feat!: add support for file fields in forms (#334)

Author: m4tx

Cargo.lock

@@ -5,13 +5,14 @@ members = [
     "cot-codegen",
     "cot-macros",
     # Examples
-    "examples/hello-world",
-    "examples/todo-list",
-    "examples/sessions",
     "examples/admin",
-    "examples/json",
-    "examples/custom-task",
     "examples/custom-error-pages",
+    "examples/custom-task",
+    "examples/file-upload",
+    "examples/hello-world",
+    "examples/json",
+    "examples/sessions",
+    "examples/todo-list",
 ]
 resolver = "2"
 
@@ -86,13 +87,14 @@ hex = "0.4"
 hmac = "0.12"
 http = "1.3"
 http-body = "1"
-http-body-util = "0.1"
+http-body-util = "0.1.3"
 humantime = "2"
 indexmap = "2"
 insta = { version = "1", features = ["filters"] }
 insta-cmd = "0.6"
 mime_guess = { version = "2", default-features = false }
 mockall = "0.13"
+multer = "3"
 password-auth = { version = "1", default-features = false }
 petgraph = { version = "0.8", default-features = false }
 pin-project-lite = "0.2"

Cargo.toml

@@ -159,8 +159,8 @@ impl AdminModelDeriveBuilder {
                     ::std::boxed::Box::new(<<Self as #crate_ident::form::Form>::Context as #crate_ident::form::FormContext>::new())
                 }
 
-                fn form_context_from_self(&self) -> ::std::boxed::Box<dyn #crate_ident::form::FormContext> {
-                    ::std::boxed::Box::new(<Self as #crate_ident::form::Form>::to_context(self))
+                async fn form_context_from_self(&self) -> ::std::boxed::Box<dyn #crate_ident::form::FormContext> {
+                    ::std::boxed::Box::new(<Self as #crate_ident::form::Form>::to_context(self).await)
                 }
 
                 async fn save_from_request(

cot-macros/src/admin.rs

@@ -147,7 +147,7 @@ impl FormDeriveBuilder {
 
         self.fields_as_context_from_request
             .push(quote!(stringify!(#field_ident) => {
-                #crate_ident::form::FormField::set_value(&mut self.#field_ident, value)
+                #crate_ident::form::FormField::set_value(&mut self.#field_ident, value).await?
             }));
 
         let val_ident = format_ident!("val_{}", field_ident);
@@ -160,7 +160,7 @@ impl FormDeriveBuilder {
             quote!(#field_ident: #val_ident.expect("Errors should have been returned by now")),
         );
         self.fields_as_to_context
-            .push(quote!(context.#field_ident.set_value(::std::borrow::Cow::Owned(self.#field_ident.to_field_value()))));
+            .push(quote!(context.#field_ident.set_value(#crate_ident::form::FormFieldValue::new_text(self.#field_ident.to_field_value())).await.expect("Setting value from text should never fail")));
 
         self.fields_as_errors
             .push(quote!(#field_ident: Vec<#crate_ident::form::FormFieldValidationError>));
@@ -215,7 +215,7 @@ impl FormDeriveBuilder {
                     }
                 }
 
-                fn to_context(
+                async fn to_context(
                     &self
                 ) -> Self::Context {
                     use #crate_ident::form::FormContext;
@@ -272,6 +272,7 @@ impl FormDeriveBuilder {
                 #( #fields_as_struct_fields, )*
             }
 
+            #[#crate_ident::__private::async_trait]
             #[automatically_derived]
             impl #crate_ident::form::FormContext for #context_struct_name {
                 fn new() -> Self {
@@ -289,10 +290,10 @@ impl FormDeriveBuilder {
                     Box::new([#( #fields_as_dyn_field_ref, )*].into_iter())
                 }
 
-                fn set_value(
+                async fn set_value(
                     &mut self,
                     field_id: &str,
-                    value: ::std::borrow::Cow<str>,
+                    value: #crate_ident::form::FormFieldValue<'_>,
                 ) -> ::core::result::Result<(), #crate_ident::form::FormFieldValidationError> {
                     match field_id {
                         #( #fields_as_context_from_request, )*

cot-macros/src/form.rs

@@ -41,6 +41,7 @@ http.workspace = true
 humantime.workspace = true
 indexmap.workspace = true
 mime_guess.workspace = true
+multer.workspace = true
 password-auth = { workspace = true, features = ["std", "argon2"] }
 pin-project-lite.workspace = true
 schemars = { workspace = true, optional = true }

cot/Cargo.toml

@@ -304,7 +304,7 @@ async fn edit_model_instance_impl(
     } else if let Some(object_id) = object_id {
         let object = get_object(&mut request, &*manager, object_id).await?;
 
-        manager.form_context_from_object(object)
+        manager.form_context_from_object(object).await
     } else {
         manager.form_context()
     };
@@ -441,7 +441,7 @@ pub trait AdminModelManager: Send + Sync {
     /// that if you always return the same object type from these methods,
     /// you can safely downcast the object to the same type in this method
     /// as well.
-    fn form_context_from_object(&self, object: Box<dyn AdminModel>) -> Box<dyn FormContext>;
+    async fn form_context_from_object(&self, object: Box<dyn AdminModel>) -> Box<dyn FormContext>;
 
     /// Saves the object by using the form data from given request.
     ///
@@ -531,13 +531,13 @@ impl<T: AdminModel + Send + Sync + 'static> AdminModelManager for DefaultAdminMo
         T::form_context()
     }
 
-    fn form_context_from_object(&self, object: Box<dyn AdminModel>) -> Box<dyn FormContext> {
+    async fn form_context_from_object(&self, object: Box<dyn AdminModel>) -> Box<dyn FormContext> {
         let object_casted = object
             .as_any()
             .downcast_ref::<T>()
             .expect("Invalid object type");
 
-        T::form_context_from_self(object_casted)
+        T::form_context_from_self(object_casted).await
     }
 
     async fn save_from_request(
@@ -603,7 +603,7 @@ pub trait AdminModel: Any + Send + 'static {
         Self: Sized;
 
     /// Get the form context with the data pre-filled from this model instance.
-    fn form_context_from_self(&self) -> Box<dyn FormContext>;
+    async fn form_context_from_self(&self) -> Box<dyn FormContext>;
 
     /// Save the model instance from the form data in the request.
     ///

cot/src/admin.rs

@@ -149,6 +149,7 @@ impl_error_from_repr!(crate::router::path::ReverseError);
 impl_error_from_repr!(crate::db::DatabaseError);
 impl_error_from_repr!(tower_sessions::session::Error);
 impl_error_from_repr!(crate::form::FormError);
+impl_error_from_repr!(crate::form::FormFieldValueError);
 impl_error_from_repr!(crate::auth::AuthError);
 impl_error_from_repr!(crate::request::PathParamsDeserializerError);
 impl_error_from_repr!(crate::request::extractors::StaticFilesGetError);
@@ -189,6 +190,12 @@ pub(crate) enum ErrorRepr {
         expected: &'static str,
         actual: String,
     },
+    /// The request does not contain a form.
+    #[error(
+        "Request does not contain a form (expected `application/x-www-form-urlencoded` or \
+        `multipart/form-data` content type, or a GET or HEAD request)"
+    )]
+    ExpectedForm,
     /// Could not find a route for the request.
     #[error("Not found: {message:?}")]
     NotFound { message: Option<String> },
@@ -218,6 +225,9 @@ pub(crate) enum ErrorRepr {
     /// An error occurred while parsing a form.
     #[error("Failed to process a form: {0}")]
     Form(#[from] crate::form::FormError),
+    /// An error occurred while trying to retrieve the value of a form field.
+    #[error("Failed to retrieve the value of a form field: {0}")]
+    FormFieldValueError(#[from] crate::form::FormFieldValueError),
     /// An error occurred while trying to authenticate a user.
     #[error("Failed to authenticate user: {0}")]
     Authentication(#[from] crate::auth::AuthError),