Variant: Write Variant Values as JSON

parquet-variant/Cargo.toml

@@ -35,5 +35,7 @@ rust-version = "1.83"
 [dependencies]
 arrow-schema = { workspace = true }
 chrono = { workspace = true }
+serde_json = "1.0"
+base64 = "0.21"
 
 [lib]

parquet-variant/examples/variant_to_json_examples.rs

@@ -0,0 +1,55 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! Example showing how to convert Variant values to JSON
+
+use parquet_variant::{
+    variant_to_json, variant_to_json_string, variant_to_json_value, VariantBuilder,
+};
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut builder = VariantBuilder::new();
+
+    {
+        let mut person = builder.new_object();
+        person.append_value("name", "Alice");
+        person.append_value("age", 30i32);
+        person.append_value("email", "[email protected]");
+        person.append_value("is_active", true);
+        person.append_value("score", 95.7f64);
+        person.append_value("department", "Engineering");
+        person.finish();
+    }
+
+    let (metadata, value) = builder.finish();
+    let variant = parquet_variant::Variant::try_new(&metadata, &value)?;
+
+    let json_string = variant_to_json_string(&variant)?;
+    let json_value = variant_to_json_value(&variant)?;
+    let pretty_json = serde_json::to_string_pretty(&json_value)?;
+    println!("{}", pretty_json);
+
+    let mut buffer = Vec::new();
+    variant_to_json(&mut buffer, &variant)?;
+    let buffer_result = String::from_utf8(buffer)?;
+
+    // Verify all methods produce the same result
+    assert_eq!(json_string, buffer_result);
+    assert_eq!(json_string, serde_json::to_string(&json_value)?);
+
+    Ok(())
+}

parquet-variant/src/lib.rs

@@ -33,8 +33,10 @@ mod decoder;
 mod variant;
 // TODO: dead code removal
 mod builder;
+mod to_json;
 #[allow(dead_code)]
 mod utils;
 
 pub use builder::*;
+pub use to_json::{variant_to_json, variant_to_json_string, variant_to_json_value};
 pub use variant::*;