The path of an HTTP request is used to address a resource. openUTM uses the path information to determine the TAC and therefore the program unit to which an HTTP request is to be sent.
A user has various options for specifying which TAC openUTM is to call for an HTTP request with a particular path.
One way this can be done is using the HTTP-DESCRIPTOR generation statement. This statement allows
- to define the mapping of the path to a TAC and
- to supply additional parameters to influence the handling of such a request by openUTM.
For example, you can specify that openUTM on BS2000 systems should convert the message into the locally used EBCDIC code, or that openUTM should call an additional user program, called an HTTP exit, before calling the TAC. This user program can, e.g. transform the message from the format used by an HTTP client into the format expected by the addressed program unit.
When you specify the path in the HTTP-DESCRIPTOR generation statement, you can also use a wildcard character that allows you to easily assign different path specifications that match at the beginning to the same TAC.
Another way of calling a program unit of a UTM application via an HTTP request is to write the TAC of the program unit directly in the path information.
Example: http://<host:port>/KDCINF?STAT
By this request the TAC KDCINF is called, provided the caller has the authorization to use this TAC (see also the USER-AUTH operand of the BCAMAPPL generation statement). The character string "STAT" is transferred to the program unit as data.
openUTM tries to map the path directly to a TAC whenever the path was not specified in an HTTP-DESCRIPTOR statement.