proc ds2 ;
ds2_options sas;
/* Note: The HTTP package currently uses the tkhttp extension,
         not the more recent and improved tkhttpc extension. */
package tap_RESTCallout /overwrite=yes;
    dcl package tap_logger mLogr();
    dcl package http mHclnt();
    dcl nvarchar(16384) mURL;
    
    method tap_RESTCallout(); mURL = ' '; end;

    /*----------------------------------------------------------------*/
    method createPost( nvarchar(16384) url,
                       int             timeout,   /* in milliseconds */
                       nvarchar(256)   userid,
                       nvarchar(256)   password,
                       in_out int      rc );
        dcl varchar(16384) hdrVal;
        hdrVal = 'application/json; charset=utf-8';
        /* NOTE: HTTP pkg does not currently accept user/passwd args. */
        createPost( url, hdrVal, hdrVal, timeout, userid, password, rc);
    end;

    /*----------------------------------------------------------------*/
    method createPost( nvarchar(16384) url,
                       nvarchar(16384) contentType,
                       nvarchar(16384) accept,
                       int             timeout,   /* in milliseconds */
                       nvarchar(256)   userid,
                       nvarchar(256)   password,
                       in_out int      rc );

        /* NOTE:  D2HTTP does not yet support credentials. */

        if ( missing( url ) ) then do;
            rc = 1;
            mLogr.err( 'createPost method requires a URL argument.' );
            return;
        end;

        rc = 0;
        if ( url ^= mURL ) then do;
            mURL = url;
            if ( mLogr.isDebugEnabled() ) then
                mLogr.debug( 'Creating POST request for ' || url );
            rc = mHclnt.createPostMethod( url );
            if ( not rc ) then
                if ( null( contentType ) ) then
                    rc = mHclnt.setRequestContentType(
                                  'application/json; charset=utf-8' );
                else
                    rc = mHclnt.setRequestContentType( contentType );

            if ( not rc ) then
                if ( null( Accept ) ) then
                    rc = mHclnt.addRequestHeader( 'Accept',
                                  'application/json; charset=utf-8' );
                else
                    rc = mHclnt.addRequestHeader( 'Accept', Accept );

            if ( not rc ) then
                rc = mHclnt.setSocketTimeout( timeout );
        end;
    end;

    /*----------------------------------------------------------------*/
    method executePost( nvarchar(67108864) payload,
                        in_out int         hstat,
                        in_out int         rc,
                        in_out nvarchar    respBody );
        rc = 0;
        if ( mLogr.isTraceEnabled() ) then
            mLogr.trace( 'executePost given payload: ' || payload );
        mHclnt.setRequestBodyAsString( payload );
        mHclnt.executeMethod();
        hstat = mHclnt.getStatusCode();
        if ( mLogr.isTraceEnabled() ) then do;
            dcl nvarchar(4096) respHdrs;
            mHclnt.getResponseHeadersAsString( respHdrs, rc );
            if ( not rc ) then do;
                mLogr.trace( '--- Beginning of response headers ---');
                mLogr.trace( respHdrs );
                mLogr.trace( '--- End of response headers ---------');
            end;
        end;
        mHclnt.getResponseBodyAsString( respBody, rc );
        if ( rc ) then 
            mLogr.err( 'getResponseBodyAsString rc = ' || rc );
    end;

    /*----------------------------------------------------------------*/
    method executePost( nvarchar(67108864) payload,
                        in_out int         hstat,
                        in_out int         rc,
                        in_out nvarchar    respBody,
                        nvarchar(16384)    url,
                        int                timeout,
                        nvarchar(256)      userid,
                        nvarchar(256)      password );
        hstat = 0;
        rc = 0;
        /* NOTE: HTTP pkg does not currently accept user/passwd args. */
        createPost( url, timeout, userid, password, rc );
        if ( not rc ) then
            executePost( payload, hstat, rc, respBody );
    end;

    /*----------------------------------------------------------------*/
    method executePost( nvarchar(67108864) payload,
                        in_out int         hstat,
                        in_out int         rc,
                        in_out nvarchar    respBody,
                        nvarchar(16384)    url );
        hstat = 0;
        rc = 0;
        createPost( url, 0, null, null, rc );
        if ( not rc ) then
            executePost( payload, hstat, rc, respBody );
    end;

    /*----------------------------------------------------------------*/

endpackage;
run;
quit;