Semantics-enabled Web APIs selection patterns - ConfSys

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Semantics-enabled Web APIs selection patterns Devis Bianchini, Valeria De Antonellis, Michele Melchiori Department of Information Engineering Università di Brescia - Italy Semantics-enabled Web APIs selection patterns

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Mashup application: “a situational, short-living Web application with focus on Web Interface integration that uses data and/or application logics (e.g., Web Services) originated from third parties and that are made available through Web APIs”

Semantics-enabled Web APIs selection patterns

Fast Web application development scenario Choose some relevant Web APIs Web APIs Registry

Decide which ones should be connected (exploratory perspective)

connected Glue alternative


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Fast Web application development Which open issues? Huge quantity of Web APIs requires a support for their effective selection and integration (>3k APIs in ProgrammableWeb.com, >20k user-defined mashups in Yahoo! Pipes). Heterogeneity of Web APIs (I/Os, operations).

Our contributions: 1. A browsable Web API registry built from automated matching techniques to establish semantic links among APIs 2. Semi-automated selection patterns for Web APIs


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Talk Outline

A semantic framework for Mashup development

Web API Selection patterns

The tool prototype implementation

Conclusions and future work


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We rely on existing technologies and tools

Focus of this talk

Wn

W3

URI 2

W2

W3

URI 3

Web API Registry

URI 3

URI 2 URI 1

URI 2

URI 1

W2

Wn

URI n

Component APIs


Mashup development

URI n

Web API Semantic Descriptors (SDs)

W1

URI n

W3

URI 3 URI 2

Wn

W2 URI n

W1

Recommendation of Web APIs

URI 3

Matchmaking and linking of semantic descriptors

Semantic annotation

URI 1

Developing & publishing Web API

Future work consumer/ mashup designer

component provider

OBJECTS

ACTIVITIES

ROLES

Mashup development: our vision

Web application

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Web API Annotation Web APIs are usually described using plain, unstructured HTML - semantic annotation of Web APIs is still a difficult task Semantic annotation of APIs in our framework is therefore performed according to the steps suggested in the SWEET tool [1]: (a)

identification of elements (that is, operations, inputs, outputs) in the unstructured HTML document which represents the API, to produce an hRESTS description;

(b)

search for ontologies suitable for elements annotation and of taxonomies of categories for API classification;

(c)

annotation and classification of the API according to the MicroWSMO notation.

[1] M. Maleshkova, C. Pedrinaci, and J. Domingue. Semantic annotation of Web APIs with SWEET. In Proc. of 6th Workshop on Scripting and Development for the Semantic Web, 2010. Semantics-enabled Web APIs selection patterns

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Web API Semantic Descriptor An abstract representation:

W Wii == 〈uri 〈uriii,CAT(W ,CAT(Wii),OP(W ),OP(Wii),EV(W ),EV(Wii)〉 )〉 opl ∈OP(Wi) op opll == 〈method 〈methodll,addr ,addrll,IN(op ,IN(opll),OUT(op ),OUT(opll)〉 )〉

concept


set of concepts

evm ∈EV(Wi) ev (ev m)〉 evmm == 〈type 〈typemm,OUT ,OUTev )〉 ev(evm

set of concepts

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Functional coupling between Web APIs

A Web API descriptor Wi can be functionally coupled with another Web API descriptor Wj if: 1.

CouplIO(Wi, Wj) ≥ θ ∈ [0..1] (functional coupling degree)

Union set of the outputs of the event evi


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Functional similarity between Web APIs A Web API descriptor Wi is functionally similar to another Web API descriptor Wj if: 1. 2.

The categories of Wi and Wj are compatible SimIO(Wi, Wj) ≥ δ ∈ [0..1] (functional similarity degree)

Union of the input sets of all the Wj operations


Union of the output sets of all the Wi operations

Concept affinity

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Web API Registry

The registry design is based on the Web APIs conceptual description:

• semantic descriptor of the API (semantic annotation)

• semantic links between similar and coupled Web APIs


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Web API Registry ComingSoon InternetVideoArchive 0.37 Coupl IO=

Cou

plI = O 0. 90

GoogleMaps Coupl

IO =0.78

SimIO=0.60

FindMovieTheatres u Co

CouplIO=0.83

1 0.8 = O

65

pl I

Co

upl

IO = 0

MoviesAndTheatres

.73

SimIO=0.86 1.00 = l O pI Co u


CouplIO=0.60

MapViewer

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Web API Selection Patterns σ = 〈W Goal,, m , δ Goal,,