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Class: EventMachine::Protocols::HttpClient

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Connection
Instance Chain:
Inherits: EventMachine::Connection
Defined in: lib/em/protocols/httpclient.rb

Overview

Examples:

EventMachine.run {
  http = EventMachine::Protocols::HttpClient.request(
    :host => server,
    :port => 80,
    :request => "/index.html",
    :query_string => "parm1=value1&parm2=value2"
  )
  http.callback {|response|
    puts response[:status]
    puts response[:headers]
    puts response[:content]
  }
}

Constant Summary

Deferrable - Included

Pool

Class Method Summary

Connection - Inherited

.new

Override .new so subclasses don't have to call super and can ignore connection-specific arguments.

Instance Attribute Summary

Connection - Inherited

#comm_inactivity_timeout

comm_inactivity_timeout returns the current value (float in seconds) of the inactivity-timeout property of network-connection and datagram-socket objects.

#comm_inactivity_timeout=

Allows you to set the inactivity-timeout property for a network connection or datagram socket.

#error?

Returns true if the connection is in an error state, false otherwise.

#notify_readable=

Watches connection for readability.

#notify_readable?,
#notify_writable=

Watches connection for writeability.

#notify_writable?

Returns true if the connection is being watched for writability.

#paused?,
#pending_connect_timeout

The duration after which a TCP connection in the connecting state will fail.

#pending_connect_timeout=

Sets the duration after which a TCP connection in a connecting state will fail.

#signature, #watch_only?

Instance Method Summary

Deferrable - Included

#callback

Specify a block to be executed if and when the Deferrable object receives a status of :succeeded.

#cancel_callback

Cancels an outstanding callback to &block if any.

#cancel_errback

Cancels an outstanding errback to &block if any.

#cancel_timeout

Cancels an outstanding timeout if any.

#errback

Specify a block to be executed if and when the Deferrable object receives a status of :failed.

#fail

Sugar for set_deferred_status(:failed, ...).

#set_deferred_failure

Alias for Deferrable#fail.

#set_deferred_status

Sets the "disposition" (status) of the Deferrable object.

#set_deferred_success
#succeed

Sugar for set_deferred_status(:succeeded, ...).

#timeout

Setting a timeout on a Deferrable causes it to go into the failed state after the Timeout expires (passing no arguments to the object's errbacks).

Connection - Inherited

#associate_callback_target

conn_associate_callback_target.

#close_connection

EventMachine::Connection#close_connection is called only by user code, and never by the event loop.

#close_connection_after_writing
#connection_completed

Called by the event loop when a remote TCP connection attempt completes successfully.

#detach

Removes given connection from the event loop.

#disable_keepalive

t_disable_keepalive.

#enable_keepalive

t_enable_keepalive.

#get_cipher_bits, #get_cipher_name, #get_cipher_protocol,
#get_idle_time

The number of seconds since the last send/receive activity on this connection.

#get_outbound_data_size

conn_get_outbound_data_size.

#get_peer_cert

If TLS is active on the connection, returns the remote X509 certificate as a string, in the popular PEM format.

#get_peername

This method is used with stream-connections to obtain the identity of the remotely-connected peer.

#get_pid

Returns the PID (kernel process identifier) of a subprocess associated with this Connection object.

#get_proxied_bytes

The number of bytes proxied to another connection.

#get_sni_hostname, #get_sock_opt,
#get_sockname

Used with stream-connections to obtain the identity of the local side of the connection.

#get_status

Returns a subprocess exit status.

#initialize

Stubbed initialize so legacy superclasses can safely call super.

#original_method,
#pause

Pause a connection so that EventMachine#send_data and #receive_data events are not fired until #resume is called.

#post_init

Called by the event loop immediately after the network connection has been established, and before resumption of the network loop.

#proxy_completed

called when the reactor finished proxying all of the requested bytes.

#proxy_incoming_to

EventMachine::Connection#proxy_incoming_to is called only by user code.

#proxy_target_unbound

Called by the reactor after attempting to relay incoming data to a descriptor (set as a proxy target descriptor with EventMachine.enable_proxy) that has already been closed.

#receive_data

Called by the event loop whenever data has been received by the network connection.

#reconnect

Reconnect to a given host/port with the current instance.

#resume

Resume a connection's EventMachine#send_data and #receive_data events.

#send_data

Call this method to send data to the remote end of the network connection.

#send_datagram

Sends UDP messages.

#send_file_data

Like Connection#send_data, this sends data to the remote end of the network connection.

#set_sock_opt,
#ssl_handshake_completed

Called by ::EventMachine when the SSL/TLS handshake has been completed, as a result of calling #start_tls to initiate SSL/TLS on the connection.

#ssl_verify_peer

Called by ::EventMachine when :verify_peer => true has been passed to EventMachine#start_tls.

#start_tls

Call EventMachine#start_tls at any point to initiate TLS encryption on connected streams.

#stop_proxying

A helper method for EventMachine.disable_proxy

#stream_file_data

Open a file on the filesystem and send it to the remote peer.

#unbind

called by the framework whenever a connection (either a server or client connection) is closed.

Constructor Details

.newHttpClient

[ GitHub ]

  
# File 'lib/em/protocols/httpclient.rb', line 68

def initialize
  warn "HttpClient is deprecated and will be removed. EM-Http-Request should be used instead."
  @connected = false
end

Class Method Details

.request(args = {})

Parameters:

  • args (Hash) (defaults to: {})

    The request arguments

Options Hash (args):

  • :host (String)

    The host IP/DNS name

  • :port (Integer)

    The port to connect too

  • :verb (String)

    The request type [GET | POST | DELETE | PUT]

  • :request (String)

    The request path

  • :basic_auth (Hash)

    The basic auth credentials (:username and :password)

  • :content (String)

    The request content

  • :contenttype (String)

    The content type (e.g. text/plain)

  • :query_string (String)

    The query string

  • :host_header (String)

    The host header to set

  • :cookie (String)

    Cookies to set

[ GitHub ]

  
# File 'lib/em/protocols/httpclient.rb', line 84

def self.request( args = {} )
  args[:port] ||= 80
  EventMachine.connect( args[:host], args[:port], self ) {|c|
    # According to the docs, we will get here AFTER post_init is called.
    c.instance_eval {@args = args}
  }
end

Instance Method Details

#connection_completed

We send the request when we get a connection. AND, we set an instance variable to indicate we passed through here. That allows #unbind to know whether there was a successful connection. NB: This naive technique won't work when we have to support multiple requests on a single connection.

[ GitHub ]

  
# File 'lib/em/protocols/httpclient.rb', line 103

def connection_completed
  @connected = true
  send_request @args
end

#dispatch_response

[ GitHub ]

  
# File 'lib/em/protocols/httpclient.rb', line 285

def dispatch_response
  @read_state = :base
  set_deferred_status :succeeded, {
    :content => @content,
    :headers => @headers,
    :status => @status
  }
  # TODO, we close the connection for now, but this is wrong for persistent clients.
  close_connection
end

#parse_response_line (private)

We get called here when we have received an HTTP response line. It's an opportunity to throw an exception or trigger other exceptional handling.

[ GitHub ]

  
# File 'lib/em/protocols/httpclient.rb', line 273

def parse_response_line
  if @headers.first =~ /\AHTTP\/1\.[01] ([\d]{3})/
    @status = $1.to_i
  else
    set_deferred_status :failed, {
      :status => 0 # crappy way of signifying an unrecognized response. TODO, find a better way to do this.
    }
    close_connection
  end
end

#post_init

[ GitHub ]

  
# File 'lib/em/protocols/httpclient.rb', line 92

def post_init
  @start_time = Time.now
  @data = "".dup
  @read_state = :base
end

#receive_data(data)

[ GitHub ]

  
# File 'lib/em/protocols/httpclient.rb', line 180

def receive_data data
  while data and data.length > 0
    case @read_state
    when :base
      # Perform any per-request initialization here and don't consume any data.
      @data = "".dup
      @headers = []
      @content_length = nil # not zero
      @content = "".dup
      @status = nil
      @chunked = false
      @chunk_length = nil
      @read_state = :header
      @connection_close = nil
    when :header
      ary = data.split( /\r?\n/m, 2 )
      if ary.length == 2
        data = ary.last
        if ary.first == ""
          if (@content_length and @content_length > 0) || @chunked || @connection_close
            @read_state = :content
          else
            dispatch_response
            @read_state = :base
          end
        else
          @headers << ary.first
          if @headers.length == 1
            parse_response_line
          elsif ary.first =~ /\Acontent-length:\s*/i
            # Only take the FIRST content-length header that appears,
            # which we can distinguish because @content_length is nil.
            # TODO, it's actually a fatal error if there is more than one
            # content-length header, because the caller is presumptively
            # a bad guy. (There is an exploit that depends on multiple
            # content-length headers.)
            @content_length ||= $'.to_i
          elsif ary.first =~ /\Aconnection:\s*close/i
            @connection_close = true
          elsif ary.first =~ /\Atransfer-encoding:\s*chunked/i
            @chunked = true
          end
        end
      else
        @data << data
        data = ""
      end
    when :content
      if @chunked && @chunk_length
        bytes_needed = @chunk_length - @chunk_read
        new_data = data[0, bytes_needed]
        @chunk_read += new_data.length
        @content += new_data
        data = data[bytes_needed..-1] || ""
        if @chunk_length == @chunk_read && data[0,2] == "\r\n"
          @chunk_length = nil
          data = data[2..-1]
        end
      elsif @chunked
        if (m = data.match(/\A(\S*)\r\n/m))
          data = data[m[0].length..-1]
          @chunk_length = m[1].to_i(16)
          @chunk_read = 0
          if @chunk_length == 0
            dispatch_response
            @read_state = :base
          end
        end
      elsif @content_length
        # If there was no content-length header, we have to wait until the connection
        # closes. Everything we get until that point is content.
        # TODO: Must impose a content-size limit, and also must implement chunking.
        # Also, must support either temporary files for large content, or calling
        # a content-consumer block supplied by the user.
        bytes_needed = @content_length - @content.length
        @content += data[0, bytes_needed]
        data = data[bytes_needed..-1] || ""
        if @content_length == @content.length
          dispatch_response
          @read_state = :base
        end
      else
        @content << data
        data = ""
      end
    end
  end
end

#send_request(args)

[ GitHub ]

  
# File 'lib/em/protocols/httpclient.rb', line 108

def send_request args
  args[:verb] ||= args[:method] # Support :method as an alternative to :verb.
  args[:verb] ||= :get # IS THIS A GOOD IDEA, to default to GET if nothing was specified?

  verb = args[:verb].to_s.upcase
  unless ["GET", "POST", "PUT", "DELETE", "HEAD"].include?(verb)
    set_deferred_status :failed, {:status => 0} # TODO, not signalling the error type
    return # NOTE THE EARLY RETURN, we're not sending any data.
  end

  request = args[:request] || "/"
  unless request[0,1] == "/"
    request = "/" + request
  end

  qs = args[:query_string] || ""
  if qs.length > 0 and qs[0,1] != '?'
    qs = "?" + qs
  end

  version = args[:version] || "1.1"

  # Allow an override for the host header if it's not the connect-string.
  host = args[:host_header] || args[:host] || "_"
  # For now, ALWAYS tuck in the port string, although we may want to omit it if it's the default.
  port = args[:port].to_i != 80 ? ":#{args[:port]}" : ""

  # POST items.
  postcontenttype = args[:contenttype] || "application/octet-stream"
  postcontent = args[:content] || ""
  raise "oversized content in HTTP POST" if postcontent.length > MaxPostContentLength

  # ESSENTIAL for the request's line-endings to be CRLF, not LF. Some servers misbehave otherwise.
  # TODO: We ASSUME the caller wants to send a 1.1 request. May not be a good assumption.
  req = [
    "#{verb} #{request}#{qs} HTTP/#{version}",
    "Host: #{host}#{port}",
    "User-agent: Ruby EventMachine",
  ]

    if verb == "POST" || verb == "PUT"
      req << "Content-type: #{postcontenttype}"
      req << "Content-length: #{postcontent.length}"
    end

    # TODO, this cookie handler assumes it's getting a single, semicolon-delimited string.
    # Eventually we will want to deal intelligently with arrays and hashes.
    if args[:cookie]
      req << "Cookie: #{args[:cookie]}"
    end

    # Allow custom HTTP headers, e.g. SOAPAction
    args[:custom_headers].each do |k,v|
      req << "#{k}: #{v}"
    end if args[:custom_headers]

    # Basic-auth stanza contributed by Matt Murphy.
    if args[:basic_auth]
      basic_auth_string = ["#{args[:basic_auth][:username]}:#{args[:basic_auth][:password]}"].pack('m').strip.gsub(/\n/,'')
      req << "Authorization: Basic #{basic_auth_string}"
    end

    req << ""
    reqstring = req.map {|l| "#{l}\r\n"}.join
    send_data reqstring

    if verb == "POST" || verb == "PUT"
      send_data postcontent
    end
end

#unbind

[ GitHub ]

  
# File 'lib/em/protocols/httpclient.rb', line 296

def unbind
  if !@connected
    set_deferred_status :failed, {:status => 0} # YECCCCH. Find a better way to signal no-connect/network error.
  elsif (@read_state == :content and @content_length == nil)
    dispatch_response
  end
end