passed output from the server as it is received by the routine. This can be used to provide realtime output, rather than waiting for (for example) a login to complete before displaying the server's response.

class methods
new
Net::Telnet.new(options ) ->aSession
Net::Telnet.new(options ) {| str | block } ->aSession
Connects to a server.options is aHash with zero or more of the following:

Option
Default
Meaning
Binmode
false
If true, no end-of-line processing will be performed.
Host
localhost
Name or address of server's host.
Port
23
Name or number of service to call.
Prompt
/[$%#>]/
Pattern that matches the host's prompt.
Telnetmode
true
Iffalse, ignore the majority of telnet embedded escape sequences. Used when talking with a non-telnet server.
Timeout
10
Time in seconds to wait for a server response (both during connection and during regular data transmission).
Waittime
0
Time to wait for prompt to appear in received data stream.

instance methods
binmode
aSession.binmode ->true orfalse
Returns the current value of theBinmode flag.

binmode=
aSession.binmode =true orfalse
Sets theBinmode flag, returning the new value.

cmd
aSession.cmd(options ) ->aString
aSession.cmd(options ) {| str | block } ->aString
Sends a string to the server and waits (using a timeout) for a string that matches a pattern to be returned by the server. If the parameter is not aHash, it is sent as a string to the server, and the pattern to match and the timeout are thePrompt andTimeout options given whenaSession was created. Ifoptions is aHash, thenoptions['String'] is sent to the server.options['Match'] may be used to override the classPrompt parameter, andoptions['Timeout'] the timeout. The method returns the complete server response.

login
aSession.login(options,password=nil ) ->aString
aSession.login(options,password=nil ) {| str | block } ->aString
Ifoptions is aHash, a username is taken fromoptions['Name'] and a password fromoptions['Password']; otherwise,options is assumed to be the username, andpassword the password. The method waits for the server to send the string matching the pattern/login[:]*\z/ and sends the username. If a password is given, it then waits for the server to send/Password[:]*\z/ and sends the password. The method returns the full server response.

print
aSession.print(aString )
SendsaString to the server, honoringTelnetmode,Binarymode, and any additional modes negotiated with the server.

telnetmode
aSession.telnetmode ->true orfalse
Returns the current value of theTelnetmode flag.

telnetmode=
aSession.telnetmode=true orfalse
Sets theTelnetmode flag, returning the new value.

waitfor
aSession.waitfor(options ) ->aString
aSession.waitfor(options ) {| str | block } ->aString
Waits for the server to respond with a string that matches a string or pattern. Ifoptions is not aHash, it is compared against the cumulative server output as that output is received usingoptions.===. It is likely that you will want to use a regular expression in this case.
Ifoptions is aHash, thenoptions['Match'],options['Prompt'], oroptions['String'] provides the match. In the latter case, the string will be converted to a regular expression before being used.options may also include the keys ``Timeout'' and ``Waittime'' to override the class options of the same names.

write
aSession.write(aString )
WritesaString to the server with no translation.

CGI Development

class CGI
Parent:
Object
Version:
1.6

Index:

escape escapeElement escapeHTML new parse pretty rfc1123_date unescape unescapeElement unescapeHTML[ ]cookieshas_key?headerkeysoutparams

require "cgi"

cgi = CGI.new("html3")  # add HTML generation methods

cgi.out {

  CGI.pretty (

    cgi.html {

      cgi.head { cgi.title{"TITLE"} } +

      cgi.body {

        cgi.form {

          cgi.textarea("get_text") +

          cgi.br +

          cgi.submit

        } +

        cgi.h1 { "This is big!" } +

        cgi.center { "Jazz Greats of the 20" +

          cgi.small {"th"} + " century" + cgi.hr

        } + cgi.p + cgi.table ('BORDER' => '5') {

          cgi.tr { cgi.td {"Artist"} + cgi.td {"Album"} } +

          cgi.tr { cgi.td {"Davis, Miles"} +

          cgi.td {"Kind of Blue"} }

        }

      }

    }

  ) # CGI.pretty is a method call, not a block

}

(The output of this script is shown in Figure 26.2 on page 499.)
TheCGI class provides support for programs used as a Web server CGI (Common Gateway Interface) script. It contains several methods for accessing fields in a CGI form, manipulating ``cookies'' and the environment, and outputting formatted HTML.
Since environment variables contain a lot of useful information for a CGI script,CGI makes accessing them very easy---environment variables are accessible as attributes ofCGI objects. For instance,cgi.auth_type returns the value ofENV["AUTH_TYPE"]. To create the method name, the environment variable name is translated to all lowercase, and the ``HTTP_'' prefix is stripped off. Thus,HTTP_USER_AGENT would be available as the methoduser_agent.
Cookies are represented using a separate object of classCGI::Cookie, containing the following accessors:
Accessor
Description
name
Name of this cookie
value
Array of values
path
Path (optional)
domain
Domain (optional)
expires
Time of expiry, defaults toTime.now (optional)
secure
true for a secure cookie
Figure not available...
You create a cookie object usingCGI_Cookie.new, which takes as arguments the accessors listed above, orCGI_Cookie.parse, which takes an encoded string and returns a cookie object.

class methods
escape
CGI.escape(aString ) ->aNewString
Returns a URL-encoded string made from the given argument, where unsafe characters (not alphanumeric, ``_'', ``-'', or ``.'') are encoded using ``%xx'' escapes.

escapeElement
CGI.escapeElement(aString[,elements]^*) ->aNewString
Returns a string made from the given argument with certain HTML-special characters escaped. The HTML elements given inelements will be escaped; other HTML elements will not be affected.

print CGI::escapeElement('<BR><A HREF="url"></A><P>', "A", "IMG")

produces:

<BR><A HREF="url"></A><P>

escapeHTML
CGI.escapeHTML(aString ) ->aNewString
Returns a string made from the given argument with HTML-special characters (such as ``&'',``"'',``<'',``>'') quoted using ``&'', ``"'', ``<'', ``>'', and so on.

new
CGI.new([aString]^*) ->aSession
Returns a newCGI object. If HTML output is required, the desired standards level must be given inaString (otherwise, no output routines will be created). The level may be one of:

String
Standards Level
String
Standards Level
``html3''
HTML 3.2
``html4''
HTML 4.0 Strict
``html4Tr''
HTML 4.0 Transitional
``html4Fr''
HTML 4.0 Frameset
parse
CGI.parse(aString ) ->aHash
Parses a query string and returns a hash of itskey-value pairs.

pretty
CGI.pretty(anHTMLString,aLeaderString=" " ) ->aSession
Formats the givenanHTMLString in a nice, readable format, optionally prefixing each line withaLeaderString.

rfc1123_date
CGI.rfc1123_date(aTime ) ->aString
Returns a string representing the given time according to RFC 1123 (for instance,Mon, 1 Jan 2001 00:00:00 GMT).

unescape
CGI.unescape(aString ) ->aNewString
Returns a string containing ``unsafe'' characters made from the given URL-encoded argument, where unsafe characters were encoded using ``%'' escapes.

unescapeElement
CGI.unescapeElement(aString[,elements]^*) ->aNewString
Returns a string with the selected escaped HTML elements expanded to the actual characters.

unescapeHTML
CGI.unescapeHTML(aString ) ->aNewString
Returns a string made from the given argument with HTML-special quoted characters expanded to the actual characters.

instance methods
[ ]
aSession[[aString]⁺] ->anArray
Returns the values of the given field names from the CGI form in anArray. See the note on multipart forms on page 503.

cookies
aSession.cookies ->aHash
Returns a newHash object containingkey-value pairs of cookie keys and values.

has_key?
aSession.has_key(aString ) ->true orfalse
Returnstrue if the form contains a field namedaString.

header
aSession.header(aContentType="text/html" ) ->aString
aSession.header(aHash ) ->aString
Returns a string containing the given headers (in theMOD_RUBY environment, the resulting header is sent immediately instead). If a hash is given as an argument, then thekey-value pairs will be used to generate headers.

keys
aSession.keys ->anArray
Returns an array of all existing field names for the form.

out
aSession.out(aContentType="text/html" ) { block } ->nil
aSession.out(aHash ) { block } ->nil
Generates HTML output using the results of the block as the content. Headers are generated as withCGI#header. See the example at the start of this section.

params
aSession.params ->aHash
Returns a newHash object containingkey-value pairs of field names and values from the form.

HTML Output Methods

In addition,CGI supports the following HTML output methods. Each of these methods is named after the corresponding HTML feature (or close to it). Those tags that require content (such asblockquote) take an optional block; the block should return aString that will be used as the content for the feature. These methods may take arguments as indicated, or as a hash with the given names as keys.
\

a(url)
a(HREF=> )

base(url)
base(HREF=> )

blockquote(cite="") {aString }
blockquote(CITE=> ) {aString }

caption(align=nil) {aString }
caption(ALIGN=> ) {aString }

checkbox(name=nil,value=nil,checked=nil)
checkbox(NAME,VALUE,CHECKED=> )

checkbox_group(name=nil,[items]⁺)
checkbox_group(NAME,VALUES=> )

Items may be individualString names, or any of: an array of [name,checked ], an array of [value,name ], or an array of [value,name,checked ]. The value for the hash key VALUES should be an array of these items.

file_field(name="",size=20,maxlength=nil)
file_field(NAME,SIZE,MAXLENGTH=> )

form(method="post",action=nil,enctype="application/x-www-form-urlencoded" ) {aStr }
form(METHOD,ACTION,ENCTYPE=> ) {aStr }

hidden(name="",value=nil)
hidden(NAME,VALUE=> )

html() {aString }
html(PRETTY,DOCTYPE=> ) {aString }

img_button(src="",name=nil,alt=nil)
img_button(SRC,NAME,ALT=> )

img(src="",alt="",width=nil,height=nil)
img(SRC,ALT,WIDTH,HEIGHT=> )

multipart_form(action=nil,enctype="multipart/form-data" ) {aString }
multipart_form(METHOD,ACTION,ENCTYPE=> ) {aString }

password_field(name="",value=nil,size=40,maxlength=nil)
password_field(NAME,VALUE,SIZE,MAXLENGTH=> )

popup_menu(name="",items)
popup_menu(NAME,SIZE,MULTIPLE,VALUES(array of items)=> )

Items may be individualString names, or any of: an array of [name,selected ], an array of [value,name ], or an array of [value,name,selected ]. The value for the hash key VALUES should be an array of these items.

radio_button(name="",value=nil,checked=nil)
radio_button(NAME,VALUE,CHECKED=> )

radio_group(name="",items)
radio_group(NAME,VALUES(array of items)=> )

Items may be individualString names, or any of: an array of [name,selected ], an array of [value,name ], or an array of [value,name,selected ]. The value for the hash key VALUES should be an array of these items.

reset(value=nil,name=nil)
reset(VALUE,NAME=> )

scrolling_list(alias for popup_menu )
scrolling_list(=> )

submit(value=nil,name=nil)
submit(VALUE,NAME=> )

text_field(name="",value=nil,size=40,maxlength=nil)
text_field(NAME,VALUE,SIZE, MAXLENGTH => )

textarea(name="",cols=70,rows=10 )
textarea(NAME,COLS,ROWS=> )

In addition, all HTML tags are supported as methods, includingtitle,head,body,br,pre, and so on. The block given to the method must return aString, which will be used as the content for that tag type. Not all tags require content:<P>, for example, does not. The available tags vary according to the supported HTML level---Table 26.1 on page 503 lists the complete set. For these methods, you can pass in a hash with attributes for the given tag. For instance, you might pass in'BORDER'=>'5' to thetable method to set the border width of the table.
HTML tags available as methods
{HTML 3}
a address applet area b base basefont big blockquote body br caption center cite code dd dfn dir div dl dt em font form h1 h2 h3 h4 h5 h6 head hr html i img input isindex kbd li link listing map menu meta ol option p param plaintext pre samp script select small strike strong style sub sup table td textarea th title tr tt u ul var xmp

{HTML 4}
a abbr acronym address area b base bdo big blockquote body br button caption cite code col colgroup dd del dfn div dl dt em fieldset form h1 h2 h3 h4 h5 h6 head hr html i img input ins kbd label legend li link map meta noscript object ol optgroup option p param pre q samp script select small span strong style sub sup table tbody td textarea tfoot th thead title tr tt ul var
{HTML 4 Transitional}
a abbr acronym address applet area b base basefont bdo big blockquote body br button caption center cite code col colgroup dd del dfn dir div dl dt em fieldset font form h1 h2 h3 h4 h5 h6 head hr html i iframe img input ins isindex kbd label legend li link map menu meta noframes noscript object ol optgroup option p param pre q s samp script select small span strike strong style sub sup table tbody td textarea tfoot th thead title tr tt u ul var

frame frameset

Multipart Form Values

When dealing with a multipart form, the array returned byCGI#[] is composed of objects of classTempfile, with the following dynamically added methods:
Method
Description
read
Body
local_path
Path to local file containing the content
original_filename
Original filename of the content
content_type
Content type

class CGI::Session
Parent:
Object
Version:
1.6

Index:

new[ ][ ]=deleteupdate

ACGI::Session maintains a persistent state for web users in a CGI environment. Sessions may be memory-resident or may be stored on disk. See the discussion on page 146 for details.

class methods
new
CGI::Session.new(aCgi,[aHash]^*) ->aSession
Returns a new session object for theCGI query. Options that may be given inaHash include:

Option
Description
session_key
Name of CGI key for session identification.
session_id
Value of session id.
new_session
Iftrue, create a new session id for this session. Iffalse, use an existing session identified bysession_id. If omitted, use an existing session if available, otherwise create a new one.
database_manager
Class to use to save sessions; may beCGI::Session::FileStore orCGI::Session::MemoryStore (or user defined if you're brave). Default isFileStore.
tmpdir
ForFileStore, directory for session files.
prefix
ForFileStore, prefix of session filenames.

instance methods
[ ]
aSession[aKey ] ->aValue
Returns the value for the given key.

[ ]=
aSession[aKey ] =aValue ->aValue
Sets the value for the given key.

delete
aSession.delete

Calls thedelete method of the underlying database manager. ForFileStore, deletes the physical file containing the session. ForMemoryStore, removes the session from memory.

update
aSession.update

Calls theupdate method of the underlying database manager. ForFileStore, writes the session data out to disk. Has no effect withMemoryStore.