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simplified the macros

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This commit is contained in:
Nathan Buck
2025-07-14 23:22:28 -04:00
parent a096885f02
commit 3e75cd00ff
1 changed files with 68 additions and 194 deletions
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220
src/lib.rs
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@ -5,13 +5,22 @@ use syn::{parse_macro_input, Lit, ItemEnum, DeriveInput, Fields, Data};
#[proc_macro_derive(HttpRequest, attributes(http_get))]
pub fn derive_http_get_request(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let name = &input.ident;
let query_name = &input.ident;
let query_name_str = query_name.to_string();
// Extract the base URL from #[http_get(url = "...")]
// Derive response enum name by replacing "Query" suffix with "Response"
let response_name_str = if query_name_str.ends_with("Query") {
query_name_str.trim_end_matches("Query").to_string() + "Response"
} else {
panic!("HttpRequest derive macro expects the struct name to end with 'Query'");
};
let response_name = format_ident!("{}", response_name_str);
// Extract base URL from #[http_get(url = "...")]
let mut base_url = None;
for attr in &input.attrs {
if attr.path().is_ident("http_get") {
let _ = attr.parse_nested_meta(|meta| {
if attr.path.is_ident("http_get") {
attr.parse_nested_meta(|meta| {
if meta.path.is_ident("url") {
let value: Lit = meta.value()?.parse()?;
if let Lit::Str(litstr) = value {
@ -19,50 +28,58 @@ pub fn derive_http_get_request(input: TokenStream) -> TokenStream {
}
}
Ok(())
});
}).unwrap();
}
}
let base_url = base_url.expect("Missing #[http_get(url = \"...\")] attribute");
let base_url_lit = Lit::Str(syn::LitStr::new(&base_url, proc_macro2::Span::call_site()));
let base_url_lit = syn::LitStr::new(&base_url, proc_macro2::Span::call_site());
let expanded = match &input.data {
Data::Struct(data_struct) => {
let fields = match &data_struct.fields {
Fields::Named(named) => &named.named,
_ => panic!("#[derive(HttpRequest)] only supports structs with named fields"),
};
let mut query_param_code = Vec::new();
for field in fields {
let ident = field.ident.clone().unwrap();
// Collect query parameters from fields named "lnk_p_*"
let query_param_code = if let Data::Struct(data_struct) = &input.data {
if let Fields::Named(fields_named) = &data_struct.fields {
fields_named.named.iter().filter_map(|field| {
let ident = field.ident.as_ref()?;
let field_name = ident.to_string();
if field_name.starts_with("lnk_p_") {
let key = &field_name["lnk_p_".len()..];
query_param_code.push(quote! {
Some(quote! {
query_params.push((#key.to_string(), self.#ident.to_string()));
});
})
} else {
None
}
}).collect::<Vec<_>>()
} else {
Vec::new()
}
} else {
Vec::new()
};
quote! {
impl Queryable for #name {
fn send(
// Generate the impl
let expanded = quote! {
#[async_trait::async_trait]
impl Queryable for #query_name {
type Response = #response_name;
async fn send(
&self,
headers: Option<Vec<(&str, &str)>>,
) -> Result<Response, std::io::Error> {
use urlencoding::encode;
) -> Result<Self::Response, Box<dyn std::error::Error + Send + Sync>> {
use awc::Client;
use urlencoding::encode;
let mut query_params: Vec<(String, String)> = Vec::new();
#(#query_param_code)*
let mut url = #base_url_lit.to_string();
if !query_params.is_empty() {
let query_parts: Vec<String> = query_params.iter()
let query_string: String = query_params.iter()
.map(|(k, v)| format!("{}={}", k, encode(v)))
.collect();
.collect::<Vec<_>>()
.join("&");
url.push('?');
url.push_str(&query_parts.join("&"));
url.push_str(&query_string);
}
let client = Client::default();
@ -74,157 +91,14 @@ pub fn derive_http_get_request(input: TokenStream) -> TokenStream {
}
}
let response = rt::System::new()
.block_on(async {
request.send()
.await
.map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e.to_string()))
})?;
let response = request.send().await?;
let bytes = response.body().await?;
let body_bytes = rt::System::new()
.block_on(async {
response.body()
.await
.map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e.to_string()))
})?;
let body = Response::receive(body_bytes.to_vec())
.map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e.to_string()))?;
Ok(body)
}
}
}
}
Data::Enum(data_enum) => {
let mut variant_arms = Vec::new();
for variant in &data_enum.variants {
let vname = &variant.ident;
match &variant.fields {
Fields::Unnamed(fields) if fields.unnamed.len() == 1 => {
variant_arms.push(quote! {
#name::#vname(inner) => inner.send(headers.clone()).await,
});
}
_ => panic!("#[derive(HttpRequest)] enum variants must have a single unnamed field"),
}
}
quote! {
impl Queryable for #name {
fn send(
&self,
headers: Option<Vec<(&str, &str)>>,
) -> Result<Response, std::io::Error> {
match self {
#(#variant_arms)*
}
}
}
}
}
_ => panic!("#[derive(HttpRequest)] only supports structs and enums"),
};
TokenStream::from(expanded)
}
#[proc_macro_attribute]
pub fn http_response(_attr: TokenStream, item: TokenStream) -> TokenStream {
let item_for_ast = item.clone();
let item_for_quote = item.clone();
let ast: DeriveInput = parse_macro_input!(item_for_ast as DeriveInput);
let name = &ast.ident;
let impl_block = match &ast.data {
Data::Struct(_) => {
// Impl for struct: deserialize entire response body as Self
quote! {
#[async_trait::async_trait]
impl Responsable for #name
where
Self: serde::de::DeserializeOwned + Sized + Send,
{
async fn receive(mut resp: awc::ClientResponse) -> Result<Self, Box<dyn std::error::Error>> {
let parsed = resp.json::<Self>().await?;
// Deserialize into associated Response type
let parsed: Self::Response = serde_json::from_slice(&bytes)?;
Ok(parsed)
}
}
}
}
Data::Enum(data_enum) => {
// Impl for enum with tuple variants of length 1 (newtype variants)
let variant_arms = data_enum.variants.iter().filter_map(|variant| {
let vname = &variant.ident;
match &variant.fields {
Fields::Unnamed(fields) if fields.unnamed.len() == 1 => {
let inner_ty = &fields.unnamed.first().unwrap().ty;
Some(quote! {
if let Ok(inner) = serde_json::from_slice::<#inner_ty>(&body) {
return Ok(#name::#vname(inner));
}
})
}
_ => None,
}
});
quote! {
#[async_trait::async_trait]
impl Responsable for #name
where
Self: Sized + Send,
{
async fn receive(mut resp: awc::ClientResponse) -> Result<Self, Box<dyn std::error::Error>> {
let body = resp.body().await?; // Bytes, sized!
#(#variant_arms)*
Err(Box::new(std::io::Error::new(
std::io::ErrorKind::Other,
concat!("No matching enum variant in ", stringify!(#name))
)))
}
}
}
}
_ => panic!("#[http_response] only supports structs and tuple-style enum variants"),
};
let original: syn::Item = syn::parse(item_for_quote).expect("Failed to parse item as syn::Item");
let output = quote! {
#original
#impl_block
};
output.into()
}
#[proc_macro_derive(ResponseVec)]
pub fn derive_response_vec(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let name = &input.ident;
let expanded = quote! {
impl Responsable for #name {
/// Deserializes all responses sequentially into a Vec<Self>.
/// Assumes `Self` implements `DeserializeOwned`.
pub async fn response_vec(
responses: Vec<awc::ClientResponse>,
) -> Result<Vec<Self>, std::error::Error>
where
Self: Sized + serde::de::DeserializeOwned,
{
let mut results = Vec::with_capacity(responses.len());
for resp in responses {
let item = resp.json::<Self>().await?;
results.push(item);
}
Ok(results)
}
}
};
TokenStream::from(expanded)