(SOT) Change in em-http-request: 0.3.0 => 1.0.0

luislavena · December 17, 2011, 6:36pm

I am trying to bring some older code up to date. It works fine with
em-request-http 0.3.0. With 1.0.0 it breaks, revealing my lack of
understanding Ruby, among other things. The following code reveals the
problem:

require ‘rubygems’
require ‘eventmachine’
#gem ‘em-http-request’, ‘=0.3.0’
require ‘em-http-request’

class PhrcRequest < EM::HttpRequest
def initialize(*args)
puts “HERE”
super(args)
end
end

r = PhrcRequest.new(‘http://example.com/’)

puts r.inspect

With em-request-http 1.0.0 (the newest version on my system), the output
is:

#<EventMachine::HttpConnection:0x7fb4d804a120 @middleware=[],
@deferred=true,
@uri=“http://example.com/”,
@connopts=#<HttpConnectionOptions:0x7fb4d804a580
@port=80, @tls={}, @proxy=nil, @inactivity_timeout=10,
@host=“example.com”,
@connect_timeout=5>>

With version 0.3.0 (the gem statement uncommented), the output is:

HERE
#<PhrcRequest:0x7f130c1891a8 @uri=#<Addressable::URI:0x3f89860c4730
URI:http://example.com/>>

Can someone explain to me how calling new() for one class returns an
object of
another class? And how I can work around it. And is this a bug in
EM::HttpRequest that I should report?

TIA,
Jeffrey

Jeffrey_LSTaylor · December 17, 2011, 6:51pm

With version 0.3.0 (the gem statement uncommented), the output is:

HERE
#<PhrcRequest:0x7f130c1891a8 @uri=#<Addressable::URI:0x3f89860c4730
URI:http://example.com/>>

Can someone explain to me how calling new() for one class returns an object of
another class? And how I can work around it. And is this a bug in
EM::HttpRequest that I should report?

new is a method that can be overridden like any other, as you can see
at

github.com

igrigorik/em-http-request/blob/master/lib/em-http/request.rb

module EventMachine
  class HttpRequest
    @middleware = []

    def self.new(uri, options={})
      uri = uri.clone
      connopt = HttpConnectionOptions.new(uri, options)

      c = HttpConnection.new
      c.connopts = connopt
      c.uri = uri
      c
    end

    def self.use(klass, *args, &block)
      @middleware << klass.new(*args, &block)
    end

    def self.middleware
      @middleware

This file has been truncated. show original

I don’t know anything about the innards of em-http-request, so I can
only advise searching through the source to see where the
functionality you were trying to override has gone.

Fred

Jeffrey_LSTaylor · December 17, 2011, 6:56pm

Quoting Jeffrey L. Taylor [email protected]:

class PhrcRequest < EM::HttpRequest

#<PhrcRequest:0x7f130c1891a8 @uri=#<Addressable::URI:0x3f89860c4730
URI:http://example.com/>>

Can someone explain to me how calling new() for one class returns an object of
another class? And how I can work around it. And is this a bug in
EM::HttpRequest that I should report?

Use the source! Looking at the 1.0.0 code, it overrides self.new(),
doesn’t
call initialize() and returns an HttpConnection. This strikes me as
abuse of
the language and certainly violates the principle of least surprise. It
also
effectively blocks inheritance. Can anyone tell me how this is not a
bug?

Jeffrey