1. A Semantic Description Language for
RESTful Web Services
to Combat Semaphobia
Markus Lanthaler
Graz University of Technology

2. Web services are increasingly popular

3. Why do we Why do we
need a website? need an API?
1995 2000 2005 2010
Of course we Of course we
have a website have an API
Adapted from T. Vitvar’s and J. Musser’s ECOWS 2010 Keynote,
“ProgrammableWeb.com: Statistics, Trends, and Best Practices”

4. Lightweight semantic annotations
start to gain acceptance

5. Increasing interest in the relationship of
RESTful services and Linked Data

7. Need a machine-readable
service description
© Clever Cupcakes

8. © Nesster
All previous efforts assume
RPC-style. REST is different.

9. Semaphobia!?

10. simplicity
son

11. Metadata Element description
Model
Prefixes Links Type ref.
Semantics Properties Items
Media type &
Prefix Name URI Target SEREDASj desc.
Predicate Object(s) Name
Request
Semantics
SEREDASj d.
Variables Semantics
Model
Predicate Object(s) Name Binding Predicate Object(s)
ref.

12. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}

13. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
{
"meta": {
"prefixes": {
"foaf": "http://xmlns.com/foaf/0.1/",
"ex": "http://example.com/onto#",
...
},
},

14. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
"type": "object",
"model": "[foaf:Person]",
"properties": {
"id": {
"type": "number", "model": "[ex:id]" },
"first_name": {
"type": "string", "model": "[foaf:firstName]" },
"last_name": {
"type": "string", "model": "[foaf:surname]" },
...

15. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
"type": "object",
"model": "[foaf:Person]",
"properties": {
"id": {
"type": "number", "model": "[ex:id]" },
"first_name": {
"type": "string", "model": "[foaf:firstName]" },
"last_name": {
"type": "string", "model": "[foaf:surname]" },
...

16. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
"type": "object",
"model": "[foaf:Person]",
"properties": {
"id": {
"type": "number", "model": "[ex:id]" },
"first_name": {
"type": "string", "model": "[foaf:firstName]" },
"last_name": {
"type": "string", "model": "[foaf:surname]" },
...

17. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
"type": "object",
"model": "[foaf:Person]",
"properties": {
"id": {
"type": "number", "model": "[ex:id]" },
"first_name": {
"type": "string", "model": "[foaf:firstName]" },
"last_name": {
"type": "string", "model": "[foaf:surname]" },
...

18. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
"links": {
"/user/search{?query}": {
"mediaType": "application/json",
"seredasjDescription": "personlist.json",
"semantics": {
"[iana:relation]": "[iana:search]" },
"variables": {
"query": { "model": "[foaf:name]" }
}
},

19. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
"/user/{id}": {
"mediaType": "application/json",
"seredasjDescription": "#",
"variables": {
"id": {
"binding": "#properties/knows/id"
} },
"requestDescription": "#"
}
}

20. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}

21. A person. (object)
id number
first_name string The first name of a person.
last_name string The surname of some person.
gender string The gender of this Agent (typically but
not necessarily 'male' or 'female').
knows array A person known by this person
(indicating some level of reciprocated
interaction between the parties).
A person. (object)
id number
name string A name for some thing.

23. strong emphasis on simplicity many use
cases
son
discovery and composition

24. Thank You
© 2011, Markus Lanthaler. Some Rights Reserved.
http://creativecommons.org/licenses/by-nc-sa/3.0/

25. Questions?
Markus Lanthaler
Markus.Lanthaler@student.TUGraz.at

26. Image Credits
(3) Adapted from T. Vitvar’s and J. Musser’s ECOWS 2010 Keynote,
“ProgrammableWeb.com: Statistics, Trends, and Best Practices”
(7) http://en.wikipedia.org/wiki/The_Scream
(9) http://www.flickr.com/photos/clevercupcakes/4397152402/
(10) http://www.flickr.com/photos/nesster/3168425434/

27. Bonus Slides

28. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
"knows": {
"type": "array",
"model": "[foaf:knows]",
"items": {
"type": "object", "model": "[foaf:Person]",
"properties": {
"id": {
"type": "number", "model": "[ex:id]" },
...

29. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
"knows": {
"type": "array",
"model": "[foaf:knows]",
"items": {
"type": "object", "model": "[foaf:Person]",
"properties": {
"id": {
"type": "number", "model": "[ex:id]" },
...

30. {
"id": 556410,
"first_name": "Markus",
"last_name": "Lanthaler",
"gender": "male",
"knows": [
{ "id": 586807, "name": "Christian Gütl" },
{ "id": 790980, "name": "John Doe" } ]
}
"knows": {
"type": "array",
"model": "[foaf:knows]",
"items": {
"type": "object", "model": "[foaf:Person]",
"properties": {
"id": {
"type": "number", "model": "[ex:id]" },
...

31. @base <http://example.com/user/556410> .
<#> rdf:type foaf:Person .
<#> ex:id 556410 .
<#> foaf:firstName "Markus" .
<#> foaf:surname "Lanthaler" .
<#> foaf:gender "male" .
<#> foaf:knows <#knows/0> .
<#knows/0> rdf:type foaf:Person .
<#knows/0> ex:id 586807 .
<#knows/0> foaf:name "Christian Gütl" .
<#> foaf:knows <#knows/1> .
<#knows/1> rdf:type foaf:Person .
<#knows/1> ex:id 790980 .
<#knows/1> foaf:name "John Doe" .
<http://example.com/user/586807> owl:sameAs <#knows/0> .
<http://example.com/user/790980> owl:sameAs <#knows/1> .