1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162
//! JSON and serialization //! //! # What is JSON? //! //! JSON (JavaScript Object Notation) is a way to write data in JavaScript. Like XML, it allows to //! encode structured data in a text format that can be easily read by humans. Its simple syntax //! and native compatibility with JavaScript have made it a widely used format. //! //! Data types that can be encoded are JavaScript types (see the `serde_json:Value` enum for more //! details): //! //! * `Bool`: equivalent to rust's `bool` //! * `I64`: equivalent to rust's `i64` //! * `U64`: equivalent to rust's `u64` //! * `F64`: equivalent to rust's `f64` //! * `String`: equivalent to rust's `String` //! * `Array`: equivalent to rust's `Vec<T>`, but also allowing objects of different types in the //! same array //! * `Object`: equivalent to rust's `BTreeMap<String, serde_json::Value>`; set the //! `preserve_order` feature to use `LinkedHashMap<String, serde_json::Value>` instead //! * `Null` //! //! An object is a series of string keys mapping to values, in `"key": value` format. Arrays are //! enclosed in square brackets ([ ... ]) and objects in curly brackets ({ ... }). A simple JSON //! document encoding a person, his/her age, address and phone numbers could look like //! //! ```ignore //! { //! "FirstName": "John", //! "LastName": "Doe", //! "Age": 43, //! "Address": { //! "Street": "Downing Street 10", //! "City": "London", //! "Country": "Great Britain" //! }, //! "PhoneNumbers": [ //! "+44 1234567", //! "+44 2345678" //! ] //! } //! ``` //! //! If we assume that `FirstName` is optional and all other fields are mandatory, the above JSON could //! correspond to the following Rust structs: //! //! ```ignore //! #[derive(Serialize, Deserialize)] //! struct Data { //! #[serde(rename="FirstName")] // to comply with Rust coding standards //! first_name: Option<String>, //! LastName: String, //! Age: u32, //! Address: Address, //! PhoneNumbers: Vec<String> //! } //! //! #[derive(Serialize, Deserialize)] //! struct Address { //! Street: String, //! City: String, //! Country: String //! } //! ``` //! //! # Type-based Serialization and Deserialization //! //! Serde provides a mechanism for low boilerplate serialization & deserialization of values to and //! from JSON via the serialization API. To be able to serialize a piece of data, it must implement //! the `serde::Serialize` trait. To be able to deserialize a piece of data, it must implement the //! `serde::Deserialize` trait. Serde provides provides an annotation to automatically generate //! the code for these traits: `#[derive(Serialize, Deserialize)]`. //! //! The JSON API also provides an enum `serde_json::Value` and a method `to_value` to serialize //! objects. A `serde_json::Value` value can be serialized as a string or buffer using the //! functions described above. You can also use the `json::Serializer` object, which implements the //! `Serializer` trait. //! //! # Examples of use //! //! ## Parsing a `str` to `Value` and reading the result //! //! ```rust //! extern crate serde_json; //! //! use serde_json::Value; //! //! fn main() { //! let data: Value = serde_json::from_str("{\"foo\": 13, \"bar\": \"baz\"}").unwrap(); //! println!("data: {:?}", data); //! // data: {"bar":"baz","foo":13} //! println!("object? {}", data.is_object()); //! // object? true //! //! let obj = data.as_object().unwrap(); //! let foo = obj.get("foo").unwrap(); //! //! println!("array? {:?}", foo.as_array()); //! // array? None //! println!("u64? {:?}", foo.as_u64()); //! // u64? Some(13u64) //! //! for (key, value) in obj.iter() { //! println!("{}: {}", key, match *value { //! Value::U64(v) => format!("{} (u64)", v), //! Value::String(ref v) => format!("{} (string)", v), //! _ => format!("other") //! }); //! } //! // bar: baz (string) //! // foo: 13 (u64) //! } //! ``` #![cfg_attr(feature = "clippy", feature(plugin))] #![cfg_attr(feature = "clippy", plugin(clippy))] #![cfg_attr(feature = "clippy", deny(clippy, clippy_pedantic))] // Because of "JavaScript"... fixed in Manishearth/rust-clippy#1071 #![cfg_attr(feature = "clippy", allow(doc_markdown))] // Whitelisted clippy_pedantic lints #![cfg_attr(feature = "clippy", allow( // integer and float ser/de requires these sorts of casts cast_possible_truncation, cast_possible_wrap, cast_precision_loss, cast_sign_loss, // string ser/de uses indexing and slicing indexing_slicing, // things are often more readable this way shadow_reuse, shadow_unrelated, single_match_else, stutter, // not practical missing_docs_in_private_items, ))] #![deny(missing_docs)] extern crate num_traits; extern crate core; #[macro_use] extern crate serde; extern crate itoa; extern crate dtoa; #[cfg(feature = "preserve_order")] extern crate linked_hash_map; pub use self::de::{Deserializer, StreamDeserializer, from_iter, from_reader, from_slice, from_str}; pub use self::error::{Error, ErrorCode, Result}; pub use self::ser::{Serializer, escape_str, to_string, to_string_pretty, to_vec, to_vec_pretty, to_writer, to_writer_pretty}; pub use self::value::{Map, Value, from_value, to_value}; pub mod builder; pub mod de; pub mod error; pub mod ser; pub mod value; mod read;