add validation builder

src/form.rs

@@ -11,11 +11,11 @@ use web_sys::FormData;
 ///
 /// This can be useful to use the same validation logic on the front
 /// end and backend without duplicating the logic.
-pub struct Validator<FD> {
+pub struct FormValidator<FD> {
     pub(crate) validations: Vec<Rc<dyn ValidationFn<FD>>>,
 }
 
-impl<FD: FormToolData> Validator<FD> {
+impl<FD: FormToolData> FormValidator<FD> {
     /// Validates the given form data.
     ///
     /// This runs all the validation functions for all the fields
@@ -40,8 +40,8 @@ pub struct Form<FD: FormToolData> {
 
 impl<FD: FormToolData> Form<FD> {
     /// Gets the [`Validator`] for this form.
-    pub fn validator(self) -> Validator<FD> {
-        Validator {
+    pub fn validator(self) -> FormValidator<FD> {
+        FormValidator {
             validations: self.validations,
         }
     }
@@ -57,10 +57,10 @@ impl<FD: FormToolData> Form<FD> {
     }
 
     /// Splits this [`Form`] into it's parts.
-    pub fn to_parts(self) -> (RwSignal<FD>, Validator<FD>, View) {
+    pub fn to_parts(self) -> (RwSignal<FD>, FormValidator<FD>, View) {
         (
             self.fd,
-            Validator {
+            FormValidator {
                 validations: self.validations,
             },
             self.view,
@@ -131,7 +131,7 @@ pub trait FormToolData: Default + Clone + 'static {
     ///
     /// However, the code to render the views are not configured out, it
     /// simply doesn't run, so the view needs to compile even on the server.
-    fn get_validator() -> Validator<Self> {
+    fn get_validator() -> FormValidator<Self> {
         let builder = FormBuilder::new(Self::default(), Self::Style::default());
         let builder = Self::build_form(builder);
         builder.validator()

src/form_builder.rs

@@ -4,7 +4,7 @@ use crate::{
         FieldSetter, ParseFn, RenderFn, UnparseFn, ValidationCb, ValidationFn,
         VanityControlBuilder, VanityControlData,
     },
-    form::{Form, FormToolData, Validator},
+    form::{Form, FormToolData, FormValidator},
     styles::FormStyle,
 };
 use leptos::{
@@ -305,8 +305,8 @@ impl<FD: FormToolData, FS: FormStyle> FormBuilder<FD, FS> {
         }
     }
 
-    pub(crate) fn validator(&self) -> Validator<FD> {
-        Validator {
+    pub(crate) fn validator(&self) -> FormValidator<FD> {
+        FormValidator {
             validations: self.validations.clone(),
         }
     }

src/lib.rs

@@ -1,7 +1,9 @@
 pub mod controls;
-pub mod form;
-pub mod form_builder;
+mod form;
+mod form_builder;
 pub mod styles;
+mod validation_builder;
 
-pub use form::{Form, FormToolData, Validator};
+pub use form::{Form, FormToolData, FormValidator};
 pub use form_builder::FormBuilder;
+pub use validation_builder::ValidationBuilder;

src/validation_builder.rs

@@ -0,0 +1,140 @@
+use crate::controls::ValidationFn;
+use std::fmt::Display;
+
+/// A helper builder that allows you to specify a validation function
+/// declaritivly
+///
+/// Using this builder is not required as validation functions can just be
+/// closures, but for simple validation function this builder can be helpful
+///
+/// Validations are run in the order that they are called in the builder.
+pub struct ValidationBuilder<T: 'static> {
+    /// The name of the field, for error messages.
+    name: String,
+    /// The functions to be called when validating.
+    functions: Vec<Box<dyn Fn(&str, &T) -> Result<(), String> + 'static>>,
+}
+
+impl<T: 'static> Default for ValidationBuilder<T> {
+    fn default() -> Self {
+        ValidationBuilder {
+            name: String::from("Field"),
+            functions: Vec::new(),
+        }
+    }
+}
+
+impl<T: 'static> ValidationBuilder<T> {
+    /// The name of the field that is being validated.
+    ///
+    /// This is the name that will be used for error messages.
+    pub fn named(mut self, name: impl ToString) -> Self {
+        self.name = name.to_string();
+        self
+    }
+
+    /// Builds the action validation function.
+    pub fn build(self) -> impl ValidationFn<T> {
+        move |value| {
+            for f in self.functions.iter() {
+                match f(self.name.as_str(), value) {
+                    Ok(()) => {}
+                    err => return err,
+                }
+            }
+            Ok(())
+        }
+    }
+}
+
+impl ValidationBuilder<String> {
+    /// Requires the field to not be empty.
+    pub fn required(mut self) -> Self {
+        self.functions.push(Box::new(move |name, value| {
+            if value.is_empty() {
+                Err(format!("{} is required", name))
+            } else {
+                Ok(())
+            }
+        }));
+        self
+    }
+
+    /// Requires the field's length to be at least `min_len`.
+    pub fn min_len(mut self, min_len: usize) -> Self {
+        self.functions.push(Box::new(move |name, value| {
+            if value.len() < min_len {
+                Err(format!("{} must be >= {} characters", name, min_len))
+            } else {
+                Ok(())
+            }
+        }));
+        self
+    }
+
+    /// Requires the field's length to be less than or equal to `min_len`.
+    pub fn max_len(mut self, max_len: usize) -> Self {
+        self.functions.push(Box::new(move |name, value| {
+            if value.len() < max_len {
+                Err(format!("{} must be <= {} characters", name, max_len))
+            } else {
+                Ok(())
+            }
+        }));
+        self
+    }
+}
+
+impl<T: PartialOrd<T> + Display + 'static> ValidationBuilder<T> {
+    /// Requires the value to be at least `min_value` according to
+    /// `PartialOrd`.
+    pub fn min_value(mut self, min_value: T) -> Self {
+        self.functions.push(Box::new(move |name, value| {
+            if value < &min_value {
+                Err(format!("{} mut be >= {}", name, min_value))
+            } else {
+                Ok(())
+            }
+        }));
+        self
+    }
+
+    /// Requires the value to be at most `max_value` according to
+    /// `PartialOrd`.
+    pub fn max_value(mut self, max_value: T) -> Self {
+        self.functions.push(Box::new(move |name, value| {
+            if value > &max_value {
+                Err(format!("{} mut be <= {}", name, max_value))
+            } else {
+                Ok(())
+            }
+        }));
+        self
+    }
+}
+
+impl<T: PartialEq<T> + Display + 'static> ValidationBuilder<T> {
+    /// Requires the field to be in the provided whitelist.
+    pub fn whitelist(mut self, whitelist: Vec<T>) -> Self {
+        self.functions.push(Box::new(move |name, value| {
+            if !whitelist.contains(value) {
+                Err(format!("{} cannot be {}", name, value))
+            } else {
+                Ok(())
+            }
+        }));
+        self
+    }
+
+    /// Requires the field to not be in the provided blacklist.
+    pub fn blacklist(mut self, blacklist: Vec<T>) -> Self {
+        self.functions.push(Box::new(move |name, value| {
+            if blacklist.contains(value) {
+                Err(format!("{} cannot be {}", name, value))
+            } else {
+                Ok(())
+            }
+        }));
+        self
+    }
+}