update readme

README.md

@@ -1,35 +1,59 @@
-# Sinaweibopy 
+# snspy 
+
+SNSPY is a stand-alone Python script which provides
 
-A stand-alone Python script which provides
 * OAuth2.0 authentication
 * API calling wrapper
-
+
+for any social network providers.
+
 http://michaelliao.github.com/sinaweibopy/
 
 Developed and mantained by Michael Liao. Please feel free to report bugs and
 your suggestions at [here](https://github.com/michaelliao/sinaweibopy).
 
 ## OAuth2.0
 
-After setting up your [Open Weibo Account](http://open.weibo.com) and
-registering for an application, you will receive `YOUR_APP_KEY` and
-`YOUR_APP_SECRET`. Together with `YOUR_CALLBACK_URL`, these are the environment
-variables required by sinaweibopy.
+OAuth 2 is a protocol focuses on client developer simplicity while providing 
+specific authorization flows for web applications.
+
+There are many social networks provides OAuth 2 authentication and APIs, and 
+snspy is a simple API wrapper for any social network such as Twitter, Facebook, 
+LinkedIn, Sina Weibo, etc.
+
+snspy provides a unique API interface for developers and difference of each 
+social network APIs are handled by its `mixin`.
+
+## Basic Usage
+
+You need to register your OAuth 2 application on the social network you choose:
+
+[Tweeter]()
+[Facebook]()
+[LinkedIn]()
+[Sina Weibo]()
+[QQ Connect]()
+
+After setting up your account and registering for an application, you will receive 
+`YOUR_APP_KEY` and `YOUR_APP_SECRET`. Together with `YOUR_CALLBACK_URL`, these are 
+the environment variables required by snspy. And you can create the APIClient now:
 
 ```python
-from weibo import APIClient
-
+from snspy import APIClient
+from snspy import TwitterMixin      # suppose you are using Twitter
+
 APP_KEY = 'YOUR_APP_KEY'            # app key
 APP_SECRET = 'YOUR_APP_SECRET'      # app secret
 CALLBACK_URL = 'YOUR_CALLBACK_URL'  # callback url
+
+client = APIClient(TwitterMixin, app_key=APP_KEY, app_secret=APP_SECRET, redirect_uri=CALLBACK_URL)
 ```
+
 Put on your website a link which redirect the user to the following
 authorization URL:
 
 ```python
-client = APIClient(app_key=YOUR_APP_KEY, app_secret=YOUR_APP_SECRET,
-                   redirect_uri=YOUR_CALLBACK_URL)
-url = client.get_authorize_url()    # redirect the user to `url'
+url = client.get_authorize_url()    # redirect the user to 'url'
 ```
 
 After granting the privileges, the user will be redirected to
@@ -39,8 +63,16 @@ get the access token using this `SOME_CODE`.
 ```python
 r = client.request_access_token(SOME_CODE)
 access_token = r.access_token  # access token，e.g., abc123xyz456
-expires_in = r.expires_in      # token expires in
-client.set_access_token(access_token, expires_in)
+expires = r.expires      # token expires time, UNIX timestamp, e.g., 1384826449.252 (10:01 am, 19 Nov 2013, UTC+8:00)
+NOTE: you should store the access_token for later use.
+```
+
+After got access token you can init the APIClient any time:
+
+```python
+client = APIClient(TwitterMixin,
+                   app_key=APP_KEY, app_secret=APP_SECRET, redirect_uri=CALLBACK_URL,
+                   access_token=YOUR_ACCESS_TOKEN, expires=EXPIRES_TIME)
 ```
 
 Then, you are free to call whatever API you like. For example,