The document discusses migrating SOAP-based web services to RESTful services. It outlines limitations of SOAP services and advantages of RESTful services. The approach involves clustering similar SOAP operations, identifying resources and resource methods, and wrapping the SOAP services as RESTful APIs. The approach was validated on a case study of over 60 public WSDL files with good precision and recall. Future work involves validating the approach on more WSDL files and extending it to migrate other legacy systems.

1. Migrating of SOAP-based Services to
RESTful Services
Bipin Upadhyaya
Queen’s University

2. Limitations of SOAP-based Services
No Web in traditional web services
No use of scalability features of Web
Service provider dependent interfaces
Problematic standardization process
Infighting
Lack of architectural coherence
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3. RESTful Services
A resource is any entity that can be identified or
named
Uniform interface for all resources
Hypermedia as the engine of application state
(HATEOAS)
Not only the name of resources but also the
relationships between resources
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4. Links and Forms
Resources
<xml>
<book>
2. Response
<name>Night Star </name>
<author> </author> 1. Request
</book>
<a rel=“review” href=“http://..order/ns/reveiw” />
GET http://../book?search=Night Star
<a rel=“order” href=“http://..order/ns” />
</xml>
GET http://..order/ns/reveiw
3. Request
How does client know about Resources ?
Initial starting node
And then the user agent is guided through the response
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5. “….. 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]
Total Service : 2198
Protocol usage by API [src: programmableweb.com]
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6. Motivation
RESTful services has various advantages over
SOAP-based services
Scalability of component interactions
Generality of interfaces
Independence in components deployment
New services and service clients support
RESTful services
SOA
P
RE S
T
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7. WSDL
I/O
Parameters
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8. Overview of Our Approach
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9. Clustering WSDL Operations
Criteria for Clustering
2 * ((5 + 1))
similarity (GetAllCustomer , GetCustomerByID ) = = .923
5 + 5 + 2 +1 9

10. Identifying Resources From a Cluster
Extract Nouns
Input and output parameters is considered as
noun
Find word relationship/hierarchy between
extracted words
Find resource/container relationship
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11. 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.
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12. Example Identify Noun
getModifiedCustomer getCustomerByCustID getAllCustomer
Semantic Customer Customer Customer
Output Customer Customer Customer[]
Operation
Input - CustID --
Operation
Resource : /customer
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13. Identifying Resource Methods
Semantic analysis of each operation
Extract and analyze verbs from the operation
names
Based on fan-in and fan-out of the operations
In case of conflict, revisit the cluster to form the
new URI.
Example :
getCards()  Extract verb  get [Equivalent to HTTP operation
Get]
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14. Example Identify Resource Methods
getModifiedCustomer getCustomerByCustID getAllCustomer
Semantic Customer Customer Customer
Output Customer Customer Customer[]
Operation
Input - CustID --
Operation
Verb GET, Modified GET GET
Resource : /customer/modified Resource : /customer/{custid} Resource : /customer
HTTP-Method: GET HTTP-Method: GET HTTP-Method: GET
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15. 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

16. Example
/campaign GetCampaings GET
CreateOrUpdateCampaign POST
DeleteCampaign DELETE
/campaign/account/recepients GetCampaignAccountRecepients GET
DeleteCampaignAccountRecepient DELETE
CreateOrUpdateCampaignAccountRecepient POST
/ ImportCampaignAccountRecepients POST
campaign/account/recepients?
#methodname=
ImportCampaignAccountRecep
ients 16

17. Resource Verification
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18. Wrapping SOAP-based Services
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19. 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.
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20. Case Study
Category # #Predicted #misidentified #Actual Precision Recall
Methods Resources Resources Resources
Finance 59 35 8 40 0.77 0.67
Government 39 25 2 27 0.92 0.85
Travel/ 132 97 16 110 0.83 0.73
Tourism
Ecommerce 102 80 14 90 0.82 0.73
Others 78 47 6 53 0.87 0.77
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21. Performance Measurement
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22. 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.