Intro API Lesson

intro_api.ipynb

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   "source": [
    "This lesson teaches you how to make requests to an API. We will use the [Requests](http://docs.python-requests.org/en/latest/) library to send requests to pyvideo.org.\n",
    "\n",
    "## Prerequisites\n",
    "\n",
    "* Be familiar with variables, lists, dictionaries, loops, and conditionals. You can learn these concepts\n",
    "  by working through [Learn Python The Hard Way](http://learnpythonthehardway.org/book/).\n",
    "* Install the [Requests](http://docs.python-requests.org/en/latest/) library."
   ]
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   "cell_type": "code",
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   "source": [
    "import requests"
   ]
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   "cell_type": "markdown",
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   "source": [
    "We will use the pyvideo.org api for this lesson because pyvideo.org does not require authorization for GET requests.\n",
    "\n",
    "The [PyCon APAC 2014](http://pyvideo.org/category/59/pycon-apac-2014) conference is listed on pyvideo.org for people to look at.\n",
    "To get information about the conference in a machine readable format, we will call the pyvideo.org `category` API.\n",
    "\n",
    "The URL to get category information about the conference is: http://pyvideo.org/api/v2/category/pycon-apac-2014\n",
    "\n",
    "## Learning Objective\n",
    "\n",
    "* Print a list of all the videos from the PyCon APAC 2014 conference"
   ]
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  {
   "cell_type": "code",
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   "source": [
    "response = requests.get(\"http://pyvideo.org/api/v2/category/pycon-apac-2014\")"
   ]
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   "cell_type": "markdown",
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   "source": [
    "Before using the response, we should test whether the request was successful. Responses have status\n",
    "codes, and 200 is a successful response.\n",
    "[List of successful status codes](https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#2xx_Success)\n",
    "                                  \n",
    "The Requests library provides the status code in a variable called `status_code` and a boolean, `ok` that is\n",
    "True if the response is success.\n",
    "\n",
    "We've saved the response to our request in a variable called `response`. You can use `response.ok` to test if the response was successful."
   ]
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     "text": [
      "The request is a success. Now we can look for the videos\n"
     ]
    }
   ],
   "source": [
    "# Check for a successful response.\n",
    "if response.ok:\n",
    "    print(\"The requested is a success. Now we can look for the videos\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The pyvideo API replies to our request with JSON. The Requests library provides a method to convert json data to a python dictionary. We will save the dictionary to a variable called `conference`"
   ]
  },
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   "source": [
    "conference = response.json()"
   ]
  },
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   "cell_type": "code",
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   "outputs": [
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     "text": [
      "dict_keys(['slug', 'title', 'description', 'whiteboard', 'videos', 'start_date', 'url', 'added'])\n"
     ]
    }
   ],
   "source": [
    "# Look at the keys of the dictionary. The 'videos' item has a list of all the videos for the conference.\n",
    "print(conference.keys())"
   ]
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       "40"
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     "execution_count": 6,
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   "source": [
    "# How many videos are in the conference?\n",
    "len(conference['videos'])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "'http://pyvideo.org/api/v2/video/3262'"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# What is the url for the first video?\n",
    "conference['videos'][0]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "As an example, we will make a request by hand to get information about the first video"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": true
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   "outputs": [],
   "source": [
    "video_response = requests.get('http://pyvideo.org/api/v2/video/3262')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
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   "source": [
    "video = video_response.json()"
   ]
  },
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   "metadata": {
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     "text": [
      "dict_keys(['video_flv_length', 'video_webm_length', 'source_url', 'recorded', 'id', 'video_webm_download_only', 'summary', 'video_mp4_download_only', 'title', 'video_ogv_length', 'whiteboard', 'video_mp4_length', 'copyright_text', 'updated', 'video_webm_url', 'state', 'tags', 'thumbnail_url', 'slug', 'video_flv_url', 'video_mp4_url', 'video_ogv_download_only', 'added', 'video_ogv_url', 'duration', 'embed', 'description', 'language', 'category', 'quality_notes', 'speakers', 'video_flv_download_only'])\n"
     ]
    }
   ],
   "source": [
    "# video is a dictionary based on the response from pyvideo.org.\n",
    "# What information has pyvideo.org returned?\n",
    "print(video.keys())"
   ]
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   "source": [
    "# 'title' is one of the keys in the response for a video.\n",
    "video['title']"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Earlier we made a request to http://pyvideo.org/api/v2/category/pycon-apac-2014 to get information about the PyCon APAC 2014 conference. The information from the response is saved in a variable called `conference`. This dictionary has a key called `videos` which has a list of all the videos.\n",
    "\n",
    "Using what you know about lists and loops, how would you print a list of all the video titles for PyCon APAC 2015?\n",
    "\n",
    "You will need to go through all the videos in the list, and send a request to the video api to get a response with the title of the video."
   ]
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