One document matched: draft-ietf-cdni-control-triggers-03.xml
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<rfc category="std" docName="draft-ietf-cdni-control-triggers-03"
ipr="trust200902">
<front>
<title abbrev="CDN Interconnect Triggers">CDNI Control Interface /
Triggers</title>
<author fullname="Rob Murray" initials="R" surname="Murray">
<organization>Velocix (Alcatel-Lucent)</organization>
<address>
<postal>
<street>3 Ely Road</street>
<city>Milton</city>
<region>Cambridge</region>
<code>CB24 6DD</code>
<country>UK</country>
</postal>
<email>rmurray@velocix.com</email>
</address>
</author>
<author fullname="Ben Niven-Jenkins" initials="B" surname="Niven-Jenkins">
<organization>Velocix (Alcatel-Lucent)</organization>
<address>
<postal>
<street>3 Ely Road</street>
<city>Milton</city>
<region>Cambridge</region>
<code>CB24 6DD</code>
<country>UK</country>
</postal>
<email>ben@velocix.com</email>
</address>
</author>
<date day="2" month="July" year="2014"/>
<abstract>
<t>This document describes the part of the CDN Interconnect Control
Interface that allows a CDN to trigger activity in an interconnected CDN
that is configured to deliver content on its behalf. The upstream CDN
can use this mechanism to request that the downstream CDN pre-positions
metadata or content, or that it re-validate or purge metadata or
content. The upstream CDN can monitor the status of activity that it has
triggered in the downstream CDN.</t>
</abstract>
<note title="Requirements Language">
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in <xref
target="RFC2119">RFC 2119</xref>.</t>
</note>
</front>
<middle>
<section title="Introduction">
<t><xref target="RFC6707"/> introduces the Problem scope for CDN
Interconnection (CDNI) and lists the four categories of interfaces that
may be used to compose a CDNI solution (Control, Metadata, Request
Routing, Logging).</t>
<t><xref target="I-D.ietf-cdni-framework"/> expands on the information
provided in <xref target="RFC6707"/> and describes each of the
interfaces and the relationships between them in more detail.</t>
<t>This document describes the "CI/T" interface, "CDNI Control interface
/ Triggers". It does not consider those parts of the control interface
that relate to configuration, bootstrapping or authentication of CDN
Interconnect interfaces. Requirements for CI/T are the "High" and
"Medium" priority requirements for the CI identified in section 4 of
<xref target="I-D.ietf-cdni-requirements"/>, reproduced here for
convenience:</t>
<t><list style="empty">
<t>CI-1 [HIGH] The CDNI Control interface shall allow the Upstream
CDN to request that the Downstream CDN, including downstream
cascaded CDNs, delete an object or set of objects and/or its CDNI
metadata from the CDN surrogates and any storage. Only the object(s)
and CDNI metadata that pertain to the requesting Upstream CDN are
allowed to be purged.</t>
<t>CI-2 [MED] The CDNI Control interface should allow for multiple
content items identified by a Content Collection ID to be purged
using a single Content Purge action.</t>
<t>CI-3 [MED] The CDNI Control interface should allow the Upstream
CDN to request that the Downstream CDN, including downstream
cascaded CDNs, mark an object or set of objects and/or its CDNI
metadata as "stale" and revalidate them before they are delivered
again.</t>
<t>CI-4 [HIGH] The CDNI Control interface shall allow the Downstream
CDN to report on the completion of these actions (by itself, and
including downstream cascaded CDNs, in a manner appropriate for the
action (e.g. synchronously or asynchronously). The confirmation
receipt should include a success or failure indication. The failure
indication along with the reason are used if the Downstream CDN
cannot delete the content in its storage.</t>
<t>CI-5 [MED] The CDNI Control interface should support initiation
and control by the Upstream CDN of pre-positioned CDNI metadata
acquisition by the Downstream CDN.</t>
<t>CI-6 [MED] The CDNI Control interface should support initiation
and control by the Upstream CDN of pre-positioned content
acquisition by the Downstream CDN.</t>
</list></t>
<t><list style="symbols">
<t><xref target="model-for-triggers"/> outlines the model for the
CI/T Interface at a high level.</t>
<t><xref target="collections-of-triggers"/> describes collections of
Trigger Resources.</t>
<t><xref target="trigger-interface"/> defines the web service
provided by the dCDN.</t>
<t><xref target="properties-of-triggers"/> lists properties of
Trigger Requests and Status Resources.</t>
<t><xref target="json-encoding"/> defines a JSON encoding for
Trigger Requests and Status Resources.</t>
<t><xref target="examples"/> contains example messages.</t>
</list></t>
<section anchor="terminology" title="Terminology">
<t>This document reuses the terminology defined in <xref
target="RFC6707"/>.</t>
</section>
</section>
<section anchor="model-for-triggers" title="Model for CDNI Triggers">
<t>A trigger, sent from the uCDN to the dCDN, is a request for dCDN to
do some work relating to data originating from the uCDN.</t>
<t>The trigger may request action on either metadata or content, the
following actions can be requested:</t>
<t><list style="symbols">
<t>preposition - used to instruct the dCDN to fetch metadata from
the uCDN, or content from any origin including the uCDN.</t>
<t>invalidate - used to instruct the dCDN to revalidate specific
metadata or content before re-using it.</t>
<t>purge - used to instruct the dCDN to delete specific metadata or
content.</t>
</list></t>
<t>The CI/T interface is a web service offered by the dCDN. It allows
creation and deletion of triggers, and tracking of the triggered
activity. When the dCDN accepts a trigger it creates a resource
describing status of the triggered activity, a Trigger Status Resource.
The uCDN MAY poll Trigger Status Resources to monitor progress.</t>
<t>Requests to invalidate and purge metadata or content apply to all
variants of that data with a given URI.</t>
<t>The dCDN maintains a collection of Trigger Status Resources for each
uCDN, each uCDN only has access to its own collection and the location
of that collection is shared when CDN interconnection is
established.</t>
<t>To trigger activity in the dCDN, the uCDN will POST to the collection
of Trigger Status Resources. If the dCDN accepts the trigger, it creates
a new Trigger Status Resource and returns its location to the uCDN. To
monitor progress, the uCDN MAY GET the Trigger Status Resource. To
cancel a trigger, or remove a trigger from the collection once its
activity has been completed, the uCDN MAY DELETE the Trigger Status
Resource.</t>
<t>In addition to the collection of all Trigger Status Resources for
uCDN, uCDN has access to filtered views of that collection. These
filtered views are defined in <xref target="collections-of-triggers"/>
and include collections of active and completed triggers. These
collections provide a mechanism for polling the status of multiple
jobs.</t>
<t><xref target="high-level-trigger-flow"/> is an example showing the
basic message flow used by the uCDN to trigger activity in dCDN, and for
uCDN to discover the status of that activity. Only successful triggering
is shown. Examples of the messages are given in <xref
target="examples"/>.</t>
<figure anchor="high-level-trigger-flow"
title="Basic CDNI Message Flow for Triggers">
<artwork><![CDATA[ uCDN dCDN
| (1) POST http://dcdn.example.com/triggers/uCDN |
[ ] --------------------------------------------------> [ ]--+
| [ ] | (2)
| (3) HTTP 201 Response [ ]<-+
[ ] <-------------------------------------------------- [ ]
| Loc: http://dcdn.example.com/triggers/uCDN/123 |
| |
. . .
. . .
. . .
| |
| (4) GET http://dcdn.example.com/triggers/uCDN/123 |
[ ] --------------------------------------------------> [ ]
| [ ]
| (5) HTTP 200 Trigger Status Resource [ ]
[ ] <-------------------------------------------------- [ ]
| |
| |
]]></artwork>
</figure>
<t>The steps in <xref target="high-level-trigger-flow"/> are:</t>
<t><list style="numbers">
<t>uCDN triggers action in the dCDN by posting to a collection of
Trigger Status Resources, "http://dcdn.example.com/triggers/uCDN".
The URL of this was given to the uCDN when the trigger interface was
established.</t>
<t>dCDN authenticates the request, validates the trigger and if it
accepts the request, creates a new Trigger Status Resource.</t>
<t>dCDN responds to the uCDN with an HTTP 201 response status, and
the location of the Trigger Status Resource.</t>
<t>uCDN may repeatedly poll the Trigger Status Resource in the
dCDN.</t>
<t>dCDN responds with the Trigger Status Resource, describing
progress or results of the triggered activity.</t>
</list></t>
<t>The remainder of this document describes the messages, Trigger Status
Resources, and collections of Trigger Status Resources in more
detail.</t>
<section title="Timing of Triggered Activity">
<t>Timing of triggered activity is under the dCDN's control, including
its start-time and pacing of the activity in the network.</t>
<t>Invalidate and purge triggers MUST be applied to all data acquired
before the trigger was created in the dCDN. The dCDN may apply the
triggers to data acquired after trigger creation.</t>
<t>If the uCDN wishes to invalidate or purge content, then immediately
pre-position replacement content at the same URLs, it SHOULD ensure
the dCDN has completed the invalidate/purge before initiating the
prepositioning. Otherwise, the dCDN may pre-position the new content
then immediately invalidate or purge it (as a result of the two uCDN
requests running in parallel).</t>
</section>
<section title="Trigger Results">
<t>Each Trigger Request may operate on multiple data items. The
trigger MUST NOT be reported as "complete" unless all actions can be
completed successfully, otherwise it MUST be reported as "failed" or
"processed". The reasons for failure and URLs or Patterns affected
SHOULD be enumerated in the Trigger Status Resource. For more detail,
see section <xref target="error-handling"/>.</t>
<t>If a dCDN is also acting as a uCDN in a cascade, it MUST forward
triggers to any downstream CDNs that may have data affected by the
trigger. The trigger MUST NOT be reported as complete in a CDN until
it is complete in all of its downstream CDNs. A trigger MAY be
reported as failed as soon as it fails in a CDN or in any of its
downstream CDNs.</t>
</section>
</section>
<section anchor="collections-of-triggers"
title="Collections of Trigger Status Resources">
<t>As described in <xref target="model-for-triggers"/>, Trigger Status
Resources exist in dCDN to report the status of activity triggered by
each uCDN.</t>
<t>A collection of Trigger Status Resources is a resource that contains
a reference to each Trigger Status Resource in that collection.</t>
<t>To trigger activity in the dCDN, the uCDN creates a new Trigger
Status Resource by posting to the dCDN's collection of uCDN's Trigger
Status Resources. The URL of each Trigger Status Resource is generated
by the dCDN when it accepts the trigger, and returned to the uCDN. This
immediately enables the uCDN to check the status of that trigger.</t>
<t>The dCDN MUST present a different set of Trigger Status Resources to
each interconnected uCDN. Trigger Status Resources belonging to a uCDN
MUST NOT be visible to any other client. The dCDN may, for example,
achieve this by offering different collection URLs to uCDNs, or by
filtering the response based on the client uCDN.</t>
<t>The dCDN resource representing the collection of all the uCDN's
Trigger Status Resources is accessible to the uCDN. This collection
lists all of the uCDN triggers that have been accepted by the dCDN, and
have not yet been deleted by the uCDN, or expired and removed by the
dCDN (as described in section <xref target="deleting-triggers"/>).</t>
<t>In order to allow the uCDN to check status of multiple jobs in a
single request, the dCDN SHOULD also maintain collections representing
filtered views of the collection of all Trigger Status Resources. The
filtered collections are:<list style="symbols">
<t>Pending - Trigger Status Resources for triggers that have been
accepted, but not yet acted upon.</t>
<t>Active - Trigger Status Resources for triggered activity that is
currently being processed in the dCDN.</t>
<t>Complete - Trigger Status Resources representing activity that
completed successfully, or for which no further status updates will
be made by the dCDN.</t>
<t>Failed - Trigger Status Resources representing activity that
failed.</t>
</list></t>
</section>
<section anchor="trigger-interface" title="CDNI Trigger interface">
<t>This section describes an interface to enable an upstream CDN to
trigger defined activities in a downstream CDN. The interface is
intended to be independent of the set of activities defined now, or that
may be defined in future.</t>
<t>CI/T is built on the principles of RESTful web services. Requests are
made over HTTP, and the HTTP Method defines the operation the request
would like to perform. The corresponding HTTP Response returns the
status of the operation in the HTTP Status Code and returns the current
representation of the resource (if appropriate) in the Response Body.
HTTP Responses from servers implementing CI/T that contain a response
body SHOULD include an ETag to enable validation of cached versions of
returned resources.</t>
<t>Servers implementing CI/T MUST support the HTTP GET, HEAD, POST and
DELETE methods as defined in <xref target="RFC7231"/>. The only
representation specified in this document is JSON, <xref
target="RFC7159"/>.</t>
<t>The URL of the dCDN's collections of Trigger Status Resources need to
be either discovered by, or configured in, the uCDN. The mechanism for
discovery of those URLs is outside the scope of this document.</t>
<t>Trigger Requests are POSTed to the dCDN's collection of all Trigger
Status Resources. If the trigger is accepted by the dCDN, it creates a
new Trigger Status Resource and returns its URI to the dCDN in an HTTP
201 response. The triggered activity can then be monitored by the uCDN
using that resource and the collections described in <xref
target="collections-of-triggers"/>.</t>
<t>The URI of each Trigger Status Resource is returned to the uCDN when
it is created. This means all Trigger Status Resources can be
discovered, so CI/T servers are free to assign whatever structure they
desire to the URIs for CI/T resources. CI/T clients MUST NOT make any
assumptions regarding the structure of CI/T URIs or the mapping between
CI/T objects and their associated URIs. Therefore any URIs present in
the examples below are purely illustrative and are not intended to
impose a definitive structure on CI/T interface implementations.</t>
<t>The CI/T interface builds on top of HTTP, so CI/T servers may make
use of any HTTP feature when implementing the CI/T interface. For
example, a CI/T server may make use of HTTP's caching mechanisms to
indicate that a requested response/representation has not been modified,
reducing the processing needed to determine whether the status of
triggered activity has changed.</t>
<t>This specification is neutral with regard to the transport below the
HTTP layer.</t>
<t>The dCDN MUST ensure that activity triggered by the uCDN only affects
metadata or content originating from that uCDN. Since only one CDN can
be authoritative for a given item of metadata or content, this
requirement means there cannot be any "loops" in trigger requests
between CDNs.</t>
<section title="Creating Triggers">
<t>To create a new trigger, the uCDN makes an HTTP POST to the
unfiltered collection of its triggers. The request body of that POST
is a Trigger Request.</t>
<t>The dCDN validates and authenticates that request, if it is
malformed or the uCDN does not have sufficient access rights it MAY
reject the request immediately. In this case, it MUST respond with an
appropriate 4xx HTTP error code and a resource MUST NOT be created on
dCDN.</t>
<t>If the request is accepted, the uCDN MUST create a new Trigger
Status Resource. The HTTP response to the dCDN MUST have status code
201 and the URI of the Trigger Status Resource in the Location header
field. The HTTP response SHOULD include the content of the newly
created Trigger Status Resource, this is recommended particularly in
cases where the trigger has completed immediately.</t>
<t>Once a Trigger Status Resource has been created the dCDN MUST NOT
re-use its location, even after that resource has been removed.</t>
<t>The "request" property of the Trigger Status Resource contains the
information posted in the body of the Trigger Request. Note that this
need not be a byte-for-byte copy. For example, in the JSON
representation the dCDN may re-serialise the information
differently.</t>
<t>If the dCDN is not able to track triggered activity, it MUST
indicate that indicate that it has accepted the request but will not
be providing further status updates. To do this, it sets the "status"
of the Trigger Status Resource to "processed". In this case, CI/T
processing should continue as for a "complete" request, so the Trigger
Status Resource MUST be added to the dCDN's collection of Complete
Triggers. The dCDN SHOULD also provide an estimated completion time
for the request, by using the "etime" property of the Trigger Status
Resource. This will allow the uCDN to schedule prepositioning after an
earlier delete of the same URLs is expected to have finished.</t>
<t>If the dCDN is able to track triggered activity, the trigger is
queued by the dCDN for later action, the "status" property of the
Trigger Status Resource MUST be "pending". Once trigger processing has
started the "status" MUST be "active". Finally, once the triggered
activity is complete, the trigger status MUST be set to "complete" or
"failed".</t>
<t>A trigger may result in no activity in the dCDN if, for example, it
is an invalidate or purge request for data the dCDN has not yet
acquired, or a prepopulate request for data it has already acquired
and which is still valid. In this case, the "status" of the Trigger
Status Resource MUST be "processed" or "complete", and the Trigger
Status Resource MUST be added to the dCDN's collection of Complete
Triggers.</t>
<t>Once created, Trigger Status Resources may be deleted by the uCDN
but not modified. The dCDN MUST reject PUT and POST requests from the
uCDN to Trigger Status Resources using HTTP status code 403.</t>
</section>
<section title="Checking Status">
<t>The uCDN has two ways to check progress of activity it has
triggered in the dCDN, described in the following sections.</t>
<t>To check for change in status of a resource or collection of
resources without re-fetching the whole resource or collection, Entity
Tags SHOULD be used by the uCDN as cache validators, as defined in
<xref target="RFC7232"/>.</t>
<t>The dCDN SHOULD use the cache control headers for responses to GETs
for Trigger Status Resources and Collections to indicate the frequency
at which it recommends uCDN should poll for change.</t>
<section title="Polling Trigger Status Resource collections">
<t>The uCDN can fetch the collection of its Trigger Status
Resources, or filtered views of that collection.</t>
<t>This makes it possible to poll status of all triggered activity
in a single request. If the dCDN moves a Trigger Status Resource
from the Active to the Completed collection, the uCDN may chose to
fetch the result of that activity.</t>
<t>When polling in this way, the uCDN SHOULD use HTTP Entity Tags to
monitor for change, rather than repeatedly fetching the whole
collection.</t>
</section>
<section title="Polling Trigger Status Resources">
<t>The uCDN has a reference (URI provided by the dCDN) for each
Trigger Status Resource it has created, it may fetch that resource
at any time.</t>
<t>This MAY be used to retrieve progress information, and to fetch
the result of triggered activity.</t>
</section>
</section>
<section anchor="deleting-triggers" title="Deleting Triggers">
<t>The uCDN MAY delete Trigger Status Resources at any time, using the
HTTP DELETE method.</t>
<t>Once deleted, the references to a Trigger Status Resource MUST be
removed from all Trigger Status Resource collections. Subsequent
requests for the resource MUST be handled as required by HTTP, and so
will receive responses with status 404 or 410.</t>
<t>If a "pending" Trigger Status Resource is deleted, the dCDN SHOULD
NOT start processing of that activity. Deleting a "pending" trigger
does not however guarantee that it is not started because the uCDN
cannot control the timing of that activity. Processing may, for
example, start after the DELETE is sent by the uCDN but before the
DELETE is processed by the dCDN.</t>
<t>If an "active" Trigger Status Resource is deleted, the dCDN MAY
stop processing the triggered activity. However, as with deletion of a
"pending" trigger, the dCDN does not guarantee this.</t>
<t>Deletion of a "complete", "processed" or "failed" Trigger Status
Resource requires no processing in the dCDN other than deletion of the
resource.</t>
</section>
<section title="Expiry of Trigger Status Resources">
<t>The dCDN MAY choose to automatically delete Trigger Status
Resources some time after they become "complete", "processed" or
"failed". In this case, the dCDN will remove the resource and respond
to subsequent requests for it with HTTP status 404 or 410.</t>
<t>If the dCDN performs this housekeeping, it MUST have reported the
length of time after which completed Trigger Status Resources become
stale via a property of the collection of all Trigger Status
Resources. It is recommended that Trigger Status Resources are not
automatically deleted for at least 24 hours after they become
"complete", "processed" or "failed".</t>
<t>To ensure it has access to the status of its completed and failed
triggers, it is recommended that the uCDN's polling interval is half
the time after which records for completed activity will be considered
stale.</t>
</section>
<section anchor="error-handling" title="Error Handling">
<t>A CI/T server may reject a trigger request using HTTP status codes.
For example, 400 if the request is malformed, or 401 if the client
does not have permission to create triggers or it is trying to act on
another CDN's data.</t>
<t>If any part of the trigger request fails, the trigger SHOULD be
reported as "failed" once its activity is complete or if no further
errors will be reported. The "errors" property in the Trigger Status
Resource will be used to enumerate which actions failed and the
reasons for failure, and may be present while the trigger is still
"pending" or "active", if the trigger is still running for some URLs
or Patterns in the trigger request.</t>
<t>Once a request has been accepted, processing errors are reported in
the Trigger Status Resource using a list of "ErrorDesc". Each
ErrorDesc is used to report errors against one or more of the URLs or
Patterns in the trigger request.</t>
<t>If a surrogate affected by a trigger is offline in the dCDN, or the
dCDN is unable to pass a trigger request on to any of its cascaded
dCDNs; the dCDN SHOULD report an error if the request is abandoned.
Otherwise, it SHOULD keep the trigger in state "pending" or "active"
until it's acted upon or the uCDN chooses to cancel it. Or, if the
request is queued and the dCDN will not report further status, the
dCDN MAY report the trigger as "processed", in which case it SHOULD
also provide an estimated completion time.</t>
<t>Note that an "invalidate" trigger may be reported as "complete"
when surrogates that may have the data are offline. In this case,
surrogates MUST NOT use the affected data without first revalidating
it when they are back online. This does not apply to "preposition" or
"purge" triggers.</t>
</section>
</section>
<section anchor="properties-of-triggers" title="Properties of Triggers">
<section title="Properties of Trigger Requests">
<t>Properties of Trigger Requests are defined in the following
subsections.</t>
<t><list style="empty">
<t>Property: type<list style="empty">
<t>Description: This property defines the type of the
trigger.</t>
<t>Type: TriggerType</t>
<t>Mandatory: Yes</t>
</list></t>
</list></t>
<t><list style="empty">
<t>Property: metadata.urls<list style="empty">
<t>Description: The uCDN URL for the metadata the trigger
applies to.</t>
<t>Type: URLs</t>
<t>Mandatory: No, but at least one of 'metadata.*' or
'content.*' MUST be present and non-empty.</t>
</list></t>
</list><list style="empty">
<t>Property: content.urls<list style="empty">
<t>Description: URLs of content data the trigger applies to,
see <xref target="content-urls"/>.</t>
<t>Type: URLs</t>
<t>Mandatory: No, but at least one of 'metadata.*' or
'content.*' MUST be present and non-empty.</t>
</list></t>
</list><list style="empty">
<t>Property: content.ccid<list style="empty">
<t>Description: The Content Collection IDentifier of data the
trigger applies to.</t>
<t>Type: List of strings</t>
<t>Mandatory: No, but at least one of 'metadata.*' or
'content.*' MUST be present and non-empty.</t>
</list></t>
</list><list style="empty">
<t>Property: metadata.patterns<list style="empty">
<t>Description: The metadata the trigger applies to.</t>
<t>Type: List of PatternMatch</t>
<t>Mandatory: No, but at least one of 'metadata.*' or
'content.*' MUST be present and non-empty, and
metadata.patterns MUST NOT be present if the TriggerType is
Preposition.</t>
</list></t>
</list><list style="empty">
<t>Property: content.patterns<list style="empty">
<t>Description: The content data the trigger applies to.</t>
<t>Type: List of PatternMatch</t>
<t>Mandatory: No, but at least one of 'metadata.*' or
'content.*' MUST be present and non-empty, and
content.patterns MUST NOT be present if the TriggerType is
Preposition.</t>
</list></t>
</list></t>
<section anchor="content-urls" title="Content URLs">
<t>To refer to content in the dCDN, the uCDN MUST present URLs in
the same form clients will use to access content in that dCDN, after
transformation to remove any surrogate-specific parts of a
302-redirect URL form. By definition, it is always possible to
locate content based on URLs in this form.</t>
<t>If content URLs are transformed by an intermediate CDN in a
cascade, that intermediate CDN MUST transform URLs in trigger
requests it passes to its dCDN.</t>
<t>When processing trigger requests, CDNs MUST ignore the URL scheme
(http or https) in comparing URLs. For example, for an invalidate or
purge trigger, content MUST invalidated or purged regardless of the
protocol clients use to request it.</t>
</section>
</section>
<section anchor="properties-of-trigger-resources"
title="Properties of Trigger Status Resources">
<t><list style="empty">
<t>Property: trigger<list style="empty">
<t>Description: The properties of trigger request that created
this record.</t>
<t>Type: TriggerRequest</t>
<t>Mandatory: Yes</t>
</list></t>
</list></t>
<t><list style="empty">
<t>Property: ctime<list style="empty">
<t>Description: Time at which the request was received by the
dCDN. Time is determined by the dCDN, there is no requirement
to synchronise clocks between interconnected CDNs.</t>
<t>Type: AbsoluteTime</t>
<t>Mandatory: Yes</t>
</list></t>
</list></t>
<t><list style="empty">
<t>Property: mtime<list style="empty">
<t>Description: Time at which the resource was last modified.
Time is determined by the dCDN, there is no requirement to
synchronise clocks between interconnected CDNs.</t>
<t>Type: AbsoluteTime</t>
<t>Mandatory: Yes</t>
</list></t>
</list><list style="empty">
<t>Property: etime<list style="empty">
<t>Description: Estimate of the time at which the dCDN expects
to complete the activity. Time is determined by the dCDN,
there is no requirement to synchronise clocks between
interconnected CDNs.</t>
<t>Type: AbsoluteTime</t>
<t>Mandatory: No</t>
</list></t>
</list></t>
<t><list style="empty">
<t>Property: status<list style="empty">
<t>Description: Current status of the triggered activity.</t>
<t>Type: TriggerStatus</t>
<t>Mandatory: Yes</t>
</list></t>
</list></t>
<t><list style="empty">
<t>Property: errors<list style="empty">
<t>Description: List of ErrorDesc.</t>
<t>Mandatory: No.</t>
</list></t>
</list></t>
</section>
<section title="Properties of ErrorDesc">
<t>An ErrorDesc object is used to report failure for URLs and patterns
in a trigger request.<list style="empty">
<t>Property: error<list style="empty">
<t>Type: ErrorCode.</t>
<t>Mandatory: Yes.</t>
</list></t>
</list><list style="empty">
<t>Property: metadata.urls, content.urls, metadata.patterns,
content.patterns<list style="empty">
<t>Description: Metadata and content references copied from
the trigger request. Only those URLs and patterns to which the
error applies shall be included in each property, but those
URLs and patterns MUST be exactly as they appear in the
request, the dCDN must not generalise the URLs. (For example,
if the uCDN requests prepositioning of URLs
"http://ucdn.example.com/a" and "http://ucdn.example.com/b",
the dCDN must not generalise its error report to Pattern
"http://ucdn.example.com/*").</t>
<t>Mandatory: At least one of these properties is mandatory in
each ErrorDesc.</t>
</list></t>
</list><list style="empty">
<t>Property: description<list style="empty">
<t>Description: A String containing a human-readable
description of the error.</t>
<t>Mandatory: No.</t>
</list></t>
</list></t>
</section>
<section title="Properties of Trigger Collections">
<t><list style="empty">
<t>Property: triggers<list style="empty">
<t>Description: Links to Trigger Status Resources in the
collection.</t>
<t>Type: URLs.</t>
<t>Mandatory: Yes</t>
</list></t>
</list><list style="empty">
<t>Property: staleresourcetime<list style="empty">
<t>Description: The length of time for which the dCDN
guarantees to keep a completed Trigger Status Resource. After
this time, the dCDN MAY delete the resource and all references
to it from collections.</t>
<t>Type: Integer, time in seconds.</t>
<t>Mandatory: Yes, in the collection of all Trigger Status
Resources if the dCDN deletes stale entries. If the property
is present in the filtered collections, it MUST have the same
value as in the collection of all Trigger Status
Resources.</t>
</list></t>
</list></t>
</section>
<section title="Trigger Resource Simple Data Type Descriptions">
<t>This section describes the simpler data types that are used for
properties of Trigger Status resources.</t>
<section anchor="trigger-type" title="TriggerType">
<t>This type defines the type of action being triggered, permitted
actions are:<list style="symbols">
<t>Preposition - a request for the dCDN to acquire metadata or
content.</t>
<t>Invalidate - a request for the dCDN to invalidate metadata or
content. After servicing this request the dCDN will not use the
specified data without first re-validating it using, for
example, an "If-None-Match" HTTP request. The dCDN need not
erase the associated data.</t>
<t>Purge - a request for the dCDN to erase metadata or content.
After servicing the request, the specified data MUST NOT be held
on dCDN.</t>
</list></t>
</section>
<section anchor="trigger-status" title="TriggerStatus">
<t>This type describes the current status of a Trigger, possible
values are:</t>
<t><list style="symbols">
<t>Pending – the trigger has not yet been acted upon.</t>
<t>Active – the trigger is currently being acted upon.</t>
<t>Complete – the triggered activity completed
successfully.</t>
<t>Processed - the trigger has been accepted and no further
status update will be made (may be used in cases where
completion cannot be confirmed).</t>
<t>Failed – the triggered activity could not be
completed.</t>
</list></t>
</section>
<section title="URLs">
<t>This type describes a set of references to metadata or content,
it is simply a list of absolute URLs.</t>
</section>
<section title="AbsoluteTime">
<t>Times are expressed in seconds since the UNIX epoch.</t>
</section>
<section title="ErrorCode">
<t>This type is used by dCDN to report failures in trigger
processing.</t>
<t><list style="symbols">
<t>EMETA - the dCDN was unable to acquire metadata required to
fulfil the request.</t>
<t>ECONTENT - the dCDN was unable to acquire content
(preposition triggers only).</t>
<t>EPERM - the uCDN does not have permission to trigger the
requested activity (for example, the data is owned by another
CDN).</t>
<t>EREJECT - the dCDN is not willing to fulfil the request (for
example, a preposition request for content at a time when dCDN
would not accept Request Routing requests from uCDN).</t>
<t>ECDN - An internal error in the dCDN or one of its downstream
CDNs.</t>
</list></t>
</section>
</section>
</section>
<section anchor="json-encoding" title="JSON Encoding of Objects">
<t>The encoding for a CI/T object is a JSON object containing a
dictionary of (key,value) pairs where the keys are the property names,
and the values are the associated property values.</t>
<t>The keys of the dictionary are the names of the properties associated
with the object and are therefore dependent on the specific object being
encoded (i.e. dependent on the MIME Media Type of the returned
resource). Likewise, the values associated with each key are dependent
on the specific object being encoded (i.e. dependent on the MIME Media
Type of the returned resource).</t>
<t>The "trigger" property of the top level JSON object lists the
requested action.</t>
<t><list style="empty">
<t>Key: trigger<list style="empty">
<t>Description: An object specifying the trigger type and a set
of data to act upon.</t>
<t>Type: A JSON object.</t>
<t>Mandatory: Yes.</t>
</list></t>
</list></t>
<t>Object keys in JSON are case sensitive and therefore any dictionary
key defined by this document (for example the names of CI/T object
properties) MUST always be represented in lowercase.</t>
<t>In addition to the properties of an object, the following additional
keys MAY be present.</t>
<t><list style="empty">
<t>Key: base<list style="empty">
<t>Description: Provides a prefix for any relative URLs in the
object. This is similar to the XML base tag <xref
target="XML-BASE"/>. If absent, all URLs in the remainder of the
document MUST be absolute URLs.</t>
<t>Type: URI</t>
<t>Mandatory: No</t>
</list></t>
</list></t>
<t><list style="empty">
<t>Key: _links<list style="empty">
<t>Description: The relationships of this object to other
addressable objects.</t>
<t>Type: Array of Relationships.</t>
<t>Mandatory: Yes</t>
</list></t>
</list></t>
<section title="JSON Encoding of Embedded Types">
<section title="TriggerType">
<t><list style="empty">
<t>Key: type<list style="empty">
<t>Description: One of "preposition", "invalidate" or
"purge".</t>
<t>Type: string</t>
</list></t>
</list></t>
</section>
<section title="TriggerStatus">
<t><list style="empty">
<t>Key: status<list style="empty">
<t>Description: One of "pending", "active", "failed",
"complete"</t>
<t>Type: string</t>
</list></t>
</list></t>
</section>
<section title="PatternMatch">
<t>A PatternMatch is encoded as a JSON Object containing a string to
match and flags describing the type of match.</t>
<t><list style="empty">
<t>Key: pattern<list style="empty">
<t>Description: A pattern for string matching. The pattern
may contain the wildcards * and ?, where * matches any
sequence of characters (including the empty string) and ?
matches exactly one character. The three literals \ , * and
? MUST be escaped as \\, \* and \?</t>
<t>Type: String</t>
<t>Mandatory: Yes</t>
</list>Key: case-sensitive<list style="empty">
<t>Description: Flag indicating whether or not
case-sensitive matching should be used.</t>
<t>Type: Boolean</t>
<t>Mandatory: No, default is case-insensitive match.</t>
</list>Key: match-query-string<list style="empty">
<t>Description: Flag indicating whether or not the query
string should be included in the pattern match.</t>
<t>Type: Boolean</t>
<t>Mandatory: No, default is not to include query.</t>
</list></t>
</list>Example of case-sensitive prefix match against
"http://www.example.com/trailers/":</t>
<figure>
<artwork><![CDATA[{
"pattern": "http://www.example.com/trailers/*",
"case-sensitive": true
}]]></artwork>
</figure>
</section>
<section title="ErrorDesc">
<t>ErrorDesc is encoded as a JSON object with the following
keys:</t>
<t><list style="empty">
<t>Key: error<list style="empty">
<t>Type: ErrorCode</t>
<t>Mandatory: Yes</t>
</list>Keys: metadata.urls, content.urls<list style="empty">
<t>Type: Array of strings</t>
<t>Mandatory: At least one of metadata.* or content.* MUST
be present.</t>
</list>Keys: metadata.patterns, content.patterns<list
style="empty">
<t>Type: Array of PatternMatch</t>
<t>Mandatory: At least one of metadata.* or content.* MUST
be present.</t>
</list></t>
<t>Key: description<list style="empty">
<t>Type: String</t>
<t>Mandatory: No.</t>
</list></t>
</list></t>
</section>
<section title="ErrorCode">
<t>One of the strings "EMETA", "ECONTENT", "EPERM", "EREJECT" or
"ECDN".</t>
</section>
</section>
<section anchor="media-types" title="MIME Media Types">
<t><xref target="triggers-media-types-table"/> lists the MIME Media
Type for the trigger request, and each trigger object (resource) that
is retrievable through the CI/T interface.</t>
<texttable anchor="triggers-media-types-table"
title="MIME Media Types for CDNI Trigger resources">
<ttcol>Data Object</ttcol>
<ttcol>MIME Media Type</ttcol>
<c>TriggerRequest</c>
<c>application/cdni.ci.TriggerRequest+json</c>
<c>TriggerStatus</c>
<c>application/cdni.ci.TriggerStatus+json</c>
<c>TriggerCollection</c>
<c>application/cdni.ci.TriggerCollection+json</c>
</texttable>
<t/>
</section>
</section>
<section anchor="examples" title="Examples">
<t>The following sections provide examples of different CI/T objects
encoded as JSON.</t>
<t>No authentication is shown in the following illustrative examples, it
is anticipated that authentication mechanisms will be aligned with other
CDNI Interfaces as and when those mechanisms are defined.</t>
<t>Discovery of the triggers interface is out of scope of this document.
In an implementation, all URLs are under the control of the dCDN. The
uCDN MUST NOT attempt to ascribe any meaning to individual elements of
the path. In examples in this section, the following URLs are used as
the location of the collections of triggers:</t>
<t><list style="symbols">
<t>Collection of all Triggers belonging to one uCDN:<list
style="empty">
<t>http://dcdn.example.com/triggers</t>
</list></t>
<t>Filtered collections:<list style="empty">
<t>Pending: http://dcdn.example.com/triggers/pending</t>
<t>Active: http://dcdn.example.com/triggers/active</t>
<t>Complete: http://dcdn.example.com/triggers/complete</t>
<t>Failed: http://dcdn.example.com/triggers/failed</t>
</list></t>
</list></t>
<section title="Creating Triggers">
<t>Examples of uCDN triggering activity in dCDN:</t>
<section title="Preposition">
<t>An example of a preposition request, a POST to the "AllTriggers"
collection.</t>
<t>Note that "metadata.patterns" and "content.patterns" are not
allowed in a preposition trigger request.</t>
<figure>
<artwork><![CDATA[REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
Content-Type: application/cdni.ci.TriggerRequest+json
Content-Length: 315
{
"trigger" : {
"type": "preposition",
"metadata.urls" : [ "http://metadata.example.com/a/b/c" ],
"content.urls" : [
"http://www.example.com/a/b/c/1",
"http://www.example.com/a/b/c/2",
"http://www.example.com/a/b/c/3",
"http://www.example.com/a/b/c/4"
]
}
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 02 Jul 2014 18:57:19 GMT
Content-Length: 472
Content-Type: application/cdni.ci.TriggerStatus+json
Location: http://dcdn.example.com/triggers/0
Server: example-server/0.1
{
"ctime": 1404327439,
"etime": 1404327447,
"mtime": 1404327439,
"status": "pending",
"trigger": {
"content.urls": [
"http://www.example.com/a/b/c/1",
"http://www.example.com/a/b/c/2",
"http://www.example.com/a/b/c/3",
"http://www.example.com/a/b/c/4"
],
"metadata.urls": [
"http://metadata.example.com/a/b/c"
],
"type": "preposition"
}
}]]></artwork>
</figure>
</section>
<section title="Invalidate">
<t>An example of an invalidate request, another POST to the
"AllTriggers" collection. This instructs the dCDN to re-validate the
content at "http://www.example.com/a/index.html", as well as any
metadata and content whose URLs are prefixed by
"http://metadata.example.com/a/b/" and "http://www.example.com/a/b/"
respectively, using case-insensitive matching.</t>
<figure>
<artwork><![CDATA[REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
Content-Type: application/cdni.ci.TriggerRequest+json
Content-Length: 352
{
"trigger" : {
"type": "invalidate",
"metadata.patterns" : [
{ "pattern" : "http://metadata.example.com/a/b/*" }
],
"content.urls" : [ "http://www.example.com/a/index.html" ],
"content.patterns" : [
{ "pattern" : "http://www.example.com/a/b/*",
"case-sensitive" : true
}
]
}
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Length: 551
Content-Type: application/cdni.ci.TriggerStatus+json
Location: http://dcdn.example.com/triggers/1
Server: example-server/0.1
{
"ctime": 1404327440,
"etime": 1404327448,
"mtime": 1404327440,
"status": "pending",
"trigger": {
"content.patterns": [
{
"case-sensitive": true,
"pattern": "http://www.example.com/a/b/*"
}
],
"content.urls": [
"http://www.example.com/a/index.html"
],
"metadata.patterns": [
{
"pattern": "http://metadata.example.com/a/b/*"
}
],
"type": "invalidate"
}
}]]></artwork>
</figure>
<t/>
</section>
</section>
<section title="Examining Trigger Status">
<t>Once triggers have been created, the uCDN can check their status as
shown in these examples.</t>
<section title="Collection of All Triggers">
<t>The uCDN can fetch the set of all the triggers it has created and
which have not yet been deleted or removed as expired. After
creation of the "preposition" and "invalidate" triggers shown above,
this collection might look as follows:</t>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 153
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "9179988753593038498"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": [
"http://dcdn.example.com/triggers/0",
"http://dcdn.example.com/triggers/1"
]
}]]></artwork>
</figure>
</section>
<section title="Filtered Collections of Triggers">
<t>The filtered collections are also available to uCDN. Before the
dCDN starts processing the two triggers shown above, both will
appear in the collection of Pending Triggers, for example:</t>
<figure>
<artwork><![CDATA[RREQUEST:
GET /triggers/pending HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 153
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "5012053611544832286"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": [
"http://dcdn.example.com/triggers/0",
"http://dcdn.example.com/triggers/1"
]
}]]></artwork>
</figure>
<t/>
<t>At this point, if no other triggers had been created, the other
filtered views of the triggers would be empty. For example:</t>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers/complete HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 56
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "2986340333785000363"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": []
}]]></artwork>
</figure>
<t/>
</section>
<section title="Trigger Status Resources">
<t>The Trigger Status Resources can also be examined for detail
about individual triggers. For example, for the "preposition" and
"invalidate" triggers from previous examples:</t>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers/0 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 472
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "-3651695664007658154"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerStatus+json
{
"ctime": 1404327439,
"etime": 1404327447,
"mtime": 1404327439,
"status": "pending",
"trigger": {
"content.urls": [
"http://www.example.com/a/b/c/1",
"http://www.example.com/a/b/c/2",
"http://www.example.com/a/b/c/3",
"http://www.example.com/a/b/c/4"
],
"metadata.urls": [
"http://metadata.example.com/a/b/c"
],
"type": "preposition"
}
}]]></artwork>
</figure>
<t/>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers/1 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 551
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "-7664987687828084413"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerStatus+json
{
"ctime": 1404327440,
"etime": 1404327448,
"mtime": 1404327440,
"status": "pending",
"trigger": {
"content.patterns": [
{
"case-sensitive": true,
"pattern": "http://www.example.com/a/b/*"
}
],
"content.urls": [
"http://www.example.com/a/index.html"
],
"metadata.patterns": [
{
"pattern": "http://metadata.example.com/a/b/*"
}
],
"type": "invalidate"
}
}]]></artwork>
</figure>
</section>
<section title="Polling for Change">
<t>The uCDN may use the Entity Tags of collections or resources when
polling for change in status, as shown in the following
examples:</t>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers/pending HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
If-None-Match: "5012053611544832286"
RESPONSE:
HTTP/1.1 304 Not Modified
Content-Length: 0
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "5012053611544832286"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerCollection+json]]></artwork>
</figure>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers/0 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
If-None-Match: "-3651695664007658154"
RESPONSE:
HTTP/1.1 304 Not Modified
Content-Length: 0
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "-3651695664007658154"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerStatus+json]]></artwork>
</figure>
<t/>
<t>When the triggered activity is complete, the contents of the
filtered collections will be updated, along with their Entity Tags.
For example, when the two example triggers are complete, the
collections of pending and complete triggers may look like:</t>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers/pending HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 56
Expires: Wed, 02 Jul 2014 18:58:24 GMT
Server: example-server/0.1
Etag: "-4471185573414616962"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:24 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": []
}]]></artwork>
</figure>
<t/>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers/complete HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 153
Expires: Wed, 02 Jul 2014 18:58:31 GMT
Server: example-server/0.1
Etag: "-1508172875796647067"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:31 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": [
"http://dcdn.example.com/triggers/0",
"http://dcdn.example.com/triggers/1"
]
}]]></artwork>
</figure>
</section>
<section title="Cancelling or Removing a Trigger">
<t>To request the dCDN to cancel a Trigger, the uCDN may delete the
Trigger Resource. It may also delete completed and failed triggers
to reduce the size of the collections. For example, to remove the
"preposition" request from earlier examples:</t>
<figure>
<artwork><![CDATA[REQUEST:
DELETE /triggers/0 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 204 No Content
Date: Wed, 02 Jul 2014 18:57:31 GMT
Content-Length: 0
Content-Type: text/html; charset=UTF-8
Server: example-server/0.1]]></artwork>
</figure>
<t/>
<t>This would, for example, cause the collection of completed
triggers shown in the example above to be updated to:</t>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers/complete HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 106
Expires: Wed, 02 Jul 2014 18:58:31 GMT
Server: example-server/0.1
Etag: "-1842390246836476263"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:31 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": [
"http://dcdn.example.com/triggers/1"
]
}]]></artwork>
</figure>
</section>
<section title="Error Reporting">
<t>In this example the uCDN has requested prepositioning of
"http://newsite.example.com/index.html", but the dCDN was unable to
locate metadata for that site:</t>
<figure>
<artwork><![CDATA[REQUEST:
GET /triggers/2 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 505
Expires: Wed, 02 Jul 2014 19:16:48 GMT
Server: example-server/0.1
Etag: "-6310233270471598826"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 19:15:48 GMT
Content-Type: application/cdni.ci.TriggerStatus+json
{
"ctime": 1404328544,
"errors": [
{
"content.urls": [
"http://newsite.example.com/index.html"
],
"description":
"No HostIndex entry found for newsite.example.com",
"error": "EMETA"
}
],
"etime": 1404328552,
"mtime": 1404328548,
"status": "active",
"trigger": {
"content.urls": [
"http://newsite.example.com/index.html"
],
"type": "preposition"
}
}]]></artwork>
</figure>
</section>
</section>
</section>
<section title="IANA Considerations">
<t/>
<section anchor="mime-types" title="CI/T MIME Media Types">
<t>The IANA is requested to allocate the following MIME Media Types in
the MIME Media Types registry:</t>
<t><list style="symbols">
<t>application/cdni.ci.TriggerRequest</t>
<t>application/cdni.ci.TriggerStatus</t>
<t>application/cdni.ci.TriggerCollection</t>
</list>Use of these types is specified in <xref
target="media-types"/> of the present document.</t>
</section>
</section>
<section anchor="Security" title="Security Considerations">
<section title="Authentication, Confidentiality, Integrity Protection">
<t>A CI/T dCDN server implementation MUST support TLS transport for
HTTP (https) as per <xref target="RFC2818"/>. The use of TLS for
transport of the CI/T interface allows the dCDN and the uCDN to
authenticate each other (to ensure they are receiving trigger requests
from, or reporting status to, an authenticated CDN).</t>
<t>HTTP requests that attempt to access or operate on CI/T data
belonging to another CDN MUST be rejected using either HTTP "403
Forbidden" or "404 Not Found". (Note that in a "diamond"
configuration, where one uCDN's content can be acquired via more than
one directly-connected uCDN, it may not be possible for the dCDN to
determine from which uCDN it acquired content. In this case, it MUST
allow each upstream that may have been responsible for acquisition of
that content to act upon it using trigger requests.)</t>
<t>Trigger creation requests that attempt to operate on metadata or
content not acquired from the uCDN making the request MUST be
rejected. The rejection can either be signalled to dCDN using HTTP
"403 Forbidden" or "404 Not Found", or a Trigger Status Resource can
be created with an ErrorDesc value of EPERM for any affected URLs.</t>
<t>In an environment where any such protection is required, TLS SHOULD
be used for transport of the CI/T requests and responses, unless
alternate methods are used for ensuring that only authorised clients
are able to access their own data (such as setting up an IPsec tunnel
between the two CDNs, or using a physically secured internal network
between two CDNs that are owned by the same corporate entity). Both
parties of the transaction (the uCDN and the dCDN) SHOULD use mutual
authentication.</t>
<t>A CI/T implementation MUST support the
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 cipher suite (<xref
target="RFC5288"/>). An implementation of the CI/T Interface SHOULD
prefer cipher suites which support perfect forward secrecy over cipher
suites that don't.</t>
</section>
<section title="Denial of Service">
<t>This document does not define a specific mechanism to protect
against Denial of Service (DoS) attacks on the CI/T. However, CI/T
endpoints can be protected against DoS attacks through the use of TLS
transport and/or via mechanisms outside the scope of the CI/T
interface, such as firewalling or use of Virtual Private Networks
(VPNs).</t>
</section>
</section>
<section anchor="Acknowledgements" title="Acknowledgements">
<t>The authors thank Kevin Ma for his ongoing input.</t>
</section>
</middle>
<back>
<references title="Normative References">
&rfc2119;
&rfc7231;
&rfc7232;
&rfc7159;
&rfc3986;
</references>
<references title="Informative References">
&rfc6707;
&I-D.draft-ietf-cdni-framework-14;
&I-D.draft-ietf-cdni-requirements-17;
&I-D.draft-ietf-cdni-metadata-06;
&rfc4287;
&rfc2818;
&rfc5288;
<reference anchor="XML-BASE">
<front>
<title>XML Base (Second Edition) -
http://www.w3.org/TR/xmlbase/</title>
<author fullname="Jonathan" initials="J" role="editor"
surname="Marsh">
<organization/>
</author>
<author fullname="Richard" initials="R" role="editor"
surname="Tobin">
<organization/>
<address>
<postal>
<street/>
<city/>
<region/>
<code/>
<country/>
</postal>
<phone/>
<facsimile/>
<email/>
<uri/>
</address>
</author>
<date day="28" month="January" year="2009"/>
</front>
</reference>
</references>
</back>
</rfc>
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