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fix: use `#[server(default)]` to pass use default values for a field (#2231)

This commit is contained in:
Greg Johnston 2024-01-26 14:46:31 -05:00 committed by GitHub
parent 1f9dad421f
commit b367b68a43
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GPG Key ID: B5690EEEBB952194
2 changed files with 58 additions and 49 deletions
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10
leptos_macro/src/lib.rs
View File

@ -915,6 +915,16 @@ pub fn slot(args: proc_macro::TokenStream, s: TokenStream) -> TokenStream {
/// Whatever encoding is provided to `input` should implement `IntoReq` and `FromReq`. Whatever encoding is provided
/// to `output` should implement `IntoRes` and `FromRes`.
///
/// ## Default Values for Parameters
///
/// Individual function parameters can be annotated with `#[server(default)]`, which will pass
/// through `#[serde(default)]`. This is useful for the empty values of arguments with some
/// encodings. The URL encoding, for example, omits a field entirely if it is an empty `Vec<_>`,
/// but this causes a deserialization error: the correct solution is to add `#[server(default)]`.
/// ```rust,ignore
/// pub async fn with_default_value(#[server(default)] values: Vec<u32>) /* etc. */
/// ```
///
/// ## Important Notes
/// - **Server functions must be `async`.** Even if the work being done inside the function body
/// can run synchronously on the server, from the client’s perspective it involves an asynchronous

97
server_fn_macro/src/lib.rs
View File

@ -55,6 +55,54 @@ pub fn server_macro_impl(
}
});
let fields = body
.inputs
.iter_mut()
.map(|f| {
let typed_arg = match f {
FnArg::Receiver(_) => {
return Err(syn::Error::new(
f.span(),
"cannot use receiver types in server function macro",
))
}
FnArg::Typed(t) => t,
};
// strip `mut`, which is allowed in fn args but not in struct fields
if let Pat::Ident(ident) = &mut *typed_arg.pat {
ident.mutability = None;
}
// allow #[server(default)] on fields
let mut default = false;
let mut other_attrs = Vec::new();
for attr in typed_arg.attrs.iter() {
if !attr.path().is_ident("server") {
other_attrs.push(attr.clone());
continue;
}
attr.parse_nested_meta(|meta| {
if meta.path.is_ident("default") && meta.input.is_empty() {
default = true;
Ok(())
} else {
Err(meta.error(
"Unrecognized #[server] attribute, expected \
#[server(default)]",
))
}
})?;
}
typed_arg.attrs = other_attrs;
if default {
Ok(quote! { #[serde(default)] pub #typed_arg })
} else {
Ok(quote! { pub #typed_arg })
}
})
.collect::<Result<Vec<_>>>()?;
let dummy = body.to_dummy_output();
let dummy_name = body.to_dummy_ident();
let args = syn::parse::<ServerFnArgs>(args.into())?;
@ -130,60 +178,11 @@ pub fn server_macro_impl(
};
// build struct for type
let mut body = body;
let fn_name = &body.ident;
let fn_name_as_str = body.ident.to_string();
let vis = body.vis;
let attrs = body.attrs;
let fields = body
.inputs
.iter_mut()
.map(|f| {
let typed_arg = match f {
FnArg::Receiver(_) => {
return Err(syn::Error::new(
f.span(),
"cannot use receiver types in server function macro",
))
}
FnArg::Typed(t) => t,
};
// strip `mut`, which is allowed in fn args but not in struct fields
if let Pat::Ident(ident) = &mut *typed_arg.pat {
ident.mutability = None;
}
// allow #[server(default)] on fields — TODO is this documented?
let mut default = false;
let mut other_attrs = Vec::new();
for attr in typed_arg.attrs.iter() {
if !attr.path().is_ident("server") {
other_attrs.push(attr.clone());
continue;
}
attr.parse_nested_meta(|meta| {
if meta.path.is_ident("default") && meta.input.is_empty() {
default = true;
Ok(())
} else {
Err(meta.error(
"Unrecognized #[server] attribute, expected \
#[server(default)]",
))
}
})?;
}
typed_arg.attrs = other_attrs;
if default {
Ok(quote! { #[serde(default)] pub #typed_arg })
} else {
Ok(quote! { pub #typed_arg })
}
})
.collect::<Result<Vec<_>>>()?;
let fn_args = body
.inputs
.iter()