JsonCpp problem with sorting output json - case / alphabetical problem

Question

I have an issue with JsonCpp library in C++ and sorting of keys after the json is produced. I found that JsonCpp is ignoring alphabetical order if there is Lowercase and Uppercase difference. It always favors Uppercase first and then alphabetical order.

Lets say we have this code to produce

Json::Value aJsonResult(Json::objectValue);

aJsonResult["ShuttersOpen"] = "test";
aJsonResult["ShutterType"] = "test";
aJsonResult["ShutterWidth"] = "test";

Json::StreamWriterBuilder aBuilder;
aBuilder["indentation"] = "";
return Json::writeString(aBuilder, aJsonResult).c_str();

But this produces output below, notice how ShuttersOpen key is last, even though its not correct.

{
    "ShutterType": "test",
    "ShutterWidth": "test",
    "ShuttersOpen": "test"
}

Any ideas how to fix this, I could not find any documentation on the official site

because of unit tests, I need to have it uniformed across the solution — marhyno
– marhyno, Commented Aug 1, 2024 at 14:22
but if it is not ordered, why you want to test that it is ordered? — 463035818_is_not_an_ai
– 463035818_is_not_an_ai, Commented Aug 1, 2024 at 14:24
Fix your tooling, you're depending on implementation details. One approach would be to use jq to pipe both expected and actual JSON through and then compare the result, so that you get similar formatting and ordering. — Ulrich Eckhardt
– Ulrich Eckhardt, Commented Aug 1, 2024 at 14:30
Just to confirm: JsonCpp has no way to impose order on map elements. nlohmann::json could be done that way, but I agree with others - unit tests should not add extra requirements to production code. If you have external JSON as expected value, parse it and compare parsed objects (ignoring order on map members). — Yksisarvinen
– Yksisarvinen, Commented Aug 1, 2024 at 14:35

Gilles Ottervanger · Accepted Answer · 2024-08-01 16:43:20Z

2

In lexicographical order, capital letters precede lowercase letters. "Z" < "a".

edited Aug 1, 2024 at 16:43

answered Aug 1, 2024 at 14:28

Gilles Ottervanger

6713 silver badges13 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

marhyno Over a year ago

okay, got it, I was hoping there would something like in c# to make all keys lowercase and sort them when creating a json

Collectives™ on Stack Overflow

JsonCpp problem with sorting output json - case / alphabetical problem

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related