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Description

This example shows: how to set different type of keys in BUFR messages.

Source code

bufr_set_keys.c
/*
 * Copyright 2005-2015 ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
 * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
 */

/*
 * C Implementation: bufr_set_keys
 *
 * Description: how to set different type of keys in BUFR messages.
 *
 */

#include "eccodes.h"

void usage(char* prog) {
    printf("usage: %s infile\n",prog);
    exit(1);
}

int main(int argc,char* argv[])
{
    FILE* in = NULL;
    FILE* out = NULL;
    
    /* message handle. Required in all the eccodes calls acting on a message.*/
    codes_handle* h=NULL;
    
    long longVal;
    /*double doubleVal;*/
    int i, err=0;
    int cnt=0;
    size_t size = 0;
    char* infile = "../../data/bufr/syno_multi.bufr";
    const void *buffer = NULL;
    
    if (argc != 2) {
        usage(argv[0]);
        return 1;
    }

    in = fopen(infile,"r");
    out = fopen(argv[1],"w");

    if (!in || !out) {
        perror("ERROR: unable to open files");
        fclose(out);
        fclose(in);
        return 1;
    }
    
    /* loop over the messages in the bufr file */
    while ((h = codes_handle_new_from_file(NULL,in,PRODUCT_BUFR,&err)) != NULL || err != CODES_SUCCESS)
    {
        if (h == NULL) {
            printf("Error: unable to create handle for message %d\n",cnt);
            cnt++;
            continue;
        }
    
        printf("message: %d\n",cnt);
    
        /* we need to instruct ecCodes to expand the descriptors 
          i.e. unpack the data values */
        /*CODES_CHECK(codes_set_long(h,"unpack",1),0);*/
    
        /* This is the place where you may wish to modify the message*/
        /*E.g. we change the centre and 2m temperature */
           
        /* set centre */
        longVal=222;
        CODES_CHECK(codes_set_long(h, "centre", longVal),0);
        printf("  set centre to: %ld\n",longVal);
        
        /* check centre */
        CODES_CHECK(codes_get_long(h,"centre",&longVal),0);
        printf("  centre's new value is: %ld\n",longVal);
        
        /*doubleVal=240.+i*2.;
        CODES_CHECK(codes_set_double(h,"airTemperatureAt2M",doubleVal),0);
        printf("  set airTemperatureAt2M to: %f\n",doubleVal);*/
        
        /* get the modified message in a buffer */
        CODES_CHECK(codes_get_message(h,&buffer,&size),0);
       
        /* write the buffer to a file */
        if(fwrite(buffer,1,size,out) != size) {
            perror(argv[0]);
            return 1;
        }
 
        /* delete handle */
        codes_handle_delete(h);
        
        cnt++;
    }
    
    fclose(in);
    return 0;
}
bufr_set_keys.f90
! Copyright 2005-2015 ECMWF.
!
! This software is licensed under the terms of the Apache Licence Version 2.0
! which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
! 
! In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
! virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
!
!  FORTRAN 90 implementation: bufr_set_keys
!
!  Description: how to set different type of keys in BUFR messages.
!
!
program bufr_set_keys
  use eccodes
  implicit none
  integer                                       :: err,i,iret
  integer                                       :: infile,outfile
  integer                                       :: ibufr
  integer                                       :: count=0
  integer(kind=4)                               :: centre, centreNew
  double precision, dimension(:,:), allocatable :: field2D
  
  ! open input file 
  call codes_open_file(infile,'../../data/bufr/syno_multi.bufr','r')
  
  ! open output file
  call codes_open_file(outfile,'bufr_set_keys_test_f.tmp.bufr','w')
  
  ! the first bufr message is loaded from file
  ! ibufr is the bufr id to be used in subsequent calls
  call codes_bufr_new_from_file(infile,ibufr,iret)

  do while (iret/=CODES_END_OF_FILE)

    write(*,*) 'message: ',count
    
    ! This is the place where you may wish to modify the message 
    ! E.g. we change the centre and 2m temperature 
    
    ! set centre
    centre=222
    call codes_set(ibufr,'centre',222)
    write(*,*) '  set centre to:',centre
    
    ! check centre's new value
    centreNew=0
    call codes_get(ibufr,'centre',centreNew)
    write(*,*) '  centre''s new value:',centreNew
 
    ! write modified message to a file
    call codes_write(ibufr,outfile)
  
    ! relase the handle
    call codes_release(ibufr)
    
    ! next message from source
    call codes_bufr_new_from_file(infile,ibufr,iret)
    
    count=count+1
    
  end do
    
  call codes_close_file(infile)
  call codes_close_file(outfile)

end program bufr_set_keys
bufr_set_keys.py
# Copyright 2005-2015 ECMWF.
#
# This software is licensed under the terms of the Apache Licence Version 2.0
# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
#
# In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
# virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.

#
# Python implementation: bufr_set_keys
#
# Description: how to set different type of keys in BUFR messages.
#
#

import traceback
import sys

from eccodes import *

INPUT='../../data/bufr/syno_multi.bufr'
OUTPUT='bufr_set_keys_test_p.tmp.bufr'
VERBOSE=1 # verbose error reporting
  
def example():
    
    # open bufr file
    fin = open(INPUT)

    # open otput bufr file
    fout = open(OUTPUT,'w')
    
    cnt=0    
    
    # loop for the messages in the file
    while 1:
        
        # get handle for message
        gid = codes_bufr_new_from_file(fin)
        if gid is None: break

        print "message: %s" % cnt
        
        # we need to instruct ecCodes to expand all the descriptors
        # i.e. unpack the data values
        #codes_set(gid,'unpack',1);
        
        # This is the place where you may wish to modify the message
        # E.g. we change the centre and 2m temperature
        
        # set centre
        val=222
        print '  set centre to: %d' % val
        
        key='centre'
        if not codes_is_defined(gid,key): 
            raise Exception("Key: " + key + " was not defined")
        codes_set(gid,key,val)
        
        #check centre's value
        print '  %s''s new value is: %d' % (key,codes_get(gid,key))
   
        # write modified message to output
        codes_write(gid,fout)
    
        cnt+=1

        # delete handle
        codes_release(gid)

    fin.close()
    fout.close()
    

def main():
    try:
        example()
    except CodesInternalError,err:
        if VERBOSE:
            traceback.print_exc(file=sys.stderr)
        else:
            print >>sys.stderr,err.msg

        return 1

if __name__ == "__main__":
    sys.exit(main())
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