domain: introduce UserId to make uid case insensitive

Note that if there was a non-lowercase user already in the DB, it cannot
be found again. To fix this, run in the DB:

sqlite> UPDATE users SET user_id = LOWER(user_id);

server/src/domain/handler.rs

@@ -3,10 +3,41 @@ use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
 use std::collections::HashSet;
 
+#[derive(PartialEq, Eq, Clone, Debug, Default, Serialize, Deserialize)]
+#[cfg_attr(not(target_arch = "wasm32"), derive(sqlx::FromRow))]
+#[serde(from = "String")]
+pub struct UserId(String);
+
+impl UserId {
+    pub fn new(user_id: &str) -> Self {
+        Self(user_id.to_lowercase())
+    }
+
+    pub fn as_str(&self) -> &str {
+        self.0.as_str()
+    }
+
+    pub fn into_string(self) -> String {
+        self.0
+    }
+}
+
+impl std::fmt::Display for UserId {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+impl From<String> for UserId {
+    fn from(s: String) -> Self {
+        Self::new(&s)
+    }
+}
+
 #[derive(PartialEq, Eq, Debug, Serialize, Deserialize)]
 #[cfg_attr(not(target_arch = "wasm32"), derive(sqlx::FromRow))]
 pub struct User {
-    pub user_id: String,
+    pub user_id: UserId,
     pub email: String,
     pub display_name: String,
     pub first_name: String,
@@ -19,7 +50,7 @@ impl Default for User {
     fn default() -> Self {
         use chrono::TimeZone;
         User {
-            user_id: String::new(),
+            user_id: UserId::default(),
             email: String::new(),
             display_name: String::new(),
             first_name: String::new(),
@@ -33,12 +64,12 @@ impl Default for User {
 pub struct Group {
     pub id: GroupId,
     pub display_name: String,
-    pub users: Vec<String>,
+    pub users: Vec<UserId>,
 }
 
 #[derive(PartialEq, Eq, Debug, Serialize, Deserialize, Clone)]
 pub struct BindRequest {
-    pub name: String,
+    pub name: UserId,
     pub password: String,
 }
 
@@ -47,6 +78,7 @@ pub enum UserRequestFilter {
     And(Vec<UserRequestFilter>),
     Or(Vec<UserRequestFilter>),
     Not(Box<UserRequestFilter>),
+    UserId(UserId),
     Equality(String, String),
     // Check if a user belongs to a group identified by name.
     MemberOf(String),
@@ -62,13 +94,13 @@ pub enum GroupRequestFilter {
     DisplayName(String),
     GroupId(GroupId),
     // Check if the group contains a user identified by uid.
-    Member(String),
+    Member(UserId),
 }
 
 #[derive(PartialEq, Eq, Debug, Serialize, Deserialize, Clone, Default)]
 pub struct CreateUserRequest {
     // Same fields as User, but no creation_date, and with password.
-    pub user_id: String,
+    pub user_id: UserId,
     pub email: String,
     pub display_name: Option<String>,
     pub first_name: Option<String>,
@@ -78,7 +110,7 @@ pub struct CreateUserRequest {
 #[derive(PartialEq, Eq, Debug, Serialize, Deserialize, Clone, Default)]
 pub struct UpdateUserRequest {
     // Same fields as CreateUserRequest, but no with an extra layer of Option.
-    pub user_id: String,
+    pub user_id: UserId,
     pub email: Option<String>,
     pub display_name: Option<String>,
     pub first_name: Option<String>,
@@ -106,17 +138,17 @@ pub struct GroupIdAndName(pub GroupId, pub String);
 pub trait BackendHandler: Clone + Send {
     async fn list_users(&self, filters: Option<UserRequestFilter>) -> Result<Vec<User>>;
     async fn list_groups(&self, filters: Option<GroupRequestFilter>) -> Result<Vec<Group>>;
-    async fn get_user_details(&self, user_id: &str) -> Result<User>;
+    async fn get_user_details(&self, user_id: &UserId) -> Result<User>;
     async fn get_group_details(&self, group_id: GroupId) -> Result<GroupIdAndName>;
     async fn create_user(&self, request: CreateUserRequest) -> Result<()>;
     async fn update_user(&self, request: UpdateUserRequest) -> Result<()>;
     async fn update_group(&self, request: UpdateGroupRequest) -> Result<()>;
-    async fn delete_user(&self, user_id: &str) -> Result<()>;
+    async fn delete_user(&self, user_id: &UserId) -> Result<()>;
     async fn create_group(&self, group_name: &str) -> Result<GroupId>;
     async fn delete_group(&self, group_id: GroupId) -> Result<()>;
-    async fn add_user_to_group(&self, user_id: &str, group_id: GroupId) -> Result<()>;
-    async fn remove_user_from_group(&self, user_id: &str, group_id: GroupId) -> Result<()>;
-    async fn get_user_groups(&self, user: &str) -> Result<HashSet<GroupIdAndName>>;
+    async fn add_user_to_group(&self, user_id: &UserId, group_id: GroupId) -> Result<()>;
+    async fn remove_user_from_group(&self, user_id: &UserId, group_id: GroupId) -> Result<()>;
+    async fn get_user_groups(&self, user_id: &UserId) -> Result<HashSet<GroupIdAndName>>;
 }
 
 #[cfg(test)]
@@ -129,17 +161,17 @@ mockall::mock! {
     impl BackendHandler for TestBackendHandler {
         async fn list_users(&self, filters: Option<UserRequestFilter>) -> Result<Vec<User>>;
         async fn list_groups(&self, filters: Option<GroupRequestFilter>) -> Result<Vec<Group>>;
-        async fn get_user_details(&self, user_id: &str) -> Result<User>;
+        async fn get_user_details(&self, user_id: &UserId) -> Result<User>;
         async fn get_group_details(&self, group_id: GroupId) -> Result<GroupIdAndName>;
         async fn create_user(&self, request: CreateUserRequest) -> Result<()>;
         async fn update_user(&self, request: UpdateUserRequest) -> Result<()>;
         async fn update_group(&self, request: UpdateGroupRequest) -> Result<()>;
-        async fn delete_user(&self, user_id: &str) -> Result<()>;
+        async fn delete_user(&self, user_id: &UserId) -> Result<()>;
         async fn create_group(&self, group_name: &str) -> Result<GroupId>;
         async fn delete_group(&self, group_id: GroupId) -> Result<()>;
-        async fn get_user_groups(&self, user: &str) -> Result<HashSet<GroupIdAndName>>;
-        async fn add_user_to_group(&self, user_id: &str, group_id: GroupId) -> Result<()>;
-        async fn remove_user_from_group(&self, user_id: &str, group_id: GroupId) -> Result<()>;
+        async fn get_user_groups(&self, user_id: &UserId) -> Result<HashSet<GroupIdAndName>>;
+        async fn add_user_to_group(&self, user_id: &UserId, group_id: GroupId) -> Result<()>;
+        async fn remove_user_from_group(&self, user_id: &UserId, group_id: GroupId) -> Result<()>;
     }
     #[async_trait]
     impl LoginHandler for TestBackendHandler {