WordPress wp-admin download db backup

wp_export_db.php

<?php
/**
 * Checks that the filename has correct extensions
 */
function validate_export( $filename ){
	$ext = explode(".", $filename);
	if( $ext[1] && $ext[1] != "sql" ){
		return false;
	}
	if( $ext[2] && $ext[2] != "gz" ){
		return false;
	}
	return true;
}

/**
 * Create a backup of the db using wp-cli
 * then delete the backup whether the user aborts or not
 * Requires wp-cli
 */
function wpcli_export() {
	if( isset($_POST["filename"]) && validate_export($_POST["filename"]) ) {
		$file = ABSPATH . $_POST["filename"];
		$out = shell_exec("wp --quiet --allow-root db export - | gzip > ". $file);
		header('Content-Disposition: attachment; filename='.basename($file));
		header('Content-Length: ' . filesize($file));
		header('Content-Type: application/octet-stream');
		header("Content-Transfer-Encoding: Binary");
		readfile($file);
		ignore_user_abort(true);
		// explicitly delete the file for both conditions
		if (connection_aborted()) {
			unlink($file);
		}else {
			unlink($file);
		}
	}else{
		echo "<script>alert('Wrong filetype chosen for database export.');history.back();</script>";
	}
	exit();
}

/**
 * Register custom menu pages
 */
function exportdb_menu_page() {
	add_menu_page( 
		__( 'Export DB', 'textdomain' ),
		'Export DB',
		'manage_options',
		'export_db',
		'exportdb_page',
		'dashicons-database-export',
		6
	);
	// set domain to null to hide from admin menu
	add_submenu_page(
		null,
		'Export Now',
		'Export Now',
		'manage_options',
		'export-now',
		'wpcli_export'
	);
	// use the first example from here to get the string to put after "load-"
	// https://developer.wordpress.org/reference/hooks/load-page-php/#user-contributed-notes
	add_action("load-admin_page_export-now", 'wpcli_export', 10, 1);
}
add_action( 'admin_menu', 'exportdb_menu_page' );

/**
 * Export DB menu render callback
 */
function exportdb_page() { ?>
	<style>
		.hide-me {
			display: none;
		}
		p {
			font-size: 16px;
			line-height: 1em;
			margin: .5em 0;
		}
		form {
			margin-top: 2em;
		}
		input {
			width: 130px;
		}
		.col {
			padding: 10px 0;
			display: flex;
			flex-direction: column;
		}
		/* Yoink: https://codepen.io/avstorm/pen/gofFm */
		.btn {
			width: 130px;
			position: relative;
			background: #000;
			border: 0;
			padding: 14px 42px;
			border-radius: 3px;
			cursor: pointer;
			overflow: hidden;
			outline: none;
			font-weight: 400;
			color: #fff;
			letter-spacing: 0.2em;
			box-shadow: 0 8px 32px rgba(0,0,0,0.2);
			transition: all 0.2s ease;
		}
		.btn:after {
			content: '';
			position: absolute;
			top: 0;
			left: -200%;
			width: 200%;
			height: 100%;
			transform: skewX(-20deg);
			background-image: linear-gradient(to right, transparent, rgba(255,255,255,0.3), transparent);
		}
		.btn:hover:after {
			animation: shine 1.6s ease;
		}
		.btn:active {
			transform: translateY(1px);
			box-shadow: 0 4px 16px rgba(0,0,0,0.2);
		}

		@-moz-keyframes shine {
			100% {
				left: 200%;
			}
		}
		@-webkit-keyframes shine {
			100% {
				left: 200%;
			}
		}
		@-o-keyframes shine {
			100% {
				left: 200%;
			}
		}
		@keyframes shine {
			100% {
				left: 200%;
			}
		}
	</style>
	<h1>Export DB</h1>
	<p>This will export a backup of the database with wp-cli, then compresses it using gzip.</p>
	<p>After clicking <em>Export Now</em>, you will be prompeted to dowload the newly created backup.</p>
	<p>This does not save a copy of the backup on the server.</p>
	<p><a href="https://wp-cli.org/" target="_blank">wp-cli</a> is required on the server hosting this website.</p>
	<form id="export-form" action="/wp-admin/admin.php?page=export-now" method="post">
		<div class="col">
			<p><em>.sql.gz</em> file extension is <strong>required</strong>.</p>
			<div class="col">
				<label for="filename">Save file name:</label>
				<input id="fname" type="text" name="filename" value="backup.sql.gz" />
			</div>
		</div>
		<div class="col">
			<button id="sbmt" class="btn">Export</button>
		</div>
	</form>
	<p id="err" class="hide-me" style="color:red;">Must be .sql.gz file</p>
	<script>
		const err = document.getElementById("err");
		const sbmit = document.getElementById("submit");
		sbmit.addEventListener("click", function() {
			err.classList.add("hide-me");
		});

		const export_form = document.getElementById("export-form");
		const btn = document.getElementById("sbmt");
		btn.addEventListener("click", function(){
			export_form.submit();
		});
		function validation(event) {
			const fname = document.getElementById("fname").value.split('.');
			if(fname[1] != "sql") {
				err.classList.remove("hide-me");
				event.preventDefault();
			}
			if(fname[2] != "gz") {
				err.classList.remove("hide-me");
				event.preventDefault();
			}
			return true;
		}
		export_form.addEventListener("submit", validation);
	</script>
<?php }