Initial commit of mailTemplate()

For using PHP files as email templates, including the headers

1 files changed, 137 insertions, 0 deletions

diff --git a/mailTemplate.php b/mailTemplate.php
new file mode 100644
index 0000000..2481f5e
--- /dev/null
+++ b/mailTemplate.php
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+<?php
+/*
+ * mailTemplate is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ *
+ * mailTemplate is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * mailTemplate. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Send an email using a PHP template file.
+ *
+ * This function causes the PHP engine to parse the PHP file specified by #_filename, which should output an
+ * [RFC-822](https://tools.ietf.org/html/rfc822) (and its
+ * [successors](https://en.wikipedia.org/wiki/Email#Message_format)) style message.
+ * The function then extracts the headers from the message, grabs the "To" and "Subject" lines from it, and then passes
+ * the "To:", "Subject:", message body, and remaining headers, to the php
+ * [mail()](https://secure.php.net/manual/en/function.mail.php) function.
+ *
+ * As an example, consider template file "thanks.php"
+ *
+ *    To: <<?= $email ?>>
+ *    Subject: Thank you for your request
+ *    Content-Type: text/plain; charset=utf-8
+ *
+ *    Dear <?= $name =>,
+ *
+ *    Thankyou for your request, one of our staff will contact you <?= $when =>.
+ *    <?php if ($important) { ?>
+ *
+ *    Your request is important to us.
+ *    <?php } ?>
+ *    
+ * Which could then be called with:
+ *
+ *    mailTemplate("thanks.php", [
+ *            'email' => "dave@example.com",
+ *            'name' => "Dave",
+ *            'when' => "tomorrow",
+ *            'important' => FALSE,
+ *        ]};
+ *
+ * Note that, as of this implementation, #_filename is read using
+ * [include](https://secure.php.net/manual/en/function.include.php), so it uses the file-finding rules defined therein.
+ * 
+ * Also, it is worth remembering that PHP eats newlines directly following a PHP close tag. Therefore, if you have:
+ *
+ *    To: <?= $recipient ?>
+ *    Subject: ...
+ *
+ * Then the newline following the close tag will be eaten by the PHP parser, and you'll end up with:
+ *
+ *    To: example@example.comSubject: ...
+ *
+ * To work around this, you need to either make the closing tag not the last thing on the line (e.g. by adding a
+ * trailing space to the line), or forcibly output a newline yourself from within the PHP, e.g.:
+ *
+ *    To: <?= $recipient."\n" ?>
+ *    Subject: ...
+ *
+ * @param string $_filename Filename of PHP template file to send.
+ * @param mixed $v Associated array of variables to be made available to the mail template.
+ *
+ * @return bool TRUE on success, FALSE on failure.
+ */
+function mailTemplate($_filename, $v)
+{
+	ob_start();
+	extract($v, EXTR_OVERWRITE);
+	if (!include($_filename)) {
+		/* Don't need to raise a warning here, include will do that for us. */
+		ob_end_clean();
+		return FALSE;
+	}
+	$email = explode("\n", ob_get_clean());
+
+	$to = "";
+	$subject = "";
+	$headers = [];
+	for ($i = 0; $i < count($email); ++$i) {
+		$line = rtrim($email[$i], "\r");
+		if ($line == "") {
+			++$i;
+			break;
+		}
+		$matches = [];
+		if (preg_match("/^([^:]+): (.*)/", $line, $matches) != 1) {
+			error_log("mailTemplate: " . $_filename . ":" . $i . ": Invalid header: ". $line);
+			return FALSE;
+		}
+		if ($matches[1] == "To") {
+			$to = $matches[2];
+		}
+		else if ($matches[1] == "Subject") {
+			$subject = $matches[2];
+		}
+		else {
+			$headers[] = $line;
+		}
+	}
+
+	$missing = [];
+	if ($to == "")
+		$missing[] = "To:";
+	if ($subject == "")
+		$missing[] = "Subject:";
+	if (count($missing)) {
+		error_log("mailTemplate: " . $_filename . ":" . $i . ": Missing header(s): " . implode(", ", $missing));
+		return FALSE;
+	}
+	if ($i >= count($email)) {
+		error_log("mailTemplate: " . $_filename . ":" . $i . ": Missing email body");
+		return FALSE;
+	}
+
+	if (isset($GLOBALS['_DEBUG']) && $GLOBALS['_DEBUG']) {
+		echo "To: {$to}\r\n";
+		echo "Subject: {$subject}\r\n";
+		if (count($headers)) {
+			echo implode("\r\n", $headers)."\r\n";
+		}
+		echo "\r\n";
+		echo implode("\n", array_slice($email, $i));
+		return TRUE;
+	}
+
+	return mail($to, $subject, implode("\n", array_slice($email, $i)), implode("\r\n", $headers));
+}
+
+?>