Class: Yahns::TeeInput

Inherits:
StreamInput show all
Defined in:
lib/yahns/tee_input.rb

Overview

acts like tee(1) on an input input to provide a input-like stream while providing rewindable semantics through a File/StringIO backing store. On the first pass, the input is only read on demand so your Rack application can use input notification (upload progress and like). This should fully conform to the Rack::Lint::InputWrapper specification on the public API. This class is intended to be a strict interpretation of Rack::Lint::InputWrapper functionality and will not support any deviations from it.

When processing uploads, Yahns exposes a TeeInput object under “rack.input” of the Rack environment.

Instance Method Summary collapse

Methods inherited from StreamInput

#__rsize, #__tlsbuf, #each, #eof!, #eof?, #filter_body, #read_all

Constructor Details

#initialize(client, request) ⇒ TeeInput

Initializes a new TeeInput object. You normally do not have to call this unless you are writing an HTTP server.



19
20
21
22
23
 
# File 'lib/yahns/tee_input.rb', line 19

def initialize(client, request)
  @len = request.content_length
  super
  @tmp = client.class.tmpio_for(@len)
end

Instance Method Details

#close ⇒ Object

returns nil



111
112
113
 
# File 'lib/yahns/tee_input.rb', line 111

def close # returns nil
  @tmp = @tmp.close
end

#consume! ⇒ Object

consumes the stream of the socket



98
99
100
101
102
 
# File 'lib/yahns/tee_input.rb', line 98

def consume!
  junk = ""
  rsize = __rsize
  nil while read(rsize, junk)
end

#gets ⇒ Object

:call-seq:

ios.gets   => string or nil

Reads the next “line” from the I/O stream; lines are separated by the global record separator ($/, typically “n”). A global record separator of nil reads the entire unread contents of ios. Returns nil if called at the end of file. This takes zero arguments for strict Rack::Lint compatibility, unlike IO#gets.



81
82
83
 
# File 'lib/yahns/tee_input.rb', line 81

def gets
  @client ? tee(super) : @tmp.gets
end

#read(*args) ⇒ Object

:call-seq:

ios.read([length [, buffer ]]) => string, buffer, or nil

Reads at most length bytes from the I/O stream, or to the end of file if length is omitted or is nil. length must be a non-negative integer or nil. If the optional buffer argument is present, it must reference a String, which will receive the data.

At end of file, it returns nil or “” depend on length. ios.read() and ios.read(nil) returns “”. ios.read(length [, buffer]) returns nil.

If the Content-Length of the HTTP request is known (as is the common case for POST requests), then ios.read(length [, buffer]) will block until the specified length is read (or it is the last chunk). Otherwise, for uncommon “Transfer-Encoding: chunked” requests, ios.read(length [, buffer]) will return immediately if there is any data and only block when nothing is available (providing IO#readpartial semantics).



68
69
70
 
# File 'lib/yahns/tee_input.rb', line 68

def read(*args)
  @client ? tee(super) : @tmp.read(*args)
end

#rewind ⇒ Object

:call-seq:

ios.rewind    => 0

Positions the ios pointer to the beginning of input, returns the offset (zero) of the ios pointer. Subsequent reads will start from the beginning of the previously-buffered input.



91
92
93
94
95
 
# File 'lib/yahns/tee_input.rb', line 91

def rewind
  return 0 if 0 == @tmp.size
  consume! if @client
  @tmp.rewind # Rack does not specify what the return value is here
end

#size ⇒ Object

:call-seq:

ios.size  => Integer

Returns the size of the input. For requests with a Content-Length header value, this will not read data off the socket and just return the value of the Content-Length header as an Integer.

For Transfer-Encoding:chunked requests, this requires consuming all of the input stream before returning since there’s no other way to determine the size of the request body beforehand.

This method is no longer part of the Rack specification as of Rack 1.2, so its use is not recommended. This method only exists for compatibility with Rack applications designed for Rack 1.1 and earlier. Most applications should only need to call read with a specified length in a loop until it returns nil.



41
42
43
44
45
46
47
 
# File 'lib/yahns/tee_input.rb', line 41

def size
  @len and return @len
  pos = @tmp.pos
  consume!
  @tmp.pos = pos
  @len = @tmp.size
end

#tee(buffer) ⇒ Object 



104
105
106
107
108
109
 
# File 'lib/yahns/tee_input.rb', line 104

def tee(buffer)
  if buffer && buffer.size > 0
    @tmp.write(buffer)
  end
  buffer
end