pythonlib/parse_command: automatically parse json and csv output

python/grass/script/core.py

@@ -27,6 +27,9 @@
 import string
 import random
 import shlex
+import json
+import csv
+import io
 from tempfile import NamedTemporaryFile
 from pathlib import Path
 
@@ -543,40 +546,52 @@ def read_command(*args, **kwargs):
 
 def parse_command(*args, **kwargs):
     """Passes all arguments to read_command, then parses the output
-    by parse_key_val().
+    by default with parse_key_val().
 
-    Parsing function can be optionally given by <em>parse</em> parameter
-    including its arguments, e.g.
+    If the command has parameter <em>format</em> and is called with
+    <em>format=json</em>, the output will be parsed into a dictionary.
+    Similarly, with <em>format=csv</em> the output will be parsed into
+    a list of lists (CSV rows).
 
     ::
 
-        parse_command(..., parse = (grass.parse_key_val, { 'sep' : ':' }))
+        parse_command("v.db.select", ..., format="json")
 
-    or you can simply define <em>delimiter</em>
+    Custom parsing function can be optionally given by <em>parse</em> parameter
+    including its arguments, e.g.
 
     ::
 
-        parse_command(..., delimiter = ':')
+        parse_command(..., parse=(gs.parse_key_val, {'sep': ':'}))
+
+    Parameter <em>delimiter</em> is deprecated.
 
     :param args: list of unnamed arguments (see start_command() for details)
     :param kwargs: list of named arguments (see start_command() for details)
 
     :return: parsed module output
     """
+
+    def parse_csv(result):
+        return list(csv.reader(io.StringIO(result)))
+
     parse = None
     parse_args = {}
     if "parse" in kwargs:
         if isinstance(kwargs["parse"], tuple):
             parse = kwargs["parse"][0]
             parse_args = kwargs["parse"][1]
         del kwargs["parse"]
-
-    if "delimiter" in kwargs:
-        parse_args = {"sep": kwargs["delimiter"]}
-        del kwargs["delimiter"]
+    elif kwargs.get("format") == "json":
+        parse = json.loads
+    elif kwargs.get("format") == "csv":
+        parse = parse_csv
 
     if not parse:
         parse = parse_key_val  # use default fn
+        if "delimiter" in kwargs:
+            parse_args = {"sep": kwargs["delimiter"]}
+            del kwargs["delimiter"]
 
     res = read_command(*args, **kwargs)