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PY: Get Posts

Tutorial pulls a list of the posts from the blockchain with selected filter and tag then displays output.

Full, runnable src of Get Posts can be downloaded as part of the PY tutorials repository.

This tutorial will explain and show you how to access the Crea blockchain using the crea-python library to fetch list of posts filtered by a filter and tag

Intro

In Crea there are built-in filters popular, skyrockets, created, active, promoted etc. which helps us to get list of posts. get_discussions_by_popular(query), get_discussions_by_skyrockets(query), get_discussions_by_now(query), etc. functions are built-in in official library crea-python that we are going to use throughout all Python tutorials.

Steps

  1. App setup - Library install and import
  2. Filters list - List of filters to select from
  3. Query details - Form a query
  4. Print output - Print results in output

1. App setup

In this tutorial we use 3 packages, pick - helps us to select filter interactively. crea - crea-python library, interaction with Blockchain. pprint - print results in better format.

First we import all three library and initialize Crea class

    import pprint
    from pick import pick
    # initialize Crea class
    from crea import Crea

    s = Crea()

2. Filters list

Next we will make list of filters and setup pick properly.

    title = 'Please choose filter: '
    #filters list
    options = ['popular', 'skyrockets', 'active', 'created', 'promoted']
    # get index and selected filter name
    option, index = pick(options, title)

This will show us list of filters to select in terminal/command prompt. And after selection we will get index and filter name to index and option variables.

3. Query details

Next we will form a query. In Crea,

query = {
    "limit":2, #number of posts
    "tag":"" #tag of posts
    }
#post list for selected query
posts = {0: s.get_discussions_by_popular(query),
         1: s.get_discussions_by_skyrockets(query),
         2: s.get_discussions_by_active(query),
         3: s.get_discussions_by_now(query),
         4: s.get_discussions_by_promoted(query)
}

Above code shows example of query and simple list of function that will fetch post list with user selected filter.

4. Print output

Next, we will print result, post list and selected filter name.

    # print post list for selected filter
    pprint.pprint(posts[index])
    pprint.pprint("Selected: "+option)

The example of result returned from the service is a JSON object with the following properties:

[
    {
        "id": 37338948,
        "author": "crearyblog",
        "permlink": "join-team-creary-at-tokenfest",
        "category": "creary",
        "parent_author": "",
        "parent_permlink": "creary",
        "title": "Join Team Creary at TokenFest!",
        "body":
            "<a href=\"https://tokenfest.adria.digital\"><img src=\"https://i.imgur.com/fOScDIW.png\"/></a>\n\nHello Crearians! If you’d like to meet Team Creary live-in-person, or are just interested in attending what promises to be a great blockchain conference, join us at <a href=\"https://tokenfest.adria.digital/\">TokenFest</a> in San Francisco from March 15th to 16th. \n\nCreary CEO, Ned Scott, will be participating in a fireside chat alongside Creary’s CTO, Harry Schmidt, as well as the creator of Utopian.io, Diego Pucci. Creary will also be hosting the opening party on Thursday night and we’d certainly love to meet as many of you as possible IRL, so head on over to https://tokenfest.adria.digital/ and get your tickets while you can. \n\n*Team Creary*",
        "json_metadata":
            "{\"tags\":[\"creary\",\"tokenfest\",\"conference\"],\"image\":[\"https://i.imgur.com/fOScDIW.png\"],\"links\":[\"https://tokenfest.adria.digital\",\"https://tokenfest.adria.digital/\"],\"app\":\"creary/0.1\",\"format\":\"markdown\"}",
        "last_update": "2018-03-07T23:22:54",
        "created": "2018-03-07T20:56:36",
        "active": "2018-03-13T01:40:21",
        "last_payout": "1970-01-01T00:00:00",
        "depth": 0,
        "children": 29,
        "net_rshares": "11453442114933",
        "abs_rshares": "11454054795840",
        "vote_rshares": "11454054795840",
        "children_abs_rshares": "13568695606090",
        "cashout_time": "2018-03-14T20:56:36",
        "max_cashout_time": "1969-12-31T23:59:59",
        "total_vote_weight": 3462435,
        "reward_weight": 10000,
        "total_payout_value": "0.000 CBD",
        "curator_payout_value": "0.000 CBD",
        "author_rewards": 0,
        "net_votes": 77,
        "root_comment": 37338948,
        "max_accepted_payout": "0.000 CBD",
        "percent_crea_dollars": 10000,
        "allow_replies": true,
        "allow_votes": true,
        "allow_curation_rewards": true,
        "beneficiaries": [],
        "url": "/creary/@crearyblog/join-team-creary-at-tokenfest",
        "root_title": "Join Team Creary at TokenFest!",
        "pending_payout_value": "46.436 CBD",
        "total_pending_payout_value": "0.000 CREA",
        "active_votes": [
            {
                "voter": "crearyblog",
                "weight": 0,
                "rshares": "1870813909383",
                "percent": 10000,
                "reputation": "128210130644387",
                "time": "2018-03-07T20:56:36"
            },
            {
                "voter": "kevinwong",
                "weight": 526653,
                "rshares": "2208942520687",
                "percent": 5000,
                "reputation": "374133832002581",
                "time": "2018-03-08T04:27:00"
            }
        ],
        "replies": [],
        "author_reputation": "128210130644387",
        "promoted": "0.000 CBD",
        "body_length": 754,
        "reblogged_by": []
    },
    {

    }
]
'Selected: skyrockets'

From this result you have access to everything associated to the posts including additional metadata which is a JSON string (that must be decoded to use), active_votes info, post title, body, etc. details that can be used in further development of application with Python.

That’s it!

To Run the tutorial

  1. review dev requirements
  2. clone this repo
  3. cd tutorials/04_get_posts
  4. pip install -r requirements.txt
  5. python index.py
  6. After a few moments, you should see output in terminal/command prompt screen.