obs-streamer-tools-plugin/core/tests/test_json.cpp

/*
streamer-tools OBS Camera Plugin - JSON reader tests
Copyright (C) 2026 CyberCoveLLC <jknapp85@gmail.com>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0
*/

#include <string>
#include <vector>

#include "stplugin/json.h"
#include "test_util.h"

using stplugin::json::Value;
using stplugin::json::parse;

static void testRealResponses()
{
    // The exact shape apps/server/src/obs/plugin.routes.ts returns.
    const Value slots = parse(
        R"({"slots":[{"identity":"cam1","displayName":"Alice","live":true},)"
        R"({"identity":"cam2","displayName":"Bob","live":false}]})");
    ST_ASSERT(slots.valid());
    ST_ASSERT(slots.isObject());
    ST_ASSERT(slots["slots"].isArray());
    ST_ASSERT_EQ(slots["slots"].size(), std::size_t(2));
    ST_ASSERT_EQ(slots["slots"].at(0)["identity"].asString(), std::string("cam1"));
    ST_ASSERT_EQ(slots["slots"].at(0)["displayName"].asString(), std::string("Alice"));
    ST_ASSERT_EQ(slots["slots"].at(0)["live"].asBool(), true);
    ST_ASSERT_EQ(slots["slots"].at(1)["live"].asBool(true), false);

    const Value token = parse(
        R"({"lkToken":"eyJhbGciOiJIUzI1NiJ9.abc.def","wsUrl":"wss://streamers.example.com",)"
        R"("identity":"obs:main-room:Ab_1-cd2"})");
    ST_ASSERT_EQ(token["lkToken"].asString(), std::string("eyJhbGciOiJIUzI1NiJ9.abc.def"));
    ST_ASSERT_EQ(token["wsUrl"].asString(), std::string("wss://streamers.example.com"));
    ST_ASSERT_EQ(token["identity"].asString(), std::string("obs:main-room:Ab_1-cd2"));

    const Value error = parse(R"({"error":"not found"})");
    ST_ASSERT_EQ(error["error"].asString(), std::string("not found"));
}

// One backslash, as it appears in the JSON *text* being parsed.
//
// Every JSON input below that contains a backslash is built by concatenation
// rather than written as a literal. Two separate portability problems make
// the obvious spellings unsafe, both observed on the Windows CI runner:
//   - MSVC still forms escape sequences and universal-character-names inside
//     RAW string literals, which it must not: R"( ... backslash-u-d-8-3-d ... )"
//     is a hard compile error ("a universal-character-name specifies an
//     invalid character"), and a raw string containing backslash-slash is an
//     "illegal escape sequence".
//   - A doubled backslash immediately followed by 'u' inside an ordinary
//     literal sits on a genuinely murky corner of translation phase 1, where
//     compilers have historically disagreed about whether a
//     universal-character-name is formed.
// Concatenation sidesteps both: no backslash is ever adjacent to a 'u' in
// the source text at all.
static const std::string kBS = "\\";

static void testScalarsAndEscapes()
{
    ST_ASSERT(parse("null").isNull());
    ST_ASSERT_EQ(parse("true").asBool(), true);
    ST_ASSERT_EQ(parse("false").asBool(true), false);
    ST_ASSERT_EQ(parse("0").asNumber(), 0.0);
    ST_ASSERT_EQ(parse("-12").asNumber(), -12.0);
    ST_ASSERT_EQ(parse("1.5e2").asNumber(), 150.0);
    ST_ASSERT_EQ(parse("\"\"").asString("x"), std::string(""));

    // "a\"b\\c\/d"  ->  a"b\c/d
    ST_ASSERT_EQ(parse("\"a" + kBS + "\"b" + kBS + kBS + "c" + kBS + "/d\"").asString(),
                 std::string("a\"b\\c/d"));
    // "\n\t\r\b\f"
    ST_ASSERT_EQ(parse("\"" + kBS + "n" + kBS + "t" + kBS + "r" + kBS + "b" + kBS + "f\"").asString(),
                 std::string("\n\t\r\b\f"));

    // \uXXXX escapes, including a surrogate pair (an emoji in a display name
    // is entirely plausible and must not corrupt the dropdown).
    ST_ASSERT_EQ(parse("\"" + kBS + "u0041\"").asString(), std::string("A"));
    ST_ASSERT_EQ(parse("\"caf" + kBS + "u00e9\"").asString(), std::string("caf\xc3\xa9"));
    ST_ASSERT_EQ(parse("\"" + kBS + "ud83d" + kBS + "ude00\"").asString(),
                 std::string("\xf0\x9f\x98\x80"));

    // Whitespace everywhere legal.
    ST_ASSERT_EQ(parse("  {\n \"a\" :\t[ 1 , 2 ]\r\n} ")["a"].size(), std::size_t(2));
}

static void testMalformedIsRejectedNotCrashed()
{
    const std::vector<std::string> bad = {
        "",
        "   ",
        "{",
        "}",
        "[",
        "[1,",
        "[1,]",
        "{\"a\"}",
        "{\"a\":}",
        "{\"a\":1,}",
        "{a:1}",
        "{'a':1}",
        "\"unterminated",
        "\"bad" + kBS + "escape\"",     // not a JSON escape character
        "\"" + kBS + "u00\"",           // truncated code point
        "\"" + kBS + "uZZZZ\"",         // non-hex code point
        "\"" + kBS + "ud83d\"",         // lone high surrogate
        "\"" + kBS + "ude00\"",         // lone low surrogate
        "01",                            // leading zero
        "+1",
        ".5",
        "1.",
        "1e",
        "1e+",
        "tru",
        "nulll",
        "{}garbage",                     // trailing content
        "[1,2] [3]",
        "\"raw\ncontrol\"",              // literal control char inside a string
        "\xff\xfe",                      // binary garbage
        "<!DOCTYPE html><html><body>502 Bad Gateway</body></html>",
    };
    for (const std::string &text : bad) {
        const Value v = parse(text);
        ST_ASSERT(!v.valid());
        // Accessors on an invalid value must still be safe and return the
        // caller's fallback.
        ST_ASSERT_EQ(v["anything"].asString("fallback"), std::string("fallback"));
        ST_ASSERT_EQ(v.at(0).asNumber(-1.0), -1.0);
        ST_ASSERT_EQ(v.size(), std::size_t(0));
    }
}

static void testDepthLimit()
{
    // Deep-but-legal nesting is rejected rather than recursed into, so a
    // hostile response cannot overflow the stack inside OBS.
    std::string deep;
    const int depth = stplugin::json::kMaxDepth + 50;
    for (int i = 0; i < depth; ++i)
        deep += "[";
    for (int i = 0; i < depth; ++i)
        deep += "]";
    ST_ASSERT(!parse(deep).valid());

    // Just inside the limit still parses.
    std::string shallow;
    for (int i = 0; i < stplugin::json::kMaxDepth - 1; ++i)
        shallow += "[";
    shallow += "1";
    for (int i = 0; i < stplugin::json::kMaxDepth - 1; ++i)
        shallow += "]";
    ST_ASSERT(parse(shallow).valid());
}

static void testWrongTypesFallBack()
{
    const Value v = parse(R"({"n":5,"s":"x","b":true,"arr":[1],"obj":{}})");
    ST_ASSERT_EQ(v["n"].asString("fallback"), std::string("fallback"));
    ST_ASSERT_EQ(v["s"].asNumber(-1.0), -1.0);
    ST_ASSERT_EQ(v["s"].asBool(true), true);
    ST_ASSERT_EQ(v["missing"].asString("fallback"), std::string("fallback"));
    ST_ASSERT_EQ(v["arr"].at(5).asNumber(-1.0), -1.0);
    ST_ASSERT_EQ(v["obj"].at(0).asNumber(-1.0), -1.0);
    ST_ASSERT_EQ(v["n"]["deeper"].asString("fallback"), std::string("fallback"));
}

int main()
{
    testRealResponses();
    testScalarsAndEscapes();
    testMalformedIsRejectedNotCrashed();
    testDepthLimit();
    testWrongTypesFallBack();
    return st_test_report("json");
}