From caccd81c3eb7954662d20cab10cc3afeeabca615 Mon Sep 17 00:00:00 2001
From: Christian Cleberg <hello@cleberg.net>
Date: Sat, 2 Dec 2023 11:23:08 -0600
Subject: initial commit

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+date = 2021-04-23
+title = "Roll Your Own Static Commenting System in PHP"
+description = "Learn how to skip the tedium of finding the proper commenting system by simply rolling your own in PHP."
+draft = false
++++
+
+## The Terrible-ness of Commenting Systems
+
+The current state of affairs regarding interactive comment systems is, well,
+terrible. It is especially awful if you're a privacy conscious person who does
+not generally load third-party scripts or frames on the websites you visit.
+
+Even further, many comment systems are charging exorbitant fees for something
+that should be standard.
+
+Of course, there are some really terrible options:
+
+-   Facebook Comments
+-   Discourse
+
+There are some options that are better but still use too many scripts, frames,
+or social integrations on your web page that could impact some users:
+
+-   Disqus
+-   Isso
+-   Remark42
+
+Lastly, I looked into a few unique ways of generating blog comments, such as
+using Twitter threads or GitHub issues to automatically post issues. However,
+these both rely on external third-party sites that I don't currently use.
+
+## Stay Static with Server-Side Comments
+
+The main issue for my personal use-case is that my blog is completely, 100%
+static. I use PHP on the back-end but website visitors only see HTML and a
+single CSS file. No external javascript and no embedded frames.
+
+So, how do we keep a site static and still allow users to interact with blog
+posts? The key actually pretty simple - I'm already using PHP, so why not rely
+on the classic HTML `<form>` and a PHP script to save the comments somewhere? As
+it turns out, this was a perfect solution for me.
+
+The second issue for my personal use-case is that I am trying to keep the
+contents of my website accessible over time, as described by @brandur, in his
+post entitled
+[Blog with Markdown + Git, and degrade gracefully through time](https://brandur.org/fragments/graceful-degradation-time)
+.
+
+This means I cannot rely on a database for comments, since I do not rely on a
+database for any other part of my websites.
+
+I blog in plain Markdown files, commit all articles to Git, and ensure that
+future readers will be able to see the source data long after I'm gone, or the
+website has gone offline. However, I still haven't committed any images served
+on my blog to Git, as I'm not entirely sold on Git LFS yet - for now, images can
+be found at [img.0x4b1d.org](https://img.0x4b1d.org).
+
+Saving my comments back to the Git repository ensures that another aspect of my
+site will degrade gracefully.
+
+## Create a Comment Form
+
+Okay, let's get started. The first step is to create an HTML form that users can
+see and utilize to submit comments. This is fairly easy and can be changed
+depending on your personal preferences.
+
+Take a look at the code block below for the form I currently use. Note that
+`<current-url>` is replaced automatically in PHP with the current post's URL, so
+that my PHP script used later will know which blog post the comment is related
+to.
+
+The form contains the following structure:
+
+1. `<form>` - This is the form and will determine which PHP script to send the
+   comment to.
+2. `<section hidden>` - This section is hidden from the user and is used to
+   ensure that we know which blog post sent the comment.
+3. `<section>` Display Name (Optional) - Used to accept a display name, if
+   entered.
+4. `<section>` Comment (Required) - Used to accept the user's full comment.
+   Markdown is allowed.
+5. `<button>` - A button to submit the form.
+
+```html
+<form action="/comment.php" method="POST">
+	<h3>Leave a Comment</h3>
+	<section hidden>
+		<label class="form-label" for="postURL">Post URL</label>
+		<input
+			class="form-control"
+			id="postURL"
+			name="postURL"
+			type="text"
+			value="<current-url>"
+		/>
+	</section>
+	<section>
+		<label class="form-label" for="userName">Display Name</label>
+		<input
+			class="form-control"
+			id="userName"
+			name="userName"
+			placeholder="John Doe"
+			type="text"
+		/>
+	</section>
+	<section>
+		<label class="form-label" for="userContent">Your Comment</label>
+		<textarea
+			class="form-control"
+			id="userContent"
+			name="userContent"
+			rows="3"
+			placeholder="# Feel free to use Markdown"
+			aria-describedby="commentHelp"
+			required
+		></textarea>
+		<div id="commentHelp" class="form-text">
+			Comments are saved as Markdown and cannot be edited or deleted.
+		</div>
+	</section>
+	<button type="submit">Submit</button>
+</form>
+```
+
+## Handle Comments via POST
+
+Now that we have a form and can submit comments, we need to create a PHP script
+so that the server can fetch the comment data and save it. Make sure your PHP
+script name matches the name you entered in the `action` field in your form.
+
+See the code block below for the contents of my `comment.php` script. We perform
+the following tasks in this script:
+
+1. Grab the POST data from the HTML form.
+2. Sanitize the comment data with `htmlentities`.
+3. Set the display name to `Anonymous` if it was left blank.
+4. Create a PHP object that combines all of this data.
+5. Check if our destination file `comments.json` exists.
+6. If so, convert the PHP object to JSON and save it to the file.
+7. If the `comments.json` file does not exist, the script will exit with an
+   error. You can alter this to ensure it creates the script, but my source code
+   includes the file by default, so it will always exist.
+8. Finally, send the user back to the `#comments` section of the blog post they
+   just read.
+
+```php
+// Get the content sent from the comment form
+$comment = htmlentities($_POST['userContent']);
+$post_url = $_POST['postURL'];
+
+// Set default values if blank
+if (isset($_POST['userName']) && trim($_POST['userName']) !== "") {
+    $username = $_POST['userName'];
+} else {
+    $username = 'Anonymous';
+}
+
+// Create an empty PHP object
+$user_object = new stdClass();
+
+// Add object content
+$user_object->timestamp = date('Y-m-d H:i:s');
+$user_object->username = $username;
+$user_object->comment = $comment;
+$user_object->post_url = $post_url;
+
+// Append JSON to file
+$file_name = 'comments.json';
+if (file_exists($file_name)) {
+    $source_data = file_get_contents($file_name);
+    $temp_array = json_decode($source_data);
+    array_push($temp_array, $user_object);
+    $json_data = json_encode($temp_array, JSON_PRETTY_PRINT);
+    file_put_contents($file_name, $json_data);
+} else {
+    die('Error: The "comments.json" file does not exist.');
+}
+
+// Send the user back
+header('Location: ' . $post_url . '#comments');
+```
+
+If you're using Apache, make sure the `www-data` user on your server has the
+correct permissions to your website directory or else it will not be able to
+write to `comments.json`.
+
+```sh
+chgrp -R www-data /path/to/website/
+chmod -R g+w comments.json
+```
+
+## Display User Comments
+
+Now that we can submit comments, and they are saved to the `comments.json` file,
+let's make sure we can show those comments in each blog post.
+
+The code block below shows the function I use to decode my `comments.json` file,
+check if the comments apply to the current post, and then display them.
+
+This piece of code should **really** be inside a function (or at least in an
+organized PHP workflow). Don't just copy-and-paste and expect it to work. You
+need to at least supply a `$query` variable depending on the page visited.
+
+```php
+$query = 'your-blog-post.html';
+
+// Load saved comments
+$comments_file = 'comments.json';
+$comments_raw = file_get_contents($comments_file);
+$comments = json_decode($comments_raw);
+$comment_section = '<section id="comments" class="comments"><h3>Comments</h3>';
+foreach ($comments as $comment) {
+    if ($comment->post_url == "https://example.com/post/" . $query) {
+        // Assign metadata to variables
+        $comment_timestamp = $comment->timestamp;
+        $comment_username = $comment->username;
+        $comment_content = $comment->comment;
+
+        // Parse the comment, in case it contains Markdown
+        $comment_md = Parsedown::instance()->text($comment_content);
+        $comment_html = new DOMDocument();
+        $comment_html->loadHTML($comment_md);
+        $comment_html_links = $comment_html->getElementsByTagName('a');
+        foreach ($comment_html_links as $comment_html_link) {
+            $comment_html_link->setAttribute('rel', 'noreferrer');
+            $comment_html_link->setAttribute('target', '_blank');
+        }
+        $comment_secured_html = $comment_html->saveHTML();
+
+        // Apply metadata to comments section
+        $comment_section .= '<div class="user-comment"><div class="row"><label>Timestamp:</label><p>' . $comment_timestamp . '</p></div><div class="row"><label>Name:</label><p>' . $comment_username . '</p></div><div class="row markdown"><label>Comment:</label><div class="comment-markdown">' . $comment_secured_html . '</div></div></div>';
+    }
+}
+
+echo $comment_section;
+```
+
+## Bonus: Create a 'Recent Comments' Page
+
+Finally, the last part of my current system is to create a Recent Comments page
+so that I can easily check-in on my blog and moderate any spam. As an
+alternative, you could use PHP's `mail()` function to email you for each blog
+comment.
+
+The code to do this is literally the same code as the previous section, I just
+make sure it is printed when someone visits `https://example.com/comments/`.
+
+## Possible Enhancements
+
+This comment system is by no means a fully-developed system. I have noted a few
+possible enhancements here that I may implement in the future:
+
+-   Create a secure moderator page with user authentication at
+    `https://blog.example.com/mod/`. This page could have the option to edit or
+    delete any comment found in `comments.json`.
+-   Create a temporary file, such as `pending_comments.json`, that will store
+    newly-submitted comments and won't display on blog posts until approved by a
+    moderator.
+-   Create a `/modlog/` page with a chronological log, showing which moderator
+    approved which comments and why certain comments were rejected.
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