# Wechat
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Wechat API wrapper in Elixir.
## Installation
1. Add `wechat` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[{:wechat, "~> 0.1.0"}]
end
```
2. Ensure `wechat` is started before your application:
```elixir
def application do
[applications: [:wechat]]
end
```
## Config
* Add config in `config.exs`
```elixir
config :wechat, Wechat,
appid: "wechat app id",
secret: "wechat app secret",
token: "wechat token",
encoding_aes_key: "32bits key" # 只有"兼容模式"和"安全模式"才需要配置这个值
```
## Usage
* access_token
```elixir
iex> Wechat.access_token
"Bgw6_cMvFrE3hY3J8U6oglhvlzHhMpAQma0Wjam4XsLx8F6XP4pfZzsezBdpfth2BNAdUK6wA23S7D3fSePt7meG9a1gf9LhEmXjxGelnTjJLaIQMYumrCHE_9gcFVXaHIHcAGACDC"
```
* user
```elixir
iex> Wechat.User.list
%{count: 4,
data: %{openid: ["oi00OuFrmNEC-QMa0Kikycq6A7ys",
"oi00OuKAhA8bm5okpaIDs7WmUZr4", "oi00OuOdjK0TicVUmovudbSP5Zq4",
"oi00OuBgG2mko_pOukCy00EYCwo4"]},
next_openid: "oi00OuBgG2mko_pOukCy00EYCwo4", total: 4}
iex> Wechat.User.info("oi00OuKAhA8bm5okpaIDs7WmUZr4")
%{city: "宝山", country: "中国", groupid: 0,
headimgurl: "http://wx.qlogo.cn/mmopen/7raJSSs9gLVJibia6sAXRvr8jajXfQFWiagrLwrRIZjMHCEXOxYf6nflxcpl4WkT7gz8Sa4tO32avnI0dlNLn24yA/0",
language: "zh_CN", nickname: "小爆炸的爸爸",
openid: "oi00OuKAhA8bm5okpaIDs7WmUZr4", province: "上海", remark: "",
sex: 1, subscribe: 1, subscribe_time: 1449812483, tagid_list: [],
unionid: "o2oUsuOUzgNL-JSLtIp8b3FzkI-M"}
```
* media
```elixir
iex> file = Wechat.Media.download("GuSq91L0FXQFOIFtKwX2i5UPXH9QKnnu63_z4JHZwIw3TMIn1C-xm8hX3nPWCA")
iex> File.write!('/tmp/file', file)
```
## Plug
* `Wechat.Plugs.CheckUrlSignature`
* Check url signature
* [接入指南](http://mp.weixin.qq.com/wiki?t=resource/res_main&id=mp1421135319&token=&lang=zh_CN)
* `Wechat.Plugs.CheckMsgSignature`
* Parse xml message (support decrypt msg)
* [消息加密解密技术方案](http://mp.weixin.qq.com/wiki/2/3478f69c0d0bbe8deb48d66a3111ff6e.html)
## Plug Usage (in Phonenix controller)
* router.ex
```elixir
defmodule MyApp.Router do
pipeline :api do
plug :accepts, ["json"]
end
scope "/wechat", MyApp do
pipe_through :api
# validate wechat server config
get "/", WechatController, :index
# receive wechat push message
post "/", WechatController, :create
end
end
```
* wechat_controller.ex
```elixir
defmodule MyApp.WechatController do
use MyApp.Web, :controller
plug Wechat.Plugs.CheckUrlSignature
plug Wechat.Plugs.CheckMsgSignature when action in [:create]
def index(conn, %{"echostr" => echostr}) do
text conn, echostr
end
def create(conn, _params) do
msg = conn.assigns[:msg]
reply = build_text_reply(msg, msg.content)
render conn, "text.xml", reply: reply
end
defp build_text_reply(%{tousername: to, fromusername: from}, content) do
%{from: to, to: from, content: content}
end
end
```
* text.xml.eex
```xml
<xml>
<MsgType><![CDATA[text]]></MsgType>
<Content><![CDATA[<%= @reply.content %>]]></Content>
<ToUserName><![CDATA[<%= @reply.to %>]]></ToUserName>
<FromUserName><![CDATA[<%= @reply.from %>]]></FromUserName>
<CreateTime><%= DateTime.to_unix(DateTime.utc_now) %></CreateTime>
</xml>
```