MindTouch Community Portal
Logged in: Logged in as: Log in
Register
Search:
Page last modified 12:42, 6 Nov 2008 by arnec
User:arnec > Junk > Dream Message Bus > EventSubscriber
Page Notifications Off

EventSubscriber

    Default Implementation

    Assembly: mindtouch.dream
    Class:MindTouch.Dream.PubSubService
    SID: sid://services.mindtouch.com/dream/s...2008/10/pubsub

    Xmpp Implementation

    Assembly: mindtouch.dream.bus.xmpp
    Class:MindTouch.Dream.Bus.Xmpp.MessageBusSubscriberService
    SID: sid://services.mindtouch.com/dream/s...008/10/subxmpp

    Overview

    The EventSubscriber accepts subscription sets from subscribers and filters and propagates messages it receives accordingly. In general, the location of an EventPublisher will be provided by the environment to each service via the <uri.subservice> configuration value. The URI provided in the configuration value is rooted at {service}/subscribe, so that subscription calls are done against the provided URI, without the postfix.

    Verb:Suffix Description
    POST:subscribe Initialize subscriptions from a subscription set
    GET:subscribe Retrieve the combined subscription set
    GET:subscribe/{subscription-location} Retrieve present subscription set
    PUT:subscribe/{subscription-location} Replaces an existing subscription set
    DELETE:subscribe/{subscription-location} Delete an existing subscription set at the location
    POST:register Allow an upstream subscriber to register itself to listen to subscriptions
    DELETE:register Remove a registration

     

    Data Types

    Subscription Set 

    <subscription-set max-failures="...">
    <!-- the uri of the service registering the subscription set -->
    <uri.owner>...</uri.owner>

    <!-- the set can have 1 or more subscription blocks. @id will be assigned by
        the server if none was provided -->
    <subscription id="...">

        <!-- each subscription can include 1 or more channels. Channels are OR-ed
            for matching events -->
        <channel>channel:///some/channel</channel>
        ...

        <!-- There can be zero or one filter elements. Filters are opaque to the subscriber
            and represent a contract between the publication and subscription endpoints.
            Filter contracts must be rooted by a single elements, since the subscriber
            will combine many filter sets to push the subscriptions upstream, so elements
            may become intermingled. -->
        <filter>
            ...
        </filter>

        <!-- There can be zero or one proxy. If it exists it is used as the
            destination for matched events -->
        <uri.proxy>...</uri.proxy>

        <!-- There can be 1 or more recipients. If there is more than one recipient
            a proxy must be defined. If the event has recipients, the intersection
            between event and subscription recipients is used to filter matches. 
            @auth-token is used upstream to qualify recipients for an event -->
        <uri.recipient auth-token="...">...</uri.recipient>
        ... 

    </subscription>
    ...
</subscription-set>

    Channels

    Channels are URIs. There generalized format is:

    {system}://{instance}/{action-path}

    In subscription sets, channels accept wild cards at the instance or end of action. The following are all valid channel patterns:

    channel://*/some/exact/path
deki://some-instance/wildcard/path/*
channel://*/*

    Features

    POST:subscribe

    Register a subscription set with the EventSubscriber which is used to filter and dispatch incoming events. Matching events are dispatched to the the uri.recipient or uri.proxy in the event format specified for EventPublisher. If the EventSubscriber is one in a chain of pub/sub services, it builds a combined subscription set from all subscriptions for all recipients it handles and posts it to the upstream publisher as its subscription set.

    Access: Public
    Request body

    Xml document following the subscription set specified above.

    Response
    Status Response Body Description
    Created (201) -- operation completed successfully. Response contains Location header
    Conflict (409) -- A set for that owner already exists. Response contains a Content-Location header for the location of the conflicting subscription set
    Version History

     

    GET:subscribe

    Retrieve the combined subscription set that the EventSubscriber pushes to an upstream subscriber

    Access: Internal
    Response
    Status Response Body Description
    OK (200) text/xml operation completed successfully

     

    GET:subscribe/{location}

    Retrieve a subscription set, along with each subscriptions statistics

    Access: Internal
    Response
    Status Response Body Description
    OK (200) text/xml operation completed successfully

     

    PUT:subscribe/{location}

    Replace an existing subscription set

    Access: Internal
    Response
    Status Response Body Description
    OK (200) -- operation completed successfully

     

    DELETE:subscribe/{location}

    Remove an existing subscription set

    Access: Internal
    Response
    Status Response Body Description
    OK (200) -- operation completed successfully

     

    Tag page
    What links here

    Files 0

    Attach file or image
     
    You must login to post a comment.
    MindTouch Social Knowledge Base

    Copyright © 2011 MindTouch, Inc. Powered by