tinydb-yaml-nb.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "from tinydb import TinyDB\n",
    "from tinydb.storages import Storage, touch\n",
    "\n",
    "import yaml\n",
    "import sys"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "class TestYamlStorage(Storage):\n",
    "    \n",
    "    \"\"\"\n",
    "    Store the data in a YAML file.\n",
    "    Written following the example at http://tinydb.readthedocs.io/en/latest/extend.html#write-a-custom-storage\n",
    "    \"\"\"\n",
    "    def __init__(self, filename):  # (1)\n",
    "        super().__init__()\n",
    "        self.filename = filename\n",
    "        touch(filename)\n",
    "\n",
    "    def read(self):\n",
    "        with open(self.filename) as handle:\n",
    "            try:\n",
    "                # data = ruamel.yaml.load(handle, ruamel.yaml.RoundTripLoader)\n",
    "                # data = yaml.safe_load(handle.read())\n",
    "                data = yaml.load(handle.read())\n",
    "                return data\n",
    "            except yaml.YAMLError:\n",
    "                return None  # (3)\n",
    "\n",
    "    def write(self, data):\n",
    "#         print('writing data: {}'.format(data))\n",
    "        with open(self.filename, 'w') as handle:\n",
    "            yaml.dump(data, stream=sys.stdout)\n",
    "            yaml.dump(data, handle)\n",
    "                # ruamel.yaml.dump(data, stream=handle, Dumper=ruamel.yaml.RoundTripDumper)\n",
    "\n",
    "    def close(self):  # (4)\n",
    "        pass\n",
    "\n",
    "\n",
    "def flush(f):\n",
    "    import os\n",
    "    # flush existing file for consistency\n",
    "    try:\n",
    "        os.remove(f)\n",
    "    except FileNotFoundError:\n",
    "        pass"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "dicts = [\n",
    "    dict(name='Homer', age=38),\n",
    "    dict(name='Marge', age=34),\n",
    "    dict(name='Bart', age=10)\n",
    "]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "_default: {}\n",
      "_default:\n",
      "  1: {age: 38, name: Homer}\n",
      "  2: {age: 34, name: Marge}\n",
      "  3: {age: 10, name: Bart}\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[{'age': 38, 'name': 'Homer'},\n",
       " {'age': 34, 'name': 'Marge'},\n",
       " {'age': 10, 'name': 'Bart'}]"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "flush('db.yaml')\n",
    "db = TinyDB('db.yaml', storage=TestYamlStorage)\n",
    "# this works as expected\n",
    "db.insert_multiple(dicts)\n",
    "db.all()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "_default:\r\n",
      "  1: {age: 38, name: Homer}\r\n",
      "  2: {age: 34, name: Marge}\r\n",
      "  3: {age: 10, name: Bart}\r\n"
     ]
    }
   ],
   "source": [
    "%cat db.yaml"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "_default: {}\n",
      "_default: {}\n"
     ]
    }
   ],
   "source": [
    "flush('db.yaml')\n",
    "db = TinyDB('db.yaml', storage=TestYamlStorage)\n",
    "%cat db.yaml"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "_default:\n",
      "  1: {age: 38, name: Homer}\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[{'age': 38, 'name': 'Homer'}]"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "db.insert(dicts[0])\n",
    "db.all()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "_default:\n",
      "  1: !!python/object/new:tinydb.database.Element\n",
      "    dictitems: {age: 38, name: Homer}\n",
      "    state: {eid: 1}\n",
      "  2: {age: 34, name: Marge}\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[{'age': 38, 'name': 'Homer'}, {'age': 34, 'name': 'Marge'}]"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "db.insert(dicts[1])\n",
    "db.all()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "_default:\r\n",
      "  1: !!python/object/new:tinydb.database.Element\r\n",
      "    dictitems: {age: 38, name: Homer}\r\n",
      "    state: {eid: 1}\r\n",
      "  2: {age: 34, name: Marge}\r\n"
     ]
    }
   ],
   "source": [
    "%cat db.yaml"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.4.3+"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 0
}

The documentation in TinyDB has been updated to fix this issue. https://github.com/msiemens/tinydb/blob/master/docs/extend.rst