Building Streaming REST APIs with Ruby

Bullwinkle_Moose · 2 days

Here's how to do it with just plain old Rack (note you need to use unicorn or thin as the webserver):

This is the app.ru file. Just run unicorn app.ru.

use Rack::Chunked

require 'thread'

class StreamingBody < Struct.new(:q)
  def each
    while chunk = q.pop
      yield chunk
    end
  end
end

run lambda { |env|
  q = Queue.new

  Thread.new { # Producer thread
    loop do
      q.push "\nChunky Monkey"
      sleep 0.1
    end
  }

  # Main thread is the consumer thread
  [200, {'Content-Type' => 'text/plain'}, StreamingBody.new(q)]
}

joshuadavey · 4 days

I know this is a nitpick, so please read this in Comic Book Guy voice:

ActiveSupport provides the group_by and sort_by methods on collections

Enumerable provides group_by and sort_by. You don't need ActiveSupport for these two methods:

>> RUBY_VERSION
=> "1.8.7"
>> [].method(:group_by)
=> #<Method: Array(Enumerable)#group_by>
>> [].method(:sort_by)
=> #<Method: Array(Enumerable)#sort_by>

imperator96 · 26 days

How does this project relate to the Ruby installer? Why should I support this over the already existing (and free) project?

Doing the legwork to get gems working better on windows, and pushing changes up to ruby-core is admirable, and I would support that (and by support, I mean support with cash money). But supporting development of a commercial product that competes with an already existing (and free) project leaves me with many doubts. Especially since one of the maintainers of the free product is a ruby-core dev.

Can you explain why I should donate to this and not just send Luis a check?

onso · 1 month

Seems like a load path problem. You need to tell ruby where to find files when you call "require". Try: ruby -I. test.rb to tell ruby to search the current directory when calls are made to require.

kbedell · 1 month

T-shirt, but no pants. Today is PANTS OFF DANCE OFF day.

Denommus · 1 month

I MUST TAKE THIS.

tenderlove · 1 month

I should have mentioned, if you'd like turned on by default, change this line and recompile. I'm not sure what your stack traces will look like though. :(

Hope that helps!

EDIT: looks like you don't have to recompile. Just make sure to set compile_option before any code gets loaded:

code = <<-eocode
  class Tailcall
    def fact_helper(n, res)
      if n == 1
        res
      else
        fact_helper(n - 1, n * res)
      end
    end
    def fact(n)
      fact_helper(n, 1)
    end
  end
eocode

eval code.sub(/Tailcall/, 'NotTailcall')

RubyVM::InstructionSequence.compile_option = {
  :tailcall_optimization => true,
  :trace_instruction     => false
}

# Any code you want with TCO should happen after you've tweaked compile_option
eval code

FACTSIZE = 30_000

begin
  NotTailcall.new.fact(FACTSIZE)
rescue SystemStackError
  puts "DOH!"
end

begin
  Tailcall.new.fact(FACTSIZE)
rescue SystemStackError
  puts "DOH!"
end

tenderlove · 1 month

Actually, the VM does support TCO. It's just not enabled by default. Here is an example computing Factorials. The non TCO version will stack overflow where the other will not:

code = <<-eocode
  class Tailcall
    def fact_helper(n, res)
      if n == 1
        res
      else
        fact_helper(n - 1, n * res)
      end
    end
    def fact(n)
      fact_helper(n, 1)
    end
  end
eocode

option = {
  tailcall_optimization: true,
  trace_instruction: false,
}

iseq = RubyVM::InstructionSequence.new(code, "hello", nil, nil, option).eval

eval code.sub(/Tailcall/, 'NotTailcall')

FACTSIZE = 30_000

begin
  NotTailcall.new.fact(FACTSIZE)
rescue SystemStackError
  puts "DOH!"
end

begin
  Tailcall.new.fact(FACTSIZE)
rescue SystemStackError
  puts "DOH!"
end

EDIT: Fixed my words. Ugh.

tenderlove · 1 month

Happy April 1st!

scottjshea · 3 months

I'M A TEAPOT

scottjshea · 3 months

I GET rest, I just don't POST it everywhere.

scottjshea · 3 months

Does this mean Enterprise companies hire via SOAP requests?

sinisterff · 3 months

Nice. I like undercover nerd shirts.

that_one_christian · 3 months

I always assumed there was more than one person named Christian on reddit.

jpozdena · 5 months

Ya. It looks like it's been deprecated since at least 2004. Probably needs better docs and for more people to run ruby with -w, otherwise the rb_warn will not show up.

Edit:

In fact, I don't think the code path shown in this article will actually touch the "Ruby rulez" part. You have to call the encrypt method with an argument in order to hit the warning. Here is the original code from the article which produces no warnings:

require 'openssl'

@cipher = OpenSSL::Cipher.new('aes-256-cbc')
@cipher.encrypt

@cipher.key = @cipher.random_key
@cipher.iv  = @cipher.random_iv # bye bye "OpenSSL for Ruby rulez!"


@cipher.update("I'm gonna be encrypted")
output = @cipher.final

My updated version that actually hits the rb_scan_args code path:

require 'openssl'

@cipher = OpenSSL::Cipher.new('aes-256-cbc')
@cipher.encrypt 'foo'

@cipher.key = @cipher.random_key
@cipher.iv  = @cipher.random_iv # bye bye "OpenSSL for Ruby rulez!"


@cipher.update("I'm gonna be encrypted")
output = @cipher.final

highway61 · 5 months

I have ten degrees of awesome. ;-)

tenderlove · 5 months

ya, that's why I mentioned that we should fix this in Bundler. If Bundler could better understand the checked out repository, or even generate a gemspec when it checked out (or updated) a git repo, then we wouldn't need to have the gemspec checked in. I'd prefer to not check in the gemspec, but if I want to work with bundler and edge deps, I must.

tenderlove · 5 months

Look at my fork on github and figure out how to integrate systemtap! ;-)

tenderlove · 5 months

I think using a dir glob would probably be slightly slower than the generated gemspec, but definitely faster than the subshell. I just prefer using a generated gemspec because file add / delete don't happen that often, and I always mess up my dir globs (editor temp files, random scripts I leave in the repo, etc). I think I might be a messy programmer! :(

retardo · 7 months

FFFUUUUUUUUU. I always forget to submit my own posts. ;-)

tenderlove

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