Sample Program (SAP Library - Internet Communication Framework)

Sample Program

The following ABAP program executes a HTTP request. The request’s destination is the ABAP program itself, as the SAP Web Application Server can function both as a server and as a client.

report HTTP_Test.

* data declarations

data: client type ref to if_http_client.

…

The following parameters must be specified. If nothing is entered, the following default values are used: host (default value: current host), service (default value: port 80 for HTTP and port 443 for HTTPS), protocol (default: HTTP/1.0), path to the required service, as described in Implementation (default: /sap/public/ping). If the connection using the Destination (SM59) is used when the client object is created, these parameters must be set accordingly in the destination.

data: host type string value = ‘host.wdf.sap-ag.de’,

service type string value = ‘8080’,

path type string value = '/sap/public/ping',

errortext type string. "used for error handling

The object of the type CL_HTTP_CLIENT is created (step 1). As described, there are two possibilities here, which are juxtaposed below.

In one case, the create method is called; here you must enter the required host and port, and you can also enter the proxy setting. This overrides any configuration that was made in Transaction SICF (see also Configuring Proxies).

In the other case, the destination that was maintained in Transaction SM59 is used (method create_by_destination). Only the name of the destination and the client need be specified here. In both cases, you have to define exceptions (not shown here) and query the last error code.

The object client can be used to access all data (request, response, header field, and so on).

The scheme determines whether HTTP or HTTPS is to be used.

* create HTTP client object(s)
call method cl_http_client=>create exporting host = host_str service = service_str proxy_host = proxy_host proxy_service = proxy_service scheme = scheme importing client = client exceptions argument_not_found = 1 internal_error = 2 plugin_not_active = 3 others = 4.	call method cl_http_client=>create_by_destination exporting destination = dest importing client = client exceptions destination_not_found = 1 internal_error = 2 argument_not_found = 3 destination_no_authority = 4 plugin_not_active = 5 others = 6.
if sy-subrc <> 0. write: / ‘Create failed, subrc = ', sy-subrc. exit. endif.

Header fields for the requests are set here. Setting the HTTP request method to GET is optional. (If this field is not set, the system uses GET if the HTTP request does not contain a body. Otherwise, it uses POST.) You must set the request URI unless the whole path was specified as a path prefix using the Destination (SM59). Here you use method set_request_uri of class cl_http_utility.

* set header fields

call method client->request->set_header_field

   exporting name = '~request_method'

             value = 'GET'.

…

* Set request protocol

   if protocol = 'HTTP/1.0'.

call method client->request->set_header_field

         exporting   name = '~server_protocol'

                     value = 'HTTP/1.0'.

    else.

call method client->request->set_header_field

         exporting   name = '~server_protocol'

                     value = 'HTTP/1.1'.

    endif.

cl_http_utility=>set_request_uri( request = client->request

uri = uri ).

Any number of fields in the control block can be filled (step 2).

You can also request that the response is compressed with the gzip-process for sending:

* should server send its response in gzip, if possible

if cl_http_client=>c_compression_supported =

if_http_client=>co_enabled.

call method client->request->set_header_field

exporting name = 'accept-encoding'

value = 'gzip'.

endif.

Additional Options

You can use method SET_COOKIE of IF_HTTP_ENTITY to set a cookie. You can use this to maintain the status in the session.

You can deactivate attributes PROPERTYTYPE_LOGON_POPUP and PROPERTYTYPE_REDIRECT which have the default value CO_ENABLED (set to CO_DISABLED).

You can set PROPERTYTYPE_ACCEPT_COOKIE to different values. The default value is CO_DISABLED, but values CO_ENABLED (always accept cookies), CO_PROMPT (send a dialog box when cookies are received to ask if the cookie should be accepted) and CO_EVENT (cookie handling using event EVENTKIND_HANDLE_COOKIE of interface IF_HTTP_CLIENT) are also available.

Before the request is sent, you can also enter the necessary logon data using the AUTHENTICATE()method of interface IF_HTTP_CLIENT.

Now, the request is sent (step 3).

* Send

call method client->send

  exporting timeout = timeout

      exceptions http_communication_failure  = 1

           http_invalid_state          = 2

           http_processing_failed      = 3

                 others                      = 4.

  if sy-subrc <> 0.

    call method client->get_last_error

      importing code = subrc

               message = errortext.

    write: / 'communication_error( send )',

           / 'code: ', subrc, 'message: ', dummy.

        exit.

endif.

Here, the last error must be queried, using client->get_last_error.

Now, the response is received and the client object is filled with the response data (step 7).

* receive

    call method client->receive

      exceptions http_communication_failure  = 1

           http_invalid_state          = 2

           http_processing_failed      = 3

                 others                      = 4.

  if sy-subrc <> 0.

    call method client->get_last_error

      importing code = subrc

               message = errortext.

    write: / 'communication_error( receive )',

           / 'code: ', subrc, 'message: ', dummy.

        exit.

endif.

Exceptions and error queries must be inserted here too.

If the connection is no longer being used, you must close the client object and the connection, as follows:

* close

call method client->close

exceptions http_invalid_state = 1

others = 2.

To document the successful test, the output routine is called at this point.

* output

perform write_document.

Caution

The ABAP code above is only a simple example, and is not an example of professional work!