v.net: Add JSON output support by tangelll · Pull Request #7088 · OSGeo/grass

tangelll · 2026-02-14T20:05:07Z

This PR adds JSON output support to the v.net module using the gjson/parson library.

Description

This PR introduces JSON output support for the v.net module, specifically for the operation=nodes task. This enhancement allows users to programmatically capture network statistics (such as new node counts) for use in automated workflows and testing pipelines.

Changes

Core Logic: Integrated G_JSON support in main.c to handle structured output.
CLI Arguments: Added a new format parameter to choose between plain (default) and json.
Documentation: Updated v.net.md with usage examples and guidelines for JSON output.
Testing: Added an automated Python test case in testsuite/test_v_net.py to ensure output consistency.

How to Test

To verify the implementation, you can use the North Carolina sample dataset.

Manual Verification:

# Copy sample data
g.copy vector=streets_wake,my_streets

# Run the module with JSON format for nreport
testsuite % v.net input=my_streets_ready operation=nreport nlayer=2 format=json

#Run the module with JSON format for report
v.net input=streets output=test_vnet operation=report  format=json

Expected JSON Output :

[
{
"line_cat": 49599,
"start_node_cat": -1,
"end_node_cat": -1
},
...
]

Automated Test Suite: Run the newly added test case:

python3 vector/v.net/testsuite/test_v_net.py

Copying features...
100%
Building topology for vector map test_vnet@PERMANENT...
Registering primitives...
40000
Copying attributes...
Building topology for vector map test_vnet@PERMANENT...
Registering primitives...
50000
v.net complete. 323 lines (network arcs) written to output.

.
Copying features...
100%
Building topology for vector map test_vnet@PERMANENT...
Registering primitives...
40000
Copying attributes...
Building topology for vector map test_vnet@PERMANENT...
Registering primitives...
50000
v.net complete. 156 lines (network arcs) written to output.

.
Copying attributes...
Building topology for vector map test_vnet@PERMANENT...
Registering primitives...
90000
v.net complete. 41813 new points (nodes) written to output.

.v.net complete.
.v.net complete.
.OK

vector/v.net/testsuite/test_v_net.py

petrasovaa

Please use pre-commit.

vector/v.net/testsuite/test_v_net.py

vector/v.net/args.c

petrasovaa · 2026-02-17T01:46:29Z

vector/v.net/report.c

        struct boxlist *List;
+        G_JSON_Value *root_value = NULL;
+        G_JSON_Array *root_array = NULL;
+        if (format && strcmp(format, "json") == 0) {


See the other tools with json support, they use enums.

vector/v.net/v.net.md

petrasovaa · 2026-02-17T01:53:00Z

vector/v.net/v.net.md

+]
+```
+
+### Produce Report in JSON format


To be consistent with the other examples, use nc_spm_08_grass7 dataset. Consider moving the json example more towards the top where the example is already using report.

vector/v.net/testsuite/test_v_net.py

tangelll · 2026-02-19T20:15:27Z

I added a check for G_OPT_F_FORMAT in args.c because it was causing a segmentation fault and UI warnings on my environment when the description was missing.

petrasovaa · 2026-02-20T03:23:10Z

vector/v.net/args.c

+    opt->format->key = "format";
+    if (!opt->format->description)
+        opt->format->description = _("Output format");


There should not be any need to add these.

Suggested change

opt->format->key = "format";

if (!opt->format->description)

opt->format->description = _("Output format");

"After removing those parts and running make, the build gets stuck at the UI description generation step with the following warnings: 'Missing option key' and 'Description for option <?> missing'.

I tested it and it works fine for me. Look at other usages of G_OPT_F_FORMAT.

Maybe you'd need to clean before make, like make clean, make libsclean, or make distclean. With the last one, you'd need to run configure again

petrasovaa · 2026-02-20T03:25:33Z

vector/v.net/report.c

                              nnodes, x, y, z, cat_line);
            }
-            fprintf(stdout, "%d %d %d\n", cat_line, cat_node[0], cat_node[1]);
+            if (root_array) {


It would be more readable to test the format enum value than root_array

.pre-commit-config.yaml

vector/v.net/Makefile

tangelll · 2026-02-24T21:22:36Z

Hi @petrasovaa , just wanted to check if you had a chance to look at this PR when you have a moment. Thanks!

petrasovaa · 2026-02-25T02:49:56Z

vector/v.net/report.c

+                        G_JSON_Value *lines_val =
+                            root_arr ? G_json_value_init_array() : NULL;
+
+                        if (root_arr) {


My previous comment about testing the enum instead of root_array applies here as well and check other places.

petrasovaa · 2026-02-25T02:55:31Z

vector/v.net/Makefile

-LIBES = $(VECTORLIB) $(GISLIB) $(DBMILIB)
-DEPENDENCIES = $(VECTORDEP) $(GISDEP) $(DBMIDEP)
+LIBES = $(VECTORLIB) $(GISLIB) $(DBMILIB) $(PARSONLIB)
+DEPENDENCIES = $(VECTORDEP) $(GISDEP) $(DBMIDEP) $(PARSONDEP)


The other Makefiles don't add PARSONDEP, I am honestly not sure about this, but to keep it consistent, I would remove this.

petrasovaa · 2026-02-25T22:12:19Z

Was it closed by mistake?

echoix · 2026-02-26T00:24:13Z

Reviewing is hard when force merged are made after there was a first review. Not only we Connor just read where we left off, but comments posted are on commits (and lines) that don't exist anymore, and are now kind of "detached" from the PR changed files view (and commits view)

echoix · 2026-02-26T00:26:26Z

The commit 72dd6b2 seems affected by a bad rebase, its tricky when we force-push.

tangelll · 2026-02-26T02:04:26Z

The commit 72dd6b2 seems affected by a bad rebase, its tricky when we force-push.

Hi!, yes you are right I opened a clean new branch and I will pull request it from there today.. thank you!.

echoix · 2026-02-26T03:14:14Z

We didn't review more since, you might as well fix up the same branch, so we still have the context of what we already discussed (instead of having it lost in a new PR)

tangelll · 2026-02-28T15:28:11Z

@echoix I've verified the changes locally with super-linter. Could you please approve the workflows to run the CI tests?

echoix · 2026-02-28T16:37:27Z

vector/v.net/testsuite/test_v_net.py

+        """Verify that v.net report produces valid and accurate JSON output"""
+        vnet_module = SimpleModule(
+            "v.net",
+            input="streets_net",


Where is this found? It doesn't seem to be in the test dataset, or created just for the test, as the same tests fail on all platforms

You are right, streets_net was part of my local North Carolina sample dataset and I mistakenly assumed it was available in the test environment. I will update the test to either use a standard test dataset.Sorry for the oversight!

echoix · 2026-02-28T16:39:42Z

vector/v.net/testsuite/test_v_net.py

Could you double check which of the tests take long? In the error logs, these 6 tests in the file took 69 seconds to run on Ubuntu, which is quite long in my opinion. Maybe they were already long, but take a look to see if it is the newly added tests.

About 38.4sec on macOS (the Apple silicon chips are really fast, so it's normal, about 2x as fast as the Linux runners usually).

66 sec for the Linux CMake

Windows didn't finish run it yet.

I've optimized the tests to address the execution time concerns. The v.net network preparation steps are now moved to setUpClass, so they only run once for the entire test suite. My local tests show a significant reduction in total runtime. I've also ensured that existing tests and the tearDown logic remain intact.

What was the before and after (approx), and what was the other tests to compare to?

I realized I was preparing the heavy streets dataset twice (once for each new test). I have now moved the network preparation to setUpClass so it only runs once. This fixed the slowdown. Before it was 38 sec. in my local mac now it is 28 sec. in my local mac.

tangelll mentioned this pull request Feb 14, 2026

v.net: Add JSON output support for nodes operation #6999

Closed

github-actions bot added vector Related to vector data processing Python Related code is in Python C Related code is in C module docs markdown Related to markdown, markdown files tests Related to Test Suite labels Feb 14, 2026

github-actions bot reviewed Feb 15, 2026

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github-actions bot reviewed Feb 17, 2026

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petrasovaa requested changes Feb 17, 2026

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tangelll force-pushed the vnet-json branch from 474c4a3 to 3728e05 Compare February 19, 2026 20:13

github-actions bot added the CI Continuous integration label Feb 19, 2026

petrasovaa requested changes Feb 20, 2026

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tangelll force-pushed the vnet-json branch from 550430c to 0ba9283 Compare February 21, 2026 15:40

github-actions bot added the CMake label Feb 21, 2026

petrasovaa reviewed Feb 25, 2026

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tangelll force-pushed the vnet-json branch from fccb894 to 72dd6b2 Compare February 25, 2026 15:10

github-actions bot added translation Message translation related libraries general labels Feb 25, 2026

tangelll closed this Feb 25, 2026

tangelll and others added 3 commits February 27, 2026 02:24

pre-commit.fix

3b95796

Tools is used for test , pre-commit fix is made and v.net.md is fixed.

6a837f6

fixing the pull problem, i used rebase instead and back to my works.

4b3e8dc

tangelll force-pushed the vnet-json branch from 5ad00b5 to 4b3e8dc Compare February 26, 2026 23:34

github-actions bot added vector Related to vector data processing Python Related code is in Python C Related code is in C module docs markdown Related to markdown, markdown files tests Related to Test Suite labels Feb 27, 2026

CMakeList grass parson is added

d117aca

github-actions bot added the CMake label Feb 27, 2026

echoix reviewed Feb 28, 2026

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tangelll added 3 commits March 1, 2026 00:24

remove the te street_net and optimize the test time.

f490ab0

bring test_nodes back

107dda4

bring back the commad line

35fbcf6

	opt->format->key = "format";
	if (!opt->format->description)
	opt->format->description = _("Output format");

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tangelll commented Feb 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Description

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How to Test

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tangelll commented Feb 19, 2026

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tangelll commented Feb 14, 2026 •

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