COBOL REST consumer

In order to develop a COBOL REST consumer (client-side), to invoke REST Web Service, the COBOL program should take advantage of HTTPClient class that allows to communicate with COBOL REST producer entry points through HTTP protocol. Also to allow definition of HTTP parameters, an HTTPData.Params class is provided.

In the isCOBOL sample folder you find the folder eis/webservices/rest/client that contains an example of COBOL client program called "CLIENTH.cbl" of previous "ISFUNCTIONS.cbl" server service.

This program has the objective to invoke ISFUNCTION_GETZIP service and ISFUNCTION_GETCITY to have the zip code of San Diego and to have the name of the city whose zip code is 89044.

This program must take the following steps:

•	Include HTTPClient and HTTPData.Params classes in COBOL repository:

configuration section.        repository.            class http-client as "com.iscobol.rts.HTTPClient"            class http-param  as "com.iscobol.rts.HTTPData.Params".

•	Establish the connection with REST Web Service using doGet() method and checking the success of the operation using getResponseCode() method:

http:>doGet("http://127.0.0.1:8080/isfunctions/servlet/isCobol(ISFUNCTIONS)")            http:>getResponseCode (response-code)

•	Prepare the city name as parameter to be pass to the service

move "San Diego" to city-zipCode.           set params = http-param:>new():>add("get_Zip_Code", city-zipCode).

•	Invoke the ISFUNCTION_GETZIP with prepared parameter and getting back the zip code:

http:>doGet ("http://127.0.0.1:8080/isfunctions/"                         "servlet/isCobol(ISFUNCTION_GETZIP)", params)              http:>getResponseCode (response-code)            if response-code = 200               http:>getResponseJSON (isfunction-recivedZipCode)

where isfunction-receivedZipCode working storage structure is defined like:

01  isfunction-recivedZipCode identified by "".             03 identified by "Zip_Code".                05 zipCode  pic x any length.

and 92123 is the zip code of San Diego saved into zipCode COBOL variable.

A similar approach should be the following, have the city name provide the zip code.

•	Compile the program with the command:

iscc client.cbl

•	and run it with the command:

iscrun CLIENTH

this is the result: