Struct serde_json::error::Error

source · 
pub struct Error { /* private fields */ }
Expand description

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

Implementations§

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.

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.

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
Examples found in repository?
src/error.rs (line 81)
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    pub fn is_io(&self) -> bool {
        self.classify() == Category::Io
    }

    /// Returns true if this error was caused by input that was not
    /// syntactically valid JSON.
    pub fn is_syntax(&self) -> bool {
        self.classify() == Category::Syntax
    }

    /// 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_data(&self) -> bool {
        self.classify() == Category::Data
    }

    /// 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.
    pub fn is_eof(&self) -> bool {
        self.classify() == Category::Eof
    }
}

/// Categorizes the cause of a `serde_json::Error`.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum Category {
    /// The error was caused by a failure to read or write bytes on an IO
    /// stream.
    Io,

    /// The error was caused by input that was not syntactically valid JSON.
    Syntax,

    /// The 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.
    Data,

    /// The 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.
    Eof,
}

#[cfg(feature = "std")]
#[allow(clippy::fallible_impl_from)]
impl From<Error> for io::Error {
    /// 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)
    ///             }
    ///         }
    ///     }
    /// }
    /// ```
    fn from(j: Error) -> Self {
        if let ErrorCode::Io(err) = j.err.code {
            err
        } else {
            match j.classify() {
                Category::Io => unreachable!(),
                Category::Syntax | Category::Data => io::Error::new(io::ErrorKind::InvalidData, j),
                Category::Eof => io::Error::new(io::ErrorKind::UnexpectedEof, j),
            }
        }
    }

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

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

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.

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§

Formats the value using the given formatter. Read more
Formats the value using the given formatter. Read more
The lower-level source of this error, if any. Read more
👎Deprecated since 1.42.0: use the Display impl or to_string()
Read more
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type based access to context intended for error reports. Read more
Raised when there is general error when deserializing a type. Read more
Raised when a Deserialize receives a type different from what it was expecting. Read more
Raised when a Deserialize receives a value of the right type but that is wrong for some other reason. Read more
Raised when deserializing a sequence or map and the input data contains too many or too few elements. Read more
Raised when a Deserialize enum type received a variant with an unrecognized name. Read more
Raised when a Deserialize struct type received a field with an unrecognized name. Read more
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
Raised when a Deserialize struct type received more than one of the same field. Read more
Used when a Serialize implementation encounters any error while serializing a type. Read more

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)
            }
        }
    }
}
The type of the deserializer being converted into.
Convert this value into a deserializer.

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

🔬This is a nightly-only experimental API. (provide_any)
Data providers should implement this method to provide all values they are able to provide by using demand. Read more
Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.