The way I've done it is to use a variable in the meta-data.
For example, I've got 3 urls
http://jsonplaceholder.typicode.com/posts/1
http://jsonplaceholder.typicode.com/posts/10
http://jsonplaceholder.typicode.com/posts?userId=1
Base URL in REST adaptor
http://jsonplaceholder.typicode.com/posts
Master
FILENAME=SAMPLE_JSON_REST, SUFFIX=REST , MFD_PROFILE=common/sample_json_rest_obj, $
VARIABLE NAME=&&OBJ, DEFAULT='1', $
SEGMENT=M6ILO, SEGTYPE=S0, $
FIELDNAME=__RESPONSE, USAGE=TX80L, ACTUAL=TX, ACCESS_PROPERTY=(INTERNAL), $
SEGMENT=RESPONSE, SEGTYPE=S0, SEGSUF=JSON , PARENT=M6ILO, POSITION=__RESPONSE, $
FIELDNAME=JSON_DUMMY_EL, ALIAS=JSON_DUMMY_EL, USAGE=A1, ACTUAL=A1, ACCESS_PROPERTY=(INTERNAL),
PROPERTY=ELEMENT, $
FIELDNAME=USERID, ALIAS=userId, USAGE=P33, ACTUAL=A33,
REFERENCE=JSON_DUMMY_EL, PROPERTY=ELEMENT, $
FIELDNAME=ID, ALIAS=id, USAGE=P33, ACTUAL=A33,
REFERENCE=JSON_DUMMY_EL, PROPERTY=ELEMENT, $
FIELDNAME=TITLE, ALIAS=title, USAGE=A74, ACTUAL=A74,
REFERENCE=JSON_DUMMY_EL, PROPERTY=ELEMENT, $
FIELDNAME=BODY, ALIAS=body, USAGE=A158, ACTUAL=A158,
REFERENCE=JSON_DUMMY_EL, PROPERTY=ELEMENT, $
Acx
SEGNAME=M6ILO,
CONNECTION=SAMPLE,
OBJECT=&&OBJ,
SERVICETYPE=REST,
HTTPMETHOD=GET,
RESTRESPONSE=JSON, $
MFD Profile (that you don't need if you set the value of &&OBJ before you run report):
-*-SET &&OBJ=10;
-SET &&OBJ='?userId=1';
Just set the &&OBJ to the extended value that you require.
"There is no limit to what you can achieve ... if you don’t care who gets the credit." Roger Abbott