Message template

The HTML form of the message is formatted using the standard HTML-email templates [1]. The content is provided by two viewlet managers [2]: one for the pre-roll and one for the main html message.

┌─HTML message─────────────────────────────────────────┐
│                                                      │
│  ┌─Pre-roll viewlet manager────────────────────────┐ │
│  │ gs.group.list.email.html.interfaces.IPreroll    │ │
│  └─────────────────────────────────────────────────┘ │
│                                                      │
│ ┌─HTML message viewlet manager─────────────────────┐ │
│ │ gs.group.list.email.html.interfaces.IHTMLMessage │ │
│ │                                                  │ │
│ │ ┌─Prologue viewlet─────────────────────────────┐ │ │
│ │ │ gs-group-list-email-html-prologue            │ │ │
│ │ └──────────────────────────────────────────────┘ │ │
│ │                                                  │ │
│ │ ┌─Body viewlet─────────────────────────────────┐ │ │
│ │ │ gs-group-list-email-html-body                │ │ │
│ │ └──────────────────────────────────────────────┘ │ │
│ │                                                  │ │
│ │ ┌─Files viewlet────────────────────────────────┐ │ │
│ │ │ gs-group-list-email-html-files               │ │ │
│ │ └──────────────────────────────────────────────┘ │ │
│ │                                                  │ │
│ └──────────────────────────────────────────────────┘ │
│                                                      │
│ ┌─Links viewlet────────────────────────────────────┐ │
│ │ gs-group-list-email-html-links                   │ │
│ └──────────────────────────────────────────────────┘ │
│                                                      │
└──────────────────────────────────────────────────────┘

Pre-roll

The pre-roll part of an HTML message is unformatted hidden text that is slotted before the rest of the message. It is picked up by email clients that use it for a summary (or preview) of the message: think of it like a second subject-line.

The viewlet manager groupserver.EmailHTMLPreroll (gs.group.list.email.html.interfaces.IPreroll) is normally filled by the File notice viewlets.

The File notice viewlets state that there is one or more files listed in the files viewlet:

• One (gs-group-list-email-html-preroll-file) provides a short notice that there is a file listed in the appendix of a message,
• The other (gs-group-list-email-html-preroll-files) provides a short notice that there are multiple files listed in the appendix of a message.

There is also a summary provided when there are no files present (gs-group-list-email-html-preroll-nofile). It just spells out the origin of the message (the site and group names).

HTML message

The HTML message viewlet manager groupserver.EmailHTML (gs.group.list.email.html.interfaces.IHTMLMessage) provides the bulk of what people see in the message. There are three viewlets shipped by default: a prologue, the body proper, and the files.

Prologue

The prologue of a message appears at the top of the message body, before the body proper. The prologue contains the metadata for the post:

• Who made the post (name and photo),
• The group the post was made to, and
• The topic the group was made to.

It also provides many links to the profile, group, and topic respectively.

Body

The Plan body (gs-group-list-email-html-body-plain) viewlet writes out the body of the post much as it was when it was sent in. It is currently the text version of the message, with newlines replaced with <br /> elements. Like the post on the web, bottom-quoting is removed (replaced with a link to the post).

Files

Files are large burden for a list, as they dramatically increase the size of the message for little gain. Because of this the attached files are replaced with links to the files on the Web. The Files list viewlet (gs-group-list-email-html-files) provides this list.

Links

The Links (gs-group-list-email-html-links) are a group of HTTP and mailto links to perform some common functions. The first three links are rendered as buttons, while the last two are rendered as normal links.

Reply:

The Reply link provides a mailto URI to send an email to the group with a nice tidy Subject header. The link is mostly there to stop the New topic link from being confusing: without the Reply it looks as if you can only start topics. The link is only shown if the reply-to setting for a group is group (the default).

New topic:

Most people are happy replying to a group using the Reply button in their email client. However, many are unaware that they can start topics. To combat this the New topic link provides a mailto URI to email the group. (Unusually for a GroupServer mailto URI the Subject is blank.) The New topic link is hidden if the reply-to setting for a group is author.

Topic:

The Topic link is an HTTP-link to the topic page, just like the topic-title in the Prologue.

Unsubscribe:

As required by legislation, the Unsubscribe link removes a person from a group. The link contains a mailto URI that sends a message to the group, with the the Subject header set to Unsubscribe. A mailto URI is used — rather than sending the person to the Leave page — so passwords do not have to be used.

The Unsubscribe email command is processed by gs.group.member.leave.command

Daily digest:

A handy link copied from our friends at E-Democracy.org, the Digest a mailto URI that points to the group with the Subject header set to Digest on.

The Digest on command is processed by gs.group.member.email.settings.

[1]	See the gs.content.email.layout product <https://github.com/groupserver/gs.content.email.layout>

[2]	See the zope.viewlet product <https://pypi.python.org/pypi/zope.viewlet/>