1.
SIMPLE
SERVERS
CLEVER
CLIENTS
Ruben Verborgh
Hypermedia APIs
that make sense

2.
HOW DO WE
MEASURE
SUCCESS?

3.
MY API IS GOOD
BECAUSE I USE SWAGGER.
YOUR API SUCKS
BECAUSE IT’S NOT REST.
MY API IS DOING HYPERMEDIA,
LIKE, FOR REAL.

4.
MY WEBSITE IS GOOD
BECAUSE I USE FLASH.
YOUR WEBSITE SUCKS
BECAUSE THE MENU IS ON TOP.
MY WEBSITE REQUIRES ONLY
3 CLICKS TO ACCESS STUFF.

5.
API DESIGN
IS STUCK WHERE
WEB INTERACTION DESIGN
WAS 15 YEARS AGO.

6.
WEB INTERACTION DESIGN
IN 2015 IS MEASURABLE:
HOW LONG DOES IT TAKE
CUSTOMERS TO BUY
WHAT THEY WANT?

7.
WEB INTERACTION DESIGN
IN 2015 IS MEASURABLE:
HOW OFTEN IS
OUR CONTENT SHARED
ON TWITTER?

8.
HOW CAN WE
MEASURE WEB API
DESIGN DECISIONS?

9.
HOW CAN WE
MEASURE WEB API
DESIGN DECISIONS?
www.docsduds.com

10.
PUBLISHING
LINKED DATA
QUANTIFYING
WEB APIS
MAKING SENSE
WITH HYPERMEDIA
1
2
3

11.
PUBLISHING
LINKED DATA
QUANTIFYING
WEB APIS
MAKING SENSE
WITH HYPERMEDIA
1
2
3

12.
LINKED DATA
CAPTURES FACTS
WITH LINKS

13.
http://dbpedia.org/
resource/Nikola_Tesla
http://dbpedia.org/
resource/Thomas_Edison
http://xmlns.com/foaf/
0.1/knows
“Nikola”
http://xmlns.com/foaf/
0.1/givenName
RDF

14.
{
"@id": "dbpedia:Nikola_Tesla",
"foaf:knows": "dbpedia:Thomas_Edison",
"foaf:givenName": "Nikola"
JSON-LD
!
!
!
!
}

15.
WIKIPEDIA IS
TRANSLATED INTO
500 MILLION
LINKED DATA FACTS.

16.
IT CAN BE QUERIED
BY THE WEB’S
MOST POWERFUL API.

17.
SPARQLQUERY LANGUAGE

18.
?
?
?
SPARQL

19.
WHICH FRENCH CITIES
HAVE A POPULATION OF
MORE THAN 200.000?
SPARQL

20.
WHICH MOVIES WERE
DIRECTED BY WOMEN
WHO WROTE NOVELS?
SPARQL

21.
SPARQL
WEB API

22.
THE WEB API
IS THE SAME
AS THE LANGUAGE:
ASK ANYTHING

23.
/SPARQL?QUERY=
WHICH FRENCH CITIES
HAVE A POPULATION OF
MORE THAN 200.000?
SPARQL

24.
/SPARQL?QUERY=
WHICH MOVIES WERE
DIRECTED BY WOMEN
WHO WROTE NOVELS?
SPARQL

25.
IT’S LIKE THE
GRAPHQL OF
LINKED DATA
WITHOUT MONEY

26.
THE SPARQL API
IS SO POWERFUL THAT
THAT MOST ENDPOINTS
ARE DOWN
> 1.5 DAY EACH MONTH

27.
THE SPARQL API
IS SO POWERFUL THAT
THAT MOST ENDPOINTS
ARE DOWN
> 1.5 DAY EACH MONTH

28.
PUBLISHING
LINKED DATA
QUANTIFYING
WEB APIS
MAKING SENSE
WITH HYPERMEDIA
1
2
3

29.
SPARQL
WEB API
LET’S MEASURE THE

30.
S!
C

31.
S!
C
!
C
!
C
!
C
!
C
!
C
!
C

32.
EACH CLIENT SENDS
UNIQUE REQUESTS, SO
CACHING IS INEFFECTIVE
REQUESTS CAN BE
ARBITRARILY COMPLICATED
THE INTERFACE
IS EXPENSIVE

33.
1 240 CLIENTS
SPARQL API
QUERIES
PER HOUR
100 200

34.
SPARQL API
1 240 CLIENTS100 200
SERVER
CPU LOAD

35.
SPARQL API
1 240 CLIENTS100 200
CLIENT
CPU LOAD

36.
SPARQL API
1 240 CLIENTS100 200
CACHE
REUSE

37.
WHO WILL PAY
FOR SUCH AN
EXPENSIVE API?

38.
PUBLISHING
LINKED DATA
QUANTIFYING
WEB APIS
MAKING SENSE
WITH HYPERMEDIA
1
2
3

39.
WHAT IF WE MADE
A BETTER API?
GUESS WHAT?
THAT’S WHAT
EVERYBODY DOES!

40.
2005 2010 2015
186
2,418
14,368
NUMBER
OF APIS

41.
2005 2010 2015
186
2,418
14,368
NUMBER
OF CLIENTS

42.
HOW CAN WE
THEN EXECUTE
UNIFORM QUERIES?
WE DON’T.

43.
HOW CAN WE
THEN QUERY
MULTIPLE APIS?
WE CAN’T.

44.
WHAT IF WE MADE
A SIMPLER API THAT
EXPLAINED ITSELF
WITH HYPERMEDIA?

45.
“I DON’T DO
SERVER
”

46.
“BUT I DO
SERVER
”

47.
“SO IF I
WANT TO DO
CLIENT
”

48.
“THEN I NEED
TO ASK YOU
CLIENT
”

49.
“AND COMBINE IT
MYSELF INTO
CLIENT
”

50.
CLIENTS STILL
ANSWER COMPLEX
SPARQL QUERIES,
JUST NOT WITH
THE SPARQL API

51.
SERVER
TRIPLE PATTERN
FRAGMENTS API

52.
SERVER CLIENT
SPARQL API
TPF API
(nothing)

53.
SIMPLE
SERVER
CLEVER
CLIENT
TPF API

54.
1 240 CLIENTS
SPARQL API
QUERIES
PER HOUR
TPF API
100 200

55.
SPARQL API
TPF API
1 240 CLIENTS100 200
SERVER
CPU LOAD

56.
SPARQL API
TPF API
1 240 CLIENTS100 200
CLIENT
CPU LOAD

57.
SPARQL API
TPF API
1 240 CLIENTS100 200
CACHE
REUSE

58.
RESPONSES CONTAIN
HYPERMEDIA CONTROLS
IN JSON-LD USING THE
HYDRA VOCABULARY

59.
{
"@id": "http://fragments.dbpedia.org/2015/en#dataset",
"search": {
"template": "/2015/en{?subject,predicate,object}",
"mapping": [
{ "variable": "subject", "property": "rdf:subject" },
{ "variable": "predicate", "property": "rdf:predicate" },
{ "variable": "object", "property": "rdf:object" }
]
}
}
JSON-LD

60.
I CAN DO
I CAN DO
I CAN DO
I CAN DO

61.
2005 2010 2015
186
2,418
14,368
664,368
NUMBER
OF APIS

62.
2005 2010 2015
186
2,418
14,368
NUMBER
OF CLIENTS
14,369

63.
TRY A SIMPLE SERVER
AND A CLEVER CLIENT
data.linkeddatafragments.org
client.linkeddatafragments.org

64.
PUBLISHING
LINKED DATA
QUANTIFYING
WEB APIS
MAKING SENSE
WITH HYPERMEDIA
1
2
3

65.
WHEN DOES
A CLIENT TRULY
HAVE POWER?

66.
IF IT SIMPLY
USES
CLEVER APIS?

67.
IF IT CLEVERLY
USES
SIMPLE APIS?

68.
IF YOU HAVE THE MONEY,
USE SPARQL OR GRAPHQL
INTELLIGENCE
IS EXPENSIVE
IF NOT, LET EACH CLIENT
USE ITS OWN CPU

69.
I STOPPED THINKING
ABOUT WEB APIS
A LONG TIME AGO
I’M NOW THINKING
ABOUT WEB CLIENTS
AND WHEN I SAY WEB,
I MEAN HYPERMEDIA

70.
I CAN’T MEASURE
HYPERMEDIA,
BUT I CAN MEASURE
CLIENTS DOING
THE SAME TASKS
ON DIFFERENT APIS

71.
HYPERMEDIA LETS
A SERVER EXPLAIN
ITS API TO CLIENTS,
SO THEY CAN USE IT
IN MEASURABLY
DIFFERENT WAYS.

72.
SIMPLE
SERVERS
CLEVER
CLIENTS
@RubenVerborgh
Hypermedia APIs
that make sense