Returning Own Error Type
#2336
Replies: 2 comments 2 replies
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change the
you can also just add a variant to your enum |
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DISCLAIMER: There follows sequential attempts to make this work, unsuccessfully Attempt 1You mean like the third try? impl From<ServerFnError> for MyAppError {
fn from(err: ServerFnError) -> MyAppError {
server_fn_error!(err)
}
}Error outputerror[E0308]: mismatched types
--> /home/opc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/server_fn-0.6.5/src/error.rs:109:22
|
101 | macro_rules! server_fn_error {
| ---------------------------- in this expansion of `server_fn_error!`
...
109 | error => (&&&&&WrapError(error)).to_server_error(),
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `MyAppError`, found `ServerFnError<ServerFnError>`
|
::: app/src/error_template.rs:109:36
|
109 | fn from(err: ServerFnError) -> MyAppError {
| ---------- expected `MyAppError` because of return type
110 | server_fn_error!(err)
| --------------------- in this macro invocation
|
= note: expected enum `MyAppError`
found enum `leptos::ServerFnError<leptos::ServerFnError>`Attempt 2So I guess I'm not understanding how to use the Tried to implement your second suggestion: #[derive(Debug, Error)]
pub enum MyAppError {
#[error("An error occured")]
Errored,
#[error("Server Error {0:?}")]
ServerFn(#[from] ServerFnError),
}Error outputerror[E0599]: the method `as_dyn_error` exists for reference `&ServerFnError`, but its trait bounds were not satisfied
--> app/src/error_template.rs:107:16
|
107 | ServerFn(#[from] ServerFnError),
| ^^^^ method cannot be called on `&ServerFnError` due to unsatisfied trait bounds
|
::: /home/opc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/server_fn-0.6.5/src/error.rs:178:1
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178 | pub enum ServerFnError<E = NoCustomError> {
| ----------------------------------------- doesn't satisfy `leptos::ServerFnError: AsDynError<'_>` or `leptos::ServerFnError: StdError`
|
= note: the following trait bounds were not satisfied:
`leptos::ServerFnError: StdError`
which is required by `leptos::ServerFnError: AsDynError<'_>`
`&leptos::ServerFnError: StdError`
which is required by `&leptos::ServerFnError: AsDynError<'_>`Attempt 3So I guess I needed to use #[derive(Debug, Error, Clone)]
pub enum MyAppError {
#[error("An error occured")]
Errored,
#[error("Server Error {0:?}")]
ServerFn(#[from] ServerFnErrorErr),
}
#[server(SrvAddTest, "/api", "Url", "add_test")]
pub async fn srv_add_test(val1: i32, val2: i32) -> Result<i32, ServerFnError<MyAppError>> {
Ok(val1 + val2)
}
#[server(SrvAddTestError, "/api", "Url", "add_test_error")]
pub async fn srv_add_test_error(val1: i32, val2: i32) -> Result<i32, ServerFnError<MyAppError>> {
Err(ServerFnError::WrappedServerError(MyAppError::Errored))
}Error Outputerror[E0277]: the trait bound `MyAppError: FromStr` is not satisfied
--> app/src/error_template.rs:114:78
|
114 | pub async fn srv_add_test(val1: i32, val2: i32) -> Result<i32, ServerFnError<MyAppError>> {
| ^^^^^^^^^^ the trait `FromStr` is not implemented for `MyAppError`
|
= help: the following other types implement trait `FromStr`:
bool
char
isize
i8
i16
i32
i64
i128
and 65 others
note: required by a bound in `leptos::server_fn::ServerFn::Error`
--> /home/opc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/server_fn-0.6.5/src/lib.rs:221:17
|
221 | type Error: FromStr + Display;
| ^^^^^^^ required by this bound in `ServerFn::Error`Attempt 4So I guess I need to implement #[derive(Debug, Error, Clone)]
pub enum MyAppError {
#[error("An error occured")]
Errored,
#[error("Server Error {0:?}")]
ServerFn(#[from] ServerFnErrorErr),
}
impl std::str::FromStr for MyAppError {
type Err = std::fmt::Error;
fn from_str(s: &str) -> Result<Self, Self::Err> {
match s {
"An error occured" => Ok(MyAppError::Errored),
_ => Ok(MyAppError::ServerFn(ServerFnErrorErr::ServerError(
"Unknown error".to_string(),
))),
}
}
}
#[server(SrvAddTest, "/api", "Url", "add_test")]
pub async fn srv_add_test(val1: i32, val2: i32) -> Result<i32, ServerFnError<MyAppError>> {
Ok(val1 + val2)
}
#[server(SrvAddTestError, "/api", "Url", "add_test_error")]
pub async fn srv_add_test_error(val1: i32, val2: i32) -> Result<i32, ServerFnError<MyAppError>> {
Err(ServerFnError::WrappedServerError(MyAppError::Errored))
}That actually compiles. let result1 = create_server_action::<SrvAddTest>();
let result1_resource = create_resource(move || result1.version().get(), |_| srv_add_test(1, 2));Error Outputerror[E0277]: the trait bound `MyAppError: _::_serde::Serialize` is not satisfied
--> app/src/lib.rs:332:28
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332 | let result1_resource = create_resource(move || result1.version().get(), |_| srv_add_test(1, 2));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `_::_serde::Serialize` is not implemented for `MyAppError`, which is required by `Result<i32, leptos::ServerFnError<MyAppError>>: Serializable`
|
= help: the following other types implement trait `_::_serde::Serialize`:
bool
char
isize
i8
i16
i32
i64
i128
and 170 others
= note: required for `leptos::ServerFnError<MyAppError>` to implement `_::_serde::Serialize`
= note: 1 redundant requirement hidden
= note: required for `Result<i32, leptos::ServerFnError<MyAppError>>` to implement `_::_serde::Serialize`
= note: required for `Result<i32, leptos::ServerFnError<MyAppError>>` to implement `Serializable`
note: required by a bound in `leptos::create_resource`
--> /home/opc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/leptos_reactive-0.6.5/src/resource.rs:103:8
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97 | pub fn create_resource<S, T, Fu>(
| --------------- required by a bound in this function
...
103 | T: Serializable + 'static,
| ^^^^^^^^^^^^ required by this bound in `create_resource`
error[E0277]: the trait bound `MyAppError: _::_serde::Deserialize<'_>` is not satisfied
--> app/src/lib.rs:332:28
|
332 | let result1_resource = create_resource(move || result1.version().get(), |_| srv_add_test(1, 2));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `_::_serde::Deserialize<'_>` is not implemented for `MyAppError`, which is required by `Result<i32, leptos::ServerFnError<MyAppError>>: Serializable`
|
= help: the following other types implement trait `_::_serde::Deserialize<'de>`:
<bool as _::_serde::Deserialize<'de>>
<char as _::_serde::Deserialize<'de>>
<isize as _::_serde::Deserialize<'de>>
<i8 as _::_serde::Deserialize<'de>>
<i16 as _::_serde::Deserialize<'de>>
<i32 as _::_serde::Deserialize<'de>>
<i64 as _::_serde::Deserialize<'de>>
<i128 as _::_serde::Deserialize<'de>>
and 175 others
= note: required for `leptos::ServerFnError<MyAppError>` to implement `_::_serde::Deserialize<'_>`
= note: 1 redundant requirement hidden
= note: required for `Result<i32, leptos::ServerFnError<MyAppError>>` to implement `for<'de> _::_serde::Deserialize<'de>`
= note: required for `Result<i32, leptos::ServerFnError<MyAppError>>` to implement `DeserializeOwned`
= note: required for `Result<i32, leptos::ServerFnError<MyAppError>>` to implement `Serializable`
note: required by a bound in `leptos::create_resource`
--> /home/opc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/leptos_reactive-0.6.5/src/resource.rs:103:8
|
97 | pub fn create_resource<S, T, Fu>(
| --------------- required by a bound in this function
...
103 | T: Serializable + 'static,
| ^^^^^^^^^^^^ required by this bound in `create_resource`Attempt 5So... I need to implement #[derive(Debug, Error, Clone, Serialize, Deserialize)]
pub enum MyAppError {
#[error("An error occured")]
Errored,
#[error("Server Error {0:?}")]
ServerFn(#[from] ServerFnErrorErr),
}Error Outputerror[E0277]: the trait bound `ServerFnErrorErr: _::_serde::Serialize` is not satisfied
--> app/src/error_template.rs:105:31
|
105 | #[derive(Debug, Error, Clone, Serialize, Deserialize)]
| ^^^^^^^^^
| |
| the trait `_::_serde::Serialize` is not implemented for `ServerFnErrorErr`
| in this derive macro expansion
...
110 | ServerFn(#[from] ServerFnErrorErr),
| ------------------------ required by a bound introduced by this call
|
::: /home/opc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/serde_derive-1.0.196/src/lib.rs:88:1
|
88 | pub fn derive_serialize(input: TokenStream) -> TokenStream {
| ---------------------------------------------------------- in this expansion of `#[derive(Serialize)]`
|
= help: the following other types implement trait `_::_serde::Serialize`:
bool
char
isize
i8
i16
i32
i64
i128
and 171 others
note: required by a bound in `serialize_newtype_variant`
--> /home/opc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/serde-1.0.196/src/ser/mod.rs:936:12
|
928 | fn serialize_newtype_variant<T: ?Sized>(
| ------------------------- required by a bound in this associated function
...
936 | T: Serialize;
| ^^^^^^^^^ required by this bound in `Serializer::serialize_newtype_variant`
error[E0277]: the trait bound `ServerFnErrorErr: _::_serde::Deserialize<'_>` is not satisfied
--> app/src/error_template.rs:110:22
|
110 | ServerFn(#[from] ServerFnErrorErr),
| ^^^^^^^^^^^^^^^^ the trait `_::_serde::Deserialize<'_>` is not implemented for `ServerFnErrorErr`
|
= help: the following other types implement trait `_::_serde::Deserialize<'de>`:
<bool as _::_serde::Deserialize<'de>>
<char as _::_serde::Deserialize<'de>>
<isize as _::_serde::Deserialize<'de>>
<i8 as _::_serde::Deserialize<'de>>
<i16 as _::_serde::Deserialize<'de>>
<i32 as _::_serde::Deserialize<'de>>
<i64 as _::_serde::Deserialize<'de>>
<i128 as _::_serde::Deserialize<'de>>
and 180 others
note: required by a bound in `newtype_variant`
--> /home/opc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/serde-1.0.196/src/de/mod.rs:2119:12
|
2117 | fn newtype_variant<T>(self) -> Result<T, Self::Error>
| --------------- required by a bound in this associated function
2118 | where
2119 | T: Deserialize<'de>,
| ^^^^^^^^^^^^^^^^ required by this bound in `VariantAccess::newtype_variant`Attempt 6So, after some guess-tyring work it compiles but with some increased compilation time. #[derive(Debug, Error, Clone, Serialize, Deserialize)]
pub enum MyAppError {
#[error("Even")]
Even,
#[error("Odd")]
Odd,
#[error("Out of Bounds")]
OutOfBounds,
#[error("Server Error {0:?}")]
ServerFn(#[from] ServerFnError<Box<MyAppError>>),
}
impl std::str::FromStr for MyAppError {
type Err = std::fmt::Error;
fn from_str(s: &str) -> Result<Self, Self::Err> {
match s {
"Even" => Ok(MyAppError::Even),
"Odd" => Ok(MyAppError::Odd),
"Out of Bounds" => Ok(MyAppError::OutOfBounds),
_ => Ok(MyAppError::ServerFn(ServerFnError::ServerError(
"Unknown error".to_string(),
))),
}
}
}
#[server(SrvAddTest, "/api", "Url", "add_test")]
pub async fn srv_add_test(val1: i32, val2: i32) -> Result<i32, ServerFnError<MyAppError>> {
Ok(val1 + val2)
}
#[server(SrvAddTestError, "/api", "Url", "add_test_error")]
pub async fn srv_add_test_error(val1: i32, val2: i32) -> Result<i32, ServerFnError<MyAppError>> {
let result = val1 + val2;
if result > 100 {
Err(ServerFnError::WrappedServerError(MyAppError::OutOfBounds))
} else if result % 2 == 0 {
Err(ServerFnError::WrappedServerError(MyAppError::Even))
} else {
Err(ServerFnError::WrappedServerError(MyAppError::Odd))
}
}Curl POST output[nix-shell:~]$ curl -v --data-urlencode val1=1 --data-urlencode val2=2 localhost:3000/api/add_test_error
* Trying [::1]:3000...
* connect to ::1 port 3000 failed: Connection refused
* Trying 127.0.0.1:3000...
* Connected to localhost (127.0.0.1) port 3000
> POST /api/add_test_error HTTP/1.1
> Host: localhost:3000
> User-Agent: curl/8.4.0
> Accept: */*
> Content-Length: 13
> Content-Type: application/x-www-form-urlencoded
>
< HTTP/1.1 500 Internal Server Error
< serverfnerror: /api/add_test_error
< content-length: 19
< date: Sun, 18 Feb 2024 15:17:55 GMT
<
* Connection #0 to host localhost left intact
WrappedServerFn|OddView Function#[component]
pub fn SrvAddView() -> impl IntoView {
let result1 = create_server_action::<SrvAddTest>();
let result1_resource = create_resource(move || result1.version().get(), |_| srv_add_test(1, 2));
let result2 = create_server_action::<SrvAddTestError>();
let result2_resource = create_resource(
move || result2.version().get(),
|_| srv_add_test_error(1, 2),
);
view! {
<Suspense fallback=move || {
view! { <p>"Loading..."</p> }
}>
{move || match result1_resource.get() {
None => view! { <p>"Loading..."</p> }.into_view(),
Some(data) => {
match data {
Ok(result) => {
view! {
"SrvAddTest: "
<p>{result}</p>
}
.into_view()
}
Err(err) => {
let err_type = std::any::type_name_of_val(&err);
view! { "Error got type "{err_type} }.into_view()
}
}
}
}}
{move || match result2_resource.get() {
None => view! { <p>"Loading..."</p> }.into_view(),
Some(data) => {
match data {
Ok(result) => {
view! {
"SrvAddTest: "
<p>{result}</p>
}
.into_view()
}
Err(err) => {
let err_type = std::any::type_name_of_val(&err);
view! { "Error got type "{err_type} }.into_view()
}
}
}
}}
</Suspense>
}
}Web View OutputFinal remarksThat's an entire morning trying to get This entire thing was frustating and I feel I never leaved the start. |
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Not sure if you're still interested in this, but leptos v0.8 finally makes this a lot easier (see #3274) It enables your server functions to return your own custom error type directly if it implements Basically (with #[derive(Debug, Clone, Error, Deserialize, Serialize)]
pub enum ApiError {
#[error("server fn error: {0}")]
ServerFn(ServerFnErrorErr),
#[error("some kind {0}")]
Custom(String)
[...]
}
impl FromServerFnError for ApiError {
fn from_server_fn_error(value: ServerFnErrorErr) -> Self {
ApiError::ServerFn(value)
}
}
#[server]
pub async fn foo(bar: u32) -> Result<(), ApiError> {
do_stuff()?;
if bar == 1 {
Err(ApiError::Custom(String::new()))
} else {
Ok(())
}
}And you can match them in the frontend easily without using any roundabout ways all you want :D |
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Thanks. I think an associated type named impl FromServerFnError for ApiError {
type Encoder = server_fn::codec::JsonEncoding;
fn from_server_fn_error(value: ServerFnErrorErr) -> Self {
ApiError::ServerFn(value)
}
} |
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I'm trying to test the feature referenced by #1830 (comment) but can't get my head how to use it.
From what I get, the From trait implements something like
From<Origin> for Dest, so the following example doesn't make sense to me, how can it returnServerFnError<MyAppError>if it's implementing a From forMyAppError?Compile output
So I guess I need to put some "real" error type on the function. Tried with
MyAppError:Compile output
So trying at random to return
MyAppErrorfrom the function:Compile output
I'm at a loss, can't wrap how to return a custom error without resorting to String conversion. Maybe starting Rust with a Leptos project was not a good idea.
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