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fix(macros): support non-String parameter types in mcp_resource #78

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Merged
avrabe merged 2 commits into from
Dec 6, 2025
Merged

fix(macros): support non-String parameter types in mcp_resource #78

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62d2ca4
fix(macros): support non-String parameter types in mcp_resource
avrabe Dec 6, 2025
b5e3ea1
test: add comprehensive edge case tests for mcp_resource macro
avrabe Dec 6, 2025
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47 changes: 41 additions & 6 deletions mcp-macros/src/mcp_tool.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@ struct ResourceInfo {
path_pattern: String,
param_names: Vec<String>,
method_param_names: Vec<syn::Ident>,
method_param_types: Vec<syn::Type>,
is_async: bool,
has_params: bool,
}
Expand Down Expand Up @@ -54,6 +55,7 @@ fn parse_uri_template(uri_template: &str) -> (String, Vec<String>) {
}

/// Extract parameter names from URI template path
/// Handles both regular params {name} and catch-all params {*name}
fn extract_uri_parameters(path: &str) -> Vec<String> {
let mut params = Vec::new();
let mut chars = path.chars().peekable();
Expand All @@ -68,7 +70,10 @@ fn extract_uri_parameters(path: &str) -> Vec<String> {
param_name.push(ch);
}
if !param_name.is_empty() {
params.push(param_name);
// Strip the leading '*' for catch-all parameters
// matchit uses {*name} syntax but stores params without the '*'
let clean_name = param_name.strip_prefix('*').unwrap_or(&param_name);
params.push(clean_name.to_string());
}
}
}
Expand Down Expand Up @@ -251,14 +256,41 @@ fn generate_matchit_resource_impl(
.iter()
.enumerate()
.map(|(param_idx, param_name)| {
if let Some(method_param) = info.method_param_names.get(param_idx) {
let method_param = match info.method_param_names.get(param_idx) {
Some(p) => p,
None => return quote! {},
};
let param_type = match info.method_param_types.get(param_idx) {
Some(t) => t,
None => return quote! {},
};

// Check if the type is String - if so, no parsing needed
let is_string_type = if let syn::Type::Path(type_path) = param_type {
type_path.path.segments.last()
.map(|seg| seg.ident == "String")
.unwrap_or(false)
} else {
false
};

if is_string_type {
// String type - just convert directly
quote! {
let #method_param = matched.params.get(#param_name)
.unwrap_or("default")
let #method_param: #param_type = matched.params.get(#param_name)
.unwrap_or("")
.to_string();
}
} else {
quote! {}
// Non-String type - parse from string
quote! {
let #method_param: #param_type = matched.params.get(#param_name)
.unwrap_or("")
.parse()
.map_err(|e| pulseengine_mcp_protocol::Error::invalid_params(
format!("Failed to parse parameter '{}': {}", #param_name, e)
))?;
}
}
})
.collect();
Expand Down Expand Up @@ -471,14 +503,16 @@ pub fn mcp_tools_impl(_attr: TokenStream, item: TokenStream) -> syn::Result<Toke
// Parse URI template to get matchit path pattern
let (path_pattern, template_param_names) = parse_uri_template(&uri_template);

// Extract method parameter names
// Extract method parameter names and types
let mut method_param_names = Vec::new();
let mut method_param_types = Vec::new();
for input in &method.sig.inputs {
match input {
syn::FnArg::Receiver(_) => continue,
syn::FnArg::Typed(pat_type) => {
if let syn::Pat::Ident(pat_ident) = &*pat_type.pat {
method_param_names.push(pat_ident.ident.clone());
method_param_types.push((*pat_type.ty).clone());
}
}
}
Expand All @@ -492,6 +526,7 @@ pub fn mcp_tools_impl(_attr: TokenStream, item: TokenStream) -> syn::Result<Toke
path_pattern,
param_names: template_param_names,
method_param_names,
method_param_types,
is_async: method.sig.asyncness.is_some(),
has_params: method.sig.inputs.len() > 1,
};
Expand Down
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