1. JSON-LD
JSON for Linked Data
Gregg Kellogg
gregg@greggkellogg.net
@gkellogg

2. JSON-LD
JSON for Linked Data
nk ing
Li
Gregg Kellogg
gregg@greggkellogg.net
@gkellogg

3. JSON
JSON has taken over service APIs

4. Tower of Babel

5. Tower of Babel
GitHub
{
"type": "User",
"followers": 35,
"html_url": "https://github.com/gkellogg",
"hireable": true,
"created_at": "2009-01-13T16:58:46Z",
"public_repos": 44,
"blog": "http://greggkellogg.net",
"bio": "Gregg is a Standards Architect ...",
"gravatar_id":
"42f948adff3afaa52249d963117af7c8",
"following": 35,
"company": "Self",
"public_gists": 4,
"location": "San Rafael, CA",
"name": "Gregg Kellogg",
"email": "gregg@kellogg-assoc.com",
"url": "https://api.github.com/users/gkellogg",
"avatar_url": "...",
"id": 46296,
"login": "gkellogg"

6. Tower of Babel
GitHub Twitter
{
{ "max_id": 195520745634406400,
"type": "User", "page": 1,
"followers": 35, "query": "%40gkellogg",
"html_url": "https://github.com/gkellogg", "results": [{
"hireable": true, "created_at": "Thu, 26 Apr 2012 14:32:33
"created_at": "2009-01-13T16:58:46Z", +0000",
"public_repos": 44, "from_user": "kendall",
"blog": "http://greggkellogg.net", "from_user_name": "Kendall Clark",
"bio": "Gregg is a Standards Architect ...", "id": 195520745634406400,
"gravatar_id": "in_reply_to_status_id":
"42f948adff3afaa52249d963117af7c8", 195518881811529729,
"following": 35, "iso_language_code": "en",
"company": "Self", "metadata": {"result_type": "recent"},
"public_gists": 4, "text": "@Gkellogg Multiple resources in a
"location": "San Rafael, CA", single JSON-LD struct/doc/message.",
"name": "Gregg Kellogg", "to_user": "Gkellogg",
"email": "gregg@kellogg-assoc.com", "to_user_id": 6125262,
"url": "https://api.github.com/users/gkellogg", "to_user_name": "Gregg Kellogg"
"avatar_url": "...", }],
"id": 46296, "results_per_page": 1,
"login": "gkellogg" "since_id": 0,
"since_id_str": "0"
}

7. Tower of Babel
GitHub Twitter Facebook
{
{ "max_id": 195520745634406400, {
"type": "User", "page": 1, "id": "1236600216",
"followers": 35, "query": "%40gkellogg", "name": "Gregg Kellogg",
"html_url": "https://github.com/gkellogg", "results": [{ "first_name": "Gregg",
"hireable": true, "created_at": "Thu, 26 Apr 2012 14:32:33 "last_name": "Kellogg",
"created_at": "2009-01-13T16:58:46Z", +0000", "link": "https://www.facebook.com/
"public_repos": 44, "from_user": "kendall", gkellogg",
"blog": "http://greggkellogg.net", "from_user_name": "Kendall Clark", "username": "gkellogg",
"bio": "Gregg is a Standards Architect ...", "id": 195520745634406400, "gender": "male",
"gravatar_id": "in_reply_to_status_id": "locale": "en_US"
"42f948adff3afaa52249d963117af7c8", 195518881811529729, }
"following": 35, "iso_language_code": "en",
"company": "Self", "metadata": {"result_type": "recent"},
"public_gists": 4, "text": "@Gkellogg Multiple resources in a
"location": "San Rafael, CA", single JSON-LD struct/doc/message.",
"name": "Gregg Kellogg", "to_user": "Gkellogg",
"email": "gregg@kellogg-assoc.com", "to_user_id": 6125262,
"url": "https://api.github.com/users/gkellogg", "to_user_name": "Gregg Kellogg"
"avatar_url": "...", }],
"id": 46296, "results_per_page": 1,
"login": "gkellogg" "since_id": 0,
"since_id_str": "0"
}

8. Introducing JSON-LD
@graph
@context
@id
JSON-based syntax to express linked data
@language
@value
@list
@type @set

9. Self-describing Messages
• Give objects types {
"@context": {
(@type) "schema": "http://schema.org/",
"Person": "schema:Person",
"colleagues": {"@id": "schema:colleagues", "@type": "@id"},
"name": "schema:name",
"image": {"@id": "schema:image", "@type": "@id"},
"url": {"@id": "schema:url", "@type": "@id"}
}
}
{
"@context": "http://example.com/context.jsonld",
"@type": "Person",
"image": "http://localhost:9393/examples/schema.org/janedoe.jpg",
"colleagues": [
"http://www.xyz.edu/students/alicejones.html",
"http://www.xyz.edu/students/bobsmith.html"
],
"name": "Jane Doe",
"url": "http://www.janedoe.com"
}

10. Self-describing Messages
• Give objects types {
"@context": {
(@type) "schema": "http://schema.org/",
"Person": "schema:Person",
•
"colleagues": {"@id": "schema:colleagues", "@type": "@id"},
Associate properties "name": "schema:name",
"image": {"@id": "schema:image", "@type": "@id"},
with IRIs "url": {"@id": "schema:url", "@type": "@id"}
}
}
{
"@context": "http://example.com/context.jsonld",
"@type": "Person",
"image": "http://localhost:9393/examples/schema.org/janedoe.jpg",
"colleagues": [
"http://www.xyz.edu/students/alicejones.html",
"http://www.xyz.edu/students/bobsmith.html"
],
"name": "Jane Doe",
"url": "http://www.janedoe.com"
}

11. Self-describing Messages
• Give objects types {
"@context": {
(@type) "schema": "http://schema.org/",
"Person": "schema:Person",
•
"colleagues": {"@id": "schema:colleagues", "@type": "@id"},
Associate properties "name": "schema:name",
"image": {"@id": "schema:image", "@type": "@id"},
with IRIs "url": {"@id": "schema:url", "@type": "@id"}
}
•
}
Use terms defined in a
referenced context {
"@context": "http://example.com/context.jsonld",
"@type": "Person",
"image": "http://localhost:9393/examples/schema.org/janedoe.jpg",
"colleagues": [
"http://www.xyz.edu/students/alicejones.html",
"http://www.xyz.edu/students/bobsmith.html"
],
"name": "Jane Doe",
"url": "http://www.janedoe.com"
}

12. Self-describing Messages
• Give objects types {
"@context": {
(@type) "schema": "http://schema.org/",
"Person": "schema:Person",
•
"colleagues": {"@id": "schema:colleagues", "@type": "@id"},
Associate properties "name": "schema:name",
"image": {"@id": "schema:image", "@type": "@id"},
with IRIs "url": {"@id": "schema:url", "@type": "@id"}
}
•
}
Use terms defined in a
referenced context {
"@context": "http://example.com/context.jsonld",
"@type": "Person",
• Specify property types
"image": "http://localhost:9393/examples/schema.org/janedoe.jpg",
"knows": [
"http://www.xyz.edu/students/alicejones.html",
in context "http://www.xyz.edu/students/bobsmith.html"
],
"name": "Jane Doe",
"url": "http://www.janedoe.com"
}

13. Language Principles

14. • Make full use of JSON syntactic
{
"@context": "http://json-ld.org/contexts/person",
representations "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
• Object defines a subject "name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
definition }

15. • Make full use of JSON syntactic
{
"@context": "http://json-ld.org/contexts/person",
representations "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
• Object defines a subject "name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
definition }
• Also used for subject
reference and value { "@id": "http://greggkellogg.net/foaf#me" }
representations

16. • Make full use of JSON syntactic
{
"@context": "http://json-ld.org/contexts/person",
representations "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
• Object defines a subject "name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
definition }
• Also used for subject
reference and value { "@id": "http://greggkellogg.net/foaf#me" }
representations
{
"@type": "Recipe",
"name": "Mom's World Famous Banana Bread",
"ingredients": [
• Arrays describe sets of unordered
values
"3 or 4 ripe bananas, smashed",
"1 egg",
"3/4 cup of sugar"
],
• Single values can skip array "nutrition": [{
"@type": ["NutritionInformation"],
"calories": ["240 calories"],
"fatContent": ["9 grams fat"]
}]
}

17. • Define terms to use short {
"@id": "http://greggkellogg.net/foaf#me",
property names "@type": "http://schema.org/Person",
"http://schema.org/name": "Gregg Kellogg",
• Convenient for JavaScript “.” "http://schema.org/knows": {
"@id": "http://www.markus-lanthaler.com/"
notation }
}
{
"@context": {
"Person": "http://schema.org/Person",
"name": "http://schema.org/name",
"knows”: "http://schema.org/knows"
},
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {"@id": "http://www.markus-lanthaler.com/"}
}

18. • Define terms to use short {
"@id": "http://greggkellogg.net/foaf#me",
property names "@type": "http://schema.org/Person",
"http://schema.org/name": "Gregg Kellogg",
• Convenient for JavaScript “.” "http://schema.org/knows": {
"@id": "http://www.markus-lanthaler.com/"
notation }
}
• Add @type coercions to
use simple string value.
{
"@context": {
"schema": "http://schema.org/",
"Person": "schema:Person",
"name": "schema:name",
"knows”: {
"@id": "schema:knows",
"@type": "@id"
},
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
}

19. • Define terms to use short {
"@id": "http://greggkellogg.net/foaf#me",
property names "@type": "http://schema.org/Person",
"http://schema.org/name": "Gregg Kellogg",
• Convenient for JavaScript “.” "http://schema.org/knows": {
"@id": "http://www.markus-lanthaler.com/"
notation }
}
• Add @type coercions to
use simple string value.
{
"@context": {
"schema": "http://schema.org/",
"Person": "schema:Person",
• Use external @context. "name": "schema:name",
"knows”: {
"@id": "schema:knows",
"@type": "@id"
}
}
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
}

20. •
{
Define referenced subject "@context": "http://json-ld.org/contexts/person",
definition with chaining "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}

21. •
{
Define referenced subject "@context": "http://json-ld.org/contexts/person",
definition with chaining "@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
• Add @language to values. "@type": "Person",
"name": "Gregg Kellogg",
"honorificSuffix": {"@value": "M.S.", "@language": "en"},
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"honorificSuffix": {"@value": "Dipl.Ing.", "@language": "de"},
"knows" "http://greggkellogg.net/foaf#me"
}
}

22. • Add @type to values. {
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
• Link to externally defined "@type": "Person",
"name": "Gregg Kellogg",
resources. "birthDate": {"@value": "1957-02-27", "@type": "xsd:date"},
"honorificSuffix": {"@value": "M.S.", "@language": "en"},
"knows": "http://www.markus-lanthaler.com/"
}

23. • Add property @type and {
"@context": {
@language definitions to "schema": "http://schema.org/",
context "Person": "schema:Person",
"name": "schema:name",
"birthDate”: {
"@id": "schema: birthDate","@type": "xsd:date"
},
"honorificSuffix”: {
"@id": "schema:honorificSuffix","@language": "en"
},
"knows”: {"@id": "schema:knows","@type": "@id"}
},
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"birthDate": "1957-02-27",
"honorificSuffix": "M.S.",
"knows": "http://www.markus-lanthaler.com/"
}

24. • More features defined in the syntax
specification*:
• @set, @list, Compact IRIs, Unlabeled
Nodes
• Embedded @context definitions
• Named Graphs
* http://json-ld.org/spec/latest/json-ld-syntax

25. Examples “In the Wild”

26. DBpedia
{
"@graph": [
{
"@id": "http://dbpedia.org/resource/DBpedia",
"http://dbpedia.org/property/genre" : [ "http://dbpedia.org/resource/Linked_Data" ]
},
{
"@id": "http://dbpedia.org/resource/Linked_Data",
"@type" : [ "http://dbpedia.org/class/yago/Buzzwords" ] ,
"http://www.w3.org/2002/07/owl#sameAs" : ["http://rdf.freebase.com/ns/m/02r2kb1"] ,
"http://www.w3.org/2000/01/rdf-schema#comment": [
{ "@value" : "Linked Open Data (LOD) bezeichnet ..." , "@language" : "de" } ,
{ "@value" : "In computing, linked Data describes ..." , "@language" : "en" } ],
"http://purl.org/dc/terms/subject" : [
"http://dbpedia.org/resource/Category:World_Wide_Web" ,
"http://dbpedia.org/resource/Category:Buzzwords" ,
"http://dbpedia.org/resource/Category:Semantic_Web"
],
...
}]
}
http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=DESCRIBE+<http://dbpedia.org/resource/
Linked_Data>&output=application%2Fld%2Bjson

27. Schema.org
Using RDFa to JSON-LD bookmarklet*
http://linter.structured-data.org/examples/
schema.org/sdo_eg_rdfa_12.html
* bookmarklet courtesy of Niklas Lindström

28. Schema.org
{
"@context": {...},
Using RDFa to JSON-LD bookmarklet* "@graph": [{
"@id": "http://linter.structured-data.org/examples/schema.org/Recipe.rdfa",
"rdfa:usesVocabulary": "http://schema.org/"
}, {
"@type": ["Recipe"],
"name": ["Mom's World Famous Banana Bread"],
"author": ["John Smith"],
"publishDate": ["2009-05-08"],
"image": [{"@id": ".../bananabread.jpg"}],
http://linter.structured-data.org/examples/ "description": ["This classic banana bread recipe ..."],
schema.org/sdo_eg_rdfa_12.html "prepTime": ["PT15M"],
"cookTime": ["PT1H"],
"recipeYield": ["1 loaf"],
"nutrition": [{
"@type": ["NutritionInformation"],
"calories": ["240 calories"],
"fatContent": ["9 grams fat"]
}],
"ingredients": [
"3 or 4 ripe bananas, smashed",
"1 egg",
"3/4 cup of sugar"
],
"recipeInstructions": ["Preheat the oven to 350 degrees..."],
"interactionCount": ["UserComments:140"]
}]
* bookmarklet courtesy of Niklas Lindström
}

29. Drupal
http://directory.occupy.net/node/20080.jsonld

30. Drupal
{
"@context": "http://drupal.example.org/context.jsonld",
"@id": "http://directory.occupy.net/occupation/al/occupy-
prishtina",
"@type": ["ows:Occupation", "schema:Organization"],
"foaf:name": "Occupy Prishtina",
"schema:name": "Occupy Prishtina",
"dc:date": "2012-02-12T21:18:08-05:00",
"dc:created": "2012-02-12T21:18:08-05:00",
"dc:modified": "2012-02-12T21:57:52-05:00",
"sioc:num_replies": 0,
"schema:foundingDate": "2011-10-15T00:00:00-04:00",
"ows:twitter_account": "@OccupyPrishtina",
"foaf:mbox": "",
"schema:telephone": "",
"foaf:phone": ""
}
http://directory.occupy.net/node/20080.jsonld

31. PaySwarm
{
"@context": "http://purl.org/payswarm/v1",
"@graph": {
"@type": "Transaction",
"transfer": {
"@type": "Transfer",
Named "amount": "7.50",
Graph "currency": "USD",
"source": "https://bluebank.com/people/manu/accounts/food",
"destination": "https://redbank.com/people/gregg/accounts/hosting",
"comment": "Chipping in for the Pizza Party tomorrow."
},
},
"signature": {
"@type": "JsonLdSignature",
Signature of "created": "2011-09-23T20:21:34Z",
"signer": "http://bluebank.com/people/manu/keys/5",
Named "signatureValue": "ExMgoDIyOGQzNGVkM...mOWM32Nj4NTIyZTkZDYMI="
Graph }
}

32. Working with data
• Expand documents to remove effect of @context.
{
"@context": "http://drupal.example.org/context.jsonld",
"@id": "http://directory.occupy.net/occupation/al/occupy-
prishtina",
"@type": ["ows:Occupation", "schema:Organization"],
"foaf:name": "Occupy Prishtina",
"schema:name": "Occupy Prishtina",
"dc:date": "2012-02-12T21:18:08-05:00",
"dc:created": "2012-02-12T21:18:08-05:00",
"dc:modified": "2012-02-12T21:57:52-05:00",
"sioc:num_replies": 0,
"schema:foundingDate": "2011-10-15T00:00:00-04:00",
"ows:twitter_account": "@OccupyPrishtina",
"foaf:mbox": "",
"schema:telephone": "",
"foaf:phone": ""
}

33. Working with data
• Expand documents to remove effect of @context.
[{
"@id": "http://directory.occupy.net/occupation/al/occupy-prishtina",
{ "@type": ["http://vocab.occupy.net/ows#Occupation", "http://schema.org/Organization"],
"@context": "http://drupal.example.org/context.jsonld", "http://purl.org/dc/terms/created": [{
"@id": "http://directory.occupy.net/occupation/al/occupy- "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"@value": "2012-02-12T21:18:08-05:00"
prishtina",
}],
"@type": ["ows:Occupation", "schema:Organization"], "http://purl.org/dc/terms/date": [{
"foaf:name": "Occupy Prishtina", "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"schema:name": "Occupy Prishtina", "@value": "2012-02-12T21:18:08-05:00"
}],
"dc:date": "2012-02-12T21:18:08-05:00",
"http://purl.org/dc/terms/modified": [{
"dc:created": "2012-02-12T21:18:08-05:00", "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"dc:modified": "2012-02-12T21:57:52-05:00", "@value": "2012-02-12T21:57:52-05:00"
"sioc:num_replies": 0, }],
"http://rdfs.org/sioc/ns#num_replies": [{
"schema:foundingDate": "2011-10-15T00:00:00-04:00",
"@type": "http://www.w3.org/2001/XMLSchema#integer",
"ows:twitter_account": "@OccupyPrishtina", "@value": "0"
"foaf:mbox": "", }],
"schema:telephone": "", "http://schema.org/foundingDate": [{
"@type": "http://www.w3.org/2001/XMLSchema#date",
"foaf:phone": ""
"@value": "2011-10-15T00:00:00-04:00"
} }],
"http://schema.org/name": ["Occupy Prishtina"],
"http://schema.org/telephone": [""],
"http://vocab.occupy.net/ows#twitter_account": ["@OccupyPrishtina"],
"http://xmlns.com/foaf/0.1/mbox": [""],
"http://xmlns.com/foaf/0.1/name": ["Occupy Prishtina"],
"http://xmlns.com/foaf/0.1/phone": [""]
}]

34. Working with data
• Compact documents to apply a @context.
[{
"@id": "http://directory.occupy.net/occupation/al/occupy-prishtina",
"@type": ["http://vocab.occupy.net/ows#Occupation", "http://schema.org/Organization"],
"http://purl.org/dc/terms/created": [{
"@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"@value": "2012-02-12T21:18:08-05:00"
}],
"http://purl.org/dc/terms/date": [{
"@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"@value": "2012-02-12T21:18:08-05:00"
}],
"http://purl.org/dc/terms/modified": [{
"@type": "http://www.w3.org/2001/XMLSchema#dateTime",
"@value": "2012-02-12T21:57:52-05:00"
}],
"http://rdfs.org/sioc/ns#num_replies": [{
"@type": "http://www.w3.org/2001/XMLSchema#integer",
"@value": "0"
}],
"http://schema.org/foundingDate": [{
"@type": "http://www.w3.org/2001/XMLSchema#date",
"@value": "2011-10-15T00:00:00-04:00"
}],
"http://schema.org/name": ["Occupy Prishtina"],
"http://schema.org/telephone": [""],
"http://vocab.occupy.net/ows#twitter_account": ["@OccupyPrishtina"],
"http://xmlns.com/foaf/0.1/mbox": [""],
"http://xmlns.com/foaf/0.1/name": ["Occupy Prishtina"],
"http://xmlns.com/foaf/0.1/phone": [""]
}]

35. Working with data
• Compact documents to apply a @context.
[{
"@id": "http://directory.occupy.net/occupation/al/occupy-prishtina",
{
"@type": ["http://vocab.occupy.net/ows#Occupation", "http://schema.org/Organization"], "@context": "http://drupal.example.org/context.jsonld",
"http://purl.org/dc/terms/created": [{ "@id": "http://directory.occupy.net/occupation/al/occupy-
"@type": "http://www.w3.org/2001/XMLSchema#dateTime", prishtina",
"@value": "2012-02-12T21:18:08-05:00" "@type": ["ows:Occupation", "schema:Organization"],
}],
"http://purl.org/dc/terms/date": [{ "foaf:name": "Occupy Prishtina",
"@type": "http://www.w3.org/2001/XMLSchema#dateTime", "schema:name": "Occupy Prishtina",
"@value": "2012-02-12T21:18:08-05:00" "dc:date": "2012-02-12T21:18:08-05:00",
}], "dc:created": "2012-02-12T21:18:08-05:00",
"http://purl.org/dc/terms/modified": [{
"@type": "http://www.w3.org/2001/XMLSchema#dateTime", "dc:modified": "2012-02-12T21:57:52-05:00",
"@value": "2012-02-12T21:57:52-05:00" "sioc:num_replies": 0,
}], "schema:foundingDate": "2011-10-15T00:00:00-04:00",
"http://rdfs.org/sioc/ns#num_replies": [{ "ows:twitter_account": "@OccupyPrishtina",
"@type": "http://www.w3.org/2001/XMLSchema#integer",
"@value": "0" "foaf:mbox": "",
}], "schema:telephone": "",
"http://schema.org/foundingDate": [{ "foaf:phone": ""
"@type": "http://www.w3.org/2001/XMLSchema#date", }
"@value": "2011-10-15T00:00:00-04:00"
}],
"http://schema.org/name": ["Occupy Prishtina"],
"http://schema.org/telephone": [""],
"http://vocab.occupy.net/ows#twitter_account": ["@OccupyPrishtina"],
"http://xmlns.com/foaf/0.1/mbox": [""],
"http://xmlns.com/foaf/0.1/name": ["Occupy Prishtina"],
"http://xmlns.com/foaf/0.1/phone": [""]
}]

36. Working with data
• Frame documents to impose structure
input
{
"@context": {
"dc": "http://purl.org/dc/elements/1.1/",
"ex": "http://example.org/vocab#",
"contains": {"@type": "@id"}
},
"@graph": [{
"@id": "http://example.org/test/#library",
"@type": "ex:Library",
"ex:contains": "http://example.org/test#book"
}, {
"@id": "http://example.org/test#book",
"@type": "ex:Book",
"dc:contributor": "Writer",
"dc:title": "My Book",
"ex:contains": "http://example.org/test#chapter"
}, {
"@id": "http://example.org/test#chapter",
"@type": "ex:Chapter",
"dc:description": "Fun",
"dc:title": "Chapter One"
}]
}

37. Working with data
• Frame documents to impose structure
input frame
{ {
"@context": { "@context": {
"dc": "http://purl.org/dc/elements/1.1/", "dc": "http://purl.org/dc/elements/1.1/",
"ex": "http://example.org/vocab#", "ex": "http://example.org/vocab#",
"contains": {"@type": "@id"} "contains": {“@id”: “ex:contains”, "@type": "@id",
}, “title”: “dc:title”
"@graph": [{ },
"@id": "http://example.org/test/#library", "@type": "ex:Library",
+
"@type": "ex:Library", "contains": {
"ex:contains": "http://example.org/test#book" "@type": "ex:Book",
}, { "contains": {
"@id": "http://example.org/test#book", "@type": "ex:Chapter"
"@type": "ex:Book", }
"dc:contributor": "Writer", }
"dc:title": "My Book", }
"ex:contains": "http://example.org/test#chapter"
}, {
"@id": "http://example.org/test#chapter",
"@type": "ex:Chapter",
"dc:description": "Fun",
"dc:title": "Chapter One"
}]
}

38. Working with data
• Frame documents to impose structure
input frame output
{ {
{
"@context": { "@context": {
"@context": {
"dc": "http://purl.org/dc/elements/1.1/", "dc": "http://purl.org/dc/elements/1.1/",
"dc": "http://purl.org/dc/elements/1.1/",
"ex": "http://example.org/vocab#", "ex": "http://example.org/vocab#",,
"ex": "http://example.org/vocab#",
"contains": {“@id”: “ex:contains”, "@type": "@id", "contains": {“@id”: “ex:contains”, "@type": "@id"
"contains": {"@type": "@id"}
“title”: “dc:title” “title”: “dc:title”
},
}, },
"@graph": [{
"@type": "ex:Library", "@graph": [{
"@id": "http://example.org/test/#library", "@id": "http://example.org/test/#library",
+
"@type": "ex:Library", "contains": {
"@type": "ex:Book", "@type": "ex:Library",
"ex:contains": "http://example.org/test#book"
"contains": { "contains": {
}, {
"@type": "ex:Chapter" "@id": "http://example.org/test#book",
"@id": "http://example.org/test#book",
} "@type": "ex:Book",
"@type": "ex:Book",
} "dc:contributor": "Writer",
"dc:contributor": "Writer",
} "title": "My Book",
"dc:title": "My Book", "contains": {
"ex:contains": "http://example.org/test#chapter" "@id": "http://example.org/test#chapter",
}, { "@type": "ex:Chapter",
"@id": "http://example.org/test#chapter", "dc:description": "Fun",
"@type": "ex:Chapter", "title": "Chapter One"
"dc:description": "Fun", }
"dc:title": "Chapter One" }
}] }]
} }
JavaScript object path: data[‘@graph][0].contains.contains.title

39. Retrofit existing APIs
GET /foaf.json HTTP/1.1
Host: greggkellogg.net
Accept: application/json,*/*;q=0.1
====================================
HTTP/1.0 200 OK
...
Content-Type: application/json
Link: <http://json-ld.org/contexts/person>; rel="describedby"; type="application/ld+json"
{
"name": "Gregg Kellogg",
"homepage": "http://greggkellogg.net/",
"depiction": "http://twitter.com/account/profile_image/gkellogg"
}

40. Macros
• Transform information
{
"type": "User",
• Add @id to data
"followers": 35,
"name": "Gregg Kellogg",
• Other programmatic
transformations
"email": "gregg@kellogg-assoc.com",
"url": "https://api.github.com/users/
gkellogg",
"avatar_url": "...",
"id": 46296,
"login": "gkellogg"
}
* json-ld-macros courtesy of Antonio Garrote

41. {
Macros
"type": "User",
"followers": 35,
"name": "Gregg Kellogg",
"email": "gregg@kellogg-assoc.com",
• Transform information
"url": "https://api.github.com/users/
gkellogg",
"avatar_url": "...",
"id": 46296,
• Add @id to data
}
"login": "gkellogg"
• Other programmatic
transformations
* json-ld-macros courtesy of Antonio Garrote

42. {
Macros
"type": "User",
"followers": 35,
"name": "Gregg Kellogg",
"email": "gregg@kellogg-assoc.com",
• Transform information
"url": "https://api.github.com/users/
gkellogg",
"avatar_url": "...",
"id": 46296,
• Add @id to data
{
}
+
"login": "gkellogg"
• Other programmatic
transformations
"https://api.github.com/users/*": {
"$": {
"@context": {
"foaf": "http://xmlns.com/foaf/0.1/",
"foaf:depiction": {"@type": "@id"},
"gh": "https://api.github.com/vocabulary#"
},
"@id": [{"f:valueof": "login"},
{"f:prefix": "http://github.com/"}],
"@ns": {
"ns:default": "gh",
"ns:replace": {"avatar_url": "foaf:depiction", "name":
"foaf:name"}
},
"@only": ["avatar_url", "name", "followers"],
"@type": ["gh:User", "foaf:Person"]
}
}
}
* json-ld-macros courtesy of Antonio Garrote

43. {
Macros
"type": "User",
"followers": 35,
"name": "Gregg Kellogg",
"email": "gregg@kellogg-assoc.com",
• Transform information
"url": "https://api.github.com/users/
gkellogg",
"avatar_url": "...",
"id": 46296,
• Add @id to data
{
}
+
"login": "gkellogg"
• Other programmatic
transformations
"https://api.github.com/users/*": {
"$": {
"@context": {
{
"foaf": "http://xmlns.com/foaf/0.1/",
"@context": {
"foaf:depiction": {"@type": "@id"},
"foaf": "http://xmlns.com/foaf/0.1/",
"gh": "https://api.github.com/vocabulary#"
"foaf:depiction": {"@type": "@id"},
},
"gh": "https://api.github.com/
"@id": [{"f:valueof": "login"},
vocabulary#"
{"f:prefix": "http://github.com/"}],
},
"@ns": {
"@id": "https://api.github.com/users/
"ns:default": "gh",
gkellogg",
"ns:replace": {"avatar_url": "foaf:depiction", "name":
"@type": ["gh:User", “foaf:Person”],
"foaf:name"}
"foaf:name": "Gregg Kellogg",
},
"foaf:depiction": "http://...",
"@only": ["avatar_url", "name", "followers"],
“gh:followers”: 35
"@type": ["gh:User", "foaf:Person"]
}
}
}
* json-ld-macros courtesy of Antonio Garrote

44. The “LD” in JSON-LD
• IRIs are first-class http://greggkellogg.net/foaf
citizens {
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
}
http://www.markus-lanthaler.com
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}

45. The “LD” in JSON-LD
• IRIs are first-class http://greggkellogg.net/foaf
citizens {
"@context": "http://json-ld.org/contexts/person",
• Object definitions may
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
be referenced or "name": "Gregg Kellogg",
"knows": "http://www.markus-lanthaler.com/"
embedded }
http://www.markus-lanthaler.com
{
{ "@context": "http://json-ld.org/contexts/person",
"@context": "http://json-ld.org/contexts/person", "@id": "http://www.markus-lanthaler.com/",
"@id": "http://greggkellogg.net/foaf#me", "@type": "Person",
"@type": "Person", "name": "Markus Lanthaler",
"name": "Gregg Kellogg", "knows" "http://greggkellogg.net/foaf#me"
"knows": { }
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}

46. RDF 
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}

47. RDF 
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}

48. RDF 
{
"@context": "http://json-ld.org/contexts/person",
"@id": "http://greggkellogg.net/foaf#me",
"@type": "Person",
"name": "Gregg Kellogg",
"knows": {
"@id": "http://www.markus-lanthaler.com/",
"@type": "Person",
"name": "Markus Lanthaler",
"knows" "http://greggkellogg.net/foaf#me"
}
}
@prefix: schema <http://schema.org/> .
<http://greggkellogg.net/foaf#me> a schema:Person;
schema:name “Gregg Kellogg”;
shema:knows <http://www.markus-lanthaler.com/> .
<http://www.markus-lanthaler.com/> a schema:Person
schema:name “Markus Lanthaler”
schema:knows <http://greggkellogg.net/foaf#me> .

49. JSON-LD API
• compact – use minimal representation
using a supplied @context
• expand – expand to full form, removing
embedded @context definitions
• frame – query for JSON-LD
• fromRDF/toRDF

50. More Information
json-ld.org JavaScript
Ruby
w3c Python
PHP
Java
Gregg Kellogg C++
gregg@greggkellogg.net
http://greggkellogg.net/
http://www.slideshare.net/gkellogg1/json-for-linked-data
@gkellogg