1. No category

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Hypermedia Workshop
Resource Architectural Constraints and the Properties They Induce
Brian Sletten (!@bsletten)
03/17/2015
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Speaker Qualifications
· Specialize in next-generation technologies
· Author of 'Resource-Oriented Architecture Patterns for Webs of Data'
· Speaks internationally about REST, Semantic Web, Data Science, Security,
Visualization, Architecture
· Worked in Defense, Finance, Retail, Hospitality, Video Game, Health Care,
Telecommunications and Publishing Industries
· International Pop Recording Artist
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Agenda
· Introduction
· Identity
· Interaction
· Representation
· Description
· Patterns
· Linked Data
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Introduction
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“ Approximately half of the talks at API
conferences start with a variation of this slide:
'we’re doing great, because there are more
than 12,000 APIs...' ”
Ruben Verborgh
http://ruben.verborgh.org/blog/2015/02/25/fostering-intelligence-by-enabling-it/
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“ Personally, I never understood how
overgrowth can be a good thing: 12,000 APIs
means 12,000 different ways of engaging in
machine-to-machine interaction. ”
Ruben Verborgh
http://ruben.verborgh.org/blog/2015/02/25/fostering-intelligence-by-enabling-it/
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“ Software architecture research investigates methods for determining how best
to partition a system, how components identify and communicate with each
other, how information is communicated, how elements of a system can evolve
independently, and how all of the above can be described using formal and
informal notations. ”
Dr. Roy T. Fielding
http://www.ics.uci.edu/~fielding/pubs/dissertation/fielding_dissertation.pdf
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“ My work is motivated by the desire to understand and evaluate the architectural
design of network- based application software through principled use of
architectural constraints, thereby obtaining the functional, performance, and
social properties desired of an architecture. ”
Dr. Roy T. Fielding
http://www.ics.uci.edu/~fielding/pubs/dissertation/fielding_dissertation.pdf
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“ An architectural style is a named, coordinated
set of architectural constraints. ”
Dr. Roy T. Fielding
http://www.ics.uci.edu/~fielding/pubs/dissertation/fielding_dissertation.pdf
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Desired Properties
· Performance
· Scalability
· Generality
· Simplicity
· Modifiability
· Extensibility
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Client Server
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Stateless Client Server
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Stateless Client Server w/ Cache and Uniform
Interface
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Layered Stateless Client Server w/ Cache and
Uniform Interface
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REST on a Slide
Credit: Architectural Styles and the Design of Network-based Software Architectures
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Identity
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“ The function of a name is to facilitate sharing. ”
Ross J. Anderson
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“ When systems become large, the scale-up problems are not linear; there is often
a qualitative change in complexity, and some things that are trivial to deal with in
a network of only a few machines and principals (such as naming) suddenly
become a big deal. ”
Ross J. Anderson
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Naming Scheme Properties
· Identity
· Disambiguation
· Scope
· Resolvability
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Uniform Naming Scheme
· http://bosatsu.net/foaf/brian.rdf
· ftp://ftp.funet.fi/pub/standards/RFC/rfc959.txt
· urn:isbn:0913966568
· https://w3id.org/people/bsletten
· TBD
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What REST Says About URLs
·
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Resource For the Current Time
http://example.com/time/timezone/EDT
http://example.com/time/timezone/PDT
http://example.com/time/state/us/hawaii
http://example.com/time/timezone/HAST
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Canonical vs Historical
http://bosatsu.net/talks/topic/rest
http://bosatsu.net/talks/conf/nfjs/2013/rest/minneapolis
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Versioning URLs
· Just don't do it
· Seriously, don't do it
· Conflates identity with representation
· Impact on API evolution
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“ Global naming leads to global network effects. ”
Architecture of the World Wide Web, Volume I
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“ Any resource anywhere can be given a URI. ”
Architecture of the World Wide Web, Volume I
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“ Any resource of significance should be given a
URI. ”
Architecture of the World Wide Web, Volume I
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“ A URI will repeatedly refer to 'the same' thing. ”
Architecture of the World Wide Web, Volume I
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“ The significance of identity for a given URI is
determined by the person who owns the URI,
who first determined what it points to. ”
Architecture of the World Wide Web, Volume I
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“ URI space does not have to be the only
universal space. ”
Architecture of the World Wide Web, Volume I
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“ What makes a cool URI? A cool URI is one
which does not change. ”
Tim Berners-Lee
Cool URIs Don't Change
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Things to Avoid
· Author name
· Status
· Access
· File name extension
· Software mechanism
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Interaction
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Application #1
Application #2
Application #3
REST API
Code
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Application #1
Application #2
Application #3
REST API
Code
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GET
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POST
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PUT
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DELETE
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HEAD
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OPTIONS
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PATCH
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OPTIONS /example/buddies.xml HTTP/1.1
Host: www.example.com
HTTP/1.1 200 OK
Allow: GET, PUT, POST, OPTIONS, HEAD, DELETE, PATCH
Accept-Patch: application/example, text/example
GET /example/buddies.xml HTTP/1.1
Host: www.example.com
HTTP/1.1 200 OK
.
.
Etag: "e0023aa4e"
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PATCH /example/buddies.xml HTTP/1.1
Host: www.example.com
Content-Type: application/example
If-Match: "e0023aa4e"
Content-Length: 100
[patch changes]
HTTP/1.1 204 No Content
Content-Location: /example/buddies.xml
ETag: "e0023aa4f"
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Idempotency
GET
"
POST
#
PUT
"
PATCH
~"
DELETE
"
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Response Codes: 2XX
Code
Meaning
200
Ok
201
Created
202
Accepted
204
Success
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Response Codes: 3XX
Code
Meaning
301
Moved Permanently
302
Found
303
See Other
304
Not Modified
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Response Codes: 4XX
Code
Meaning
400
Bad Request
401
Unauthorized
403
Forbidden
404
Not Found
405
Method Not Allowed
409
Conflict
411
Length Required
413
Entity Too Long
415
Unsupported Media Type
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Response Codes: 5XX
Code
Meaning
500
Internal Error
503
Service Unavailable
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Representation
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Hypermedia Factors (HFactors)
Credit: Mike Amundsen
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Embedded Links (LE)
Credit: Mike Amundsen
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LE Examples
// HTML
<img src="http://bosatsu.net/images/bosatsu-kanji.jpg"/>
// XInclude
<author>
<x:include href="http://bosatsu.net/snippets/bio.xml"/>
</author>
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Outbound Links (LO)
Credit: Mike Amundsen
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LO Examples
// HTML
<p>
See you at <a href="http://uberconf.com">Überconf</a>.
</p>
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Outbound Links (LT)
Credit: Mike Amundsen
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LT Examples
// HTML
<form method="get" action="http://bosatsu.net/submit">
<input type="text" name="course" value="REST"/>
<input type="submit"/>
</form>
// HTTP
http://bosatsu.net/submit?course=REST
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LT Examples
URI Templates (RFC 6570)
http://example.com/~{username}/
http://example.com/dictionary/{term:1}/{term}
http://example.com/search{?q,lang}
http://example.com/~fred/
http://example.com/~mark/
http://example.com/dictionary/c/cat
http://example.com/dictionary/d/dog
http://example.com/search?q=cat&lang=en
http://example.com/search?q=chien&lang=fr
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Non-Idempotent Links (LN)
Credit: Mike Amundsen
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LN Examples
// HTML
<form method="post" action="http://bosatsu.net/submit/">
<textarea name="feedback">Hey Buddy, nice jacket</textarea>
<input type="submit"/>
</form>
POST /submit/ HTTP/1.1
Host: bosatsu.net
Content-Type: application/x-www-form-urlencoded
Length:34
feedback=Hey+Buddy%2C+nice+jacket
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Idempotent Links (LI)
Credit: Mike Amundsen
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LI Examples
// Atom
<link rel="edit" href="http://bosatsu.net/feed/edit/1"/>
// HTML
<script type="text/javascript">
function delete(url) {
var xhr = new XMLHttpRequest();
xhr.open("DELETE", url);
}
</script>
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W3C HTML Form HTTP Extensions
http://www.w3.org/TR/form-http-extensions/
<form action="http://www.example.com/cms/hogmanay" method="PUT">
<input name="If-Unmodified-Since"
type="hidden" value="Tue, 1 Jan 2013 12:00:00 GMT"
payload="_header"/>
<textarea name="content">
For auld lang syne, my dear,
For auld lang syne.
We'll tak a cup o' kindness yet,
For auld lang syne.
And there's a hand, my trusty fere!
And gie's a hand o' thine!
And we'll tak a right gude-willie waught,
For auld lang syne.
</textarea>
<button type="submit">Update</button>
</form>
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W3C HTML Form HTTP Extensions
http://www.w3.org/TR/form-http-extensions/
<form action="http://www.example.com/logs" method="DELETE">
<label for="since">Since</label>
<input id="since" name="since" type="datetime"/>
<button type="submit">Delete</button>
</form>
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Read Context (CR)
Credit: Mike Amundsen
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CR Examples
<x:include href="http://bosatsu.net/snippets/bio.xml"
accept-language="en, en-gb; q=0.9, jp;q=0.3"/>
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Update Context (CU)
Credit: Mike Amundsen
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CU Examples
// HTML
<form method="post" action="http://bosatsu.net/submit/"
enctype="text/plain">
<textarea name="feedback">Hey Buddy, nice jacket</textarea>
<input type="submit"/>
</form>
POST /submit/ HTTP/1.1
Host: bosatsu.net
Content-Type: text/plain
Length:34
Hey+Buddy%2C+nice+jacket
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Method Context (CM)
Credit: Mike Amundsen
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CM Examples
// HTML
<form method="post" action="/feedback">
<input name="keywords" type="text" value="foo,bar,baz"/>
<input type="submit"/>
</form>
// HTML
<form method="get" action="/feedback">
<input name="keywords" type="text" value="foo,bar,baz"/>
<input type="submit"/>
</form>
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Link Context (CL)
Credit: Mike Amundsen
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CL Examples
// Atom
<entry>
<title>The Bully</title>
<link rel="edit" href="http://bosatsu.net/feed/1"/>
<id>tag:bosatsu.net,2013:3.2397</id>
<updated>2013-03-01T12:29:29Z</updated>
<published>2013-02-13T08:29:29-04:00</published>
<author>
<name>Brian Sletten</name>
</author>
<content>Hey Buddy, nice car.</content>
</entry>
// HTML
<link rel="stylesheet" href="http://bosatsu.net/css/default.css"/>
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text/uri-list
Credit: Mike Amundsen
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application/svg+xml
Credit: Mike Amundsen
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application/atom+xml
Credit: Mike Amundsen
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application/html
Credit: Mike Amundsen
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Media Selection Considerations
· Domain-Specific
· Domain-General
· Application Semantics
· Transfer Semantics
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application/vnd.amundsen.maze+xml
Credit: Mike Amundsen
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application/vnd.amundsen.maze+xml
· Domain-Specific
· Application Semantics
· Meaningful links:
· start
· north
· east
· west
· south
· exit
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Maze Starting Point
GET /examples/mazes/2d/ HTTP/1.1
Host: amundsen.com
Accept: application/vnd.amundsen.maze+xml
<maze version="1.0">
<collection>
<link href="http://amundsen.com/examples/mazes/2d/fifty-by-fifty/"
rel="maze"/>
<link href="http://amundsen.com/examples/mazes/2d/five-by-five/"
rel="maze"/>
<link href="http://amundsen.com/examples/mazes/2d/my-new-maze/"
rel="maze"/>
<link href="http://amundsen.com/examples/mazes/2d/ten-by-ten/"
rel="maze"/>
</collection>
</maze>
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Requesting a Specific Maze
GET /examples/mazes/2d/five-by-five/ HTTP/1.1
Host: amundsen.com
Accept: application/vnd.amundsen.maze+xml
<maze version="1.0">
<item>
<link href="http://amundsen.com/examples/mazes/2d/five-by-five/0:north"
rel="start" />
<debug>
...
</debug>
</item>
</maze>
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Starting a Specific Maze
GET /examples/mazes/2d/five-by-five/0:north HTTP/1.1
Host: amundsen.com
Accept: application/vnd.amundsen.maze+xml
<maze version="1.0">
<cell>
<link
href="http://amundsen.com/examples/mazes/2d/five-by-five/0:north"
rel="current" debug="0:1,1,1,0" total="25" side="5" />
<link
href="http://amundsen.com/examples/mazes/2d/five-by-five/5:east"
rel="east" />
</cell>
</maze>
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Maze Clients
· http://amundsen.com/examples/misc/maze-client.html
· https://github.com/caelum/restfulie/tree/master/full-examples/mikemaze
· http://yloiseau.net/hacks/maze/
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Credit: http://amundsen.com/media-types/collection/
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application/vnd.collections+json
Credit: Mike Amundsen
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Collections+JSON
{ "collection" :
{
"version" : "1.0",
"href" : "http://example.org/friends/"
}
}
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Collections+JSON
{ "collection" :
{
"version" : "1.0",
"href" : "http://example.org/friends/",
"links" : [],
"items" : [],
"queries" : [],
"template" : [],
"error" : []
}
}
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API Starting Point
http://example.org/api
{ "collection":
{
"version": "1.0",
"href": "http://example.org/api",
"links": [{
"rel": "account",
"href": "http://example.org/account"
}, {
"rel": "order",
"href": "http://example.org/order"
}, {
"rel": "product",
"href": "http://example.org/product"
}]
}
}
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Request Accounts
http://example.org/account
{ "collection":
{
"version": "1.0",
"href": "http://example.org/account",
"links": [{
"rel": "next",
"href": "http://example.org/account;page=2"
}],
"items": [],
"queries": [],
"template": []
}
}
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Request Accounts
http://example.org/account;page=2
{ "collection":
{
"version": "1.0",
"href": "http://example.org/account;page=2",
"links": [{
"rel": "prev",
"href": "http://example.org/account"
},
{
"rel": "next",
"href": "http://example.org/account;page=3"
}],
"items": [],
"queries": [],
"template": []
}
}
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Account Items
http://example.org/account
{ "collection":
{
"version": "1.0",
"href": "http://example.org/account",
...
"items": [
],
...
}
}
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Account Items
http://example.org/account
{
...
"items": [ {
"href": "/account/id/9468",
"data": [
{
"name": "username",
"value": "bob" },
{
"name": "id",
"value": "9468" }
],
"links": [
{
"name": "open",
"value": "/order/account/id/9468;status=open" },
{
"name": "recent",
"value": "/order/account/id/9468;status=recent" }
]
}]
...
}
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Account Queries
http://example.org/account
{
}
"collection":
{
"version": "1.0",
"href": "http://example.org/account",
...
"queries": [
],
...
}
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Account Queries
http://example.org/account
{
...
"queries": [ {
"encoding": "uri-template",
"rel" : "search",
"href" : "/account{;status,page,ipp}"
"data": [
{
"name": "status",
"value": "" },
{
"name": "page",
"value": "" },
{
"name": "ipp",
"value" : "" }
]
}]
...
}
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Account Queries
http://example.org/account;status=open;page=2
{
...
"queries": [ {
"encoding": "uri-template",
"rel" : "search",
"href" : "/account{;status,page,ipp}"
"data": [
{
"name": "status",
"value": "open" },
{
"name": "page",
"value": "2" },
{
"name": "ipp",
"value" : "" }
]
}]
...
}
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Description
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State of the Art?
· No real support for hypermedia
· Often object wrappers on either side
· Static contract
· Domain-specific
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Description Languages
· RAML
· Swagger
· Apiary.io
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Hydra + JSON-LD
http://www.hydra-cg.com
· Standard format
· Hypermedia-aware
· Arbitrary domains
· Extensible
· Interoperable w/ RDF and Linked Data
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Patterns
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Named Query Resource
Q3
Q1
Q2
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Intent
· Client-driven resource definition
· Reusable queries
· Potentially cacheable
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SPARQL Protocol
http://server/sparql?query=<URL-encoded-query>
SELECT ?s ?p ?o
WHERE {
?s ?p ?o
}
LIMIT 100
http://server/sparql?query=select%20%3Fs%20%3Fp%20%3Fo%20where%20%7B
%20%3Fs%20%3Fp%20%3Fo%20%7D%20limit%20100
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Most Important Query Ever Run
http://tinyurl.com/n9hhs68
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Consequences
· Potentially cacheable
· Client-imposed burdens on your system
· Complicated privilege models
· Linked Data Fragments
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Gateway Resource
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Intent
· Client-focused resource abstractions over external resources
· Adapter for orchestration, data aggregation and content extraction
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ql.io
prodid = select ProductID[0].Value from eBay.FindProducts where
QueryKeywords = 'macbook pro';
details = select * from eBay.ProductDetails where
ProductID in ('{prodid}') and ProductType = 'Reference';
reviews = select * from eBay.ProductReviews where
ProductID in ('{prodid}') and ProductType = 'Reference';
return select d.ProductID[0].Value as id, d.Title as title,
d.ReviewCount as reviewCount, r.ReviewDetails.AverageRating as rating
from details as d, reviews as r
where d.ProductID[0].Value = r.ProductID.Value
via route '/myapi' using method get;
curl http://tinyurl.com/p7zgg9y
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[
{ "id": "115174685",
"title": "Apple MacBook Pro A1278 13.3" Laptop - MD101LL/A (June, 2012)",
"reviewCount": 81, "rating": 4.5 },
{ "id": "84755204",
"title": "Apple MacBook Pro 13.3" Laptop - MC374LL/A (April, 2010)",
"reviewCount": 182, "rating": 4.5 },
{ "id": "108850048",
"title": "Apple MacBook Pro 13.3" Laptop (April, 2010) - Customized",
"reviewCount": 42, "rating": 4.5 },
{ "id": "108808476",
"title": "Apple MacBook Pro 15.4" Laptop (April, 2010) - Customized",
"reviewCount": 29, "rating": 4.5 },
{ "id": "78092464",
"title": "Apple MacBook Pro 13.3" Laptop - MB990LL/A (June, 2009)",
"reviewCount": 136, "rating": 4.5 }
]
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insert into bitly.shorten (longUrl) values ('http://ql.io/docs')
select long_url from bitly.shorten where shortUrl = 'http://bit.ly/uZIvmY'
insert into flickr.photos.upload with
parts "{req.parts[0]}", "{req.parts[1]}"
select * from bing.soap.search where q = "ql.io";
keyword = "ql.io";
web = select * from bing.search where q = "{keyword}";
tweets = select id as id, from_user_name as user_name, text as text
from twitter.search where q = "ql.io";
return {
"keyword": "{keyword}",
"web": "{web}",
"tweets": "{tweets}"
}
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Consequences
· Pipes and Filters vs The Web
· Table Structure vs Graph
· Potential to Lose Fidelity
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Transformation Resource
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Intent
· New resources to extract or transform content from other resources
· No impact on original resource
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RDFa Distiller
http://www.w3.org/2012/pyRdfa/Overview.html
RDFa 1.1 Distiller and Parser
Warning: This version implements RDFa 1.1 Core, including the handling of the Role Attribute. The distiller can also run in
XHTML+RDFa 1.0 mode (if the incoming XHTML content uses the RDFa 1.0 DTD and/or sets the version attribute). The package
available for download, although it may be slightly out of sync with the code running this service.
Distill by URI
Distill by File Upload
Distill by Direct Text Input
Distill by URI
URI:
Output
Format:
Turtle
Returned
content:
Only core triples
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Consequences
· Strict adherence to published commitments
· Improved by source adherence to cache controls
· Tangled authentication and authorization models
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Callback Resource
2
1
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Intent
· Support asynchronous models on the Web
· Leverage existing infrastructure
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GitHub WebHooks
http://developer.github.com/webhooks/
GitHub:Developer
API
Developers
Blog
Support
Search
API
Reference
Webhooks
Guides
Libraries
Webhooks
Events
Payloads
Ping Event
Service Hooks
Webhooks allow you to build or set up integrations which subscribe to certain events on GitHub.com. When one of those events is triggered, we’ll send
a HTTP POST payload to the webhook’s configured URL. Webhooks can be used to update an external issue tracker, trigger CI builds, update a backup
mirror, or even deploy to your production server. You’re only limited by your imagination.
Each webhook can be installed on an organization or a specific repository. Once installed, they will be triggered each time one or more subscribed
events occurs on that organization or repository.
Events
When configuring a webhook, you can choose which events you would like to receive payloads for. You can even opt-in to all current and future events.
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Consequences
· Security implications of client as 'server'
· Credential management
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Curated URI Resource
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Intent
· Abandon the baggage of resource location while maintaining its strengths
· 'Types of URLs'
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W3ID
https://w3id.org/
Permanent Identifiers for the
Web
Secure, permanent URLs for your Web application that will stand the test of time.
The purpose of this website is to provide a secure, permanent URL (http://en.wikipedia.org/wiki/URL)
re-direction service for Web applications. This service is run by the W3C Permanent Identifier
Community Group (http://www.w3.org/community/perma-id/).
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Consequences
· Constant roundtrips
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Linked Data
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Credit: Aldo Bucci
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Brian's birthday is May 26th.
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Brian's birthday is May 26th.
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https://w3id.org/people/bsletten's
http://xmlns.com/foaf/0.1/birthday is "05-26".
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A Single Fact
# N-Triple Serialization of the Fact
<https://w3id.org/people/bsletten>
<http://xmlns.com/foaf/0.1/birthday> "05-26" .
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https://w3id.org/people/bsletten's name is Brian
Sletten.
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https://w3id.org/people/bsletten's
http://xmlns.com/foaf/0.1/name is "Brian
Sletten".
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A Single Fact
# N-Triple Serialization of the Fact
<https://w3id.org/people/bsletten>
<http://xmlns.com/foaf/0.1/name> "Brian Sletten" .
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Two Facts
# N-Triple Serialization of the Facts
<https://w3id.org/people/bsletten>
<http://xmlns.com/foaf/0.1/birthday> "05-26" .
<https://w3id.org/people/bsletten>
<http://xmlns.com/foaf/0.1/name> "Brian Sletten" .
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https://w3id.org/people/bsletten is a person.
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https://w3id.org/people/bsletten
http://www.w3.org/1999/02/22-rdf-syntaxns#type http://xmlns.com/foaf/0.1/Person.
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A Single Fact
# N-Triple Serialization of the Fact
<https://w3id.org/people/bsletten>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://xmlns.com/foaf/0.1/Person> .
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Three Facts
# N-Triple Serialization of the Facts
<https://w3id.org/people/bsletten>
<http://xmlns.com/foaf/0.1/birthday> "05-26" .
<https://w3id.org/people/bsletten>
<http://xmlns.com/foaf/0.1/name> "Brian Sletten" .
<https://w3id.org/people/bsletten>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://xmlns.com/foaf/0.1/Person> .
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RDF/XML
> rdfcat --out xml facts.nt
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:foaf="http://xmlns.com/foaf/0.1/" >
<rdf:Description rdf:about="https://w3id.org/people/bsletten">
<foaf:birthday>05-26</foaf:birthday>
<foaf:name>Brian Sletten</foaf:name>
<rdf:type rdf:resource="http://xmlns.com/foaf/0.1/Person"/>
</rdf:Description>
</rdf:RDF>
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Turtle
> rdfcat --out ttl facts.nt
<https://w3id.org/people/bsletten>
a
<http://xmlns.com/foaf/0.1/Person> ;
<http://xmlns.com/foaf/0.1/birthday>
"05-26" ;
<http://xmlns.com/foaf/0.1/name>
"Brian Sletten" .
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Turtle
> rdfcat --out ttl http://bosatsu.net/turtle/brian.ttl
<https://w3id.org/people/bsletten>
<http://xmlns.com/foaf/0.1/depiction>
<http://bosatsu.net/images/briansletten.jpg> .
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Turtle
> rdfcat --out ttl facts.nt http://bosatsu.net/turtle/brian.ttl
<https://w3id.org/people/bsletten>
a
<http://xmlns.com/foaf/0.1/Person> ;
<http://xmlns.com/foaf/0.1/birthday>
"05-26" ;
<http://xmlns.com/foaf/0.1/depiction>
<http://bosatsu.net/images/briansletten.jpg> ;
<http://xmlns.com/foaf/0.1/name>
"Brian Sletten" .
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Principles
http://www.w3.org/DesignIssues/LinkedData.html
· Use URIs to name things
· Use HTTP URIs to make them resolvable
· When someone resolves a URI, provide useful information via standards
(SPARQL, RDF, etc.)
· Include links for discoverability
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DBPedia
http://dbpedia.org
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Artists for St. Patrick's Day
· Find music recommendations related to St. Patrick's Day
· Use DBPedia to find musical artists who are from Ireland
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PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX : <http://dbpedia.org/resource/>
SELECT DISTINCT ?name ?person ?artist WHERE {
?person foaf:name ?name .
?person rdf:type dbo:MusicalArtist .
?person dbo:associatedMusicalArtist ?artist .
{ ?person dbo:hometown :Republic_of_Ireland . }
UNION
{ ?person dbo:birthPlace :Republic_of_Ireland . }
}
ORDER BY ?name
http://tinyurl.com/jwtt2aj
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Linked Data Platform
http://www.w3.org/TR/ldp/
Linked Data Platform 1.0
W3C Recommendation 26 February 2015
This version:
http://www.w3.org/TR/2015/REC-ldp-20150226/
Latest published version:
http://www.w3.org/TR/ldp/
Latest editor's draft:
http://www.w3.org/2012/ldp/hg/ldp.html
Test suite:
https://dvcs.w3.org/hg/ldpwg/raw-file/default/tests/ldp-testsuite.html
Implementation report:
https://dvcs.w3.org/hg/ldpwg/raw-file/default/tests/reports/ldp.html
Previous version:
http://www.w3.org/TR/2014/PR-ldp-20141216/
Editors:
Steve Speicher, IBM Corporation
John Arwe, IBM Corporation
Ashok Malhotra, Oracle Corporation
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RelFinder
http://www.visualdataweb.org/relfinder.php
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Books
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Questions?
$ [email protected]
! @bsletten
+ http://tinyurl.com/bjs-gplus
& bsletten
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