From 820f7f8980be4a2317e52aa1bc25e196c56e1eeb Mon Sep 17 00:00:00 2001
From: Yin Guanhao <sopium@mysterious.site>
Date: Thu, 30 Nov 2023 11:41:43 +0800
Subject: [PATCH] feat: improve invalid params error

when there are optional parameters
---
 examples/server-macros.rs       |  6 +++---
 jsonrpc-utils-macros/src/lib.rs | 10 ++++++----
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/examples/server-macros.rs b/examples/server-macros.rs
index 849743c..efb682f 100644
--- a/examples/server-macros.rs
+++ b/examples/server-macros.rs
@@ -14,7 +14,7 @@ use jsonrpc_utils::{
 trait MyRpc {
     async fn sleep(&self, x: u64) -> Result<u64>;
     async fn value(&self, x: Option<u64>) -> Result<u64>;
-    async fn add(&self, (x, y): (i32, i32), z: i32) -> Result<i32>;
+    async fn add(&self, (x, y): (i32, i32), z: Option<i32>) -> Result<i32>;
     #[rpc(name = "@ping")]
     fn ping(&self) -> Result<String>;
 
@@ -37,8 +37,8 @@ impl MyRpc for RpcImpl {
         Ok(x.unwrap_or_default())
     }
 
-    async fn add(&self, (x, y): (i32, i32), z: i32) -> Result<i32> {
-        Ok(x + y + z)
+    async fn add(&self, (x, y): (i32, i32), z: Option<i32>) -> Result<i32> {
+        Ok(x + y + z.unwrap_or_default())
     }
 
     fn ping(&self) -> Result<String> {
diff --git a/jsonrpc-utils-macros/src/lib.rs b/jsonrpc-utils-macros/src/lib.rs
index d663888..e688a91 100644
--- a/jsonrpc-utils-macros/src/lib.rs
+++ b/jsonrpc-utils-macros/src/lib.rs
@@ -330,24 +330,26 @@ fn add_method(m: &mut TraitItemFn) -> Result<proc_macro2::TokenStream> {
             let mut arr = match params {
                 jsonrpc_utils::jsonrpc_core::Params::Array(arr) => arr.into_iter(),
                 jsonrpc_utils::jsonrpc_core::Params::None => Vec::new().into_iter(),
-                _ => return Err(jsonrpc_utils::jsonrpc_core::Error::invalid_params("")),
+                _ => return Err(jsonrpc_utils::jsonrpc_core::Error::invalid_params("Invalid params: invalid type map, expect an array or null")),
             };
         };
         for i in 0..required_params {
             let p = &params_names[i];
+            let p_str = LitStr::new(&p.to_string(), p.span());
             let ty = params_tys[i];
             parse_params.extend(quote! {
-                let #p: #ty = jsonrpc_utils::serde_json::from_value(arr.next().ok_or_else(|| jsonrpc_utils::jsonrpc_core::Error::invalid_params(""))?).map_err(|_|
-                    jsonrpc_utils::jsonrpc_core::Error::invalid_params("")
+                let #p: #ty = jsonrpc_utils::serde_json::from_value(arr.next().ok_or_else(|| jsonrpc_utils::jsonrpc_core::Error::invalid_params(format!("Missing required parameter `{}`", #p_str)))?).map_err(|e|
+                    jsonrpc_utils::jsonrpc_core::Error::invalid_params(format!("Invalid parameter for `{}`: {}", #p_str, e))
                 )?;
             });
         }
         for i in required_params..params_names.len() {
             let p = &params_names[i];
+            let p_str = LitStr::new(&p.to_string(), p.span());
             let ty = params_tys[i];
             parse_params.extend(quote! {
                 let #p: #ty = match arr.next() {
-                    Some(v) => jsonrpc_utils::serde_json::from_value(v).map_err(|_| jsonrpc_utils::jsonrpc_core::Error::invalid_params(""))?,
+                    Some(v) => jsonrpc_utils::serde_json::from_value(v).map_err(|e| jsonrpc_utils::jsonrpc_core::Error::invalid_params(format!("Invalid parameter for `{}`: {}", #p_str, e)))?,
                     None => None,
                 };
             });