t.vect.db.select: Add format options

temporal/t.vect.db.select/t.vect.db.select.md

@@ -40,6 +40,36 @@ start_time|end_time|DATE|SOURCE
 1849|1873|01/01/1873|Coastal Carolina University
 ```
 
+You can output the data in three formats: plain (the default), CSV, and JSON.
+
+```sh
+t.vect.db.select input=schools_stds columns="cat,CORECAPACI" format=json
+```
+
+```json
+[
+    {
+        "start_time": "2024-01-01 00:00:00",
+        "end_time": "2025-01-01 00:00:00",
+        "cat": 1,
+        "CORECAPACI": 448
+    },
+    {
+        "start_time": "2024-01-01 00:00:00",
+        "end_time": "2025-01-01 00:00:00",
+        "cat": 2,
+        "CORECAPACI": 540
+    },
+    {
+        "start_time": "2024-01-01 00:00:00",
+        "end_time": "2025-01-01 00:00:00",
+        "cat": 3,
+        "CORECAPACI": 523
+    },
+    ...
+]
+```
+
 ## SEE ALSO
 
 *[t.create](t.create.md), [t.info](t.info.md)*

temporal/t.vect.db.select/t.vect.db.select.py

@@ -36,8 +36,16 @@
 # %option G_OPT_DB_COLUMNS
 # %end
 
+# %option G_OPT_F_FORMAT
+# % options: plain,csv,json
+# % descriptions: plain;Plain text output;csv;CSV (Comma Separated Values);json;JSON (JavaScript Object Notation)
+# % answer: plain
+# % guisection: Formatting
+# %end
+
 # %option G_OPT_F_SEP
 # % label: Field separator character between the output columns
+# % answer:
 # %end
 
 # %option G_OPT_V_FIELD
@@ -50,14 +58,15 @@
 # % key: t_where
 # %end
 
+import json
+
 import grass.script as gs
+from grass.tools import Tools
 
 ############################################################################
 
 
 def main():
-    # lazy imports
-    import grass.temporal as tgis
 
     # Get the options
     input = options["input"]
@@ -66,13 +75,32 @@ def main():
     tempwhere = options["t_where"]
     layer = options["layer"]
     separator = gs.separator(options["separator"])
+    output_format = options.get("format", "plain")
 
     if where in {"", " ", "\n"}:
         where = None
 
     if columns in {"", " ", "\n"}:
         columns = None
 
+    if output_format == "csv":
+        if not separator:
+            separator = ","
+        elif len(separator) > 1:
+            gs.fatal(
+                _("A standard CSV separator (delimiter) is only one character long")
+            )
+
+    elif output_format == "json":
+        if separator:
+            gs.fatal(_("Separator option is not allowed with JSON format"))
+
+    elif not separator:  # output_format == "plain"
+        separator = "|"
+
+    # lazy imports
+    import grass.temporal as tgis
+
     # Make sure the temporal database exists
     tgis.init()
 
@@ -82,7 +110,10 @@ def main():
         "name,layer,mapset,start_time,end_time", tempwhere, "start_time", None
     )
 
+    tools = Tools()
+    json_output = []
     col_names = ""
+
     if rows:
         for row in rows:
             vector_name = "%s@%s" % (row["name"], row["mapset"])
@@ -91,52 +122,62 @@ def main():
             if row["layer"]:
                 layer = row["layer"]
 
-            select = gs.read_command(
-                "v.db.select",
+            res = tools.v_db_select(
                 map=vector_name,
                 layer=layer,
                 columns=columns,
-                separator="%s" % (separator),
+                separator=separator,
                 where=where,
+                format=output_format,
             )
 
-            if not select:
-                gs.fatal(
-                    _("Unable to run v.db.select for vector map <%s> with layer %s")
-                    % (vector_name, layer)
-                )
-            # The first line are the column names
-            list = select.split("\n")
-            count = 0
-            for entry in list:
-                if entry.strip() != "":
-                    # print the column names in case they change
-                    if count == 0:
-                        col_names_new = "start_time%send_time%s%s" % (
-                            separator,
-                            separator,
-                            entry,
-                        )
-                        if col_names != col_names_new:
-                            col_names = col_names_new
-                            print(col_names)
-                    elif row["end_time"]:
-                        print(
-                            "%s%s%s%s%s"
-                            % (
-                                row["start_time"],
+            if output_format == "json":
+                records = res["records"]
+                for record in records:
+                    new_record = {
+                        "start_time": row["start_time"],
+                        "end_time": row["end_time"],
+                    }
+                    new_record.update(record)
+                    json_output.append(new_record)
+
+            else:
+                select = res.text
+                # The first line are the column names
+                list = select.split("\n")
+                count = 0
+                for entry in list:
+                    if entry.strip() != "":
+                        # print the column names in case they change
+                        if count == 0:
+                            col_names_new = "start_time%send_time%s%s" % (
                                 separator,
-                                row["end_time"],
                                 separator,
                                 entry,
                             )
-                        )
-                    else:
-                        print(
-                            "%s%s%s%s"
-                            % (row["start_time"], separator, separator, entry)
-                        )
-                    count += 1
+                            if col_names != col_names_new:
+                                col_names = col_names_new
+                                print(col_names)
+                        elif row["end_time"]:
+                            print(
+                                "%s%s%s%s%s"
+                                % (
+                                    row["start_time"],
+                                    separator,
+                                    row["end_time"],
+                                    separator,
+                                    entry,
+                                )
+                            )
+                        else:
+                            print(
+                                "%s%s%s%s"
+                                % (row["start_time"], separator, separator, entry)
+                            )
+                        count += 1
+
+    if output_format == "json":
+        print(json.dumps(json_output, indent=4, default=str))
 
 
 if __name__ == "__main__":

temporal/t.vect.db.select/tests/t_vect_db_select_test.py

@@ -121,3 +121,67 @@ def test_t_vect_db_select_instance_where(space_time_vector_dataset):
 
     for actual, expected in zip(actual_lines, expected_lines, strict=True):
         assert actual == expected
+
+
+def test_t_vect_db_select_format_csv(space_time_vector_dataset):
+    """Verify CSV output format."""
+    tools = Tools(session=space_time_vector_dataset.session)
+
+    result = tools.t_vect_db_select(
+        input=space_time_vector_dataset.interval_name,
+        format="csv",
+        where="cat = 1",
+    )
+    assert result.returncode == 0
+
+    expected_output = """start_time,end_time,cat,observation
+2001-03-01 00:00:00,2001-04-01 00:00:00,1,100
+2001-04-01 00:00:00,2001-05-01 00:00:00,1,200
+2001-05-01 00:00:00,2001-06-01 00:00:00,1,300"""
+
+    actual_lines = result.text_split("\n")
+    expected_lines = expected_output.strip().splitlines()
+
+    for actual, expected in zip(actual_lines, expected_lines, strict=True):
+        assert actual == expected
+
+
+def test_t_vect_db_select_format_json(space_time_vector_dataset):
+    """Verify standard JSON output format."""
+    tools = Tools(session=space_time_vector_dataset.session)
+
+    result = tools.t_vect_db_select(
+        input=space_time_vector_dataset.interval_name,
+        format="json",
+        where="cat = 1",
+    )
+    assert result.returncode == 0
+
+    expected_records = [
+        {
+            "start_time": "2001-03-01 00:00:00",
+            "end_time": "2001-04-01 00:00:00",
+            "cat": 1,
+            "observation": 100,
+        },
+        {
+            "start_time": "2001-04-01 00:00:00",
+            "end_time": "2001-05-01 00:00:00",
+            "cat": 1,
+            "observation": 200,
+        },
+        {
+            "start_time": "2001-05-01 00:00:00",
+            "end_time": "2001-06-01 00:00:00",
+            "cat": 1,
+            "observation": 300,
+        },
+    ]
+
+    assert len(result) == len(expected_records)
+
+    for actual, expected in zip(result, expected_records, strict=True):
+        assert actual["start_time"] == expected["start_time"]
+        assert actual["end_time"] == expected["end_time"]
+        assert actual["cat"] == expected["cat"]
+        assert actual["observation"] == expected["observation"]