TimelineMicroservice.py

from flask import Flask, request, jsonify
import sqlite3
from flask import g
import hashlib

######################
# API USAGE
# Web server route for this API: localhost:5100
# --------------------
# Get user timeline: Send a GET request to route of getUserTimeline() fn
# Example request:
#   curl -i -X GET -H 'Content-Type:application/json' -d '{"usernameAPI":"ankita"}' http://localhost:5100/getUserTimeline;
# --------------------
# Get public timeine: Send a GET request to route of getPublicTimeline() fn
# Example request:
#   curl -i -X GET http://localhost:5100/getPublicTimeline;
# --------------------
# Get a home timeline: Send a GET request to route of getHomeTimeline() fn
# Example request:
#   curl -i -X GET -H 'Content-Type:application/json' -d '{"usernameAPI":"ankita"}' http://localhost:5100/getHomeTimeline;
# --------------------
# Post a tweet: Send a POST request to route of postTweet() fn
# Example request:
#   curl -i -X POST -H 'Content-Type:application/json' -d '{"usernameAPI":"ankita", "tweetAPI":"This is an example post"}' http://localhost:5100/postTweet;
# --------------------

######################
# Database
# db_name: UsersMicroservice.db

# table1: Users
# username
# email
# pass

# table2: Followers
# username
# usernamefollowing

# table3: Tweets
# username
# tweet
# time_stamp


# config variables
app = Flask(__name__)
DATABASE = 'UsersMicroservice.db'

# helper function to generate a response with status code and message
def get_response(status_code, message):
    return {"status_code": str(status_code), "message": str(message)}

# get db from flask g namespace
def get_db():
    db = getattr(g, '_database', None)
    if db is None:
        db = g._database = sqlite3.connect(DATABASE)
    return db

# function to execute a single query at once
def query_db(query, args=(), one=False):
    cur = get_db().execute(query, args)
    rv = cur.fetchall()
    cur.close()
    return (rv[0] if rv else None) if one else rv

# function to get user timeline
@app.route("/getUserTimeline", methods=['GET'])
def getUserTimeline():
    params = request.get_json()
    user_name = params.get('usernameAPI')
    if not user_name:
        return jsonify(get_response(status_code=409, message="username is not in request")), 409
    else:
        TweetsList = query_db('select * from Tweets where username = ? order by time_stamp desc limit 25', [user_name])
        response = jsonify(get_response(status_code=201, message=TweetsList))
        response.status_code = 201
        response.autocorrect_location_header = False
        return response

#function to get public timeline
@app.route("/getPublicTimeline", methods=['GET'])
def getPublicTimeline():
    recentTweets = query_db('select * from Tweets order by time_stamp desc limit 25')
    response = jsonify(get_response(status_code=201, message=recentTweets))
    response.status_code = 201
    response.autocorrect_location_header = False
    return response

# function to get home timeline
@app.route("/getHomeTimeline", methods=['GET'])
def getHomeTimeline():
    params = request.get_json()
    user_name = params.get('usernameAPI')
    tweets = []
    if not user_name:
        return jsonify(get_response(status_code=409, message="username is not in request")), 409
    else:
        tweets = query_db('select tweet from Tweets where username in (select usernamefollowing from Followers where username = ?) order by time_stamp desc limit 25', [user_name])
        response = jsonify(get_response(status_code=201, message=tweets))
        response.status_code = 201
        response.autocorrect_location_header = False
        return response

# function to post a tweet
@app.route("/postTweet", methods=['POST'])
def postTweet():
    params = request.get_json()
    user_name = params.get('usernameAPI')
    tweet_text = params.get('tweetAPI')
    if not user_name or not tweet_text:
        return jsonify(get_response(status_code=409, message="username / tweet is not in request")), 409
    else:
        if query_db('select username from Users where username = ?', [user_name]):
            with sqlite3.connect("UsersMicroservice.db") as con:
                cur = con.cursor()
                cur.execute("INSERT INTO Tweets (username, tweet) VALUES (?,?)", (user_name, tweet_text))
                con.commit()

            response = jsonify(get_response(status_code=201, message="Tweet posted successfully!!"))
            response.status_code = 201
            response.autocorrect_location_header = False
            return response
        else:
            return jsonify(get_response(status_code=409, message="Username does not exist. Create a user first to proceed")), 409

app.run(debug = True)