feat!: add SelectField; support more chrono form fields (#345)

Author: m4tx

cot-cli/src/project_template/Cargo.lock.template

@@ -6,6 +6,7 @@ use proc_macro2::TokenStream;
 use quote::{ToTokens, format_ident, quote};
 
 use crate::cot_ident;
+use crate::utils::PreservedStrExpr;
 
 pub(super) fn impl_form_for_struct(ast: &syn::DeriveInput) -> TokenStream {
     let opts = match FormOpts::from_derive_input(ast) {
@@ -70,7 +71,7 @@ impl FormOpts {
 struct Field {
     ident: Option<syn::Ident>,
     ty: syn::Type,
-    opt: Option<HashMap<syn::Ident, syn::Expr>>,
+    opt: Option<HashMap<syn::Ident, PreservedStrExpr>>,
 }
 
 #[derive(Debug)]
@@ -126,7 +127,9 @@ impl FormDeriveBuilder {
         self.fields_as_struct_fields_new.push({
             let custom_options_setters: Vec<_> = if let Some(opt) = opt {
                 opt.iter()
-                    .map(|(key, value)| quote!(custom_options.#key = Some(#value)))
+                    .map(|(key, value)| {
+                        quote!(custom_options.#key = ::core::option::Option::Some(#value))
+                    })
                     .collect()
             } else {
                 Vec::new()

cot-macros/src/form.rs

@@ -4,6 +4,7 @@ mod form;
 mod main_fn;
 mod model;
 mod query;
+mod utils;
 
 use darling::Error;
 use darling::ast::NestedMeta;

cot-macros/src/lib.rs

@@ -0,0 +1,68 @@
+// TODO: This should be removed when https://github.com/TedDriggs/darling/pull/346
+// is merged and released
+
+use darling::{FromMeta, Result};
+use syn::Expr;
+
+/// A wrapper around [`Expr`] that preserves the original expression
+/// without evaluating it.
+///
+/// For compatibility reasons, `darling` evaluates the expression inside string
+/// literals, which might be undesirable. In many cases,
+/// [`darling::util::parse_expr::preserve_str_literal`] can be used. However,
+/// when using [`Expr`] inside a container (such as a
+/// [`HashMap`](std::collections::HashMap)), it is not possible to use it.
+///
+/// This wrapper preserves the original expression without evaluating it.
+///
+/// # Example
+///
+/// ```compile_fail
+/// #[derive(FromMeta)]
+/// #[darling(attributes(demo))]
+/// struct Demo {
+///     option: Option<HashMap<syn::Ident, PreservedStrExpr>>,
+/// }
+/// ```
+#[repr(transparent)]
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub(crate) struct PreservedStrExpr(pub Expr);
+
+impl FromMeta for PreservedStrExpr {
+    fn from_expr(expr: &Expr) -> Result<Self> {
+        Ok(Self(expr.clone()))
+    }
+}
+
+impl From<Expr> for PreservedStrExpr {
+    fn from(value: Expr) -> Self {
+        Self(value)
+    }
+}
+
+impl From<PreservedStrExpr> for Expr {
+    fn from(value: PreservedStrExpr) -> Self {
+        value.0
+    }
+}
+
+impl quote::ToTokens for PreservedStrExpr {
+    fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
+        self.0.to_tokens(tokens);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use syn::{Meta, MetaNameValue, parse_quote};
+
+    use super::*;
+
+    #[test]
+    fn preserved_str_expr_from_meta() {
+        let name_value: MetaNameValue = parse_quote!(test = "Hello, world!");
+        let preserved = PreservedStrExpr::from_meta(&Meta::NameValue(name_value)).unwrap();
+
+        assert_eq!(preserved.0, parse_quote!("Hello, world!"));
+    }
+}

cot-macros/src/utils.rs

@@ -521,6 +521,12 @@ pub trait FormField: Display {
     ///
     /// This method should convert the value to the appropriate type for the
     /// field, such as a number for a number field.
+    ///
+    /// Note that this method might be called multiple times. This will happen
+    /// when the field has appeared in the form data multiple times, such as
+    /// in the case of a `<select multiple>` HTML element. If the field
+    /// does not support storing multiple values, it should overwrite the
+    /// previous value.
     fn set_value(
         &mut self,
         field: FormFieldValue<'_>,

cot/src/form.rs

@@ -1,4 +1,6 @@
+mod chrono;
 mod files;
+mod select;
 
 use std::fmt::{Debug, Display, Formatter};
 use std::num::{
@@ -8,32 +10,33 @@ use std::num::{
 
 use askama::filters::HtmlSafe;
 pub use files::{FileField, FileFieldOptions, InMemoryUploadedFile};
+pub(crate) use select::check_required_multiple;
+pub use select::{
+    SelectChoice, SelectField, SelectFieldOptions, SelectMultipleField, SelectMultipleFieldOptions,
+};
 
 use crate::auth::PasswordHash;
 use crate::common_types::{Email, Password};
 #[cfg(feature = "db")]
 use crate::db::{Auto, ForeignKey, LimitedString, Model};
-use crate::form::{
-    AsFormField, FormField, FormFieldOptions, FormFieldValidationError, FormFieldValue,
-    FormFieldValueError,
-};
+use crate::form::{AsFormField, FormField, FormFieldOptions, FormFieldValidationError};
 use crate::html::HtmlTag;
 
 macro_rules! impl_form_field {
     ($field_type_name:ident, $field_options_type_name:ident, $purpose:literal $(, $generic_param:ident $(: $generic_param_bound:ident $(+ $generic_param_bound_more:ident)*)?)?) => {
         #[derive(Debug)]
         #[doc = concat!("A form field for ", $purpose, ".")]
         pub struct $field_type_name $(<$generic_param>)? {
-            options: FormFieldOptions,
+            options: $crate::form::FormFieldOptions,
             custom_options: $field_options_type_name $(<$generic_param>)?,
             value: Option<String>,
         }
 
-        impl $(<$generic_param $(: $generic_param_bound $(+ $generic_param_bound_more)* )?>)? FormField for $field_type_name $(<$generic_param>)? {
+        impl $(<$generic_param $(: $generic_param_bound $(+ $generic_param_bound_more)* )?>)? $crate::form::FormField for $field_type_name $(<$generic_param>)? {
             type CustomOptions = $field_options_type_name $(<$generic_param>)?;
 
             fn with_options(
-                options: FormFieldOptions,
+                options: $crate::form::FormFieldOptions,
                 custom_options: Self::CustomOptions,
             ) -> Self {
                 Self {
@@ -43,21 +46,22 @@ macro_rules! impl_form_field {
                 }
             }
 
-            fn options(&self) -> &FormFieldOptions {
+            fn options(&self) -> &$crate::form::FormFieldOptions {
                 &self.options
             }
 
             fn value(&self) -> Option<&str> {
                 self.value.as_deref()
             }
 
-            async fn set_value(&mut self, field: FormFieldValue<'_>) -> std::result::Result<(), FormFieldValueError> {
+            async fn set_value(&mut self, field: $crate::form::FormFieldValue<'_>) -> std::result::Result<(), $crate::form::FormFieldValueError> {
                 self.value = Some(field.into_text().await?);
                 Ok(())
             }
         }
     };
 }
+pub(crate) use impl_form_field;
 
 impl_form_field!(StringField, StringFieldOptions, "a string");
 
@@ -220,7 +224,7 @@ pub struct EmailFieldOptions {
 impl Display for EmailField {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         let mut tag = HtmlTag::input("email");
-        tag.attr("name", self.name());
+        tag.attr("name", self.id());
         tag.attr("id", self.id());
         if self.options.required {
             tag.bool_attr("required");
@@ -624,7 +628,7 @@ where
     }
 }
 
-fn check_required<T: FormField>(field: &T) -> Result<&str, FormFieldValidationError> {
+pub(crate) fn check_required<T: FormField>(field: &T) -> Result<&str, FormFieldValidationError> {
     if let Some(value) = field.value() {
         if value.is_empty() {
             Err(FormFieldValidationError::Required)
@@ -661,7 +665,7 @@ impl<T: Float> Default for FloatFieldOptions<T> {
 impl<T: Float> Display for FloatField<T> {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         let mut tag: HtmlTag = HtmlTag::input("number");
-        tag.attr("name", self.name());
+        tag.attr("name", self.id());
         tag.attr("id", self.id());
         if self.options.required {
             tag.bool_attr("required");
@@ -766,6 +770,7 @@ impl_float_as_form_field!(f64);
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::form::FormFieldValue;
 
     #[test]
     fn string_field_render() {
@@ -822,7 +827,7 @@ mod tests {
         assert!(html.contains("required"));
         assert!(html.contains("minlength=\"10\""));
         assert!(html.contains("maxlength=\"50\""));
-        assert!(html.contains("name=\"test_name\""));
+        assert!(html.contains("name=\"test_id\""));
         assert!(html.contains("id=\"test_id\""));
     }