wiki:BluePrint/Messaging

Version 72 (modified by Fran Boon, 14 years ago) ( diff )

LCR

Table of Contents

    1. Core Architecture
    2. Message Flows
      1. How do we achieve this?
    3. User Interface
    4. Email
      1. Rich Text
    5. SMS
    6. Twitter
    7. XMPP
    8. Alternate implementations

Blueprint for the Messaging Module

What we need is:

Core Architecture

Instead of having several "apps" that cross-talk, such as sms, email, tweet, jabber, etc, it would be good to have a central messaging core that has 'connectors'. This would be the equivalent of a star-hub structure.

This way, additional 'connectors' could be added or used as needed without refactoring the entire code base, and would allow sending messages from one connector to another, such as sms to email or email to jabber.

Need to have per-user inboxes (e.g. to support workflow)

Message Flows

  • When a message is picked up by the handler, it decides whether it's an XForm or not.
  • If it is, then it is routed direct to the relevant resource.
  • If not then it is added to the Master Message Log (msg_log)
  • When new messages arrive in the Master Message Log, then the Parser looks for keywords & tries to Route automatically - either to a resource or to a pe_pentity (NB 'routing' to a resource is actually just 'tagging').
  • Users can view the Master Message Log via the 'Ticketing Module' UI & do manual Routing - either to a resource or a pe_pentity.
  • Users can Subscribe to Resources in order to receive copies of all messages which are routed to a resource.
    • This is done by pressing the 'Subscribe' button on the page for that Resource.
      • Button becomes 'Unsubscribe' if user already subscribed.
  • When a user visits a Resource via it's Web UI, then the RESTController scans the msg_log & provides access to associated messages in the views (display/update views have a list of associated messages in a table below the main record. list views have an extra column showing the number of messages tagged to this resource & number unread by this user (unread(read)) which is hyperlinked to a view which displays these records.
  • XML exports (such as RSS feeds) include tagged messages as linked resources:
    • S3ResourceController has a hook for a function that retrieves all message URLs for a resource: s3xrc = s3xrc.S3ResourceController(..., messaging=<function>)
    • This function takes the the resource name (=full tablename incl. prefix) and the record ID as arguments, and returns a list of URLs to messages for this resource and user, where each list item is (url, timestamp), with timestamp refering to the message timestamp
    • The XML exporter inserts one element <message url="..." unread="True/False"/> per message and resource element as child of the <resource> tag
    • This can be used for any feeds that are produced of the XML exporter
    • Requires: make RSS feeds a XML export template (which it is not up to now)

Message Flows

How do we achieve this?

  • Table msg_log is used as a replacement for the current msg_inbox, msg_outbox & ticket_log.
    • Fields: sender, subject, body, verified, actionable, assignee (multiple?), actioned, priority
      • Q: Do we move some of these 'ticketing' fields to a separate, linked ticket_msg table?
  • Table msg_tag is used to tag messages for resources.
    • Fields: message_id, resource, record (uid)
      • Q: How to display this nicely?
        • A: Give the message a tab with all distribution resources (db.tables). Once a table is selected, a second selector with all UUIDs (represented, of course) in that table appears, so you can choose the target. Use s3xrc.model.configure to add a name_nice for each table.
  • Table pe_subscription is used to maintain subscriptions for a pe_pentity.
  • Table msg_delivery_status is used to store delivery statuses.
    • Fields: message_id, pe_contact_id, status
  • Table msg_read_status is used to show that a message has been read by a user.
    • Fields: message_id, auth_user_id ('read' is assumed)
    • Q: Do we mark as read if pe_contact_id status suggests person has received message? (Fran thinks not)
    • Good to have UI to 'Mark Unread'
  • Parser has hooks for modules to plug-into?
  • Q: Do we treat a pentity the same way as any other resource?
    • Just that when a message is routed to them, it not only tags but also creates an entry in msg_delivery_status, which is scanned by the Cron task for 'pending' messages to be sent out.
  • shn_rest_controller() is modified to check msg_log for messages tagged to the resource (list) or record (display/update)
    • Views modified as above
  • 'Ticketing Module' UI
    • default view is all un-actioned messages (assigned to this user & unassigned?)
    • If a message is routed to a resource/pentity, this results in a 'create' form popup with as many fields auto-populated as possible (subject into 'name' field & body into 'comments' field, if nowhere better)
      • Q: If a message is routed to a resource, does this automatically mark ticket as 'actioned'? Provide a popup to ask this?
  • Q: How do we handle Auth restrictions?

User Interface

The home page should be a common Inbox view which, by default, shows all new unread Items (the 'Ticketing Module').

Users/Groups should be able to subscribe to incoming messages of a certain type (Project / Location / Organisation) & have these messages forwarded via SMS / Email / Twitter / etc.

Ideally there should be the ability to launch a popup/ticker to notify of new items & a portlet which can be on a user's dashboard when they login.

The 'Send Message/Alert' screen should have a small box to enter the Plain-text message which is sent to all recipients (using all available SMS/Email addresses in the Group specified).

There should be a 2nd box to create a Rich-text message, with the option of adding attachments. This content just gets sent to those members of the group with an Email address specified.

We don't need the option of having Email or SMS groups - all groups are 'Both'.

If a user is added to a group we warn about any missing details, but still allow addition (the ref is by person.id so addresses can eb added/changed later anyway).

When sending we need to provide warning messages about users for whom details weren't available.

Email

tools.py has mail settings: 

mail=MailS3()
# These settings should be made configurable as part of the Messaging Module
mail.settings.server='mail:25'
mail.sender='sahana@sahanapy.org'

& a function: 

mail.send(to, subject='None', message='None')

Can use this to send emails with dynamic data inserted into templates (like HTML pages):

There is a Cron job to check the contents of the OutBox & send pending messages. On Success it moves the message to the 'Sent' table:

Rich Text

We'd like to be able to send HTML mails for rich-text support (including attachments) This requires the use of smtplib to send MIME-encoded files:

SMS

Need to be able to support both online gateways (such as Clickatell) & local hardware such as:

The SMS Daemon to handle Inbound messages is a separate Python script.

It can distinguish between simple messages (added to the Inbox of the Messaging Module) & those which are encoded in Binary XML (the output of XForms from the J2ME client).

Implementation details are here: ​http://wiki.sahanafoundation.org/doku.php/dev:pythonsms

Q: Do we use Cron to check Outbox & signal the daemon to send Pending messages? (as for email)

Would be good to add an LCR (Least-Cost Routing engine) for SMS deliveries (so that e.g. local messages routed via modem, but International via Gateway).

Toolkits we can base on:

Hardware compatibility databases:

Twitter

Adding support for sending out/receiving alerts via Twitter would be nice.

XMPP

Alternate implementations

BluePrints

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