rust-jsonm

jsonm为Rust实现的压缩库。

原始库是用JS编写的，在此处：https://github.com/lennartcl/jsonm

jsonm是一种快速且安全地使用记忆化压缩JSON消息的方法。通过去除重复的名字和值，jsonm可以将消息的大小减少几个数量级。

jsonm打包

[
    { "firstName": "Francis", "lastName": "Doe" },
    { "firstName": "Anna", "lastName": "Smith" },
    { "firstName": "Agent", "lastName": "Smith", "isAlias": true },
    { "firstName": "Anna", "lastName": "Francis" }
]

为

[ 0,
    ["firstName", "lastName", "Francis", "Doe"],
    [3, 4, "Anna", "Smith"],
    [3, 4, "isAlias", "Agent", 8, true],
    [3, 4, 7, 5]
]

注意它是如何使用记忆化消除所有公共子串，如"firstName"的！jsonm保留了一个字典，以进一步压缩未来的消息。发送上述消息第二次，它变为

[0,[3,4,5,6],[3,4,7,8],[3,4,9,10,8,11],[3,4,7,5],1]

并且

[
    { "firstName": "Bryan", "lastName": "Fuller" },
    { "firstName": "Anna", "lastName": "Adams" },
    { "firstName": "Tim", "lastName": "Peterson" },
    { "firstName": "Francis", "lastName": "Peterson" }
]

变为

[0,[3,4,"Bryan","Fuller"],[3,4,7,"Adams"],[3,4,"Tim","Peterson"],[3,4,5,16]]

通过避免重复，jsonm可以帮助减少从Web服务器发送到客户端的消息大小。它有效地排除了客户端已经知道的所有信息。

安装

[dependencies]
"jsonm" = "0.1"

示例

#[macro_use]
extern crate serde_json;
extern crate jsonm;

use jsonm::packer::{PackOptions, Packer};
use jsonm::unpacker::Unpacker;

let mut packer = Packer::new();
let options = PackOptions::new();
let packed = packer.pack(&json!({ "bar": 1, "foo": "1" }), &options).unwrap(); // packed is ["bar", "foo", "1", "~1", 0]

let mut unpacker = Unpacker::new();
let unpacked: Value = unpacker.unpack(&packed).unwrap(); // unpacked is Object({ "bar": 1, "foo": "1" })