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RB: Get Post Details

Understand and use the most common fields of the requested content.

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

Intro

This tutorial fetches the contents of a single post and explains all data related to that post.

We will also describe the most commonly used fields from the response object.

Sections

  1. Making the api call - Use crea-rb to a specific post
    1. Example api call - make the call in code
    2. Example api call using script - using our tutorial script
    3. Example Output - output from a successful call
  2. Post Fields - General use of the method to determine …
    1. parent_author - if the content is a root post or reply
    2. last_update and created - if the content has been modified
    3. cashout_time - if the content has reached payout
    4. beneficiaries - reward routes other accounts
    5. active_votes - all votes applied
    6. json_metadata - things like tags and app
  3. Script - Delving into the example script.
  4. To Run - Running the example.

Making the api call

To request a specific post we use the get_content method:

api = Radiator::Api.new

api.get_content(author, permlink) do |content|
  # .
  # ... your code here
  # .
end

Example api call

If we want to get the post “announcing-the-crea-developer-portal” by user @crearydev

api.get_content("crearydev", "announcing-the-crea-developer-portal") do |content| ...

Example api call using script

And to do the same with our tutorial script

ruby get_post_details.rb https://creary.net/creadev/@crearydev/announcing-the-crea-developer-portal

Example Output

From the example we get the following output from our script

Post by crearydev
	title: Announcing the Crea Developer Portal!
	permlink: announcing-the-crea-developer-portal
	category: creadev
	body_length: 2342 (381 words)
	posted at: 2017-10-30T16:34:27, updated at: 2017-10-30T16:34:27, active at: 2018-04-11T10:34:00
	children: 66
	net_rshares: 0
	vote_rshares: 0
	payout:
		max_accepted_payout: 0.000 CBD
		percent_crea_dollars: 100.00 %
		payout at: 2017-11-06T16:34:27 (235.2 days ago)
		author_rewards: 0.000 CBD
		curator_payout_value: 0.000 CBD
		total_payout_value: 0.000 CBD
	promoted: 0.000 CBD
	total_vote_weight: 0
	reward_weight: 100.00 %
	net_votes: 181, upvotes: 234, downvotes: 1, unvotes: 0, total: 235, top voter: thejohalfiles
	allow_replies: true
	allow_votes: true
	allow_curation_rewards: true
	author_reputation: 14487360227924
	tags: creadev, crea, dev
	app: creary/0.1

Post fields

Most console applications that use the get_content method are probably looking for the body field. But there are many other fields to look at. Let’s break them down by use:

parent_author

In our script (get_post_details.rb), we use the ruby statement:

content.parent_author.empty?

With the above idiom, your application can determine if the content is a root post or reply. If it’s empty, then you’re working with a root post, otherwise, it’s a reply.

Once you know you’re dealing with a reply, other fields can be useful for additional details. For instance, root_author, root_permlink, and root_title can be used to figure out what the original post details are, even if the reply is deeply nested.

last_update and created

In our script, we use the ruby statement:

content.last_update == content.created

With the above idiom, your application can determine if the content has been modified since it was originally posted. If they are the same, then there has been no modification.

cashout_time

In our script, we use the ruby statement:

(cashout = Time.parse(content.cashout_time + 'Z') - Time.now.utc) > 0

With the above idiom, you can use cashout_time to determine if the content has reached payout. If cashout_time is in the future, the content has not been paid yet. You can determine the possible future payout by inspecting pending_payout_value.

You will note that we must parse the string found in content.cashout_time by appending Z (Zulu Time, aka UTC) in order for Time.parse to get the right timezone.

Even before payout, you can determine what the max_accepted_payout is. Most often, this is set to one of two values by the author:

In addition to max_accepted_payout, the author may specify how much of the author reward should be in CREA Power or liquid rewards. The most common settings are:

Once the payout time has arrived, it’s possible to determine the split between author and curation by inspecting at author_rewards and curator_payout_value.

beneficiaries

In our script, we use the ruby statement:

content.beneficiaries.any?

Some content will have a beneficiaries array. This is used to determine reward routes any account, up to eight. Payouts are in CREA Power and are expressed as a reward percentage of the author reward.

To display a list of who the beneficiaries are, use the following ruby code, as seen in the example:

content.beneficiaries.each do |beneficiary|
  puts "\t\t#{beneficiary.account}: #{'%.2f %' % (beneficiary.weight / 100.0)}"
end

Note, if you just want an array of beneficiary account names, this will work in a pinch:

accounts = content.beneficiaries.map do |beneficiary|
  beneficiary.account
end

active_votes

In our script, we use the ruby statements:

votes = content.active_votes
upvotes = votes.select { |v| v.percent > 0 }.size
downvotes = votes.select { |v| v.percent < 0 }.size
unvotes = votes.select { |v| v.percent == 0 }.size
top_voter = votes.sort_by { |v| v.rshares.to_i }.last.voter

The above idiom splits all vote types and identifies the top voter. This is because the active_votes field is an array that shows all votes applied to the content, including upvotes, downvotes, and unvotes (where a vote previously cast is revoked).

json_metadata

In our script, we use the ruby statements:

metadata = JSON[content.json_metadata || '{}'] rescue {}
tags = metadata['tags'] || []
app = metadata['app']

As you can see from the above example, json_metadata starts out as a string of JSON that can be parsed to determine things like tags and app. Other data may be present, depending on the application that created the content.

Note, we’re using rescue in case the json_metadata string contains invalid JSON because there is no validation performed on this field by the blockchain when content is broadcasted.

To Run

First, set up your workstation using the steps provided in Getting Started. Then you can create and execute the script (or clone from this repository):

*<content-url>

git clone git@github.com:creary/devportal-tutorials-rb.git
cd devportal-tutorials-rb/tutorials/05_get_post_details
bundle install
ruby get_post_details.rb <content-url>