Make GraphQLError nearly spec-compliant

Author: tomhoule

CHANGELOG.md

@@ -7,10 +7,13 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## Unreleased
 
+## [0.2.0] - 2018-07-22
+
 ### Added
 
 - Copy documentation from the GraphQL schema to the generated types (including their fields) as normal Rust documentation. Documentation will show up in the generated docs as well as IDEs that support expanding derive macros (which does not include the RLS yet).
 - Implement and test deserializing subscription responses. We also try to provide helpful error messages when a subscription query is not valid (i.e. when it has more than one top-level field).
+- Support the [new top-level errors shape from the June 2018 spec](https://github.com/facebook/graphql/blob/master/spec/Section%207%20--%20Response.md), except for the `extensions` field (see issue #64).
 
 ### Fixed
 

src/lib.rs

@@ -8,6 +8,10 @@ extern crate serde_derive;
 #[macro_use]
 extern crate graphql_query_derive;
 
+#[cfg(test)]
+#[macro_use]
+extern crate serde_json;
+
 #[doc(hidden)]
 pub use graphql_query_derive::*;
 
@@ -29,16 +33,95 @@ where
     pub query: &'static str,
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize, PartialEq)]
+pub struct Location {
+    line: i32,
+    column: i32,
+}
+
+#[derive(Debug, Serialize, Deserialize, PartialEq)]
+#[serde(untagged)]
+pub enum PathFragment {
+    Key(String),
+    Index(i32),
+}
+
+/// An element in the top-level `errors` array of a response body.
+///
+/// This tries to be as close to the spec as possible.
+///
+/// Spec: [https://github.com/facebook/graphql/blob/master/spec/Section%207%20--%20Response.md]
+#[derive(Debug, Serialize, Deserialize, PartialEq)]
 pub struct GraphQLError {
-    pub path: String,
+    pub message: String,
+    pub locations: Option<Vec<Location>>,
+    pub path: Option<Vec<PathFragment>>,
 }
 
 /// The generic shape taken by the responses of GraphQL APIs.
 ///
 /// This will generally be used with the `ResponseData` struct from a derived module.
+///
+/// Spec: [https://github.com/facebook/graphql/blob/master/spec/Section%207%20--%20Response.md]
 #[derive(Debug, Serialize, Deserialize)]
 pub struct GraphQLResponse<Data> {
     pub data: Option<Data>,
     pub errors: Option<Vec<GraphQLError>>,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn graphql_error_works_with_just_message() {
+        let err = json!({
+            "message": "I accidentally your whole query"
+        });
+
+        let deserialized_error: GraphQLError = serde_json::from_value(err).unwrap();
+
+        assert_eq!(
+            deserialized_error,
+            GraphQLError {
+                message: "I accidentally your whole query".to_string(),
+                locations: None,
+                path: None,
+            }
+        )
+    }
+
+    #[test]
+    fn full_graphql_error_deserialization() {
+        let err = json!({
+            "message": "I accidentally your whole query",
+            "locations": [{ "line": 3, "column": 13}, {"line": 56, "column": 1}],
+            "path": ["home", "alone", 3, "rating"]
+        });
+
+        let deserialized_error: GraphQLError = serde_json::from_value(err).unwrap();
+
+        assert_eq!(
+            deserialized_error,
+            GraphQLError {
+                message: "I accidentally your whole query".to_string(),
+                locations: Some(vec![
+                    Location {
+                        line: 3,
+                        column: 13,
+                    },
+                    Location {
+                        line: 56,
+                        column: 1,
+                    },
+                ]),
+                path: Some(vec![
+                    PathFragment::Key("home".to_owned()),
+                    PathFragment::Key("alone".to_owned()),
+                    PathFragment::Index(3),
+                    PathFragment::Key("rating".to_owned()),
+                ]),
+            }
+        )
+    }
+}