PythonでTwitter APIを使う ref: http://qiita.com/polikeiji/items/37f89fb4ed1a25fd912c

file1.py

@get('/twitter_login')
def twitter_login():
    auth_url, request_token_key, request_token_secret = twitter.generate_auth_url()

    # request_token_keyとrequest_token_secretをセッションに保存する。

    redirect(auth_url)

file2.py

@get('/twitter_callback')
def twitter_callback():
    # セッションに保存したリクエスト・トークン（request_token_key）、シークレット（request_token_secret）を取得する。

    oauth_verifier = request.query['oauth_verifier']

    access_token_key, access_token_secret = twitter.get_access_token(
        twitter_connect.request_token_key,
        twitter_connect.request_token_secret,
        oauth_verifier)

    twitter_user = twitter.verify_credentials(access_token_key, access_token_secret)

    # ユーザー登録とかログインとかの処理

twitter.py

# -*- coding: utf-8 -*-

import os
import urllib2
import os.path
import logging
import traceback

import oauthlib
import tweepy


CONSUMER_KEY = os.environ.get('TWITTER_CONSUMER_KEY')
CONSUMER_SECRET = os.environ.get('TWITTER_CONSUMER_SECRET')
CALLBACK_URL = os.environ.get('TWITTER_CALLBACK_URL')


#

def api(access_token = None, access_token_secret = None, with_callback_url = False):
    if with_callback_url:
        auth = tweepy.OAuthHandler(
            consumer_key = CONSUMER_KEY,
            consumer_secret = CONSUMER_SECRET,
            callback_url = CALLBACK_URL)
    else:
        auth = tweepy.OAuthHandler(
            consumer_key = CONSUMER_KEY,
            consumer_secret = CONSUMER_SECRET)

    if access_token is not None and access_token_secret is not None:
        auth.set_access_token(access_token, access_token_secret)

    return tweepy.API(auth)


# API

def get_tweets(screen_name = None, hashtag = None, count = 200):
    if screen_name is not None:
        cursor = tweepy.Cursor(api().user_timeline, 
        screen_name = screen_name, count = 200, exclude_replies = True)
    elif hashtag is not None:
        cursor = tweepy.Cursor(api().search, q = u"#{0}".format(hashtag), count = 200)

    if count is not None:
        return cursor.items(count)
    else:
        return cursor.items()

def tweet_link(tweet):
    return "https://twitter.com/{screen_name}/status/{tweet_id}".format(
        screen_name = tweet.user.screen_name,
        tweet_id = tweet.id_str)

def get_friends(screen_name):
    return tweepy.Cursor(api().friends, screen_name = screen_name, count = 200).items()


# OAuth

def generate_auth_url():
    oauth_handler = tweepy.OAuthHandler(CONSUMER_KEY, CONSUMER_SECRET, CALLBACK_URL)
    redirect_url = oauth_handler.get_authorization_url(signin_with_twitter = True)
    request_token = oauth_handler.request_token

    return redirect_url, request_token['oauth_token'], request_token['oauth_token_secret'],

def get_access_token(request_token_key, request_token_secret, oauth_verifier):
    oauth_handler = tweepy.OAuthHandler(CONSUMER_KEY, CONSUMER_SECRET)
    oauth_handler.request_token = {
        'oauth_token': request_token_key,
        'oauth_token_secret': request_token_secret,
        'oauth_callback_confirmed': True,
    }
    oauth_handler.get_access_token(oauth_verifier)

    return oauth_handler.access_token, oauth_handler.access_token_secret

def verify_credentials(access_token, access_token_secret):
    api = api(access_token, access_token_secret)
    return api.verify_credentials()


# Utility

def get_big_profile_image_url(profile_image_url):
    return profile_image_url.replace('_normal', '')