Advice Criticism on Python App

Jimbo nilly16 at yahoo.com
Wed Mar 24 01:05:09 CET 2010


I have made a Python App(really script) that will check a stocks
current values from a website & save that data to a SQLite 3 database.

I am looking for any suggestions & criticisms on what I should do
better or anything at all but mainly in these areas:
[QUOTE]
- Correct Python Layout of code
- Correct error checking: Am I catching all my errors or are my
exceptions not specific enough? Should I be using more try excepts
inside my functions?
- Are there any areas where huge errors, bugs etc could occur that I
have not compensated for?
- I am also looking for suggestions on how to write a function better,
so if you think that function is really bad & should be rewritten
completely or something I would really like to hear it.
- Anything else that you see
- Is python meant to be used in the way I have used it? To make a
'semi detailed' app?[/QUOTE]

Any advice criticism would be really helpful.

App:
[CODE]"""
 *Stock Data Builder*
   Algorithm:
      - Search website for stock
      - Get website HTML source code
      - Search code for target stock data(price,dividends,etc..)
      - Add data to text file
"""

import sys
import os
import sqlite3
import datetime
import time
import urllib2

### Global Variables ###
menu = "***Stock Program*** \n\n1. Add a Stock to track \n2. Get
Todays Tracking Data \n3. Exit \nEnter decision: "
target = '<th scope="row" class="row"><a href="/asx/research/
companyInfo.do?by=asxCode&asxCode=%s">%s</a>'
ASXurl = 'http://www.asx.com.au/asx/markets/priceLookup.do?
by=asxCodes&asxCodes='

class stock:
    code             = ""
    purchasePrice    = 0
    purchaseQuantity = 0
    price            = []  # list of recent prices
    recentBid        = []  # list of recent bids for stock
    recentOffer      = []  # list of recent offers for stock
    stockVol         = []  # list of stock quantity available on
market
    def __init__(self):
        """ Default Constructor """
        self.code             = ""
        self.purchasePrice    = 0
        self.purchaseQuantity = 0

    def constructor(self, stockCode, purPrice, purQuant):
        """ Constructor """
        self.code             = stockCode
        self.purchasePrice    = purPrice
        self.purchaseQuantity = purQuant

    def setData(self, stockCode, purPrice, purQuant, priceList,
reBidList, reOffList, popList):
        """ Defines & implements the objects' public variables """
        self.code             = stockCode
        self.purchasePrice    = purPrice
        self.purchaseQuantity = purQuant
        self.price            = priceList
        self.recentBid        = reBidList
        self.recentOffer      = reOffList
        self.stockVol         = popList

        self.printStats()

    def updateData(self, priceEle, bidEle, offerEle, populEle):
        """ Adds data to stock object's lists """
        self.price.append(priceEle)
        self.recentBid.append(bidEle)
        self.recentOffer.append(offerEle)
        self.stockVol.append(populEle)

    def printStats(self):
        """ Output Stock attributes """

        print("Stock Code: "+self.code)
        print("Stock Purchase Price: "+str(self.purchasePrice))
        print("Stock Quantity Owned: "+str(self.purchaseQuantity))
        print("***Initial Investment Value:
"+str(self.purchasePrice*self.purchaseQuantity))
        if not(len(self.price) <= 0):
            print("Stock Current Price: "+str(self.price[-1]))
            print("Recent Bid: "+str(self.recentBid[-1]))
            print("Recent Offer: "+str(self.recentOffer[-1]))
            print("Total Stock Volume in market:
"+str(self.stockVol[-1]))
            print("***Present Investment Value:
"+str(self.price[-1]*self.purchaseQuantity))
        print("\n")


### Functions ###
def connectDatabase(dbLocation, dbName, tableName):
    """ Establish & Return connection to SQLite Database """

    try:
        if not (os.path.exists(dbLocation)):
            os.mkdir(dbLocation) # create folder/dir

        os.chdir(dbLocation)        # change directory focus to
dbLocation
        conn = sqlite3.connect(dbLocation+dbName)
        cur = conn.cursor()
        try:
            createTableQ = "CREATE TABLE IF NOT EXISTS "+tableName
+" (code varchar PRIMARY KEY, purchase_price float, purchase_quantity
float, purchase_date varchar);"
            cur.execute(createTableQ)
            conn.commit()
        except:
            pass
        return conn
    except IOError or OSError:
        print "Connection to database failed"
        return False

def retrieveStockDatabase(conn, tableName):
    """ Read SQLite3 database & extract stock data into StockList """

    stockList  = []
    stockQuery = "select recent_price, recent_offer, recent_bid,
stock_volume from ? ;"
    cur = conn.cursor()
    cur.execute("select code, purchase_price, purchase_quantity from
"+tableName+";")

    for row in cur.fetchall():
        newStock = stock()
        newStock.code             = row[0]
        newStock.purchasePrice    = row[1]
        newStock.purchaseQuantity = row[2]
        cur.execute(stockQuery,[newStock.code])
        for rw in cur.fetchall():
            newStock.price.append(rw[0])
            newStock.recentOffer.append(rw[1])
            newStock.recentBid.append(rw[2])
            newStock.stockVol.append(rw[3])
        stockList.append(newStock)

    return stockList

def getDate():
    """ Return todays date in format DD:MM:YYYY """
    time = datetime.datetime.now()
    date = time.strftime("%d:%m:%Y") # string format time (%y)
    return date

def newStockDatabase(conn, stockTable, stock):
    """ Add a new stock to SQLite database if not already there
        We save the stocks code, purchase price, quantity purchased
        & date of purchase.                                       """
    cur = conn.cursor()
    try:
        createTableQ = "create table "+stock.code+" (date varchar
PRIMARY KEY, recent_price float, recent_offer float, recent_bid float,
stock_volume double);"
        stockQuery   = "insert into "+stockTable+"
values(?, ?, ?, ?);"
        cur.execute(createTableQ)
        cur.execute(stockQuery,
[stock.code,stock.purchasePrice,stock.purchaseQuant,getDate()])
        conn.commit()
    except IOError or OSError:
        print "Table may already exist or bad SQLite connection."
        return False

def webFormat(URL):

    if (URL.startswith("http://")==False):
        URL = "http://"+URL

    return URL

def getSource(URL):
    """ Retrieve HTML source code from website URL &
        save in sourceBuffer                       """

    try:
        URL = webFormat(URL) # make sure URL contains essential
"http://"
        sourceBuffer = urllib2.urlopen(URL)
        print '\nResponse code = ',sourceBuffer.code
        print 'Response headers = ',sourceBuffer.info()
        print 'Actual URL = ',sourceBuffer.geturl()
        sourceCode = sourceBuffer.read()
        sourceBuffer.close()
        return sourceCode

    except IOError:  # URLError
        print "Function Failed: Reasons could be invalid URL name \nOR
\nHTML protocol message transfer failure."
        return False # function failed

def getTargetText(targetStrtData, targetEndData, dataBuffer):
    """ Grabs target text that lies inside 'dataBuffer' string
        between targetStrtData & targetEndData                """

    try:
        result = dataBuffer.split(targetStrtData)
        result.pop(0)
        result = result[0].split(targetEndData)
        result.pop(1)
        print result
        return result
    except IOError:
        print "Function Failed: Reasons could be targetStrtData and/or
targetEndData is not present in dataBuffer."

def getStockData(htmlText, selectedStock):
    """ Extract stock data(stock code,price,etc) from htmlText """
    try:
        # Here I extract my number data from HTML text
        tempList = []
        for string in htmlText:
            for i in string.split('>'):
                for e in i.split():
                        if ('.' in e and e[0].isdigit()):
                            tempList.append(float(e))
                        elif (',' in e and e[0].isdigit() ):
                            # remove ',' chars
                            e = e.replace(',','')
                            tempList.append(float(e))

 
selectedStock.updateData(tempList[0],tempList[2],tempList[3],tempList[7])

    except IOError:  # is this the correct error I should be trying to
catch here??
        print "Function Failed: Reasons could be: sites HTML data has
changed. Consult author of program."
        return False

def createStockTracker(stockCode,stockPrice,stockQuant, stockList):
    """ Add a new stock to the database to track """
    newStock = stock()
    newStock.constructor(stockCode,stockPrice,stockQuant)
    stockList.append(newStock)
    return stockList

def writeStockToDatabase(conn, stock):
    """ Write ONLY this Stock's attributes to SQLite Database """

    cur = conn.cursor()
    date = getDate()

    tableName = stock.code
    stockquery = "insert into "+tableName+" values(?, ?, ?, ?, ?);"
    cur.execute(query,[date,stock.price[-1], stock.recentOffer[-1],
stock.recentBid[-1], stock.stockVol[-1]])
    conn.commit()

def writeAllToDatabase(conn, stockList):
    """ Enter recent Stock attributes into SQLite Database """

    cur = conn.cursor()
    date = getDate()

    for stock in stockList:
        tableName = stock.code
        stockquery = "insert into "+tableName+"
values(?, ?, ?, ?, ?);"
        cur.execute(query,[date,stock.price[-1],
stock.recentOffer[-1], stock.recentBid[-1], stock.stockVol[-1]])
        conn.commit()

### Input Functions ###
def inputNewStock():
    """ """
    print "*Please note only an Australian Securities Exchange(ASX)
listed stock can be tracked in Version 1.0."
    badInput = True

    while (badInput == True):
        try:
            code     = raw_input("Please enter the ASX code for the
stock you wish to track: ")
            price    = input("Please enter the individual stock value
for "+code+": ")
            quantity = input("Please enter the number/quantity of
stocks purchased: ")
            if (len(code)>3):
                badInput = True
            else : badInput = False
            return True
        except IOError:
            if (raw_input("Incorrect input. Note: ASX code cannot be
more than 3 chars. Press 'x' to exit or anything else to try
again")=='x'):
                return False
        badInput = True # this I am not sure if necessary to loop
correctly


### Main program loop ###
def main():
    programEnd = False;
    dbLocation = "C:\Users\Sam\Desktop\StockApp/"
    dbName     = "stockData.db"
    stockTable = "stocks"

    conn = connectDatabase(dbLocation,dbName,stockTable)
    stockList = retrieveStockDatabase(conn,stockTable)

    for s in stockList:
        s.printStats()

    while (programEnd == False):

        decision = input(menu) # Print Menu

        if (decision==1):

            if not(inputNewStock()==False):
                stockList =
createStockTracker(acode,price,quantity,stockList)
                newStockDatabase(conn,stockTable,stockList[-1])
                print("\n** New Stock **")
                stockList[-1].printStats()
                print "The stock "+code+" was successfully added to
our database. \nNow every time the program runs it will automatically
track this stock & obtain its stock attributes\n\n"
                # TO DO:
                # get new stock recent Data from internet etc.
                # add stock data to data base;
        elif (decision==2):
            if (len(stockList)>0):
                for Stock in stockList:
                    URL = ASXurl+Stock.code
                    sourceCode = getSource(URL)
                    targetData = getTargetText(target %
(Stock.code,Stock.code),"</tr>",sourceCode)
                    getStockData(targetData,Stock)
                    Stock.printStats()
                    #writeStockToDatabase(conn,Stock)
            else:
                print "You must first identify a stock to follow.
\nPlease select option 1."
        elif (decision==3):
            print "Thank you for using Stock Program. Goodbye.\n"
            programEnd = True; # Exit program

    conn.close()
    return 0 # End program

main()[/CODE]



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