Add offline support and show list of currencies

Add supporting functions to show list of currencies available and add
offline support by storing the exchange rates in a json file.

Remove the json files for testing, and use the original files instead.

Not commiting exhcange rates file, since we have a function to download
the rates if not found.

This closes #24, fixes #16.

.gitignore

@@ -1,8 +1,9 @@
 .vscode
-venv
+env
 __pycache__
 *.egg-info
 .cache
 .coverage
 .tox
 *.pyc
+fixer_rates.json

exch/cli.py

@@ -9,37 +9,50 @@
 :copyright: (c) 2017 by Anshul Chauhan
 """
 
+import json
 import click
 import pkg_resources
-from exch.helpers import fixer
-from exch.file_handling import get_default_base, get_default_target, set_default_base, set_default_target
+from exch.helpers import fixer, fixer_sync
+from exch.file_handling import get_default_base, get_default_target,\
+                               set_default_base, set_default_target
 
 CONTEXT_SETTINGS = dict(help_option_names=['-h', '--help'])
 
+RATES_FIXER_JSON_FILE = pkg_resources.resource_filename('exch', 'data/fixer_rates.json')
 DEFAULT_JSON_FILE = pkg_resources.resource_filename('exch', 'data/defaults.json')
 
 @click.command(context_settings=CONTEXT_SETTINGS)
-@click.option('--base', '-b', default=get_default_base(DEFAULT_JSON_FILE), type=str, show_default=True,
+@click.option('--base', '-b', default=get_default_base(DEFAULT_JSON_FILE),
+              type=str, show_default=True,
               help='Currency you are converting from.')
-@click.option('--target', '-t', default=get_default_target(DEFAULT_JSON_FILE), type=str, show_default=True,
-              help='Currency you\'re converting to.')
+@click.option('--target', '-t', default=get_default_target(DEFAULT_JSON_FILE),
+              type=str, show_default=True, help='Currency you\'re converting to.')
 @click.option('--amount', '-a', default=1.0, type=float, show_default=True,
               help='Amount to convert.')
 @click.option('--set_base', '-sb', is_flag=True, default=False,
               help='Set new default base.')
 @click.option('--set_target', '-st', is_flag=True, default=False,
               help='Set new default target.')
-def cli(base, target, amount, set_base, set_target):
+@click.option('--sync', is_flag=True, default=False,
+              help='Download the latest rates from web.')
+@click.option('--currency', '-c', is_flag=True, default=False,
+              help='List the currencies available.')
+def cli(base, target, amount, set_base, set_target, sync, currency):
     """
     Get the latetst currency exchange rates from:
 
     \b
         - fixer.io
     """
 
-    output = fixer(base, target, amount)
+    if sync:
+        if fixer_sync(RATES_FIXER_JSON_FILE) in range(200, 300):
+            click.echo("New rates have been saved.")
+
+    output = fixer(base, target, amount, RATES_FIXER_JSON_FILE)
     if isinstance(output, float):
-        output = "{} {} = {} {}".format(amount, base, output, target)
+        # 2:.2f for two decimal values, manually specified
+        output = "{0} {1} = {2:.2f} {3}".format(amount, base, output, target)
 
     if set_base:
         set_default_base(base, DEFAULT_JSON_FILE)
@@ -48,3 +61,12 @@ def cli(base, target, amount, set_base, set_target):
         set_default_target(target, DEFAULT_JSON_FILE)
 
     click.echo(output)
+
+    if currency:
+        with open(RATES_FIXER_JSON_FILE) as rates_json_file:
+            json_rates = json.load(rates_json_file)
+        currencies = []
+        currencies.append(json_rates['base'])
+        for key in json_rates['rates']:
+            currencies.append(key)
+        click.echo(',\n'.join(currencies))

exch/data/defaults.json

@@ -1 +1 @@
-{"target": "NZD", "base": "CAD"}
+{"target": "CAD", "base": "PHP"}

exch/file_handling.py

@@ -1,35 +1,35 @@
-""" Functions related to file(JSON) handling. """
+""" Functions related to default rates file. """
 
 import json
 
-def set_default_base(new_base, filepath):
+def set_default_base(new_base, default_rates_filepath):
     """ set new default base currency """
-    with open(filepath) as json_file:
+    with open(default_rates_filepath) as json_file:
         json_data = json.load(json_file)
 
     json_data['base'] = new_base
 
-    with open(filepath, 'w') as json_file:
-        json.dump(json_data, json_file, indent=4)
+    with open(default_rates_filepath, 'w') as json_file:
+        json.dump(json_data, json_file)
 
-def set_default_target(new_target, filepath):
+def set_default_target(new_target, default_rates_filepath):
     """ set new default arget currency """
-    with open(filepath) as json_file:
+    with open(default_rates_filepath) as json_file:
         json_data = json.load(json_file)
 
     json_data['target'] = new_target
 
-    with open(filepath, 'w') as json_file:
+    with open(default_rates_filepath, 'w') as json_file:
         json.dump(json_data, json_file)
 
-def get_default_base(filepath):
+def get_default_base(default_rates_filepath):
     """ get the currenct default base currency """
-    with open(filepath) as json_file:
+    with open(default_rates_filepath) as json_file:
         json_data = json.load(json_file)
     return json_data['base']
 
-def get_default_target(filepath):
+def get_default_target(default_rates_filepath):
     """ get the current default target currency """
-    with open(filepath) as json_file:
+    with open(default_rates_filepath) as json_file:
         json_data = json.load(json_file)
     return json_data['target']

exch/helpers.py

@@ -1,23 +1,61 @@
 """ helper functions to gather the currency rates """
 
+import json
 import requests
 
-def fixer(base, target, value, date='latest'):
-    """get currency exchange rate from fixer.io in JSON"""
+def fixer(base, target, value, file_path):
+    """
+    get currency exchange rate from fixer.io in JSON,
+    take note that all the rates are stored as EUR as base
+    """
 
-    main_api = 'http://api.fixer.io/{}?'.format(date)
-    url = requests.get(main_api, params={'base':base})
+    try:
+        """
+        try to find the json file which contains currency exchange rates
+        """
+        with open(file_path) as json_file:
+            json_rates = json.load(json_file)
+    except FileNotFoundError:
+        """
+        if file not found, 'fixer_sync' will download the latests rates,
+        the range of 200-300 is for succesful HTTP code
+        """
+        if fixer_sync(file_path) in range(200, 300):
+            with open(file_path) as json_file:
+                json_rates = json.load(json_file)
 
     try:
-        json_data = requests.get(url.url).json()
-        result = round(json_data['rates'][target] * value, 2)
-    except requests.exceptions.ConnectionError:
-        result = "Connection Error"
+        eur_to_target = json_rates['rates'][target]
+        eur_to_base = json_rates['rates'][base]
+        result = eur_to_target/eur_to_base * value
     except KeyError:
-        result = 1.00 if base == target else "KeyError: Invalid curreny"
+        if base == 'EUR':
+            result = json_rates['rates'][target] * value
+        elif target == 'EUR':
+            result = (1.0/json_rates['rates'][base]) * value
+        else:
+            result = "KeyError: Invalid curreny"
 
     return result
 
+def fixer_sync(file_path):
+    """
+    downloads the rates JSON to the local location,
+    'file_path' is the location where the fixer.io rates will the placed,
+    returns status_code, if it is 200 then file successfully created
+    """
+    url = 'http://api.fixer.io/latest'
+    response = requests.get(url, stream=True)
+    if response.status_code == 200:
+        with open(file_path, 'wb') as json_file:
+            json_file.write(response.content)
+
+    return response.status_code
+
+# function to list currencies present
+# use the above sync method to down the file if not present
+# show the date of the file present
+
 #def google_finance_converter(base, target, value):
 #    """ parse the Google Finance Converter html to extract the value"""
 #    pass

tests/test_advanced.py

@@ -1,5 +1,6 @@
 """ test the click and terminal behaviour """
 
+import os
 import json
 import pytest
 import pkg_resources
@@ -8,7 +9,6 @@
 
 FILEPATH = pkg_resources.resource_filename('exch', 'data/defaults.json')
 
-
 @pytest.fixture
 def runner():
     """ prefix alias function """
@@ -18,14 +18,14 @@ def test_click_same_currency_code():
     """ test terminal behaviour for same currency code """
     result = runner().invoke(cli, ['-t', 'USD', '-b', 'USD'])
     assert result.exit_code == 0
-    assert result.output == '1.0 USD = 1.0 USD\n'
+    assert result.output == '1.0 USD = 1.00 USD\n'
 
-def test_invalid_base_currency_code():
+def test_invalid_base_currency():
     result = runner().invoke(cli, ['-t', 'USD', '-b', 'AAA'])
     assert result.exit_code == 0
     assert result.output == "KeyError: Invalid curreny\n"
 
-def test_invalid_target_currency_code():
+def test_invalid_taget_currency():
     result = runner().invoke(cli, ['-t', 'OOO'])
     assert result.exit_code == 0
     assert result.output == "KeyError: Invalid curreny\n"
@@ -47,4 +47,12 @@ def test_setting_default_target():
     assert result.exit_code == 0
     with open(FILEPATH) as json_file:
         json_data = json.load(json_file)
+    print(json_data)
     assert json_data['target'] == 'NZD'
+
+def test_show_fixer_currencies():
+    result = runner().invoke(cli, ['-b', 'NZD', '-t', 'NZD', '-c'])
+    assert result.exit_code == 0
+    assert result.output == "1.0 NZD = 1.00 NZD\nEUR,\nAUD,\nBGN,\nBRL,\nCAD,\nCHF,\nCNY,\nCZK,\n\
+DKK,\nGBP,\nHKD,\nHRK,\nHUF,\nIDR,\nILS,\nINR,\nJPY,\nKRW,\nMXN,\nMYR,\nNOK,\
+\nNZD,\nPHP,\nPLN,\nRON,\nRUB,\nSEK,\nSGD,\nTHB,\nTRY,\nUSD,\nZAR\n"

tests/test_basic.py

@@ -1,24 +1,35 @@
 """ unit testing the helper functions """
 
+import pkg_resources
 from exch.helpers import fixer
 
+FIXER_RATES_JSON_TEST = pkg_resources.resource_filename('exch', 'data/fixer_rates.json')
+
+
 def test_fixer_same_currency_code():
     """ when the same currency is base as well as target """
-    assert fixer('USD', 'USD', 1) == 1.00
-    assert fixer('INR', 'INR', 1) == 1.00
+    assert fixer('USD', 'USD', 1, FIXER_RATES_JSON_TEST) == 1.00
+    assert fixer('INR', 'INR', 1, FIXER_RATES_JSON_TEST) == 1.00
 
 def test_fixer_usd_to_inr():
-    """ fixer_io base: USD, target: INR, on date 2017-05-12 """
-    assert fixer('USD', 'INR', 1, date='2017-05-12') == round(64.307, 2)
+    """ fixer_io base: USD, target: INR """
+    assert fixer('USD', 'INR', 1, FIXER_RATES_JSON_TEST) > 60
 
 def test_fixer_usd_to_jpy():
-    """ fixer_io base: USD, target: JPY, on date 2017-05-12 """
-    assert fixer('USD', 'JPY', 1, date='2017-05-12') == round(113.85, 2)
+    """ fixer_io base: USD, target: JPY """
+    assert fixer('USD', 'JPY', 1, FIXER_RATES_JSON_TEST) > 90
 
 def test_fixer_gbp_to_php_value_99():
-    """ fixer_io base: GBP, target: PHP, on date 2017-05-12, value: 99 """
-    assert fixer('GBP', 'PHP', 99, date='2017-05-12') == round(63.942 * 99, 2)
+    """ fixer_io base: GBP, target: PHP, value: 99 """
+    assert fixer('GBP', 'PHP', 99, FIXER_RATES_JSON_TEST) > 50
+
+def test_fixer_eur_to_aud_value_99():
+    assert fixer('EUR', 'AUD', 99, FIXER_RATES_JSON_TEST) > 1.2 * 99
+
+def test_fixer_nzd_to_eur_value():
+    """ checking since stored values are in terms of EUR as base """
+    assert fixer('NZD', 'EUR', 1, FIXER_RATES_JSON_TEST) > 0.5
 
 def test_fixer_invalid_currency():
     """ when invalid currency is passed to fixer.io """
-    assert fixer('USD', 'TTT', 1) == "KeyError: Invalid curreny"
+    assert fixer('USD', 'TTT', 1, FIXER_RATES_JSON_TEST) == "KeyError: Invalid curreny"

tests/test_file_handling.py

@@ -1,5 +1,6 @@
 """ test the JSON file handling """
 
+import pkg_resources
 import json
 from exch import file_handling
 
@@ -12,7 +13,7 @@ class TestFileHandling:
     """
     new_base = 'PHP'
     new_target = 'CAD'
-    filepath = 'tests/data_for_test_file_handling/defaults.json'
+    filepath = pkg_resources.resource_filename('exch', 'data/defaults.json')
 
     def test_set_default_base(self):
         file_handling.set_default_base(self.new_base, self.filepath)