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The Promise of rest-core

rest-core 的承諾

RubyConf.TW 2011,我介紹了 rest-core,是用 Ruby 寫成的模組化 REST client 組合包與工具組。後來組合包的東西被抽至 rest-more,於是變成給 REST APIs 使用的模組化 Ruby clients interface。

RubyConf.TW 2012,我介紹了 Ruby 上的 concurrent 應用程式伺服器。之後在 rest-core 內,加入我從以上所學到的東西,使它能輕易地發出 concurrent requests。

在不同的使用情況下,我們有時候需要使用 promise、有時候需要使用 callback。這次我將介紹該怎麼利用 promise 來達成以我們所熟習的同步風格,發出 concurrent requests;同時也能繼續用 callback 發出非同步的 concurrent requests。


The Promise of rest-core

In RubyConf.TW 2011, I talked about rest-core as A modular Ruby REST client collection/infrastructure. Later it's rephrased as Modular Ruby clients interface for REST APIs because the collection was extracted into rest-more.

In RubyConf.TW 2012, I talked about Concurrent Ruby Application Servers. Later I tried to take what I've learnt from concurrency to make rest-core better, so that we could easily make concurrent requests for accessing data via REST APIs.

This time I'll talk about how we take the advantage of Promise to make concurrent requests in an old, synchronous fashion, while still being able to use callbacks for asynchronous requests concurrently. We need both of promises and callbacks accordingly.

I'll also talk about all the nasty details about implementing them. This could be tough, be prepared!

Table of Contents

  • Introduction
  • The API / Use Cases
    • Futures / Synchronous / Blocking
      • Print the Name
      • Print the Names
      • Fire and Forget
      • Fire and Call
    • Callbacks / Asynchronous / Non-blocking
      • Fire and Call
      • Fire and Rescue
      • Callback Hell?
      • We Still need Callbacks
    • Wait! It's not yet done
      • Client#wait
      • Client.wait
    • Promise Chain: Promise#then
      • Why: It's Not Blocking Here
      • RC::Github#all
    • Promise.claim
      • Forging Response, for middleware RC::Cache
  • Streaming, the EventSource
    • SSE, Server-Sent Events
    • SSE with Rack Hijacking
    • Firebase Daemon (rest-firebase)
  • Some Background...
    • Race Conditions
    • Mutex (mutual exclusion) (lock)
    • ConditionVariable (monitor)
    • WeakRef (weak reference)
  • Concurrency Model
    • None / Blocking (For debugging purpose)
    • Thread Spawn (Default)
    • Thread Pool (Throttling)
    • Gotcha!
      • Weird Backtrace for Exceptions
      • Shutting down gracefully
      • Beware of Deadlock!
      • Beware of Timeout!
      • Inaccurate Timeout
    • Wait! Detail
      • Client.wait
      • Promise#wait
      • Promise#fulfilling
      • Promise#rejecting
      • Future#method_missing
      • Promise#yield
    • Promise Detail
      • Promise#defer
      • Promise#protected_yield
      • Promise#cancel_task
    • ThreadPool Detail
      • ThreadPool#defer
      • ThreadPool#spawn_worker
      • ThreadPool::Task
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godfat commented Jan 13, 2015

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