Crea Developer logo

Crea Developer Portal

JS: Get Post Details

By the end of this tutorial you would know how to get post details and use them appropriately.

Full, runnable src of Get Post Details can be downloaded as part of the JS tutorials repository.

The purpose of this tutorial is to a) demonstrate how to get a list of articles from the popular list on the blockchain, and b) fetch the contents of the selected post to display its title and body.

We will also explain the most commonly used fields from the response object as well as parse body of the post.

Intro

Accounts have unique permlink - permanent link for each of their posts. And Crea blockchain provides API to directly fetch current state of the post and its details. We will be using get_content to retrieve additional details. We can easily reformat data in a way that fits out application.

Steps

  1. Fetching posts Popular posts list
  2. Post content Extract content of the selected post
  3. Query result Returned data

1. Fetching posts

As mentioned in our previous tutorial we can fetch various lists of posts with different filters. Here, we are reusing some parts of that tutorial to list the top 5 popular posts.

var query = {
    tag: '', // This tag is used to filter the results by a specific post tag.
    limit: 5, // This allows us to limit the total to 5 items.
    truncate_body: 1, // This will truncate the body of each post to 1 character, which is useful if you want to work with lighter array.
};

2. Post content

On selection of a particular post from the list, openPost function is fired. This function will call the get_content function to fetch content of the post. get_content requires author and permlink of the post to fetch its data.

client.database.call('get_content', [author, permlink]).then(result => {
    const md = new Remarkable({ html: true, linkify: true });

    const body = md.render(result.body);

    const content = `<div class='pull-right'><button onclick=goback()>Close</button></div><br><h2>${
        result.title
    }</h2><br>${body}<br>`;

    document.getElementById('postList').style.display = 'none';
    document.getElementById('postBody').style.display = 'block';
    document.getElementById('postBody').innerHTML = content;
});

Crea allows any text-based format for the body, but apps often follow standard markdown with mix of few html tags. After we have fetched the content, we can use the remarkable library to parse the body of the post into a readable format. The title and body of the post are then displayed with a button at the top right corner to switch back to the post list.

document.getElementById('postList').style.display = 'block';
document.getElementById('postBody').style.display = 'none';

The “go back” function simply hides and shows the post list.

3. Query result

The result is returned from the post content as 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": []
}

From this result, you have access to everything associated with the selected post, including additional metadata which is a JSON string that must be decoded to use.

That’s it!

To Run the tutorial

  1. clone this repo
  2. cd tutorials/05_get_post_details
  3. npm i
  4. npm run dev-server or npm run start
  5. After a few moments, the server should be running at http://localhost:3000/