extract api-types crate, adopt thiserror for all errors

api-types: standalone crate with DTOs (widget, data source, layout, preset)
extracted from http-api. Shared between http-api and future SPA.

thiserror: replaced all manual Display impls with derive macros across
8 crates (config-sqlite, config-memory, tcp-server, tcp-client,
http-json, rss, media, application).

Cargo.lock

@@ -8,11 +8,20 @@ version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "683d7910e743518b0e34f1186f92494becacb047c7b6bf616c96772180fef923"
 
+[[package]]
+name = "api-types"
+version = "0.1.0"
+dependencies = [
+ "domain",
+ "serde",
+]
+
 [[package]]
 name = "application"
 version = "0.1.0"
 dependencies = [
  "domain",
+ "thiserror",
  "tokio",
 ]
 
@@ -228,6 +237,7 @@ name = "config-memory"
 version = "0.1.0"
 dependencies = [
  "domain",
+ "thiserror",
 ]
 
 [[package]]
@@ -238,6 +248,7 @@ dependencies = [
  "serde",
  "serde_json",
  "sqlx",
+ "thiserror",
  "tokio",
 ]
 
@@ -701,6 +712,7 @@ dependencies = [
 name = "http-api"
 version = "0.1.0"
 dependencies = [
+ "api-types",
  "application",
  "axum",
  "config-memory",
@@ -744,6 +756,7 @@ dependencies = [
  "domain",
  "reqwest",
  "serde_json",
+ "thiserror",
  "tokio",
 ]
 
@@ -1068,6 +1081,7 @@ dependencies = [
  "domain",
  "reqwest",
  "serde_json",
+ "thiserror",
  "tokio",
 ]
 
@@ -1493,6 +1507,7 @@ dependencies = [
  "quick-xml",
  "reqwest",
  "serde",
+ "thiserror",
  "tokio",
 ]
 
@@ -2012,6 +2027,7 @@ version = "0.1.0"
 dependencies = [
  "client-domain",
  "protocol",
+ "thiserror",
 ]
 
 [[package]]
@@ -2021,6 +2037,7 @@ dependencies = [
  "domain",
  "postcard",
  "protocol",
+ "thiserror",
  "tokio",
 ]
 

Cargo.toml

@@ -14,6 +14,7 @@ members = [
     "crates/adapters/http-json",
     "crates/adapters/rss",
     "crates/adapters/media",
+    "crates/api-types",
     "crates/bootstrap",
     "crates/client-desktop",
 ]
@@ -36,6 +37,9 @@ config-sqlite = { path = "crates/adapters/config-sqlite" }
 http-api = { path = "crates/adapters/http-api" }
 axum = { version = "0.8", features = ["macros"] }
 tower-http = { version = "0.6", features = ["cors"] }
+api-types = { path = "crates/api-types" }
+thiserror = "2.0"
+anyhow = "1.0"
 serde = { version = "1.0", default-features = false, features = ["derive", "alloc"] }
 serde_json = "1.0"
 sqlx = { version = "0.8", features = ["runtime-tokio-rustls", "sqlite"] }

crates/adapters/config-memory/Cargo.toml

@@ -5,3 +5,4 @@ edition = "2024"
 
 [dependencies]
 domain.workspace = true
+thiserror.workspace = true

crates/adapters/config-memory/src/lib.rs

@@ -6,19 +6,12 @@ use domain::{
     WidgetConfig, WidgetId,
 };
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum MemoryConfigError {
+    #[error("lock poisoned")]
     LockPoisoned,
 }
 
-impl std::fmt::Display for MemoryConfigError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            MemoryConfigError::LockPoisoned => write!(f, "lock poisoned"),
-        }
-    }
-}
-
 pub struct MemoryConfigStore {
     widgets: RwLock<HashMap<WidgetId, WidgetConfig>>,
     data_sources: RwLock<HashMap<DataSourceId, DataSource>>,

crates/adapters/config-sqlite/Cargo.toml

@@ -8,6 +8,7 @@ domain.workspace = true
 sqlx.workspace = true
 serde.workspace = true
 serde_json.workspace = true
+thiserror.workspace = true
 
 [dev-dependencies]
 tokio.workspace = true

crates/adapters/config-sqlite/src/error.rs

@@ -1,14 +1,7 @@
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum SqliteConfigError {
-    Sql(sqlx::Error),
+    #[error("sql: {0}")]
+    Sql(#[from] sqlx::Error),
+    #[error("serialization: {0}")]
     Serialization(String),
 }
-
-impl std::fmt::Display for SqliteConfigError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            SqliteConfigError::Sql(e) => write!(f, "sql: {e}"),
-            SqliteConfigError::Serialization(e) => write!(f, "serialization: {e}"),
-        }
-    }
-}

crates/adapters/http-api/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2024"
 [dependencies]
 domain.workspace = true
 application.workspace = true
+api-types.workspace = true
 axum.workspace = true
 tower-http.workspace = true
 serde.workspace = true

crates/adapters/http-api/src/lib.rs

@@ -1,4 +1,3 @@
-mod dto;
 mod routes;
 
 use std::sync::Arc;

crates/adapters/http-api/src/routes/data_sources.rs

@@ -6,7 +6,7 @@ use axum::{
 use domain::{ConfigRepository, EventPublisher};
 use application::ConfigService;
 use crate::AppState;
-use crate::dto::DataSourceDto;
+use api_types::DataSourceDto;
 
 type S<C, E> = State<AppState<C, E>>;
 

crates/adapters/http-api/src/routes/layout.rs

@@ -6,7 +6,7 @@ use axum::{
 use domain::{ConfigRepository, EventPublisher};
 use application::ConfigService;
 use crate::AppState;
-use crate::dto::LayoutDto;
+use api_types::LayoutDto;
 
 type S<C, E> = State<AppState<C, E>>;
 

crates/adapters/http-api/src/routes/presets.rs

@@ -6,7 +6,7 @@ use axum::{
 use domain::{ConfigRepository, EventPublisher};
 use application::ConfigService;
 use crate::AppState;
-use crate::dto::{PresetDto, CreatePresetDto};
+use api_types::{PresetDto, CreatePresetDto};
 
 type S<C, E> = State<AppState<C, E>>;
 

crates/adapters/http-api/src/routes/widgets.rs

@@ -6,7 +6,7 @@ use axum::{
 use domain::{ConfigRepository, EventPublisher};
 use application::ConfigService;
 use crate::AppState;
-use crate::dto::{WidgetDto, CreateWidgetDto};
+use api_types::{WidgetDto, CreateWidgetDto};
 
 type S<C, E> = State<AppState<C, E>>;
 

crates/adapters/http-json/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2024"
 domain.workspace = true
 reqwest.workspace = true
 serde_json.workspace = true
+thiserror.workspace = true
 
 [dev-dependencies]
 tokio.workspace = true

crates/adapters/http-json/src/lib.rs

@@ -4,23 +4,16 @@ pub struct HttpJsonAdapter {
     client: reqwest::Client,
 }
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum HttpJsonError {
-    Request(reqwest::Error),
+    #[error("request: {0}")]
+    Request(#[from] reqwest::Error),
+    #[error("no url configured")]
     NoUrl,
+    #[error("parse: {0}")]
     Parse(String),
 }
 
-impl std::fmt::Display for HttpJsonError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            HttpJsonError::Request(e) => write!(f, "request: {e}"),
-            HttpJsonError::NoUrl => write!(f, "no url configured"),
-            HttpJsonError::Parse(e) => write!(f, "parse: {e}"),
-        }
-    }
-}
-
 impl HttpJsonAdapter {
     pub fn new() -> Self {
         Self {

crates/adapters/media/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2024"
 domain.workspace = true
 reqwest.workspace = true
 serde_json.workspace = true
+thiserror.workspace = true
 
 [dev-dependencies]
 tokio.workspace = true

crates/adapters/media/src/error.rs

@@ -1,16 +1,9 @@
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum MediaError {
-    Request(reqwest::Error),
+    #[error("request: {0}")]
+    Request(#[from] reqwest::Error),
+    #[error("no url configured")]
     NoUrl,
+    #[error("parse: {0}")]
     Parse(String),
 }
-
-impl std::fmt::Display for MediaError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            MediaError::Request(e) => write!(f, "request: {e}"),
-            MediaError::NoUrl => write!(f, "no url configured"),
-            MediaError::Parse(e) => write!(f, "parse: {e}"),
-        }
-    }
-}

crates/adapters/rss/Cargo.toml

@@ -8,6 +8,7 @@ domain.workspace = true
 reqwest.workspace = true
 quick-xml = { version = "0.37", features = ["serialize"] }
 serde.workspace = true
+thiserror.workspace = true
 
 [dev-dependencies]
 tokio.workspace = true

crates/adapters/rss/src/error.rs

@@ -1,16 +1,9 @@
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum RssError {
-    Request(reqwest::Error),
+    #[error("request: {0}")]
+    Request(#[from] reqwest::Error),
+    #[error("no url configured")]
     NoUrl,
+    #[error("parse: {0}")]
     Parse(String),
 }
-
-impl std::fmt::Display for RssError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            RssError::Request(e) => write!(f, "request: {e}"),
-            RssError::NoUrl => write!(f, "no url configured"),
-            RssError::Parse(e) => write!(f, "parse: {e}"),
-        }
-    }
-}

crates/adapters/tcp-client/Cargo.toml

@@ -6,3 +6,4 @@ edition = "2024"
 [dependencies]
 client-domain.workspace = true
 protocol.workspace = true
+thiserror.workspace = true

crates/adapters/tcp-client/src/lib.rs

@@ -4,23 +4,16 @@ use std::time::Duration;
 use client_domain::NetworkPort;
 use protocol::MAX_FRAME_SIZE;
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum TcpClientError {
-    Io(std::io::Error),
+    #[error("io: {0}")]
+    Io(#[from] std::io::Error),
+    #[error("not connected")]
     NotConnected,
+    #[error("frame too large: {0}")]
     FrameTooLarge(usize),
 }
 
-impl std::fmt::Display for TcpClientError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            TcpClientError::Io(e) => write!(f, "io: {e}"),
-            TcpClientError::NotConnected => write!(f, "not connected"),
-            TcpClientError::FrameTooLarge(n) => write!(f, "frame too large: {n}"),
-        }
-    }
-}
-
 pub struct StdTcpClient {
     stream: Option<TcpStream>,
 }

crates/adapters/tcp-server/Cargo.toml

@@ -8,3 +8,4 @@ domain.workspace = true
 protocol.workspace = true
 tokio.workspace = true
 postcard.workspace = true
+thiserror.workspace = true

crates/adapters/tcp-server/src/error.rs

@@ -1,14 +1,7 @@
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum TcpServerError {
-    Io(std::io::Error),
+    #[error("io: {0}")]
-    Encode(postcard::Error),
+    Io(#[from] std::io::Error),
-}
+    #[error("encode: {0}")]
-
+    Encode(#[from] postcard::Error),
-impl std::fmt::Display for TcpServerError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            TcpServerError::Io(e) => write!(f, "io: {e}"),
-            TcpServerError::Encode(e) => write!(f, "encode: {e}"),
-        }
-    }
 }

crates/api-types/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "api-types"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+domain.workspace = true
+serde.workspace = true

crates/api-types/src/preset.rs

@@ -1,6 +1,6 @@
 use serde::{Serialize, Deserialize};
 use domain::*;
-use super::layout::LayoutDto;
+use crate::layout::LayoutDto;
 
 #[derive(Serialize, Deserialize)]
 pub struct PresetDto {

crates/application/Cargo.toml

@@ -5,6 +5,7 @@ edition = "2024"
 
 [dependencies]
 domain.workspace = true
+thiserror.workspace = true
 
 [dev-dependencies]
 tokio = { workspace = true }

crates/application/src/config_service.rs

@@ -11,25 +11,18 @@ pub struct ConfigService<'a, C, E> {
     events: &'a E,
 }
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum ConfigError<C: fmt::Debug, E: fmt::Debug> {
+    #[error("repository error: {0:?}")]
     Repository(C),
+    #[error("event error: {0:?}")]
     Event(E),
+    #[error("validation errors: {0:?}")]
     Validation(Vec<DataSourceValidationError>),
+    #[error("not found")]
     NotFound,
 }
 
-impl<C: fmt::Debug, E: fmt::Debug> fmt::Display for ConfigError<C, E> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            ConfigError::Repository(e) => write!(f, "repository error: {:?}", e),
-            ConfigError::Event(e) => write!(f, "event error: {:?}", e),
-            ConfigError::Validation(errors) => write!(f, "validation errors: {:?}", errors),
-            ConfigError::NotFound => write!(f, "not found"),
-        }
-    }
-}
-
 impl<'a, C, E> ConfigService<'a, C, E>
 where
     C: ConfigRepository,