added ld-expansion serde functionality (WIP)

src/astreams/resolve.rs

@@ -4,6 +4,7 @@ use reqwest::{Method, StatusCode};
 
 const LD_CONTENT_TYPE: &str = "application/ld+json";
 
+#[derive(Debug)]
 pub(crate) struct ResolveError(pub String);
 
 impl From<reqwest::Error> for ResolveError {
@@ -49,10 +50,10 @@ impl Resolver {
         }
     }
 
-    pub async fn resolve_into<'a, T: for<'de> serde::Deserialize<'de>>(
-        &self,
-        iri: String,
-    ) -> Result<T, ResolveError> {
+    pub async fn resolve_into<'a, T>(&self, iri: String) -> Result<T, ResolveError>
+    where
+        T: for<'de> serde::Deserialize<'de>,
+    {
         Ok(self
             .get(iri, |resp| async { Ok(resp.json().await?) })
             .await?)

src/astreams/serde_ext.rs

@@ -1,41 +1,148 @@
+use super::resolve::Resolver;
 use std::{fmt, marker::PhantomData};
 
-use serde::{de, Deserialize, Deserializer};
+use serde::{de::Visitor, Deserialize, Deserializer};
 
-// Allows deserialization of a single item into a vector of that item
-// As long as they implement the From<String> trait
-pub(super) fn pull_single_into_vec<'de, D, T>(deserializer: D) -> Result<Vec<T>, D::Error>
+// Allows a value that's a string to be expanded into an object AND the serialization of that object itself
+// TODO: deserializing the actual object isnt supported atm LOL
+pub(super) fn expand<'de, D, Out>(deserializer: D) -> Result<Out, D::Error>
 where
     D: Deserializer<'de>,
-    T: From<String> + serde::Deserialize<'de>,
+    Out: for<'dt> serde::Deserialize<'dt>,
 {
-    struct VecComposer<T>(PhantomData<Vec<T>>);
+    let resolver = Resolver::new();
+    struct ResolveVisitor<Out> {
+        resolver: Resolver,
+        _type: PhantomData<Out>,
+    }
 
-    impl<'de, T> de::Visitor<'de> for VecComposer<T>
+    impl<'de, Out> Visitor<'de> for ResolveVisitor<Out>
     where
-        T: From<String> + serde::Deserialize<'de>,
+        Out: for<'dt> serde::Deserialize<'dt>,
     {
-        type Value = Vec<T>;
+        type Value = Out;
 
         fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-            let name = std::any::type_name::<T>();
-            formatter.write_str(format!("expected {} or Vec<{}>", name, name).as_str())
+            formatter.write_str(std::any::type_name::<Out>())
+        }
+
+        fn visit_map<A>(self, map: A) -> Result<Self::Value, A::Error>
+        where
+            A: serde::de::MapAccess<'de>,
+        {
+            todo!()
         }
 
         fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
         where
-            E: de::Error,
+            E: serde::de::Error,
+        {
+            tokio::runtime::Runtime::new()
+                .unwrap()
+                .block_on(self.resolver.resolve_into::<Out>(value.to_string()))
+                .map_err(|e| {
+                    let name = std::any::type_name::<Out>();
+                    serde::de::Error::invalid_value(
+                        serde::de::Unexpected::Other(
+                            format!("failed resolving iri [{}]: {}", value, e.0).as_str(),
+                        ),
+                        &name,
+                    )
+                }) // TODO try this error
+        }
+
+        fn visit_seq<S>(self, visitor: S) -> Result<Self::Value, S::Error>
+        where
+            S: serde::de::SeqAccess<'de>,
+        {
+            Deserialize::deserialize(serde::de::value::SeqAccessDeserializer::new(visitor))
+        }
+    }
+
+    deserializer.deserialize_any(ResolveVisitor {
+        resolver: resolver,
+        _type: PhantomData,
+    })
+}
+
+// Allows deserialization of a single item into a vector of that item
+// As long as they implement the From<String> trait
+pub(super) fn pull_single_into_vec<'de, D, Out>(deserializer: D) -> Result<Vec<Out>, D::Error>
+where
+    D: Deserializer<'de>,
+    Out: From<String> + serde::Deserialize<'de>,
+{
+    struct VecVisitor<Out>(PhantomData<Vec<Out>>);
+
+    impl<'de, Out> Visitor<'de> for VecVisitor<Out>
+    where
+        Out: From<String> + serde::Deserialize<'de>,
+    {
+        type Value = Vec<Out>;
+
+        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+            let name = std::any::type_name::<Out>();
+            formatter.write_str(format!("{} or Vec<{}>", name, name).as_str())
+        }
+
+        fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+        where
+            E: serde::de::Error,
         {
             Ok(vec![value.to_string().into()])
         }
 
         fn visit_seq<S>(self, visitor: S) -> Result<Self::Value, S::Error>
         where
-            S: de::SeqAccess<'de>,
+            S: serde::de::SeqAccess<'de>,
         {
-            Deserialize::deserialize(de::value::SeqAccessDeserializer::new(visitor))
+            Deserialize::deserialize(serde::de::value::SeqAccessDeserializer::new(visitor))
         }
     }
 
-    deserializer.deserialize_any(VecComposer(PhantomData))
+    deserializer.deserialize_any(VecVisitor(PhantomData))
+}
+
+#[cfg(test)]
+mod tests {
+    use serde::Deserialize;
+
+    use super::expand;
+
+    #[test]
+    fn expand_context_from_iri() {
+        #[derive(Deserialize)]
+        struct WithContext {
+            #[serde(deserialize_with = "expand")]
+            pub context: super::super::context::Context,
+        }
+
+        const JSONLD_INPUT: &str = r#"{"context": "https://www.w3.org/ns/activitystreams"}"#;
+        let result =
+            serde_json::from_str::<WithContext>(JSONLD_INPUT).expect("deserializing with expand");
+
+        assert!(result.context.ctx.xsd == "http://www.w3.org/2001/XMLSchema#")
+    }
+
+    #[test]
+    fn expand_when_json_isnt_iri_but_the_object_itself() {
+        #[derive(Deserialize)]
+        struct Expanded {
+            pub id: String,
+            pub truth: bool,
+        }
+
+        #[derive(Deserialize)]
+        struct Expandable {
+            #[serde(deserialize_with = "expand")]
+            pub expansive: Expanded,
+        }
+
+        const JSONLD_INPUT: &str = r#"{"expansive": { "id": "1", "truth": true }}"#;
+        let result =
+            serde_json::from_str::<Expandable>(JSONLD_INPUT).expect("deserializing with expand");
+
+        assert!(result.expansive.id == "1");
+        assert!(result.expansive.truth)
+    }
 }