pub struct Error { /* private fields */ }Expand description
This type represents all possible errors that can occur when serializing or deserializing JSON data.
Implementations§
Source§impl Error
impl Error
Sourcepub fn line(&self) -> usize
pub fn line(&self) -> usize
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.
Sourcepub fn column(&self) -> usize
pub fn column(&self) -> usize
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 I/O stream fails immediately following a previously read newline character.
Sourcepub fn classify(&self) -> Category
pub fn classify(&self) -> Category
Categorizes the cause of this error.
Category::Io- failure to read or write bytes on an I/O streamCategory::Syntax- input that is not syntactically valid JSONCategory::Data- input data that is semantically incorrectCategory::Eof- unexpected end of the input data
Sourcepub fn is_io(&self) -> bool
pub fn is_io(&self) -> bool
Returns true if this error was caused by a failure to read or write bytes on an I/O stream.
Sourcepub fn is_syntax(&self) -> bool
pub fn is_syntax(&self) -> bool
Returns true if this error was caused by input that was not syntactically valid JSON.
Sourcepub fn is_data(&self) -> bool
pub fn is_data(&self) -> bool
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.
Sourcepub fn is_eof(&self) -> bool
pub fn is_eof(&self) -> bool
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.
Sourcepub fn io_error_kind(&self) -> Option<ErrorKind>
pub fn io_error_kind(&self) -> Option<ErrorKind>
The kind reported by the underlying standard library I/O error, if this error was caused by a failure to read or write bytes on an I/O stream.
§Example
use serde_json::Value;
use std::io::{self, ErrorKind, Read};
use std::process;
struct ReaderThatWillTimeOut<'a>(&'a [u8]);
impl<'a> Read for ReaderThatWillTimeOut<'a> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
if self.0.is_empty() {
Err(io::Error::new(ErrorKind::TimedOut, "timed out"))
} else {
self.0.read(buf)
}
}
}
fn main() {
let reader = ReaderThatWillTimeOut(br#" {"k": "#);
let _: Value = match serde_json::from_reader(reader) {
Ok(value) => value,
Err(error) => {
if error.io_error_kind() == Some(ErrorKind::TimedOut) {
// Maybe this application needs to retry certain kinds of errors.
} else {
eprintln!("error: {}", error);
process::exit(1);
}
}
};
}Trait Implementations§
Source§impl Error for Error
impl Error for Error
Source§fn source(&self) -> Option<&(dyn Error + 'static)>
fn source(&self) -> Option<&(dyn Error + 'static)>
1.0.0 · Source§fn description(&self) -> &str
fn description(&self) -> &str
Source§impl Error for Error
impl Error for Error
Source§fn custom<T: Display>(msg: T) -> Error
fn custom<T: Display>(msg: T) -> Error
Source§fn invalid_type(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self
fn invalid_type(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self
Deserialize receives a type different from what it was
expecting. Read moreSource§fn invalid_value(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self
fn invalid_value(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self
Deserialize receives a value of the right type but that
is wrong for some other reason. Read moreSource§fn invalid_length(len: usize, exp: &dyn Expected) -> Self
fn invalid_length(len: usize, exp: &dyn Expected) -> Self
Source§fn unknown_variant(variant: &str, expected: &'static [&'static str]) -> Self
fn unknown_variant(variant: &str, expected: &'static [&'static str]) -> Self
Deserialize enum type received a variant with an
unrecognized name.Source§fn unknown_field(field: &str, expected: &'static [&'static str]) -> Self
fn unknown_field(field: &str, expected: &'static [&'static str]) -> Self
Deserialize struct type received a field with an
unrecognized name.Source§fn missing_field(field: &'static str) -> Self
fn missing_field(field: &'static str) -> Self
Deserialize struct type expected to receive a required
field with a particular name but that field was not present in the
input.Source§fn duplicate_field(field: &'static str) -> Self
fn duplicate_field(field: &'static str) -> Self
Deserialize struct type received more than one of the
same field.Source§impl From<Error> for Error
impl From<Error> for Error
Source§fn from(j: Error) -> Self
fn from(j: Error) -> Self
Convert a serde_json::Error into an io::Error.
JSON syntax and data errors are turned into InvalidData I/O errors.
EOF errors are turned into UnexpectedEof I/O 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)
}
}
}
}