127 lines
		
	
	
		
			4.9 KiB
		
	
	
	
		
			Python
		
	
	
		
			Executable File
		
	
	
	
	
			
		
		
	
	
			127 lines
		
	
	
		
			4.9 KiB
		
	
	
	
		
			Python
		
	
	
		
			Executable File
		
	
	
	
	
#!/usr/bin/python3
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import requests, json, os.path
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from datetime import datetime
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from dateutil import relativedelta
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from dateutil import parser as dparser
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from dateutil.parser._parser import ParserError as DateParserError
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_years = None
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def _loadYearsTable(maxCacheSeconds=3600):
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    global _years
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    if os.path.isfile('cache.json'):
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        with open('cache.json', 'r') as f:
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            cacheUpdate, cacheYears = json.loads(f.read())
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        if (datetime.now() - dparser.isoparse(cacheUpdate)).total_seconds() < maxCacheSeconds:
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            # JSON does not allow integers as keys; so we convert them back here...
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            cacheYears = {int(y):{int(m):float(n) for m,n in ms.items()} for y,ms in cacheYears.items()}
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            _years = cacheYears
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            return
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    _years = _loadYearsTableWeb()
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def _loadYearsTableWeb():
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    print('[i] Fetching new data from ECB-Servers...')
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    url = 'https://sdw.ecb.europa.eu/quickviewexport.do?SERIES_KEY=122.ICP.M.U2.N.000000.4.ANR&type=csv'
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    resp = requests.get(url)
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    lines = resp.text.split('\n')[6:]
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    years = {} # Will later contain the monthly factor of inflation (~1.0016667) for every month
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    for line in lines:
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        vals = line.split(',')
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        year = int(vals[0][:4])
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        month = datetime.strptime(vals[0][4:],'%b').month
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        inflation = float(vals[1])
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        if not year in years:
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            years[year] = {}
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        years[year][month] = 1 + (inflation/100)/12
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    for year in years:
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        months = years[year]
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        for month in range(1,13):
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            if month not in months:
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                years[year][month] = 1 + 0.02/12 # Lets say the ECB archives their target
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    with open('cache.json', 'w') as f:
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        f.write(json.dumps([datetime.now().isoformat(),years]))
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    return years
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# Gives you the exchange rate between euros and meuros for the given date.
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# (Should always be a float < 1)
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# date should be either a datetime-object or None (= current date)
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def exchangeRate(date=None):
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    global _years
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    if _years==None:
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        _loadYearsTable()
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    if date==None:
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        date = datetime.now()
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    month, year = date.month, date.year
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    if year < 2001:
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        raise Exception('µeuro-values for €uro prices before the start of this millenium are undefined.')
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    akk = 1
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    for fullYear in range(2001, year):
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        yearlyInf = 1
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        for m in _years[fullYear]:
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            monthlyInf = _years[fullYear][m]
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            yearlyInf *= monthlyInf
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        akk *= yearlyInf
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    for fullMonth in range(1, month):
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        monthlyInf = _years[year][fullMonth]
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        akk *= monthlyInf
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    beginningOfMonth = date.replace(hour=0, minute=0, second=0, microsecond=0, day=1)
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    endOfMonth = beginningOfMonth + relativedelta.relativedelta(months=1)
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    fracOfMonth = (date - beginningOfMonth).total_seconds() / (endOfMonth - beginningOfMonth).total_seconds()
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    inflationThisMonth = 1 + fracOfMonth * (_years[year][month]-1)
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    akk *= inflationThisMonth
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    return 1/akk
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# Converts the given amount of euros to meuros for the given date. (wholeCents means it rounds to two decimal places)
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# date should be either a datetime-object or None (= current date)
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def euroToMeuro(eur,date=None,wholeCents=True):
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    return round(eur * exchangeRate(date),[64,2][wholeCents])
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# Converts the given amount of meuros to euros for the given date. (wholeCents means it rounds to two decimal places)
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# date should be either a datetime-object or None (= current date)
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def meuroToEuro(meur,date=None,wholeCents=True):
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    return round(meur / exchangeRate(date),[64,2][wholeCents])
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# Print the current amount of meuros for the given amunt of euros every <interval>-seconds.
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# Comes in handy when you want to watch your life savings slowly fade away thanks to inflation.
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def liveValue(eur,interval=10):
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    import time
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    while True:
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        print(str(eur*exchangeRate())+'µ')
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        time.sleep(interval)
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def _extractDate(s):
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    try:
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        return dparser.parse(s, fuzzy=True, dayfirst=True)
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    except DateParserError:
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        return datetime.now()
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def cliInterface():
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    import sys, re
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    arg = " ".join(sys.argv[1:]).replace(',','')
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    reFromEur = re.compile(r'(\d+(.\d\d)?)\W?(€|e|E)')
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    reFromMeur = re.compile(r'(\d+(.\d\d)?)\W?(μ|m|M)')
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    if (m := reFromEur.search(arg))!=None:
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        eurS = m.groups()[0]
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        date = _extractDate(arg[:m.span()[0]] + '-' + arg[m.span()[1]:])
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        eur = float(eurS)
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        meur = euroToMeuro(eur, date)
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        print('Exchange rate for '+date.strftime("%d.%m.%Y at %H:%M")+':')
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        print(f'{eur:.2f}€ = {meur:.2f}µ')
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    elif (m:= reFromMeur.search(arg))!=None:
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        meurS = m.groups()[0]
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        date = _extractDate(arg[:m.span()[0]] + '-' + arg[m.span()[1]:])
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        meur = float(meurS)
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        eur = meuroToEuro(meur, date)
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        print('Exchange rate for '+date.strftime("%d.%m.%Y at %H:%M")+':')
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        print(f'{meur:.2f}µ = {eur:.2f}€')
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    else:
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        print('[!] Unable to parse input')
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if __name__=='__main__':
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    cliInterface()
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