Enum rocket_contrib::Value

pub enum Value {
    Null,
    Bool(bool),
    Number(Number),
    String(String),
    Array(Vec<Value>),
    Object(Map<String, Value>),
}

Represents any valid JSON value.

Variants

Null

Represents a JSON null value.

Bool(bool)

Represents a JSON boolean.

Number(Number)

Represents a JSON number, whether integer or floating point.

String(String)

Represents a JSON string.

Array(Vec<Value>)

Represents a JSON array.

Object(Map<String, Value>)

Represents a JSON object.

Methods

impl Value

fn get<I>(&self, index: I) -> Option<&Value> where I: Index

Index into a JSON array or map. A string index can be used to access a value in a map, and a usize index can be used to access an element of an array.

Returns None if the type of self does not match the type of the index, for example if the index is a string and self is an array or a number. Also returns None if the given key does not exist in the map or the given index is not within the bounds of the array.

let object = json!({ "A": 65, "B": 66, "C": 67 });
assert_eq!(*object.get("A").unwrap(), json!(65));

let array = json!([ "A", "B", "C" ]);
assert_eq!(*array.get(2).unwrap(), json!("C"));

assert_eq!(array.get("A"), None);

Square brackets can also be used to index into a value in a more concise way. This returns Value::Null in cases where get would have returned None.

let object = json!({
    "A": ["a", "á", "à"],
    "B": ["b", "b́"],
    "C": ["c", "ć", "ć̣", "ḉ"],
});
assert_eq!(object["B"][0], json!("b"));

assert_eq!(object["D"], json!(null));
assert_eq!(object[0]["x"]["y"]["z"], json!(null));

fn get_mut<I>(&mut self, index: I) -> Option<&mut Value> where I: Index

Mutably index into a JSON array or map. A string index can be used to access a value in a map, and a usize index can be used to access an element of an array.

Returns None if the type of self does not match the type of the index, for example if the index is a string and self is an array or a number. Also returns None if the given key does not exist in the map or the given index is not within the bounds of the array.

let mut object = json!({ "A": 65, "B": 66, "C": 67 });
*object.get_mut("A").unwrap() = json!(69);

let mut array = json!([ "A", "B", "C" ]);
*array.get_mut(2).unwrap() = json!("D");

fn is_object(&self) -> bool

Returns true if the Value is an Object. Returns false otherwise.

fn as_object(&self) -> Option<&Map<String, Value>>

If the Value is an Object, returns the associated Map. Returns None otherwise.

fn as_object_mut(&mut self) -> Option<&mut Map<String, Value>>

If the Value is an Object, returns the associated mutable Map. Returns None otherwise.

fn is_array(&self) -> bool

Returns true if the Value is an Array. Returns false otherwise.

fn as_array(&self) -> Option<&Vec<Value>>

If the Value is an Array, returns the associated vector. Returns None otherwise.

fn as_array_mut(&mut self) -> Option<&mut Vec<Value>>

If the Value is an Array, returns the associated mutable vector. Returns None otherwise.

fn is_string(&self) -> bool

Returns true if the Value is a String. Returns false otherwise.

fn as_str(&self) -> Option<&str>

If the Value is a String, returns the associated str. Returns None otherwise.

fn is_number(&self) -> bool

Returns true if the Value is a Number. Returns false otherwise.

fn is_i64(&self) -> bool

Returns true if the Value is a number that can be represented by i64.

fn is_u64(&self) -> bool

Returns true if the Value is a number that can be represented by u64.

fn is_f64(&self) -> bool

Returns true if the Value is a number that can be represented by f64.

fn as_i64(&self) -> Option<i64>

If the Value is a number, represent it as i64 if possible. Returns None otherwise.

fn as_u64(&self) -> Option<u64>

If the Value is a number, represent it as u64 if possible. Returns None otherwise.

fn as_f64(&self) -> Option<f64>

If the Value is a number, represent it as f64 if possible. Returns None otherwise.

fn is_boolean(&self) -> bool

Returns true if the Value is a Boolean. Returns false otherwise.

fn as_bool(&self) -> Option<bool>

If the Value is a Boolean, returns the associated bool. Returns None otherwise.

fn is_null(&self) -> bool

Returns true if the Value is a Null. Returns false otherwise.

fn as_null(&self) -> Option<()>

If the Value is a Null, returns (). Returns None otherwise.

fn pointer(&'a self, pointer: &str) -> Option<&'a Value>

Looks up a value by a JSON Pointer.

JSON Pointer defines a string syntax for identifying a specific value within a JavaScript Object Notation (JSON) document.

A Pointer is a Unicode string with the reference tokens separated by /. Inside tokens / is replaced by ~1 and ~ is replaced by ~0. The addressed value is returned and if there is no such value None is returned.

For more information read RFC6901.

Examples

let data = json!({
    "x": {
        "y": ["z", "zz"]
    }
});

assert_eq!(data.pointer("/x/y/1").unwrap(), &json!("zz"));
assert_eq!(data.pointer("/a/b/c"), None);

fn pointer_mut(&'a mut self, pointer: &str) -> Option<&'a mut Value>

Looks up a value by a JSON Pointer and returns a mutable reference to that value.

JSON Pointer defines a string syntax for identifying a specific value within a JavaScript Object Notation (JSON) document.

A Pointer is a Unicode string with the reference tokens separated by /. Inside tokens / is replaced by ~1 and ~ is replaced by ~0. The addressed value is returned and if there is no such value None is returned.

For more information read RFC6901.

Example of Use

extern crate serde_json;

use serde_json::Value;
use std::mem;

fn main() {
    let s = r#"{"x": 1.0, "y": 2.0}"#;
    let mut value: Value = serde_json::from_str(s).unwrap();

    // Check value using read-only pointer
    assert_eq!(value.pointer("/x"), Some(&1.0.into()));
    // Change value with direct assignment
    *value.pointer_mut("/x").unwrap() = 1.5.into();
    // Check that new value was written
    assert_eq!(value.pointer("/x"), Some(&1.5.into()));

    // "Steal" ownership of a value. Can replace with any valid Value.
    let old_x = value.pointer_mut("/x").map(|x| mem::replace(x, Value::Null)).unwrap();
    assert_eq!(old_x, 1.5);
    assert_eq!(value.pointer("/x").unwrap(), &Value::Null);
}

Trait Implementations

impl Deserializer for Value

type Error = Error

fn deserialize<V>(self, visitor: V) -> Result<V::Value, Error> where V: Visitor

fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Error> where V: Visitor

fn deserialize_enum<V>(self,
                       _name: &str,
                       _variants: &'static [&'static str],
                       visitor: V)
                       -> Result<V::Value, Error> where V: Visitor

fn deserialize_newtype_struct<V>(self,
                                 _name: &'static str,
                                 visitor: V)
                                 -> Result<V::Value, Value::Error> where V: Visitor

fn deserialize_bool<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_u8<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_u16<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_u32<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_u64<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_i8<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_i16<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_i32<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_i64<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_f32<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_f64<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_char<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_str<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_string<__V>(self,
                           visitor: __V)
                           -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_unit<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_seq<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_seq_fixed_size<__V>(self,
                                   usize,
                                   visitor: __V)
                                   -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_bytes<__V>(self,
                          visitor: __V)
                          -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_byte_buf<__V>(self,
                             visitor: __V)
                             -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_map<__V>(self, visitor: __V) -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_unit_struct<__V>(self,
                                &'static str,
                                visitor: __V)
                                -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_tuple_struct<__V>(self,
                                 &'static str,
                                 usize,
                                 visitor: __V)
                                 -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_struct<__V>(self,
                           &'static str,
                           &'static [&'static str],
                           visitor: __V)
                           -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_struct_field<__V>(self,
                                 visitor: __V)
                                 -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_tuple<__V>(self,
                          usize,
                          visitor: __V)
                          -> Result<__V::Value, Value::Error> where __V: Visitor

fn deserialize_ignored_any<__V>(self,
                                visitor: __V)
                                -> Result<__V::Value, Value::Error> where __V: Visitor

impl PartialEq<str> for Value

fn eq(&self, other: &str) -> bool

impl<'a> PartialEq<&'a str> for Value

fn eq(&self, other: &&str) -> bool

impl PartialEq<String> for Value

fn eq(&self, other: &String) -> bool

impl PartialEq<Value> for Value

fn eq(&self, __arg_0: &Value) -> bool

fn ne(&self, __arg_0: &Value) -> bool

impl PartialEq<i8> for Value

fn eq(&self, other: &i8) -> bool

impl<'a> PartialEq<i8> for &'a Value

fn eq(&self, other: &i8) -> bool

impl<'a> PartialEq<i8> for &'a mut Value

fn eq(&self, other: &i8) -> bool

impl PartialEq<i16> for Value

fn eq(&self, other: &i16) -> bool

impl<'a> PartialEq<i16> for &'a Value

fn eq(&self, other: &i16) -> bool

impl<'a> PartialEq<i16> for &'a mut Value

fn eq(&self, other: &i16) -> bool

impl PartialEq<i32> for Value

fn eq(&self, other: &i32) -> bool

impl<'a> PartialEq<i32> for &'a Value

fn eq(&self, other: &i32) -> bool

impl<'a> PartialEq<i32> for &'a mut Value

fn eq(&self, other: &i32) -> bool

impl PartialEq<i64> for Value

fn eq(&self, other: &i64) -> bool

impl<'a> PartialEq<i64> for &'a Value

fn eq(&self, other: &i64) -> bool

impl<'a> PartialEq<i64> for &'a mut Value

fn eq(&self, other: &i64) -> bool

impl PartialEq<isize> for Value

fn eq(&self, other: &isize) -> bool

impl<'a> PartialEq<isize> for &'a Value

fn eq(&self, other: &isize) -> bool

impl<'a> PartialEq<isize> for &'a mut Value

fn eq(&self, other: &isize) -> bool

impl PartialEq<u8> for Value

fn eq(&self, other: &u8) -> bool

impl<'a> PartialEq<u8> for &'a Value

fn eq(&self, other: &u8) -> bool

impl<'a> PartialEq<u8> for &'a mut Value

fn eq(&self, other: &u8) -> bool

impl PartialEq<u16> for Value

fn eq(&self, other: &u16) -> bool

impl<'a> PartialEq<u16> for &'a Value

fn eq(&self, other: &u16) -> bool

impl<'a> PartialEq<u16> for &'a mut Value

fn eq(&self, other: &u16) -> bool

impl PartialEq<u32> for Value

fn eq(&self, other: &u32) -> bool

impl<'a> PartialEq<u32> for &'a Value

fn eq(&self, other: &u32) -> bool

impl<'a> PartialEq<u32> for &'a mut Value

fn eq(&self, other: &u32) -> bool

impl PartialEq<u64> for Value

fn eq(&self, other: &u64) -> bool

impl<'a> PartialEq<u64> for &'a Value

fn eq(&self, other: &u64) -> bool

impl<'a> PartialEq<u64> for &'a mut Value

fn eq(&self, other: &u64) -> bool

impl PartialEq<usize> for Value

fn eq(&self, other: &usize) -> bool

impl<'a> PartialEq<usize> for &'a Value

fn eq(&self, other: &usize) -> bool

impl<'a> PartialEq<usize> for &'a mut Value

fn eq(&self, other: &usize) -> bool

impl PartialEq<f32> for Value

fn eq(&self, other: &f32) -> bool

impl<'a> PartialEq<f32> for &'a Value

fn eq(&self, other: &f32) -> bool

impl<'a> PartialEq<f32> for &'a mut Value

fn eq(&self, other: &f32) -> bool

impl PartialEq<f64> for Value

fn eq(&self, other: &f64) -> bool

impl<'a> PartialEq<f64> for &'a Value

fn eq(&self, other: &f64) -> bool

impl<'a> PartialEq<f64> for &'a mut Value

fn eq(&self, other: &f64) -> bool

impl<I> Index<I> for Value where I: Index

type Output = Value

fn index(&self, index: I) -> &Value

Index into a serde_json::Value using the syntax value[0] or value["k"].

Returns Value::Null if the type of self does not match the type of the index, for example if the index is a string and self is an array or a number. Also returns Value::Null if the given key does not exist in the map or the given index is not within the bounds of the array.

For retrieving deeply nested values, you should have a look at the Value::pointer method.

Examples

let data = json!({
    "x": {
        "y": ["z", "zz"]
    }
});

assert_eq!(data["x"]["y"], json!(["z", "zz"]));
assert_eq!(data["x"]["y"][0], json!("z"));

assert_eq!(data["a"], json!(null)); // returns null for undefined values
assert_eq!(data["a"]["b"], json!(null)); // does not panic

impl Display for Value

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Serializes a json value into a string

impl Default for Value

The default value is Value::Null.

This is useful for handling omitted Value fields when deserializing.

Examples

use serde_json::Value;

#[derive(Deserialize)]
struct Settings {
    level: i32,
    #[serde(default)]
    extras: Value,
}

let data = r#" { "level": 42 } "#;
let s: Settings = serde_json::from_str(data)?;

assert_eq!(s.level, 42);
assert_eq!(s.extras, Value::Null);

fn default() -> Value

impl Debug for Value

fn fmt(&self, __arg_0: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl FromStr for Value

type Err = Error

fn from_str(s: &str) -> Result<Value, Error>

impl Serialize for Value

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer

Serialize this value into the given Serde serializer.

impl Deserialize for Value

fn deserialize<D>(deserializer: D) -> Result<Value, D::Error> where D: Deserializer

Deserialize this value from the given Serde deserializer.

impl From<f32> for Value

fn from(f: f32) -> Value

impl From<f64> for Value

fn from(f: f64) -> Value

impl From<i8> for Value

fn from(n: i8) -> Value

impl From<i16> for Value

fn from(n: i16) -> Value

impl From<i32> for Value

fn from(n: i32) -> Value

impl From<i64> for Value

fn from(n: i64) -> Value

impl From<isize> for Value

fn from(n: isize) -> Value

impl From<u8> for Value

fn from(n: u8) -> Value

impl From<u16> for Value

fn from(n: u16) -> Value

impl From<u32> for Value

fn from(n: u32) -> Value

impl From<u64> for Value

fn from(n: u64) -> Value

impl From<usize> for Value

fn from(n: usize) -> Value

impl Clone for Value

fn clone(&self) -> Value