Joaquim Domingos António

If you wish to ‘Create comments’ using REST API, without exposing Administrator credentials to the Front-End application, you are at the right place. Since WordPress 4.7, REST API was natively included in WordPress.
In order to ‘Create a comment’ , the authentication for a user with ‘Administrator’ role is required. While this is a deliberately done for security reasons, such implementation makes it very hard for Front-End applications to implement a simple ‘Post Comment’ or ‘Reply Comment’ function.
This plugin fulfils such requirement by extending the existing WordPress REST API endpoints.
Requirements:
Minimum PHP version: 7.0 
Minimum WordPress version: 5.5
Installation:
Download the plugin form wordpress marketplace install it like any other WordPress plugin. 
After the installation activate the plugin through the ‘Plugins’ menu in WordPress
Endpoint:
When this plugin is installed one new endpoint is added to the wp/v2 namespace.
 Endpoint 
 HTTP Verb 
 Permalinks
 */wp-json/wp/v2/comments/create 
 POST 
 enabled
 */?rest_route=/wp/v2/comments/create 
 POST 
 disabled
Usage:
<ol>
<li>Create a Comment</li>
</ol>
To create a comment using REST API, send a <code>POST</code> request to:
<blockquote>
<code>/wp-json/wp/v2/comments/create</code> – if permalinks is enabled on your wordpress website.
</blockquote>
Or
<blockquote>
<code>/?rest_route=/wp/v2/comments/create</code> if permalinks is not enabled on your wordpress website.
</blockquote>
With a JSON body, as shown bellow:
<pre><code>`Json
</code></pre>
{ 
 “post”: “Post ID”, 
 “author_name”: “Comment Author’s name”, 
 “author_email”: “Comment Author’s email”, 
 “content”: “Comment content” 
} 
 `
The content may also be send as an object:
<pre><code>`Json
</code></pre>
{ 
 “post”: “Post ID”, 
 “author_name”: “Comment Author’s name”, 
 “author_email”: “Comment Author’s email”, 
 “content”: { 
 “raw”:”Comment content” 
 } 
} 
 `
Set header to:
<pre><code>`
</code></pre>
content-type: application/json 
 ` 
If successful, you should receive a response with the data of the created comment:
<pre><code>`Json
</code></pre>
{ 
 “id”: “[comment id]”, 
 “status”: “[comment status]”, 
 “message”:”[server response message]” 
} 
 `
In response header the status code should be:
<pre><code>`Http
</code></pre>
HTTP 201 Created 
 `
<ol>
<li>Reply a comment</li>
</ol>
To reply a comment you just need to add the field parent for the parent comment to the JSON body
<pre><code>`Json
</code></pre>
{ 
 “post”: “Post ID”, 
 “author_name”: “Comment Author’s name”, 
 “author_email”: “Comment Author’s email”, 
 “content”: “Comment content”, 
 “parent”:”Comment parent ID” 
} 
 `
<blockquote>
Note: Ensure the parent is a comment id that belongs to the post informed in the field post. The comment parent post id must match the post id otherwise the following error will be shown:
</blockquote>
<pre><code>`Json
</code></pre>
{ 
 “code”: “rest_post_mismatch_parent_post_id”, 
 “message”: “Post ID and Parent post ID does not match”, 
 “data”: { 
 “status”: 400 
 } 
} 
 `
<h3>Contact</h3>
If there is any thing to say about the plugin fill free to <a href="mailto:sopport@appsdabanda.com" rel="nofollow ugc">contact us</a>.

REST API Comment

REST API Comment adds in the 'Comment creation' function to the Wordpress REST API.

Enrico Sorcinelli

JSON REST API and XML-RPC API are powerful ways to remotely interact with WordPress.
If you don’t have external applications that need to communicate with your WordPress instance using JSON REST API or XML-RPC API you should disable access to them for external requests.
In the standard WordPress installation JSON REST API and XML-RPC API are enabled by default. 
In particular the REST API is turned on also for unlogged users. This means that your WordPress instance is potentially leaking data, for example anyone could be able to:
<ul>
<li>copy easily your published contents natively with the REST API (and not with a web crawler);</li>
<li>get the list of all users (with their ID, nickname and name);</li>
<li>retrieve other information that you didn’t want to be public (such as an unlisted published page or a saved media not yet used).</li>
</ul>
Even if you could do the stuff by writing your own code using native filters, this plugin aims to help you to control JSON REST API and XML-RPC API accesses from the administration panel or programmatically by a simple API filter.
<h3>Basic Features</h3>
<ul>
<li>Disable REST API interface for unlogged users.</li>
<li>Disable JSONP support on REST API.</li>
<li>Add Basic Authentication to REST API.</li>
<li>Remove REST <code><link></code> tags, REST <code>Link</code> HTTP header and REST Really Simple Discovery (RSD) informations.</li>
<li>Setup trusted users, IP/Networks and endpoints for unlogged users REST requests.</li>
<li>Change REST endpoint prefix.</li>
<li>Disable XML-RPC API interface.</li>
<li>Remove <code><link></code> to the Really Simple Discovery (RDS) informations.</li>
<li>Remove <code>X-Pingback</code> HTTP header.</li>
<li>Setup trusted users, IP/Networks and methods for XML-RPC requests.</li>
<li>Show user’s access informations in users list administration screen.</li>
</ul>
<h3>Usage</h3>
Once the plugin is installed you can control settings in the following ways:
<ul>
<li>Using the Settings->REST XML-RPC Data Checker administration screen.</li>
<li>Programmatically, by using <code>rest_xmlrpc_data_checker_settings</code> filter (see below).</li>
</ul>
<h3>API</h3>
<h4>Hooks</h4>
<code>rest_xmlrpc_data_checker_settings</code>
Filters plugin settings values.
<pre><code>apply_filters( 'rest_xmlrpc_data_checker_settings', array $settings )
</code></pre>
<code>rest_xmlrpc_data_checker_admin_settings</code>
Filter allowing to display or not the plugin settings page in the administration.
<pre><code>apply_filters( 'rest_xmlrpc_data_checker_admin_settings', boolean $display )
</code></pre>
<code>rest_xmlrpc_data_checker_rest_error</code>
Filter JSON REST authentication error after plugin checks.
<pre><code>apply_filters( 'rest_xmlrpc_data_checker_rest_error', WP_Error|boolean $result )
</code></pre>
<code>xmlrpc_before_insert_post</code>
Filter XML-RPC post data to be inserted via XML-RPC before to insert post into database.
<pre><code>apply_filters( 'xmlrpc_before_insert_post', array|IXR_Error $content_struct, WP_User $user )
</code></pre>

REST XML-RPC Data Checker

REST XML-RPC Data Checker allow to check JSON REST and XML-RPC API requests and grant access permissions.

REST API Comment vs REST XML-RPC Data Checker