Struct indradb::Json

pub struct Json(pub Arc<Value>);

Wraps serde_json::Value in an Arc to make it more cheaply cloneable, as well as implements extra traits useful for datastore storage and querying.

Tuple Fields

0: Arc<Value>

Implementations

impl Json

pub fn new(value: Value) -> Self

Constructs a new JSON type.

Arguments

• value: The JSON value.

Methods from Deref<Target = Value>

pub 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));

pub fn is_object(&self) -> bool

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

For any Value on which is_object returns true, as_object and as_object_mut are guaranteed to return the map representation of the object.

let obj = json!({ "a": { "nested": true }, "b": ["an", "array"] });

assert!(obj.is_object());
assert!(obj["a"].is_object());

// array, not an object
assert!(!obj["b"].is_object());

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

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

let v = json!({ "a": { "nested": true }, "b": ["an", "array"] });

// The length of `{"nested": true}` is 1 entry.
assert_eq!(v["a"].as_object().unwrap().len(), 1);

// The array `["an", "array"]` is not an object.
assert_eq!(v["b"].as_object(), None);

pub fn is_array(&self) -> bool

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

For any Value on which is_array returns true, as_array and as_array_mut are guaranteed to return the vector representing the array.

let obj = json!({ "a": ["an", "array"], "b": { "an": "object" } });

assert!(obj["a"].is_array());

// an object, not an array
assert!(!obj["b"].is_array());

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

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

let v = json!({ "a": ["an", "array"], "b": { "an": "object" } });

// The length of `["an", "array"]` is 2 elements.
assert_eq!(v["a"].as_array().unwrap().len(), 2);

// The object `{"an": "object"}` is not an array.
assert_eq!(v["b"].as_array(), None);

pub fn is_string(&self) -> bool

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

For any Value on which is_string returns true, as_str is guaranteed to return the string slice.

let v = json!({ "a": "some string", "b": false });

assert!(v["a"].is_string());

// The boolean `false` is not a string.
assert!(!v["b"].is_string());

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

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

let v = json!({ "a": "some string", "b": false });

assert_eq!(v["a"].as_str(), Some("some string"));

// The boolean `false` is not a string.
assert_eq!(v["b"].as_str(), None);

// JSON values are printed in JSON representation, so strings are in quotes.
//
//    The value is: "some string"
println!("The value is: {}", v["a"]);

// Rust strings are printed without quotes.
//
//    The value is: some string
println!("The value is: {}", v["a"].as_str().unwrap());

pub fn is_number(&self) -> bool

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

let v = json!({ "a": 1, "b": "2" });

assert!(v["a"].is_number());

// The string `"2"` is a string, not a number.
assert!(!v["b"].is_number());

pub fn is_i64(&self) -> bool

Returns true if the Value is an integer between i64::MIN and i64::MAX.

For any Value on which is_i64 returns true, as_i64 is guaranteed to return the integer value.

let big = i64::max_value() as u64 + 10;
let v = json!({ "a": 64, "b": big, "c": 256.0 });

assert!(v["a"].is_i64());

// Greater than i64::MAX.
assert!(!v["b"].is_i64());

// Numbers with a decimal point are not considered integers.
assert!(!v["c"].is_i64());

pub fn is_u64(&self) -> bool

Returns true if the Value is an integer between zero and u64::MAX.

For any Value on which is_u64 returns true, as_u64 is guaranteed to return the integer value.

let v = json!({ "a": 64, "b": -64, "c": 256.0 });

assert!(v["a"].is_u64());

// Negative integer.
assert!(!v["b"].is_u64());

// Numbers with a decimal point are not considered integers.
assert!(!v["c"].is_u64());

pub fn is_f64(&self) -> bool

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

For any Value on which is_f64 returns true, as_f64 is guaranteed to return the floating point value.

Currently this function returns true if and only if both is_i64 and is_u64 return false but this is not a guarantee in the future.

let v = json!({ "a": 256.0, "b": 64, "c": -64 });

assert!(v["a"].is_f64());

// Integers.
assert!(!v["b"].is_f64());
assert!(!v["c"].is_f64());

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

If the Value is an integer, represent it as i64 if possible. Returns None otherwise.

let big = i64::max_value() as u64 + 10;
let v = json!({ "a": 64, "b": big, "c": 256.0 });

assert_eq!(v["a"].as_i64(), Some(64));
assert_eq!(v["b"].as_i64(), None);
assert_eq!(v["c"].as_i64(), None);

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

If the Value is an integer, represent it as u64 if possible. Returns None otherwise.

let v = json!({ "a": 64, "b": -64, "c": 256.0 });

assert_eq!(v["a"].as_u64(), Some(64));
assert_eq!(v["b"].as_u64(), None);
assert_eq!(v["c"].as_u64(), None);

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

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

let v = json!({ "a": 256.0, "b": 64, "c": -64 });

assert_eq!(v["a"].as_f64(), Some(256.0));
assert_eq!(v["b"].as_f64(), Some(64.0));
assert_eq!(v["c"].as_f64(), Some(-64.0));

pub fn is_boolean(&self) -> bool

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

For any Value on which is_boolean returns true, as_bool is guaranteed to return the boolean value.

let v = json!({ "a": false, "b": "false" });

assert!(v["a"].is_boolean());

// The string `"false"` is a string, not a boolean.
assert!(!v["b"].is_boolean());

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

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

let v = json!({ "a": false, "b": "false" });

assert_eq!(v["a"].as_bool(), Some(false));

// The string `"false"` is a string, not a boolean.
assert_eq!(v["b"].as_bool(), None);

pub fn is_null(&self) -> bool

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

For any Value on which is_null returns true, as_null is guaranteed to return Some(()).

let v = json!({ "a": null, "b": false });

assert!(v["a"].is_null());

// The boolean `false` is not null.
assert!(!v["b"].is_null());

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

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

let v = json!({ "a": null, "b": false });

assert_eq!(v["a"].as_null(), Some(()));

// The boolean `false` is not null.
assert_eq!(v["b"].as_null(), None);

pub fn pointer(&self, pointer: &str) -> Option<&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);

Trait Implementations

impl Clone for Json

fn clone(&self) -> Json

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Json

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

Formats the value using the given formatter.

impl Deref for Json

type Target = Value

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<'de> Deserialize<'de> for Json

fn deserialize<D>(deserializer: D) -> Result<Json, D::Error>where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl From<Arc<Value>> for Json

fn from(value: Arc<Value>) -> Self

Converts to this type from the input type.

impl From<Value> for Json

fn from(value: Value) -> Self

Converts to this type from the input type.

impl FromStr for Json

type Err = Error

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl Hash for Json

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq<Json> for Json

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

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd<Json> for Json

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for Json

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

Serialize this value into the given Serde serializer.

impl Eq for Json

impl StructuralEq for Json