# serde_json::Error - Rust
API documentation for the Rust `Error` struct in crate `serde_json`.
Keywords: rust, rustlang, rust-lang, Error

# Struct serde_json::Error [−] [src]

    pub struct Error { /* fields omitted */ }

This type represents all possible errors that can occur when serializing or deserializing JSON data.

## Implementations

### `impl Error` [src]

#### `pub fn line(&self) -> usize` [src]

One-based line number at which the error was detected.

Characters in the first line of the input (before the first newline character) are in line 1.

#### `pub fn column(&self) -> usize` [src]

One-based column number at which the error was detected.

The first character in the input and any characters immediately following a newline character are in column 1.

Note that errors may occur in column 0, for example if a read from an IO stream fails immediately following a previously read newline character.

#### `pub fn classify(&self) -> Category` [src]

Categorizes the cause of this error.

- `Category::Io` - failure to read or write bytes on an IO stream
- `Category::Syntax` - input that is not syntactically valid JSON
- `Category::Data` - input data that is semantically incorrect
- `Category::Eof` - unexpected end of the input data

#### `pub fn is_io(&self) -> bool` [src]

Returns true if this error was caused by a failure to read or write bytes on an IO stream.

#### `pub fn is_syntax(&self) -> bool` [src]

Returns true if this error was caused by input that was not syntactically valid JSON.

#### `pub fn is_data(&self) -> bool` [src]

Returns true if this error was caused by input data that was semantically incorrect.

For example, JSON containing a number is semantically incorrect when the type being deserialized into holds a String.

#### `pub fn is_eof(&self) -> bool` [src]

Returns true if this error was caused by prematurely reaching the end of the input data.

Callers that process streaming input may be interested in retrying the deserialization once more data is available.

## Trait Implementations

### `impl Debug for Error` [src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result` [src]

Formats the value using the given formatter. Read more

### `impl Display for Error` [src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result` [src]

Formats the value using the given formatter. Read more

### `impl Error for Error` [src]

#### `fn source(&self) -> Option<&(dyn Error + 'static)>` [src]

The lower-level source of this error, if any. Read more

#### `pub fn backtrace(&self) -> Option<&Backtrace>` [src]

🔬 This is a nightly-only experimental API. (`backtrace`)

Returns a stack backtrace, if available, of where this error occurred. Read more

#### `pub fn description(&self) -> &str` 1.0.0 [src]

👎 Deprecated since 1.42.0:

use the Display impl or to_string()

Read more

#### `pub fn cause(&self) -> Option<&dyn Error>`1.0.0 [src]

👎 Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

### `impl Error for Error` [src]

#### `fn custom<T: Display>(msg: T) -> Error` [src]

Used when a `Serialize` implementation encounters any error while serializing a type. Read more

### `impl Error for Error` [src]

#### `fn custom<T: Display>(msg: T) -> Error` [src]

Raised when there is general error when deserializing a type. Read more

#### `fn invalid_type(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self` [src]

Raised when a `Deserialize` receives a type different from what it was expecting. Read more

#### `pub fn invalid_value(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self` [src]

Raised when a `Deserialize` receives a value of the right type but that is wrong for some other reason. Read more

#### `pub fn invalid_length(len: usize, exp: &dyn Expected) -> Self` [src]

Raised when deserializing a sequence or map and the input data contains too many or too few elements. Read more

#### `pub fn unknown_variant(variant: &str, expected: &'static [&'static str]) -> Self` [src]

Raised when a `Deserialize` enum type received a variant with an unrecognized name. Read more

#### `pub fn unknown_field(field: &str, expected: &'static [&'static str]) -> Self` [src]

Raised when a `Deserialize` struct type received a field with an unrecognized name. Read more

#### `pub fn missing_field(field: &'static str) -> Self` [src]

Raised when a `Deserialize` struct type expected to receive a required field with a particular name but that field was not present in the input. Read more

#### `pub fn duplicate_field(field: &'static str) -> Self` [src]

Raised when a `Deserialize` struct type received more than one of the same field. Read more

### `impl From<Error> for Error` [src]

#### `fn from(j: Error) -> Self` [src]

Convert a `serde_json::Error` into an `io::Error`.

JSON syntax and data errors are turned into `InvalidData` IO errors. EOF errors are turned into `UnexpectedEof` IO errors.

    use std::io;

    enum MyError {
        Io(io::Error),
        Json(serde_json::Error),
    }

    impl From<serde_json::Error> for MyError {
        fn from(err: serde_json::Error) -> MyError {
            use serde_json::error::Category;
            match err.classify() {
                Category::Io => {
                    MyError::Io(err.into())
                }
                Category::Syntax | Category::Data | Category::Eof => {
                    MyError::Json(err)
                }
            }
        }
    }

### `impl<'de> IntoDeserializer<'de, Error> for Value` [src]

#### `type Deserializer = Self`

The type of the deserializer being converted into.

#### `fn into_deserializer(self) -> Self::Deserializer` [src]

Convert this value into a deserializer.

## Auto Trait Implementations

### `impl !RefUnwindSafe for Error` [src]

### `impl Send for Error` [src]

### `impl Sync for Error` [src]

### `impl Unpin for Error` [src]

### `impl !UnwindSafe for Error` [src]

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `pub fn type_id(&self) -> TypeId` [src]

Gets the `TypeId` of `self`. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow(&self) -> &Tⓘ

### Notable traits for &'_ mut R

`impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`
` [src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow_mut(&mut self) -> &mut Tⓘ

### Notable traits for &'_ mut R

`impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`
` [src]

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T` [src]

#### `pub fn from(t: T) -> T` [src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `pub fn into(self) -> U` [src]

Performs the conversion.

### `impl<T> ToString for T where
T: Display + ?Sized,` [src]

#### `pub default fn to_string(&self) -> String` [src]

Converts the given value to a `String`. Read more

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>` [src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>` [src]

Performs the conversion.