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 it to communicate with COBOL REST producer entry points through HTTP protocol. Also to allow the definition of HTTP parameters, an HTTPData.Params class is provided.
In the isCOBOL sample folder you will find the folder eis/webservices/rest/client that contains an example of COBOL client program called "CLIENTH.cbl" to communicate with the "ISFUNCTIONS.cbl" server service described on the previous page.
This program invokes ISFUNCTION_GETZIP service to return the zip code of San Diego, and the ISFUNCTION_GETCITY service to return the name of the city whose zip code is 89044.
This program shows how to do the following necessary 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-retrievedZipCode) |
where isfunction-retrievedZipCode working storage structure is defined like:
01 isfunction-retrievedZipCode 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 is followed to provide the city name and receive it's zip code.
• Compile the program with the command:
iscc client.cbl |
• and run it with the command:
iscrun CLIENTH |
this is the result:
