Add big decimal support to juniper

juniper/Cargo.toml

@@ -26,6 +26,7 @@ path = "benches/bench.rs"
 nightly = []
 expose-test-schema = []
 default = [
+    "bigdecimal",
     "chrono",
     "url",
     "uuid"
@@ -39,6 +40,7 @@ ordermap = { version = "0.2.11", features = ["serde-1"] }
 serde = { version = "1.0.8" }
 serde_derive = {version="1.0.2" }
 
+bigdecimal = { version = "0.0.10", optional = true }
 chrono = { version = "0.4.0", optional = true }
 serde_json = { version="1.0.2", optional = true }
 url = { version = "1.5.1", optional = true }

juniper/src/integrations/bigdecimal.rs

@@ -0,0 +1,32 @@
+use bigdecimal::BigDecimal;
+
+use Value;
+
+graphql_scalar!(BigDecimal {
+    description: "BigDecimal"
+
+    resolve(&self) -> Value {
+        Value::string(self.to_string())
+    }
+
+    from_input_value(v: &InputValue) -> Option<BigDecimal> {
+        v.as_string_value()
+         .and_then(|s| s.parse::<BigDecimal>().ok())
+    }
+});
+
+#[cfg(test)]
+mod test {
+    use bigdecimal::BigDecimal;
+
+    #[test]
+    fn bigdecimal_from_input_value() {
+        let raw = "-10.1910";
+        let input = ::InputValue::String(raw.to_string());
+
+        let parsed: BigDecimal = ::FromInputValue::from_input_value(&input).unwrap();
+        let bigdecimal = raw.parse::<BigDecimal>().unwrap();
+
+        assert_eq!(parsed, bigdecimal);
+    }
+}

juniper/src/integrations/mod.rs

@@ -2,6 +2,10 @@
 #[doc(hidden)]
 pub mod serde;
 
+#[cfg(feature = "bigdecimal")]
+/// GraphQL support for [bigdecimal](https://github.com/akubera/bigdecimal-rs) types.
+pub mod bigdecimal;
+
 #[cfg(feature = "chrono")]
 /// GraphQL support for [chrono](https://github.com/chronotope/chrono) types.
 pub mod chrono;

juniper/src/lib.rs

@@ -100,6 +100,8 @@ extern crate serde_json;
 extern crate fnv;
 extern crate ordermap;
 
+extern crate bigdecimal;
+
 #[cfg(any(test, feature = "chrono"))]
 extern crate chrono;