Class: EventMachine::HttpResponse

Inherits:
Object
  • Object
show all
Defined in:
lib/evma_httpserver/response.rb

Overview

This class provides a wide variety of features for generating and dispatching HTTP responses. It allows you to conveniently generate headers and content (including chunks and multiparts), and dispatch responses (including deferred or partially-complete responses).

Although HttpResponse is coded as a class, it’s not complete as it stands. It assumes that it has certain of the behaviors of EventMachine::Connection. You must add these behaviors, either by subclassing HttpResponse, or using the alternate version of this class, DelegatedHttpResponse. See the test cases for current information on which behaviors you have to add.

TODO, someday it would be nice to provide a version of this functionality that is coded as a Module, so it can simply be mixed into an instance of EventMachine::Connection.

Direct Known Subclasses

DelegatedHttpResponse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ HttpResponse

Returns a new instance of HttpResponse.



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# File 'lib/evma_httpserver/response.rb', line 54

def initialize
	@headers = {}
end

Instance Attribute Details

#chunks ⇒ Object

Returns the value of attribute chunks.



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# File 'lib/evma_httpserver/response.rb', line 52

def chunks
  @chunks
end

#content ⇒ Object

Returns the value of attribute content.



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# File 'lib/evma_httpserver/response.rb', line 52

def content
  @content
end

#headers ⇒ Object

Returns the value of attribute headers.



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# File 'lib/evma_httpserver/response.rb', line 52

def headers
  @headers
end

#multiparts ⇒ Object

Returns the value of attribute multiparts.



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# File 'lib/evma_httpserver/response.rb', line 52

def multiparts
  @multiparts
end

#status ⇒ Object

Returns the value of attribute status.



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# File 'lib/evma_httpserver/response.rb', line 52

def status
  @status
end

Class Method Details

.concoct_multipart_boundary ⇒ Object

TODO, this is going to be way too slow. Cache up the uuidgens.



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# File 'lib/evma_httpserver/response.rb', line 276

def self.concoct_multipart_boundary
	@multipart_index ||= 0
	@multipart_index += 1
	if @multipart_index >= 1000
		@multipart_index = 0
		@multipart_guid = nil
	end
	@multipart_guid ||= `uuidgen -r`.chomp.gsub(/\-/,"")
	"#{@multipart_guid}#{@multipart_index}"
end

Instance Method Details

Sugaring for Set-cookie headers. These are a pain because there can easily and legitimately be more than one. So we use an ugly verb to signify that. #add_set_cookies does NOT disturb the set-cookie headers which may have been added on a prior call. #set_cookie clears them out first.



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# File 'lib/evma_httpserver/response.rb', line 75

def add_set_cookie *ck
	if ck.length > 0
		h = (@headers["Set-cookie"] ||= [])
		ck.each {|c| h << c}
	end
end

#chunk(text) ⇒ Object

add a chunk to go to the output. Will cause the headers to pick up “content-transfer-encoding” Add the chunk to a list. Calling #send_chunks will send out the available chunks and clear the chunk list WITHOUT closing the connection, so it can be called any number of times. TODO!!! Per RFC2616, we may not send chunks to an HTTP/1.0 client. Raise an exception here if our user tries to do so. Chunked transfer coding is defined in RFC2616 pgh 3.6.1. The argument can be a string or a hash. The latter allows for sending chunks with extensions (someday).



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# File 'lib/evma_httpserver/response.rb', line 216

def chunk text
	@chunks ||= []
	@chunks << text
end

#content_type(*mime) ⇒ Object

sugarings for headers



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# File 'lib/evma_httpserver/response.rb', line 63

def content_type *mime
	if mime.length > 0
		@headers["Content-type"] = mime.first.to_s
	else
		@headers["Content-type"]
	end
end

#fixup_headers ⇒ Object

Examine the content type and data and other things, and perform a final fixup of the header array. We expect this to be called just before sending headers to the remote peer. In the case of multiparts, we ASSUME we will get called before any content gets sent out, because the multipart boundary is created here.



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# File 'lib/evma_httpserver/response.rb', line 143

def fixup_headers
	if @content
		@headers["Content-length"] = @content.to_s.length
	elsif @chunks
		@headers["Transfer-encoding"] = "chunked"
		# Might be nice to ENSURE there is no content-length header,
		# but how to detect all the possible permutations of upper/lower case?
	elsif @multiparts
		@multipart_boundary = self.class.concoct_multipart_boundary
		@headers["Content-type"] = "multipart/x-mixed-replace; boundary=\"#{@multipart_boundary}\""
	else
		@headers["Content-length"] = 0
	end
end

#keep_connection_open(arg = true) ⇒ Object 



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# File 'lib/evma_httpserver/response.rb', line 58

def keep_connection_open arg=true
	@keep_connection_open = arg
end

#multipart(arg) ⇒ Object

To add a multipart to the outgoing response, specify the headers and the body. If only a string is given, it’s treated as the body (in this case, the header is assumed to be empty).



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# File 'lib/evma_httpserver/response.rb', line 247

def multipart arg
	vals = if arg.is_a?(String)
		{:body => arg, :headers => {}}
	else
		arg
	end

	@multiparts ||= []
	@multiparts << vals
end

#send_body ⇒ Object

we send either content, chunks, or multiparts. Content can only be sent once. Chunks and multiparts can be sent any number of times. DO NOT close the connection or send any goodbye kisses. This method can be called multiple times to send out chunks or multiparts.



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# File 'lib/evma_httpserver/response.rb', line 162

def send_body
	if @content
		send_content
	elsif @chunks
		send_chunks
	elsif @multiparts
		send_multiparts
	else
		@content = ""
		send_content
	end
end

#send_chunks ⇒ Object

send the contents of the chunk list and clear it out. ASSUMES that headers have been sent. Does NOT close the connection. Can be called multiple times. According to RFC2616, phg 3.6.1, the last chunk will be zero length. But some caller could accidentally set a zero-length chunk in the middle of the stream. If that should happen, raise an exception. The reason for supporting chunks that are hashes instead of just strings is to enable someday supporting chunk-extension codes (cf the RFC). TODO!!! We’re not supporting the final entity-header that may be transmitted after the last (zero-length) chunk.



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# File 'lib/evma_httpserver/response.rb', line 233

def send_chunks
	send_headers unless @sent_headers
	while chunk = @chunks.shift
		raise "last chunk already sent" if @last_chunk_sent
		text = chunk.is_a?(Hash) ? chunk[:text] : chunk.to_s
		send_data "#{format("%x", text.length).upcase}\r\n#{text}\r\n"
		@last_chunk_sent = true if text.length == 0
	end
end

#send_content ⇒ Object 



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# File 'lib/evma_httpserver/response.rb', line 199

def send_content
	raise "sent content already" if @sent_content
	@sent_content = true
	send_data((@content || "").to_s)
end

#send_headers ⇒ Object

Send the headers out in alpha-sorted order. This will degrade performance to some degree, and is intended only to simplify the construction of unit tests.



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# File 'lib/evma_httpserver/response.rb', line 107

def send_headers
	raise "sent headers already" if @sent_headers
	@sent_headers = true

	fixup_headers

	ary = []
	ary << "HTTP/1.1 #{@status || 200} ...\r\n"
	ary += generate_header_lines(@headers)
	ary << "\r\n"

	send_data ary.join
end

#send_multiparts ⇒ Object

Multipart syntax is defined in RFC 2046, pgh 5.1.1 et seq. The CRLF which introduces the boundary line of each part (content entity) is defined as being part of the boundary, not of the preceding part. So we don’t need to mess with interpreting the last bytes of a part to ensure they are CRLF-terminated.



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# File 'lib/evma_httpserver/response.rb', line 264

def send_multiparts
	send_headers unless @sent_headers
	while part = @multiparts.shift
		send_data "\r\n--#{@multipart_boundary}\r\n"
		send_data( generate_header_lines( part[:headers] || {} ).join)
		send_data "\r\n"
		send_data part[:body].to_s
	end
end

#send_redirect(location) ⇒ Object 



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# File 'lib/evma_httpserver/response.rb', line 287

def send_redirect location
	@status = 302 # TODO, make 301 available by parameter
	@headers["Location"] = location
	send_response
end

#send_response ⇒ Object

This is intended to send a complete HTTP response, including closing the connection if appropriate at the end of the transmission. Don’t use this method to send partial or iterated responses. This method will send chunks and multiparts provided they are all available when we get here. Note that the default @status is 200 if the value doesn’t exist.



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# File 'lib/evma_httpserver/response.rb', line 97

def send_response
	send_headers
	send_body
	send_trailer
	close_connection_after_writing unless (@keep_connection_open and (@status || 200) == 200)
end

#send_trailer ⇒ Object

send a trailer which depends on the type of body we’re dealing with. The assumption is that we’re about to end the transmission of this particular HTTP response. (A connection-close may or may not follow.)



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# File 'lib/evma_httpserver/response.rb', line 179

def send_trailer
	send_headers unless @sent_headers
	if @content
		# no-op
	elsif @chunks
		unless @last_chunk_sent
			chunk ""
			send_chunks
		end
	elsif @multiparts
		# in the lingo of RFC 2046/5.1.1, we're sending an "epilog"
		# consisting of a blank line. I really don't know how that is
		# supposed to interact with the case where we leave the connection
		# open after transmitting the multipart response.
		send_data "\r\n--#{@multipart_boundary}--\r\n\r\n"
	else
		# no-op
	end
end

#set_cookie(*ck) ⇒ Object 



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# File 'lib/evma_httpserver/response.rb', line 81

def set_cookie *ck
	h = (@headers["Set-cookie"] ||= [])
	if ck.length > 0
		h.clear
		add_set_cookie *ck
	else
		h
	end
end