WechatPay

WechatPay API wrapper in Elixir.

:warning: Be careful, some of the Wechat’s API docs are inconsistent with the real API endpoints. I only test those APIs on a Wechat MP App.

Installation

If available in Hex, the package can be installed as:

1. Add wechat_pay to your list of dependencies in mix.exs:

   def deps do
     [{:wechat_pay, "~> 0.2.0"}]
   end

2. Ensure wechat_pay is started before your application:

   def application do
     [applications: [:wechat_pay]]
   end

Usage

Config :wechat_pay

use Mix.Config

config :wechat_pay,
  env: :sandbox, # or :production
  appid: "wx8888888888888888",
  mch_id: "1900000109",
  apikey: "192006250b4c09247ec02edce69f6a2d",
  ssl_cacertfile: "certs/ca.cert",
  ssl_certfile: "certs/client.crt",
  ssl_keyfile: "certs/client.key",
  ssl_password: "test"

:warning: If the env is :sandbox, you should fill the real appid, mch_id, apikey here, then call WechatPay.API.get_sandbox_signkey() to get the sandbox apikey, then replace the apikey with this one. It’s verbose, but it’s a workaround for using in the sandbox env.

APIs

https://pay.weixin.qq.com/wiki/doc/api/index.html

JSAPI（公众号支付）

• [x] WechatPay.API.place_order(params)
• [x] WechatPay.API.query_order(params)
• [x] WechatPay.API.close_order(params)
• [x] WechatPay.API.refund(params)
• [x] WechatPay.API.query_refund(params)
• [x] WechatPay.API.download_bill(params)
• [x] WechatPay.API.report(params)
• [x] WechatPay.HTML.generate_pay_request(prepay_id)

Native（扫码支付）

• [x] WechatPay.API.place_order(params)
• [x] WechatPay.API.query_order(params)
• [x] WechatPay.API.close_order(params)
• [x] WechatPay.API.refund(params)
• [x] WechatPay.API.query_refund(params)
• [x] WechatPay.API.download_bill(params)
• [x] WechatPay.API.report(params)
• [x] WechatPay.API.shorten_url(url)

APP（APP支付）

• [x] WechatPay.API.place_order(params)
• [x] WechatPay.API.query_order(params)
• [x] WechatPay.API.close_order(params)
• [x] WechatPay.API.refund(params)
• [x] WechatPay.API.query_refund(params)
• [x] WechatPay.API.report(params)
• [x] WechatPay.API.download_bill(params)

Example

params = %{
  device_info: "WEB",
  body: "时习-#{event.title}",
  attach: nil,
  out_trade_no: order.order_number,
  fee_type: "CNY",
  total_fee: order.fee,
  spbill_create_ip: Keyword.get(opts, :remote_ip),
  notify_url: @notify_url,
  time_start: now |> format_datetime,
  time_expire: now |> Timex.shift(hours: 1) |> format_datetime,
  trade_type: "JSAPI",
  openid: User.openid(user),
}

case WechatPay.API.place_order(params) do
  {:ok, order} ->
    order
  {:error, reason} ->
    IO.inspect reason
end

Plug

There’s a plug WechatPay.Plug.Callback to handle callback from Wechat’s server

Here’s an Pheonix example:

Router

# lib/my_app/web/router.ex
scope "/wechat", as: :wechat do
  post "/pay/callback", WechatPay.Plug.Callback, [handler: MyApp.WechatPay.CallbackHandler]
end

The Callback handler

# lib/my_app/wechat_pay/callback_handler.ex
defmodule MyApp.WechatPayCallbackHandler do
  @behaviour WechatPay.Plug.Callback.Handler

  def handle_data(conn, data) do
    IO.inspect data
    # %{
    #   appid: "wx2421b1c4370ec43b",
    #   attach: "支付测试",
    #   bank_type: "CFT",
    #   fee_type: "CNY",
    #   is_subscribe: "Y",
    #   mch_id: "10000100",
    #   nonce_str: "5d2b6c2a8db53831f7eda20af46e531c",
    #   openid: "oUpF8uMEb4qRXf22hE3X68TekukE",
    #   out_trade_no: "1409811653",
    #   result_code: "SUCCESS",
    #   return_code: "SUCCESS",
    #   sign: "594B6D97F089D24B55156CE09A5FF412",
    #   sub_mch_id: "10000100",
    #   time_end: "20140903131540",
    #   total_fee: "1",
    #   trade_type: "JSAPI",
    #   transaction_id: "1004400740201409030005092168"
    # }
  end

  # optional
  def handle_error(conn, reason, data) do
    reason == "签名失败"
    data.return_code == "FAIL"
  end
end