> For the complete documentation index, see [llms.txt](https://kelby.gitbook.io/rails-beginner-s-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kelby.gitbook.io/rails-beginner-s-guide/activesupport/activesupport_-_gzip__json.md).

# Gzip 与 JSON

**Gzip** \
 封装了标准库 [zlib](http://ruby-doc.org/stdlib-2.1.0/libdoc/zlib/rdoc/index.html)，提供 gzip 压缩/解压缩字符串功能。

```ruby
# 压缩
gzip = ActiveSupport::Gzip.compress('compress me!')
# => "\x1F\x8B\b\x00o\x8D\...\x83\f\x00\x00\x00"

# 解压缩
ActiveSupport::Gzip.decompress(gzip)
# => "compress me!"
```

**JSON** \
 提供 json 格式的编码/解码。

`encode(value, options = nil)` 将对象转换成 JSON 格式

```ruby
# 加密
# 是模块方法
ActiveSupport::JSON.encode({ team: 'rails', players: '36' })
# => "{\"team\":\"rails\",\"players\":\"36\"}"
```

`decode(json, options = {})` 将 JSON 字符串转换成 Hash

```ruby
# 解密
# 是类方法
ActiveSupport::JSON.decode("{\"team\":\"rails\",\"players\":\"36\"}")
=> {"team" => "rails", "players" => "36"}
```