The storage adapter specification for WeChat component application.

Since we need to temporarily storage some key data(e.g. access_token/component_access_token) for invoking WeChat APIs, this module is used for customizing the persistence when use elixir_wechat in a client side of WeChat component application.

Notice: as a client, we only need to implement the minimum functions to automatically append the required parameters from the persistence.

writing-custom-storage-adapter

Writing custom storage adapter

Example for WeChat third-party platform application

defmodule MyComponentAppStorageClient do
  @behaviour WeChat.Storage.ComponentClient

  @impl true
  def fetch_access_token(appid, authorizer_appid, args) do
    access_token = "Get authorizer's access_token by appid and authorizer appid from your persistence..."
    {:ok, %WeChat.Token{access_token: access_token}}
  end

  @impl ture
  def fetch_component_access_token(appid, args) do
    access_token = "Get component access_token by component appid from your persistence..."
    {:ok, %WeChat.Token{access_token: access_token}}
  end

  @impl true
  def refresh_access_token(appid, authorizer_appid, access_token, args) do
    access_token = "Refresh access_token by appid from your persistence..."
    {:ok, %WeChat.Token{access_token: access_token}}
  end

  @impl true
  def refresh_component_access_token(appid, component_access_token, args) do
    access_token = "Refresh component access_token by component appid from your persistence..."
    {:ok, %WeChat.Token{access_token: access_token}}
  end

  @impl true
  def fetch_ticket(appid, type, args) do
    ticket = "Get jsapi-ticket/card-ticket from your persistence..."
    {:ok, ticket}
  end
end

Use MyComponentAppStorageClient

Global configure MyComponentAppStorageClient

defmodule Client do
  use WeChat,
    adapter_storage: {MyComponentAppStorageClient, args}
end

defmodule Client do
  use WeChat,
    adapter_storage: MyComponentAppStorageClient
end

Dynamically set MyComponentAppStorageClient when call WeChat.request/2

WeChat.request(:post, url: ..., adapter_storage: {MyComponentAppStorageClient, args}, ...)
WeChat.request(:post, url: ..., adapter_storage: MyComponentAppStorageClient, ...)

Notice: The above args will be returned back into each implement of callback function, if not input it, args will be as an empty list in callback.