README

Appends a text or HTML block (company signature, legal disclaimer, banner...) to every message sent from Roundcube webmail.

The block is loaded when the message is sent, from a file on the server or from an external URL. The URL can carry the sender's data, so a single intranet page can serve a personal signature to each user:

https://intranet.example.com/signature.html?id={username}

Features

• Added on send, server side: users cannot remove or edit it, and it does not appear in the compose screen nor in drafts.
• HTML or plain text source. The source is told the format of the message ({format} placeholder, Accept header) and may provide a version for each; otherwise the block is converted (HTML to text for plain text messages, text to HTML otherwise).
• Placeholders in the source path/URL and in the content itself: {username}, {email}, {local}, {domain}, {name}.
• Fallback sources: a list of sources tried in order, e.g. a file per user, then a default file.
• Cache of remote blocks per user, with a configurable lifetime.
• Before the history in replies and forwards: the block goes between the answer and the quoted (or forwarded) message.
• Read-only preview in the settings: users see the HTML and text versions of their block, for each identity, without seeing the source URL.
• Failure policy: send without the block, or refuse to send.

Requirements

• Roundcube 1.6 or later
• PHP 8.0 or later

Installation

composer require cymdeveloppement/roundcube-autosignature

Then copy and edit the configuration file:

cp plugins/roundcube_autosignature/config.inc.php.dist plugins/roundcube_autosignature/config.inc.php

Add the plugin to your Roundcube configuration:

$config['plugins'] = ['roundcube_autosignature'];

Configuration

All options are documented in config.inc.php.dist.

Placeholders

In URLs the values are URL-encoded. In file paths, / and \ are removed so a value cannot leave the configured folder. In HTML content they are HTML-escaped.

Examples

One signature per user, served by the intranet:

$config['autosignature_source'] = 'https://intranet.example.com/signature.html?id={username}';

One signature per user, in the format of each message (see Choosing the format):

$config['autosignature_source'] = 'https://intranet.example.com/signature.php?id={username}&format={format}';

One file per user, with an optional hand-written text version (yann@pcm-ensemblier.com.html, yann@pcm-ensemblier.com.text) and a common fallback:

$config['autosignature_source'] = [
    '/etc/roundcube/signatures/{email}.{format}',
    '/etc/roundcube/signatures/{email}.html',   // no .text file: converted
    '/etc/roundcube/signatures/default.html',
];

A per domain disclaimer, mandatory:

$config['autosignature_source'] = 'disclaimers/{domain}.txt';
$config['autosignature_on_error'] = 'block';

Position in replies and forwards

The history starts at the reply header added by Roundcube ("On ..., X wrote:"), at the first quoted block if the user removed that header, or at the "Original Message" header of a forwarded message.

With auto, the block goes before the history, except in replies when the user writes below the quote (Settings > Preferences > Composing Messages > "When replying: start new message below the quote", the Roundcube default): the answer then comes after the quote, so the block stays at the end.

Remote source: what the server must return

Request

Roundcube sends a plain GET request to the configured URL, with the placeholders replaced and URL-encoded:

GET /signature.php?id=yann%40pcm-ensemblier.com&format=html HTTP/1.1
Host: intranet.example.com
Accept: text/html                  <- text/plain for a plain text message
Authorization: Bearer xxxxx        <- only if set in autosignature_http_headers

The request comes from the Roundcube server, not from the user's browser: no cookie nor user session is sent. To restrict access, use a token in autosignature_http_headers or filter on the IP address of the Roundcube server.

Response

When the response counts as "no signature", the next source of the list is tried, then autosignature_on_error applies. For a user without signature, answering 404 is therefore the way to fall back on a default source.

Choosing the format

Messages are written either in HTML or in plain text, depending on the editor used. The plugin tells the server which one is being sent, in two ways:

• the {format} placeholder, if the URL contains it: html or text;
• the Accept header, always sent: text/html or text/plain (unless autosignature_http_headers sets its own Accept).

The server then chooses what to return, and says what it returned with the Content-Type of the response:

So a server has two options:

• Always return HTML and ignore the requested format: the simplest, the plugin builds the text version.
• Return the requested format, to control the text version (layout, links written in full...).

Both versions can be checked in the user's settings page, which requests each format separately. When autosignature_type is set to html or text, the Content-Type of the response is ignored.

Writing the HTML

The block is inserted in an email, not in a web page. Email clients (Outlook, Gmail...) only support a limited subset of HTML:

• Use inline styles (style="...") only: many email clients ignore <style> blocks and external stylesheets, and a <style> in the <head> of the response is dropped anyway.
• Use absolute https:// URLs for images, served publicly. Set width and height. Many clients block remote images until the reader allows them.
• Prefer simple tags (<p>, <br>, <b>, <a>, <img>, <table> for layout). No JavaScript, no forms.
• Keep it short: the block is added to every message and repeated in each quoted reply.

The content is inserted as is, without filtering: the server must be trusted. Values coming from users or a directory (names, titles) must be HTML-escaped by the server.

Placeholders in the response

With autosignature_replace_vars enabled (default), {name}, {email}, {username}, {local} and {domain} are also replaced in the response (HTML-escaped in HTML). The server may thus return the same template for everyone and let Roundcube fill in the sender. {email} and {name} are those of the identity chosen in the "From" field, which the server does not know unless they are passed in the URL.

Cache

A response is kept for autosignature_cache_ttl seconds for each user, URL and format, so a change on the server shows in sent messages after that delay at most. The cache of a user is refreshed as soon as they open their "Automatic signature" settings page. Error responses are never cached.

Example endpoint (PHP)

<?php
// signature.php?id={username}&format={format}
$users = [
    'yann@pcm-ensemblier.com' => ['name' => 'Yann Challet', 'title' => 'Developer', 'phone' => '+33 1 23 45 67 89'],
];

$user = $users[$_GET['id'] ?? ''] ?? null;
if (!$user) {
    http_response_code(404);   // no signature: next source, or on_error policy
    exit;
}

$e = fn($s) => htmlspecialchars($s, ENT_QUOTES, 'UTF-8');

// Requested format: the {format} parameter, else the Accept header
$format = $_GET['format'] ?? (str_contains($_SERVER['HTTP_ACCEPT'] ?? '', 'text/plain') ? 'text' : 'html');

if ($format == 'text') {
    header('Content-Type: text/plain; charset=UTF-8');
    echo "{$user['name']}\n{$user['title']}\nTel. {$user['phone']}\nhttps://www.example.com";
    exit;
}

header('Content-Type: text/html; charset=UTF-8');
echo '<table cellpadding="0" cellspacing="0" style="font-family: Arial, sans-serif; font-size: 13px; color: #333;">'
    . '<tr><td style="padding-right: 12px;"><img src="https://www.example.com/logo.png" width="80" height="80" alt="Logo"></td>'
    . '<td><b>' . $e($user['name']) . '</b><br>' . $e($user['title']) . '<br>'
    . '<a href="tel:' . $e($user['phone']) . '" style="color: #0a58ca;">' . $e($user['phone']) . '</a></td></tr>'
    . '</table>';

Settings page

A read-only "Automatic signature" page is added to the settings. It shows the HTML version (in a sandboxed frame) and the text version of the block, with an identity selector when the user has several. The source URL is never shown. Opening the page reloads the block from its source and refreshes the cache.

Notes

• New messages get the block at the very end. In HTML messages it is wrapped in <div id="autosignature">.
• The content of the source is trusted: it is inserted as is in the message. Only use sources you control.
• If the remote page returns a full HTML document, only the content of its <body> is kept.
• The signature of the Roundcube identity is not affected: both can be used together.

License

MIT, see LICENSE.