SQL Write a BLOB to IFS

ifs_write_blob.sql

-- Write a BLOB to IFS 
-- Note1: This also works for save files
-- Note2: This also compiles on vanilla systems without QSYSINCL installed
-- Note3: I am using library QUSRSYS. I suggest you put it into your tool library
-- I doubt it is a good idea to build huge applications this way, however it 
-- is a cool example how far you can go with SQL: Have fun :) 
-- (C) Niels Liisberg 2020
----------------------------------------------------------------------------------------------
call qcmdexc ('crtsrcpf FILE(QTEMP/C) MBR(C)');
delete from qtemp.c;
insert into qtemp.c (srcdta) values 
-- Prototype warnings are chekked and OK   
--   ('#include <sys/types.h>')
--   ('#include <sys/stat.h>')
--   ('#include <fcntl.h>')
     ('#include <sqludf.h>')
    ,('int outFile;')
    ,('long pos = 1;')
    ,('long remains;')
    ,('long retlen;')
    ,('char buf [32760];')
    ,('long chunk = sizeof(buf); ')
    ,('int mode = 448; // mode_t mode = S_IRUSR | S_IWUSR | S_IXUSR;')
    ,('int opt = 106 ; // int opt =  O_WRONLY | O_CREAT | O_TRUNC | O_CCSID ;')
    ,('int rc = sqludf_length(&MAIN.BUF, &remains);')
    ,('MAIN.NAME.DAT[MAIN.NAME.LEN] =0;')
    ,('outFile = open(MAIN.NAME.DAT, opt, mode, 1252);')
    ,('while (rc == 0 && remains > 0) {')
    ,('    rc = sqludf_substr(&MAIN.BUF, pos, chunk , buf , &retlen),')
    ,('    write (outFile , buf, retlen);')
    ,('    pos += chunk;')
    ,('    remains -= chunk;')
    ,('} ')
    ,('close(outFile);')
;

create or replace procedure qusrsys.ifs_write_blob 
( 
    payload    blob(2g),
    tofile     varchar(256)
) 
external action 
modifies sql data
set option output=*print, commit=*chg, dbgview = *list
main: begin
    declare buf blob(2G); 
    declare name varchar(256) ;
    -- "buf" and "name" are in the C-code as MAIN.BUF and MAIN.NAME 
    set buf =  payload;
    set name = tofile; 
    include qtemp/c(c);
end;

-- Usecases: 

-- Simple get a stream file and put it on the IFS
call qusrsys.ifs_write_blob (
    payload =>  SYSTOOLS.HTTPGETBLOB( url => 'http://webfiles.system-method.com/packages/Icebox2pkg/ip2.tar' , httpheader => null),
    tofile =>  '/tmp/ip2.tar'
);
    

-- Savefile example
cl: crtsavf qgpl/icebox2;
call qusrsys.ifs_write_blob (
    payload =>  SYSTOOLS.HTTPGETBLOB( url => 'http://webfiles.system-method.com/packages/Icebox2pkg/icebox2.savf' , httpheader => null),
    tofile =>  '/qsys.lib/qgpl.lib/icebox2.file'
);