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mirror of https://github.com/fafhrd91/actix-web synced 2024-11-30 10:42:55 +01:00
actix-web/actix-multipart-derive/src/lib.rs
2023-07-02 01:09:15 +01:00

316 lines
9.6 KiB
Rust

//! Multipart form derive macro for Actix Web.
//!
//! See [`macro@MultipartForm`] for usage examples.
#![deny(rust_2018_idioms, nonstandard_style)]
#![warn(future_incompatible)]
#![doc(html_logo_url = "https://actix.rs/img/logo.png")]
#![doc(html_favicon_url = "https://actix.rs/favicon.ico")]
#![cfg_attr(docsrs, feature(doc_auto_cfg))]
use std::collections::HashSet;
use darling::{FromDeriveInput, FromField, FromMeta};
use parse_size::parse_size;
use proc_macro::TokenStream;
use proc_macro2::Ident;
use quote::quote;
use syn::{parse_macro_input, Type};
#[derive(FromMeta)]
enum DuplicateField {
Ignore,
Deny,
Replace,
}
impl Default for DuplicateField {
fn default() -> Self {
Self::Ignore
}
}
#[derive(FromDeriveInput, Default)]
#[darling(attributes(multipart), default)]
struct MultipartFormAttrs {
deny_unknown_fields: bool,
duplicate_field: DuplicateField,
}
#[derive(FromField, Default)]
#[darling(attributes(multipart), default)]
struct FieldAttrs {
rename: Option<String>,
limit: Option<String>,
}
struct ParsedField<'t> {
serialization_name: String,
rust_name: &'t Ident,
limit: Option<usize>,
ty: &'t Type,
}
/// Implements `MultipartCollect` for a struct so that it can be used with the `MultipartForm`
/// extractor.
///
/// # Basic Use
///
/// Each field type should implement the `FieldReader` trait:
///
/// ```
/// use actix_multipart::form::{tempfile::TempFile, text::Text, MultipartForm};
///
/// #[derive(MultipartForm)]
/// struct ImageUpload {
/// description: Text<String>,
/// timestamp: Text<i64>,
/// image: TempFile,
/// }
/// ```
///
/// # Optional and List Fields
///
/// You can also use `Vec<T>` and `Option<T>` provided that `T: FieldReader`.
///
/// A [`Vec`] field corresponds to an upload with multiple parts under the [same field
/// name](https://www.rfc-editor.org/rfc/rfc7578#section-4.3).
///
/// ```
/// use actix_multipart::form::{tempfile::TempFile, text::Text, MultipartForm};
///
/// #[derive(MultipartForm)]
/// struct Form {
/// category: Option<Text<String>>,
/// files: Vec<TempFile>,
/// }
/// ```
///
/// # Field Renaming
///
/// You can use the `#[multipart(rename = "foo")]` attribute to receive a field by a different name.
///
/// ```
/// use actix_multipart::form::{tempfile::TempFile, MultipartForm};
///
/// #[derive(MultipartForm)]
/// struct Form {
/// #[multipart(rename = "files[]")]
/// files: Vec<TempFile>,
/// }
/// ```
///
/// # Field Limits
///
/// You can use the `#[multipart(limit = "<size>")]` attribute to set field level limits. The limit
/// string is parsed using [parse_size].
///
/// Note: the form is also subject to the global limits configured using `MultipartFormConfig`.
///
/// ```
/// use actix_multipart::form::{tempfile::TempFile, text::Text, MultipartForm};
///
/// #[derive(MultipartForm)]
/// struct Form {
/// #[multipart(limit = "2 KiB")]
/// description: Text<String>,
///
/// #[multipart(limit = "512 MiB")]
/// files: Vec<TempFile>,
/// }
/// ```
///
/// # Unknown Fields
///
/// By default fields with an unknown name are ignored. They can be rejected using the
/// `#[multipart(deny_unknown_fields)]` attribute:
///
/// ```
/// # use actix_multipart::form::MultipartForm;
/// #[derive(MultipartForm)]
/// #[multipart(deny_unknown_fields)]
/// struct Form { }
/// ```
///
/// # Duplicate Fields
///
/// The behaviour for when multiple fields with the same name are received can be changed using the
/// `#[multipart(duplicate_field = "<behavior>")]` attribute:
///
/// - "ignore": (default) Extra fields are ignored. I.e., the first one is persisted.
/// - "deny": A `MultipartError::UnsupportedField` error response is returned.
/// - "replace": Each field is processed, but only the last one is persisted.
///
/// Note that `Vec` fields will ignore this option.
///
/// ```
/// # use actix_multipart::form::MultipartForm;
/// #[derive(MultipartForm)]
/// #[multipart(duplicate_field = "deny")]
/// struct Form { }
/// ```
///
/// [parse_size]: https://docs.rs/parse-size/1/parse_size
#[proc_macro_derive(MultipartForm, attributes(multipart))]
pub fn impl_multipart_form(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let input: syn::DeriveInput = parse_macro_input!(input);
let name = &input.ident;
let data_struct = match &input.data {
syn::Data::Struct(data_struct) => data_struct,
_ => {
return compile_err(syn::Error::new(
input.ident.span(),
"`MultipartForm` can only be derived for structs",
))
}
};
let fields = match &data_struct.fields {
syn::Fields::Named(fields_named) => fields_named,
_ => {
return compile_err(syn::Error::new(
input.ident.span(),
"`MultipartForm` can only be derived for a struct with named fields",
))
}
};
let attrs = match MultipartFormAttrs::from_derive_input(&input) {
Ok(attrs) => attrs,
Err(err) => return err.write_errors().into(),
};
// Parse the field attributes
let parsed = match fields
.named
.iter()
.map(|field| {
let rust_name = field.ident.as_ref().unwrap();
let attrs = FieldAttrs::from_field(field).map_err(|err| err.write_errors())?;
let serialization_name = attrs.rename.unwrap_or_else(|| rust_name.to_string());
let limit = match attrs.limit.map(|limit| match parse_size(&limit) {
Ok(size) => Ok(usize::try_from(size).unwrap()),
Err(err) => Err(syn::Error::new(
field.ident.as_ref().unwrap().span(),
format!("Could not parse size limit `{}`: {}", limit, err),
)),
}) {
Some(Err(err)) => return Err(compile_err(err)),
limit => limit.map(Result::unwrap),
};
Ok(ParsedField {
serialization_name,
rust_name,
limit,
ty: &field.ty,
})
})
.collect::<Result<Vec<_>, TokenStream>>()
{
Ok(attrs) => attrs,
Err(err) => return err,
};
// Check that field names are unique
let mut set = HashSet::new();
for field in &parsed {
if !set.insert(field.serialization_name.clone()) {
return compile_err(syn::Error::new(
field.rust_name.span(),
format!("Multiple fields named: `{}`", field.serialization_name),
));
}
}
// Return value when a field name is not supported by the form
let unknown_field_result = if attrs.deny_unknown_fields {
quote!(::std::result::Result::Err(
::actix_multipart::MultipartError::UnsupportedField(field.name().to_string())
))
} else {
quote!(::std::result::Result::Ok(()))
};
// Value for duplicate action
let duplicate_field = match attrs.duplicate_field {
DuplicateField::Ignore => quote!(::actix_multipart::form::DuplicateField::Ignore),
DuplicateField::Deny => quote!(::actix_multipart::form::DuplicateField::Deny),
DuplicateField::Replace => quote!(::actix_multipart::form::DuplicateField::Replace),
};
// limit() implementation
let mut limit_impl = quote!();
for field in &parsed {
let name = &field.serialization_name;
if let Some(value) = field.limit {
limit_impl.extend(quote!(
#name => ::std::option::Option::Some(#value),
));
}
}
// handle_field() implementation
let mut handle_field_impl = quote!();
for field in &parsed {
let name = &field.serialization_name;
let ty = &field.ty;
handle_field_impl.extend(quote!(
#name => ::std::boxed::Box::pin(
<#ty as ::actix_multipart::form::FieldGroupReader>::handle_field(req, field, limits, state, #duplicate_field)
),
));
}
// from_state() implementation
let mut from_state_impl = quote!();
for field in &parsed {
let name = &field.serialization_name;
let rust_name = &field.rust_name;
let ty = &field.ty;
from_state_impl.extend(quote!(
#rust_name: <#ty as ::actix_multipart::form::FieldGroupReader>::from_state(#name, &mut state)?,
));
}
let gen = quote! {
impl ::actix_multipart::form::MultipartCollect for #name {
fn limit(field_name: &str) -> ::std::option::Option<usize> {
match field_name {
#limit_impl
_ => None,
}
}
fn handle_field<'t>(
req: &'t ::actix_web::HttpRequest,
field: ::actix_multipart::Field,
limits: &'t mut ::actix_multipart::form::Limits,
state: &'t mut ::actix_multipart::form::State,
) -> ::std::pin::Pin<::std::boxed::Box<dyn ::std::future::Future<Output = ::std::result::Result<(), ::actix_multipart::MultipartError>> + 't>> {
match field.name() {
#handle_field_impl
_ => return ::std::boxed::Box::pin(::std::future::ready(#unknown_field_result)),
}
}
fn from_state(mut state: ::actix_multipart::form::State) -> ::std::result::Result<Self, ::actix_multipart::MultipartError> {
Ok(Self {
#from_state_impl
})
}
}
};
gen.into()
}
/// Transform a syn error into a token stream for returning.
fn compile_err(err: syn::Error) -> TokenStream {
TokenStream::from(err.to_compile_error())
}