Support jsonc format

Cargo.toml

@@ -15,11 +15,12 @@ edition = "2018"
 maintenance = { status = "actively-developed" }
 
 [features]
-default = ["toml", "json", "yaml", "ini", "ron", "json5", "convert-case", "async"]
+default = ["toml", "json", "yaml", "ini", "ron", "json5", "jsonc", "convert-case", "async"]
 json = ["serde_json"]
 yaml = ["yaml-rust"]
 ini = ["rust-ini"]
 json5 = ["json5_rs", "serde/derive"]
+jsonc = ["jsonc-parser"]
 convert-case = ["convert_case"]
 preserve_order = ["indexmap", "toml/preserve_order", "serde_json/preserve_order", "ron/indexmap"]
 async = ["async-trait"]
@@ -36,6 +37,7 @@ yaml-rust = { version = "0.4", optional = true }
 rust-ini = { version = "0.19", optional = true }
 ron = { version = "0.8", optional = true }
 json5_rs = { version = "0.4", optional = true, package = "json5" }
+jsonc-parser = { version = "0.22.1", optional = true }
 indexmap = { version = "2.0.0", features = ["serde"], optional = true }
 convert_case = { version = "0.6", optional = true }
 pathdiff = "0.2"

README.md

@@ -11,7 +11,7 @@
 
  - Set defaults
  - Set explicit values (to programmatically override)
- - Read from [JSON], [TOML], [YAML], [INI], [RON], [JSON5] files
+ - Read from [JSON], [TOML], [YAML], [INI], [RON], [JSON5], [JSONC] files
  - Read from environment
  - Loosely typed — Configuration values may be read in any supported type, as long as there exists a reasonable conversion
  - Access nested fields using a formatted path — Uses a subset of JSONPath; currently supports the child ( `redis.port` ) and subscript operators ( `databases[0].name` )
@@ -22,6 +22,7 @@
 [INI]: https://github.com/zonyitoo/rust-ini
 [RON]: https://github.com/ron-rs/ron
 [JSON5]: https://github.com/callum-oakley/json5-rs
+[JSONC]: https://github.com/dprint/jsonc-parser
 
 Please note this library
 
@@ -43,6 +44,7 @@ config = "0.13.1"
  - `toml` - Adds support for reading TOML files
  - `ron` - Adds support for reading RON files
  - `json5` - Adds support for reading JSON5 files
+ - `jsonc` - Adds support for reading JSONC files
 
 ### Support for custom formats
 

src/file/format/jsonc.rs

@@ -0,0 +1,61 @@
+use std::error::Error;
+
+use crate::error::{ConfigError, Unexpected};
+use crate::map::Map;
+use crate::value::{Value, ValueKind};
+
+use jsonc_parser::JsonValue;
+
+pub fn parse(
+    uri: Option<&String>,
+    text: &str,
+) -> Result<Map<String, Value>, Box<dyn Error + Send + Sync>> {
+    match jsonc_parser::parse_to_value(text, &Default::default())? {
+        Some(r) => match r {
+            JsonValue::String(ref value) => Err(Unexpected::Str(value.to_string())),
+            JsonValue::Number(value) => Err(Unexpected::Float(value.parse::<f64>().unwrap())),
+            JsonValue::Boolean(value) => Err(Unexpected::Bool(value)),
+            JsonValue::Object(o) => match from_jsonc_value(uri, JsonValue::Object(o)).kind {
+                ValueKind::Table(map) => Ok(map),
+                _ => unreachable!(),
+            },
+            JsonValue::Array(_) => Err(Unexpected::Seq),
+            JsonValue::Null => Err(Unexpected::Unit),
+        },
+        None => Err(Unexpected::Unit),
+    }
+    .map_err(|err| ConfigError::invalid_root(uri, err))
+    .map_err(|err| Box::new(err) as Box<dyn Error + Send + Sync>)
+}
+
+fn from_jsonc_value(uri: Option<&String>, value: JsonValue) -> Value {
+    let vk = match value {
+        JsonValue::Null => ValueKind::Nil,
+        JsonValue::String(v) => ValueKind::String(v.to_string()),
+        JsonValue::Number(number) => {
+            if let Ok(v) = number.parse::<i64>() {
+                ValueKind::I64(v)
+            } else if let Ok(v) = number.parse::<f64>() {
+                ValueKind::Float(v)
+            } else {
+                unreachable!();
+            }
+        }
+        JsonValue::Boolean(v) => ValueKind::Boolean(v),
+        JsonValue::Object(table) => {
+            let m = table
+                .into_iter()
+                .map(|(k, v)| (k, from_jsonc_value(uri, v)))
+                .collect();
+            ValueKind::Table(m)
+        }
+        JsonValue::Array(array) => {
+            let l = array
+                .into_iter()
+                .map(|v| from_jsonc_value(uri, v))
+                .collect();
+            ValueKind::Array(l)
+        }
+    };
+    Value::new(uri, vk)
+}

src/file/format/mod.rs

@@ -27,6 +27,9 @@ mod ron;
 #[cfg(feature = "json5")]
 mod json5;
 
+#[cfg(feature = "jsonc")]
+mod jsonc;
+
 /// File formats provided by the library.
 ///
 /// Although it is possible to define custom formats using [`Format`] trait it is recommended to use FileFormat if possible.
@@ -55,6 +58,10 @@ pub enum FileFormat {
     /// JSON5 (parsed with json5)
     #[cfg(feature = "json5")]
     Json5,
+
+    /// JSONC (parsed with jsonc)
+    #[cfg(feature = "jsonc")]
+    Jsonc,
 }
 
 lazy_static! {
@@ -81,6 +88,12 @@ lazy_static! {
         #[cfg(feature = "json5")]
         formats.insert(FileFormat::Json5, vec!["json5"]);
 
+        #[cfg(all(feature = "jsonc", feature = "json"))]
+        formats.insert(FileFormat::Jsonc, vec!["jsonc"]);
+
+        #[cfg(all(feature = "jsonc", not(feature = "json")))]
+        formats.insert(FileFormat::Jsonc, vec!["jsonc", "json"]);
+
         formats
     };
 }
@@ -117,13 +130,17 @@ impl FileFormat {
             #[cfg(feature = "json5")]
             FileFormat::Json5 => json5::parse(uri, text),
 
+            #[cfg(feature = "jsonc")]
+            FileFormat::Jsonc => jsonc::parse(uri, text),
+
             #[cfg(all(
                 not(feature = "toml"),
                 not(feature = "json"),
                 not(feature = "yaml"),
                 not(feature = "ini"),
                 not(feature = "ron"),
                 not(feature = "json5"),
+                not(feature = "jsonc"),
             ))]
             _ => unreachable!("No features are enabled, this library won't work without features"),
         }

src/lib.rs

@@ -6,7 +6,7 @@
 //!  - Environment variables
 //!  - String literals in well-known formats
 //!  - Another Config instance
-//!  - Files: TOML, JSON, YAML, INI, RON, JSON5 and custom ones defined with Format trait
+//!  - Files: TOML, JSON, YAML, INI, RON, JSON5, JSONC and custom ones defined with Format trait
 //!  - Manual, programmatic override (via a `.set` method on the Config instance)
 //!
 //! Additionally, Config supports:

tests/Settings-enum-test.jsonc

@@ -0,0 +1,4 @@
+{
+    // foo
+    "bar": "bar is a lowercase param",
+}

tests/Settings-invalid.jsonc

@@ -0,0 +1,4 @@
+{
+  "ok": true,
+  "error"
+}

tests/Settings.jsonc

@@ -0,0 +1,23 @@
+{
+  // c
+  /* c */
+  "debug": true,
+  "debug_json": true,
+  "production": false,
+  "arr": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
+  "place": {
+    "name": "Torre di Pisa",
+    "longitude": 43.7224985,
+    "latitude": 10.3970522,
+    "favorite": false,
+    "reviews": 3866,
+    "rating": 4.5,
+    "creator": {
+      "name": "John Smith",
+      "username": "jsmith",
+      "email": "jsmith@localhost"
+    },
+  },
+  "FOO": "FOO should be overridden",
+  "bar": "I am bar",
+}

tests/file_jsonc.rs

@@ -0,0 +1,195 @@
+#![cfg(feature = "jsonc")]
+
+use serde_derive::Deserialize;
+
+use config::{Config, File, FileFormat, Map, Value};
+use float_cmp::ApproxEqUlps;
+use std::path::PathBuf;
+
+#[derive(Debug, Deserialize)]
+struct Place {
+    name: String,
+    longitude: f64,
+    latitude: f64,
+    favorite: bool,
+    telephone: Option<String>,
+    reviews: u64,
+    creator: Map<String, Value>,
+    rating: Option<f32>,
+}
+
+#[derive(Debug, Deserialize)]
+struct Settings {
+    debug: f64,
+    production: Option<String>,
+    place: Place,
+    #[serde(rename = "arr")]
+    elements: Vec<String>,
+}
+
+fn make() -> Config {
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Jsonc))
+        .build()
+        .unwrap()
+}
+
+#[test]
+fn test_file() {
+    let c = make();
+
+    // Deserialize the entire file as single struct
+    let s: Settings = c.try_deserialize().unwrap();
+
+    assert!(s.debug.approx_eq_ulps(&1.0, 2));
+    assert_eq!(s.production, Some("false".to_string()));
+    assert_eq!(s.place.name, "Torre di Pisa");
+    assert!(s.place.longitude.approx_eq_ulps(&43.722_498_5, 2));
+    assert!(s.place.latitude.approx_eq_ulps(&10.397_052_2, 2));
+    assert!(!s.place.favorite);
+    assert_eq!(s.place.reviews, 3866);
+    assert_eq!(s.place.rating, Some(4.5));
+    assert_eq!(s.place.telephone, None);
+    assert_eq!(s.elements.len(), 10);
+    assert_eq!(s.elements[3], "4".to_string());
+    if cfg!(feature = "TODO: preserve_order") {
+        assert_eq!(
+            s.place
+                .creator
+                .into_iter()
+                .collect::<Vec<(String, config::Value)>>(),
+            vec![
+                ("name".to_string(), "John Smith".into()),
+                ("username".into(), "jsmith".into()),
+                ("email".into(), "jsmith@localhost".into()),
+            ]
+        );
+    } else {
+        assert_eq!(
+            s.place.creator["name"].clone().into_string().unwrap(),
+            "John Smith".to_string()
+        );
+    }
+}
+
+#[test]
+fn test_error_parse() {
+    let res = Config::builder()
+        .add_source(File::new("tests/Settings-invalid", FileFormat::Jsonc))
+        .build();
+
+    let path_with_extension: PathBuf = ["tests", "Settings-invalid.jsonc"].iter().collect();
+
+    assert!(res.is_err());
+    assert_eq!(
+        res.unwrap_err().to_string(),
+        format!(
+            "Expected a colon after the string or word in an object property on line 4 column 1. in {}",
+            path_with_extension.display()
+        )
+    );
+}
+
+#[derive(Debug, Deserialize, PartialEq)]
+enum EnumSettings {
+    Bar(String),
+}
+
+#[derive(Debug, Deserialize, PartialEq)]
+struct StructSettings {
+    foo: String,
+    bar: String,
+}
+#[derive(Debug, Deserialize, PartialEq)]
+#[allow(non_snake_case)]
+struct CapSettings {
+    FOO: String,
+}
+
+#[test]
+fn test_override_uppercase_value_for_struct() {
+    std::env::set_var("APP_FOO", "I HAVE BEEN OVERRIDDEN_WITH_UPPER_CASE");
+
+    let cfg = Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Jsonc))
+        .add_source(config::Environment::with_prefix("APP").separator("_"))
+        .build()
+        .unwrap();
+
+    let cap_settings = cfg.clone().try_deserialize::<CapSettings>();
+    let lower_settings = cfg.try_deserialize::<StructSettings>().unwrap();
+
+    match cap_settings {
+        Ok(v) => {
+            // this assertion will ensure that the map has only lowercase keys
+            assert_ne!(v.FOO, "FOO should be overridden");
+            assert_eq!(
+                lower_settings.foo,
+                "I HAVE BEEN OVERRIDDEN_WITH_UPPER_CASE".to_string()
+            );
+        }
+        Err(e) => {
+            if e.to_string().contains("missing field `FOO`") {
+                assert_eq!(
+                    lower_settings.foo,
+                    "I HAVE BEEN OVERRIDDEN_WITH_UPPER_CASE".to_string()
+                );
+            } else {
+                panic!("{}", e);
+            }
+        }
+    }
+}
+
+#[test]
+fn test_override_lowercase_value_for_struct() {
+    std::env::set_var("config_foo", "I have been overridden_with_lower_case");
+
+    let cfg = Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Jsonc))
+        .add_source(config::Environment::with_prefix("config").separator("_"))
+        .build()
+        .unwrap();
+
+    let values: StructSettings = cfg.try_deserialize().unwrap();
+    assert_eq!(
+        values.foo,
+        "I have been overridden_with_lower_case".to_string()
+    );
+    assert_ne!(values.foo, "I am bar".to_string());
+}
+
+#[test]
+fn test_override_uppercase_value_for_enums() {
+    std::env::set_var("APPS_BAR", "I HAVE BEEN OVERRIDDEN_WITH_UPPER_CASE");
+
+    let cfg = Config::builder()
+        .add_source(File::new("tests/Settings-enum-test", FileFormat::Jsonc))
+        .add_source(config::Environment::with_prefix("APPS").separator("_"))
+        .build()
+        .unwrap();
+    let val: EnumSettings = cfg.try_deserialize().unwrap();
+
+    assert_eq!(
+        val,
+        EnumSettings::Bar("I HAVE BEEN OVERRIDDEN_WITH_UPPER_CASE".to_string())
+    );
+}
+
+#[test]
+fn test_override_lowercase_value_for_enums() {
+    std::env::set_var("test_bar", "I have been overridden_with_lower_case");
+
+    let cfg = Config::builder()
+        .add_source(File::new("tests/Settings-enum-test", FileFormat::Jsonc))
+        .add_source(config::Environment::with_prefix("test").separator("_"))
+        .build()
+        .unwrap();
+
+    let param: EnumSettings = cfg.try_deserialize().unwrap();
+
+    assert_eq!(
+        param,
+        EnumSettings::Bar("I have been overridden_with_lower_case".to_string())
+    );
+}