Migrating of SOAP-based Services to RESTful Services

Bipin Upadhyaya

Queen’s University

Limitations of SOAP-based Services

No Web in traditional web servicesNo use of scalability features of WebService provider dependent interfacesProblematic standardization process

InfightingLack of architectural coherence

2

RESTful Services

A resource is any entity that can be identified or named

Uniform interface for all resourcesHypermedia as the engine of application state

(HATEOAS)Not only the name of resources but also the

relationships between resources

3

4

1. Request

Resources

2. Response

How does client know about Resources ?Initial starting nodeAnd then the user agent is guided through the response

Links and Forms

GET http://../book?search=Night Star

<xml><book><name>Night Star </name><author> </author></book><a rel=“review” href=“http://..order/ns/reveiw” /><a rel=“order” href=“http://..order/ns” /></xml>

GET http://..order/ns/reveiw 3. Request

“….. 85% of service requests employed on RESTful API, not SOAP, and that querying Amazon using REST was roughly six times faster than with the SOAP equivalents”

-Jeff Barr [Amazon]

Protocol usage by API [src: programmableweb.com]

Total Service : 2198

5

SSOAOAPPRRESESTT

Motivation

RESTful services has various advantages over SOAP-based servicesScalability of component interactionsGenerality of interfacesIndependence in components deployment

New services and service clients support RESTful services

6

WSDL

I/O Parameters

7

Overview of Our Approach

8

Clustering WSDL Operations

Criteria for Clustering

923.1255

))15((*2),( =

++++=rByIDGetCustomeomerGetAllCustsimilarity

9

Identifying Resources From a Cluster

Extract NounsInput and output parameters is considered as

noun

Find word relationship/hierarchy between extracted words

Find resource/container relationship

10

Identifying Resources From a Cluster

Initially rank the words, according to the place of occurrence. Words in semantic region are given highest priority,

input parameters as second and output parameters as third.

Check if the word already exits as a resource. If so give increase its priority.

Check the relationship between the words and prioritize them according to the relationship.

Combine the words to form the resource.

11

Example Identify Noun

12

getModifiedCustomer getCustomerByCustID getAllCustomer

Semantic Customer Customer Customer

Output Operation

Customer Customer Customer[]

Input Operation

- CustID --

Resource : /customer

Identifying Resource Methods

Semantic analysis of each operationExtract and analyze verbs from the operation

namesBased on fan-in and fan-out of the operationsIn case of conflict, revisit the cluster to form the

new URI.

Example : getCards() Extract verb get [Equivalent to HTTP operation

Get]

13

Example Identify Resource Methods

14

getModifiedCustomer getCustomerByCustID getAllCustomer

Semantic Customer Customer Customer

Output Operation

Customer Customer Customer[]

Input Operation

- CustID --

Verb GET, Modified GET GET

Resource : /customer/{custid}HTTP-Method: GET

Resource : /customer/modifiedHTTP-Method: GET

Resource : /customerHTTP-Method: GET

Example

Resource HTTP-Methods Functions

/customer GET GetAllCustomers

/customer/modified GET GetModifiedCustomers

/customer/{custID} GET GetAllCustomerByCustID

/servicelocations GET GetAllServiceLocations

/servicelocations/modified GET GetModifiedServiceLocations

/servicelocations/{serloc} GET GetAllServiceLocationBySerLoc 15

Example

/campaign GetCampaings GET

CreateOrUpdateCampaign POST

DeleteCampaign DELETE

/campaign/account/recepients GetCampaignAccountRecepients GET

DeleteCampaignAccountRecepient DELETE

CreateOrUpdateCampaignAccountRecepient POST

/campaign/account/recepients? #methodname= ImportCampaignAccountRecepients

ImportCampaignAccountRecepients POST

16

Resource Verification

17

Wrapping SOAP-based Services

18

Case Study

• Analyzed publicly available WSDL documents.

Category # Description

Finance 12 Services related to financial management and banks.

Government 6 Services provided by government organization.

Travel/Tourism 17 Services that are related to travel and tourism e.g., flight book, hotel booking, and taxi reservation.

Ecommerce 13 Services provided by online business e.g., Amazon, BestBuy and EBay.

Others 13 Services from domains such as weather, music search, content sharing and aggregation.

19

Case Study

20

Category # Methods

#Predicted Resources

#misidentified Resources

#ActualResources

Precision Recall

Finance 59 35 8 40 0.77 0.67Government 39 25 2 27 0.92 0.85Travel/Tourism

132 97 16 110 0.83 0.73

Ecommerce 102 80 14 90 0.82 0.73

Others 78 47 6 53 0.87 0.77

Performance Measurement

21

Conclusion and Future work

Provide a mechanism to migrate SOAP-based services to RESTful services

Validate the mechanism with larger set of WSDL files

Extend the approach to migrate other legacy systems to RESTful services.