From 9ed7cb215840ab9d445ba5e4c26885bea4bdc820 Mon Sep 17 00:00:00 2001
From: Ingvar Stepanyan <me@rreverser.com>
Date: Wed, 25 Sep 2024 03:09:36 +0100
Subject: [PATCH] Fix response parsing for ()

---
 src/client/response.rs | 12 ++++++++++--
 src/server/params.rs   |  5 +++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/client/response.rs b/src/client/response.rs
index dedc8b1..cfc3427 100644
--- a/src/client/response.rs
+++ b/src/client/response.rs
@@ -3,7 +3,9 @@ use crate::client::ResponseTransaction;
 use crate::response::ValueResponse;
 use crate::{ASCOMError, ASCOMErrorCode, ASCOMResult};
 use mime::Mime;
+use serde::de::value::UnitDeserializer;
 use serde::de::DeserializeOwned;
+use std::any::TypeId;
 
 pub(crate) trait Response: Sized {
     fn prepare_reqwest(request: reqwest::RequestBuilder) -> reqwest::RequestBuilder {
@@ -30,7 +32,7 @@ impl ResponseTransaction {
     }
 }
 
-impl<T: DeserializeOwned> Response for ASCOMResult<T> {
+impl<T: 'static + DeserializeOwned> Response for ASCOMResult<T> {
     fn from_reqwest(mime_type: Mime, bytes: &[u8]) -> eyre::Result<ResponseWithTransaction<Self>> {
         let transaction = ResponseTransaction::from_reqwest(mime_type, bytes)?;
         let ascom_error = serde_json::from_slice::<ASCOMError>(bytes)?;
@@ -38,7 +40,13 @@ impl<T: DeserializeOwned> Response for ASCOMResult<T> {
         Ok(ResponseWithTransaction {
             transaction,
             response: match ascom_error.code {
-                ASCOMErrorCode::OK => Ok(serde_json::from_slice::<ValueResponse<T>>(bytes)?.value),
+                ASCOMErrorCode::OK => Ok(if TypeId::of::<T>() == TypeId::of::<()>() {
+                    // Specialization: avoid failure when trying to parse `()` from JSON object with no `Value`.
+                    T::deserialize(UnitDeserializer::new())
+                } else {
+                    serde_json::from_slice::<ValueResponse<T>>(bytes)
+                        .map(|value_response| value_response.value)
+                }?),
                 _ => Err(ascom_error),
             },
         })
diff --git a/src/server/params.rs b/src/server/params.rs
index 3e6b62e..c37d4c9 100644
--- a/src/server/params.rs
+++ b/src/server/params.rs
@@ -7,6 +7,7 @@ use http::{Method, StatusCode};
 use indexmap::IndexMap;
 use serde::de::{DeserializeOwned, IntoDeserializer};
 use serde::Deserialize;
+use std::any::TypeId;
 use std::fmt::Debug;
 use std::hash::Hash;
 
@@ -39,11 +40,11 @@ where
             .swap_remove(name.as_ref())
             .map(|mut value| {
                 // Specialization: optimized path to avoid cloning the string.
-                if std::any::TypeId::of::<T>() == std::any::TypeId::of::<String>() {
+                if TypeId::of::<T>() == TypeId::of::<String>() {
                     return T::deserialize(value.into_deserializer());
                 }
                 // Specialization: booleans in ASCOM must be case-insensitive.
-                if std::any::TypeId::of::<T>() == std::any::TypeId::of::<bool>() {
+                if TypeId::of::<T>() == TypeId::of::<bool>() {
                     value.make_ascii_lowercase();
                 }
                 serde_plain::from_str(&value)