Using Jupyter Notebooks as Rest API Endpoint

JNB_endpoint.ipynb

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   "source": [
    "# Using Jupyter Notebooks as a Rest API Endpoint"
   ]
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "In this notebook we make a simple API that converts degrees to radians. We should end up with something like this:\n",
    "\n",
    "```shell\n",
    "$ curl \"http://serverIp:8888/convert?angle=180\"\n",
    "# {\"convertedAngle\": 3.141592653589793}\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "First, install `jupyter_kernel_gateway` package (uncomment line below to use):"
   ]
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   "outputs": [],
   "source": [
    "# !pip3 install jupyter_kernel_gateway"
   ]
  },
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   "cell_type": "code",
   "execution_count": 1,
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   "source": [
    "import math\n",
    "import json\n",
    "\n",
    "# REQUEST is the http request sent to the endpoints,\n",
    "# it's initialized to prevent error in running the notebook\n",
    "REQUEST = json.dumps({\n",
    "    'path' : {},\n",
    "    'args' : {}\n",
    "})"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Defining the endpoint (this cell response to `GET` requests on `/convert`):"
   ]
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   "cell_type": "code",
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     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{\"convertedAngle\": null}\n"
     ]
    }
   ],
   "source": [
    "# GET /convert\n",
    "req = json.loads(REQUEST)\n",
    "args = req['args']\n",
    "\n",
    "if 'angle' not in args:\n",
    "  print(json.dumps({'convertedAngle': None}))\n",
    "else:\n",
    "  # Note the [0] when retrieving the argument.\n",
    "  # This is because you could potentially pass multiple angles.\n",
    "  angle = int(args['angle'][0])\n",
    "  converted = math.radians(angle)\n",
    "  print(json.dumps({'convertedAngle': converted}))"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {
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     "end_time": "2019-10-21T21:41:09.396589Z",
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   "source": [
    "#### In terminal run:\n",
    "\n",
    "```shell\n",
    "jupyter kernelgateway  --KernelGatewayApp.api='kernel_gateway.notebook_http'  --KernelGatewayApp.seed_uri='./JNB_endpoint.ipynb'\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**sources**: [Eliot Andres blog](https://ndres.me/post/jupyter-notebook-rest-api/) and [ouseful blog](https://blog.ouseful.info/2017/09/06/building-a-json-api-using-jupyer-notebooks-in-under-5-minutes/)."
   ]
  }
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