Erlang/Elixir: 使用 OpenCV, Python 搭建图片缩略图服务器

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ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew install python
brew tap homebrew/science
brew install opencv
sudo pip install numpy
sudo pip install matplotlib

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alias python='/usr/local/bin/python'

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➜  mix new opencv_thumbnail_server --sup
* creating README.md
* creating .gitignore
* creating mix.exs
* creating config
* creating config/config.exs
* creating lib
* creating lib/opencv_thumbnail_server.ex
* creating test
* creating test/test_helper.exs
* creating test/opencv_thumbnail_server_test.exs
 
Your Mix project was created successfully.
You can use "mix" to compile it, test it, and more:
 
    cd opencv_thumbnail_server
    mix test
 
Run "mix help" for more commands.

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require Logger
defmodule OpencvThumbnailServer do
  use Application
  def start(_type, _args) do
    Logger.info "Start opencv thumbnail server"
    OpencvThumbnailServer.Supervisor.start_link()
  end
end

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defmodule OpencvThumbnailServer.Supervisor do
  use Supervisor
 
  <a href="http://www.jobbole.com/members/chkconfig">@config</a> Application.get_env :opencv_thumbnail_server, :settings
 
  def start_link() do
    Supervisor.start_link(__MODULE__, [], name: {:global,__MODULE__})
  end
 
  def init([]) do
    pool_options = @config[:poolboy]
    {_, name} = pool_options[:name]
    children = [
      :poolboy.child_spec(name, pool_options, @config[:module_name])
    ]
    supervise(children, strategy: :one_for_all, max_restarts: 1000, max_seconds: 3600)
  end
end

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defmodule OpencvThumbnailServer.Worker do
  use GenServer
  <a href="http://www.jobbole.com/members/chkconfig">@config</a> Application.get_env(:opencv_thumbnail_server, :settings)
 
  def start_link(python_module) do
    GenServer.start_link(__MODULE__, python_module, [])
  end
 
  def call_python(worker, function, args) do
    GenServer.call(worker, {:call_python, function, args}, 10_000)
  end
 
  def init(python_module) do
    IO.puts "Start worker"
    {:ok, pid} = :python.start_link([
      {:python_path, @config[:python_path]},
      {:python, @config[:python]}
    ])
    state = {python_module, pid}
    {:ok, state}
  end
 
  def handle_call({:call_python, function, args}, _from, state) do
    {module, pid} = state
    result = :python.call(pid, module, function, args)
    reply = {:ok, result}
    {:reply, reply, state}
  end
 
  def handle_call(_request, _from, state) do
    {:stop, :error, :bad_call, state}
  end
 
  def handle_info(_msg, {module,py_pid}) do
    {:stop, :error, {module,py_pid}}
  end
 
  def terminate(_reason, {_, py_pid}) do
    :python.stop(py_pid)
    :ok
  end
end

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# -*- coding: utf-8 -*-
 
import urllib2 as urllib
import numpy as np
import cv2
 
 
def load_image_url(url):
    resp = urllib.urlopen(url)
    buf = resp.read()
    return buf
 
 
def load_image_file(filename):
    image = cv2.imdecode(filename, cv2.IMREAD_COLOR)
    return image
 
def get_photo_sizes():
    return [
        [160, 160],
        [320, 320],
        [640, 640],
        [1060, 1060],
        [1280, 1280]
    ]
def show(buf):
    # print buf
    # x = cv2.imdecode(image, cv2.IMREAD_COLOR)
    # d = cv2.cvtColor(c, cv2.COLOR_RGB2BGR)
    np_ndarray = np.fromstring(buf, dtype=np.uint8)
    x = cv2.imdecode(np_ndarray, cv2.IMREAD_UNCHANGED)
    return cv2.imshow('NBA Image', x)
 
def write(buf):
    nparray = np.fromstring(buf, dtype=np.uint8)
    img = cv2.imdecode(nparray, cv2.IMREAD_UNCHANGED)
    return cv2.imwrite('/tmp/imwrite.png', img)
 
# def get_dimension():
#     url = 'http://img1.gtimg.com/16/1601/160106/16010642_1200x1000_0.jpg'
#     resp = urllib.urlopen(url)
#     buf = resp.read()
#     x = np.fromstring(buf, dtype=np.uint8)
#     img = cv2.imdecode(x, cv2.IMREAD_UNCHANGED)
#     # height = np.size(img, 0)
#     # width = np.size(img, 1)
#     height, width = image.shape[:2]
#     return (width, height)
 
def get_dimension(buffer):
    # 把原始的二进制图片数据转换为NpArray
    nparray = np.fromstring(buffer, dtype=np.uint8)
    # 把 nparray 转换为 opencv 的图像格式
    image = cv2.imdecode(nparray, cv2.IMREAD_UNCHANGED)
    height, width = image.shape[:2]
    return (width, height)
 
def convert_color():
    url = 'http://ww3.sinaimg.cn/mw690/6941baebgw1epzcuv9vmxj20me0hy0u1.jpg'
    resp = urllib.urlopen(url)
    buf = resp.read()
    x = np.fromstring(buf, dtype=np.uint8)
    img = cv2.imdecode(x, cv2.IMREAD_UNCHANGED)
 
if __name__ == '__main__':
    get_dimension()

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{:ok, <<255, 216, 255, 224, 0, 16, 74, 70, 73, 70, 0, 1, 1, 1, 0, 72,
      0, 72, 0, 0, 255, 219, 0, 67, 0, 8, 6, 6, 7, 6, 5, 8, 7, 7, 7,
      9, 9, 8, 10, 12, 20, 13, 12, 11, 11, 12, 25, 18, 19, ...>>}

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{:ok, data} = OpencvThumbnailServer.Api.load_image_url("https://segmentfault.com/img/bVwhAW")
OpencvThumbnailServer.Api.get_dimension(data)
{:ok, {800, 431}}

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pip install cookiecutter
easy_install cookiecutter
conda install -c https://conda.binstar.org/pydanny cookiecutter
brew install cookiecutter(Mac OS X)

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➜  opencv_thumbnail git:(master) tree
.
├── AUTHORS.rst
├── CONTRIBUTING.rst
├── HISTORY.rst
├── LICENSE
├── MANIFEST.in
├── Makefile
├── README.rst
├── build
│   ├── bdist.macosx-10.11-x86_64
│   └── lib
│       └── opencv_thumbnail
│           ├── __init__.py
│           └── opencv_thumbnail.py
├── dist
│   └── opencv_thumbnail-0.1.0-py2.7.egg
├── docs
│   ├── Makefile
│   ├── authors.rst
│   ├── conf.py
│   ├── contributing.rst
│   ├── history.rst
│   ├── index.rst
│   ├── installation.rst
│   ├── make.bat
│   ├── readme.rst
│   └── usage.rst
├── opencv_thumbnail
│   ├── __init__.py
│   ├── __init__.pyc
│   ├── opencv_thumbnail.py
│   └── opencv_thumbnail.pyc
├── opencv_thumbnail.egg-info
│   ├── PKG-INFO
│   ├── SOURCES.txt
│   ├── dependency_links.txt
│   ├── not-zip-safe
│   └── top_level.txt
├── requirements_dev.txt
├── setup.cfg
├── setup.py
├── tests
│   ├── __init__.py
│   └── test_opencv_thumbnail.py
├── tox.ini
└── travis_pypi_setup.py
 
9 directories, 36 files

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defmodule OpencvThumbnailServer.Api do
  alias OpencvThumbnailServer.Worker
 
  def get_dimension(data) do
    worker = :poolboy.checkout(:opencv_thumbnail_server_pool)
    {w, h} = Worker.call_python(worker, :get_dimension, [data])
    :poolboy.checkin(:opencv_thumbnail_server_pool, worker)
    {w, h}
  end
 
  def load_image_url(url) do
    worker = :poolboy.checkout(:opencv_thumbnail_server_pool)
    image_bin = Worker.call_python(worker, :load_image_url, [url])
    :poolboy.checkin(:opencv_thumbnail_server_pool, worker)
    image_bin
  end
end