On Jul 18, 2008, at 11:03 PM, <[EMAIL PROTECTED]> wrote:
Date: Fri, 18 Jul 2008 18:20:46 +0100
From: Glynn Clements <[EMAIL PROTECTED]>
Subject: Re: [GRASS-dev] Python Scripting
To: "Dan D'Alimonte" <[EMAIL PROTECTED]>, [email protected]
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset="us-ascii"
Glynn Clements wrote:
As to existing modules, what about a helper function to access then?
module.executeModule( name="r.stats", options={ "input":
"elevation.dem,slope,aspect", "fs": ",", "output": "elev.csv"},
flags=["q", "1", "n", "g"] )
This idea has occurred to me. Some comments:
Pass argument values as Python values, e.g. passing multiple values
as
lists, passing numeric types directly, etc, and have the interface
convert them to strings. Pass the flags as a single string.
module.execute( "r.stats",
options = { "input": ["elevation.dem", "slope",
"aspect"],
"fs": ",",
"output": "elev.csv" },
flags = "q1ng" )
Provide a lower-level function which simply generates the command to
pass to Popen(), for cases where you want to interact with the child
process.
I have attached a first draft of such a module, which also includes a
wrapper function for g.parser (for which an example script is also
attached).
--
Glynn Clements <[EMAIL PROTECTED]>
-------------- next part --------------
import os
import os.path
import sys
import types
import subprocess
def _make_val(val):
if isinstance(val, types.StringType):
return val
if isinstance(val, types.ListType):
return ",".join(map(_make_val, val))
if isinstance(val, types.TupleType):
return _make_val(list(val))
return str(val)
def make_command(prog, options = [], flags = "", overwrite = False,
quiet = False, verbose = False):
args = [prog]
if overwrite:
args.append("--o")
if quiet:
args.append("--q")
if verbose:
args.append("--v")
if flags:
args.append("-%s" % flags)
for opt, val in options.iteritems():
args.append("%s=%s" % (opt, _make_val(val)))
return args
def start_command(prog, options = [], flags = "", overwrite = False,
quiet = False, verbose = False, **kwargs):
args = make_command(prog, options, flags, overwrite, quiet,
verbose)
return subprocess.Popen(args, **kwargs)
def run_command(*args, **kwargs):
ps = start_command(*args, **kwargs)
return ps.wait()
def _parse_env():
options = {}
flags = {}
for var, val in os.environ.iteritems():
if var.startswith("GIS_OPT_"):
opt = var.replace("GIS_OPT_", "", 1).lower()
options[opt] = val;
if var.startswith("GIS_FLAG_"):
flg = var.replace("GIS_FLAG_", "", 1).lower()
flags[flg] = bool(int(val));
return (options, flags)
def parser():
if not os.getenv("GISBASE"):
print >> sys.stderr, "You must be in GRASS GIS to run this
program."
sys.exit(1)
if len(sys.argv) > 1 and sys.argv[1] == "@ARGS_PARSED@":
return _parse_env()
argv = sys.argv[:]
name = argv[0]
if not os.path.isabs(name):
argv[0] = os.path.normpath(os.path.join(sys.path[0], name))
os.execvp("g.parser", [name] + argv)
raise OSError("error executing g.parser")
-------------- next part --------------
#!/usr/bin/env python
# g.parser demo script for python programing
import grass
#%Module
#% description: g.parser test script (python)
#%End
#%flag
#% key: f
#% description: a flag
#%END
#%option
#% key: raster
#% type: string
#% gisprompt: old,cell,raster
#% description: raster input map
#% required : yes
#%end
#%option
#% key: vector
#% type: string
#% gisprompt: old,vector,vector
#% description: vector input map
#% required : yes
#%end
#%option
#% key: option1
#% type: string
#% description: an option
#% required : no
#%end
if __name__ == "__main__":
(options, flags) = grass.parser()
print ""
if flags['f']:
print "Flag -f set"
else:
print "Flag -f not set"
#test if parameter present:
if options['option1']:
print "Value of option1: '%s'" % options['option1']
print "Value of raster= option: '%s'" % options['raster']
print "Value of vector= option: '%s'" % options['vector']
Do you still run a GRASS command as subprocess.call([command...])? Or
is there another syntax with your wrapper script (e.g., as in the
module.execute() above)?
Michael
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