This work is from the previous pr, I have merged it all together so its

possible to continue their fine work.

Add original currency and amount fields to Bill model

Add default currency to Project model

Add minor fix to String length

Reorganize the new migration file

Crete a migration file for Project.default_currency

Change models.py to have Project.default_currency

Added new fields to to_serialize()

Update bill view to display original currencies and original amounts

Minor change to new labels

Add new fields to tests

Include default_currency field in tests.py

Datafield entry in forms

adding a stray file

added requests to the requirements file

Added another exception for catching errors related to mail

Testing to find the issue

revert change

Adding a removed change to list_bills.html template

added currency conversion to the CurrencyConversion class

fixed typo in function name

Edit BillForm to have currency dropdown and convert functionality

Show currency dropdown in BillForm

Fix minor issues with BillForm task

Edit tests.py to include missing original_currency and amount fields

Fix failing tests

Fix other failing tests

Final fix to tests

Ran black on the project directory

Make small ammendments to tests

Temporarily set maxDiff as None

Fix test failure in test_export()

formatted util file so it could pass formatting tests

changed the structure of the table in the bill view to be more reader friendly, by adding the different curriencies in their respective columns

Cleaning up pr with comments from previous prs

Signed-off-by: dark0dave <dark0dave@mykolab.com>

Now caching respone for one day to ensure it is not call often

Signed-off-by: dark0dave <dark0dave@mykolab.com>

Updated migration and currency converter to help existing bills

Signed-off-by: dark0dave <dark0dave@mykolab.com>

.gitignore

@@ -1,4 +1,3 @@
-ihatemoney.cfg
 *.pyc
 *.egg-info
 dist
@@ -13,3 +12,8 @@ build
 .pytest_cache
 ihatemoney/budget.db
 .idea/
+.envrc
+.DS_Store
+.idea
+.python-version
+

ihatemoney/currency_convertor.py

@@ -0,0 +1,46 @@
+import requests
+from cachetools import cached, TTLCache
+
+
+class Singleton(type):
+    _instances = {}
+
+    def __call__(cls, *args, **kwargs):
+        if cls not in cls._instances:
+            cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
+        return cls._instances[cls]
+
+
+class CurrencyConverter(object, metaclass=Singleton):
+    # Get exchange rates
+    default = "No Currency"
+    api_url = "https://api.exchangeratesapi.io/latest?base=USD"
+
+    def __init__(self):
+        pass
+
+    @cached(cache=TTLCache(maxsize=1, ttl=86400))
+    def get_rates(self):
+        rates = requests.get(self.api_url).json()["rates"]
+        rates[self.default] = 1.0
+        return rates
+
+    def get_currencies(self):
+        rates = [rate for rate in self.get_rates()]
+        rates.sort(key=lambda rate: "" if rate == self.default else rate)
+        return rates
+
+    def exchange_currency(self, amount, source_currency, dest_currency):
+        if (
+            source_currency == dest_currency
+            or source_currency == self.default
+            or dest_currency == self.default
+        ):
+            return amount
+
+        rates = self.get_rates()
+        source_rate = rates[source_currency]
+        dest_rate = rates[dest_currency]
+        new_amount = (float(amount) / source_rate) * dest_rate
+        # round to two digits because we are dealing with money
+        return round(new_amount, 2)

ihatemoney/forms.py

@@ -5,12 +5,15 @@ import email_validator
 from flask import request
 from flask_babel import lazy_gettext as _
 from flask_wtf.file import FileAllowed, FileField, FileRequired
+import copy
+
 from flask_wtf.form import FlaskForm
 from jinja2 import Markup
 from werkzeug.security import check_password_hash, generate_password_hash
 from wtforms.fields.core import SelectField, SelectMultipleField
 from wtforms.fields.html5 import DateField, DecimalField, URLField
 from wtforms.fields.simple import BooleanField, PasswordField, StringField, SubmitField
+from wtforms.fields.core import Label
 from wtforms.validators import (
     DataRequired,
     Email,
@@ -22,6 +25,7 @@ from wtforms.validators import (
 
 from ihatemoney.models import LoggingMode, Person, Project
 from ihatemoney.utils import eval_arithmetic_expression, slugify
+from ihatemoney.currency_convertor import CurrencyConverter
 
 
 def strip_filter(string):
@@ -31,6 +35,18 @@ def strip_filter(string):
         return string
 
 
+def get_editprojectform_for(project, **kwargs):
+    """Return an instance of EditProjectForm configured for a particular project.
+    """
+    form = EditProjectForm(**kwargs)
+    choices = copy.copy(form.default_currency.choices)
+    choices.sort(
+        key=lambda rates: "" if rates[0] == project.default_currency else rates[0]
+    )
+    form.default_currency.choices = choices
+    return form
+
+
 def get_billform_for(project, set_default=True, **kwargs):
     """Return an instance of BillForm configured for a particular project.
 
@@ -39,6 +55,23 @@ def get_billform_for(project, set_default=True, **kwargs):
 
     """
     form = BillForm(**kwargs)
+    if form.original_currency.data == "None":
+        form.original_currency.data = project.default_currency
+
+    if form.original_currency.data != CurrencyConverter.default:
+        choices = copy.copy(form.original_currency.choices)
+        choices.remove((CurrencyConverter.default, CurrencyConverter.default))
+        choices.sort(
+            key=lambda rates: "" if rates[0] == project.default_currency else rates[0]
+        )
+        form.original_currency.choices = choices
+    else:
+        form.original_currency.render_kw = {"default": True}
+        form.original_currency.data = CurrencyConverter.default
+
+    form.original_currency.label = Label(
+        "original_currency", "Currency (Default: %s)" % (project.default_currency)
+    )
     active_members = [(m.id, m.name) for m in project.active_members]
 
     form.payed_for.choices = form.payer.choices = active_members
@@ -89,6 +122,15 @@ class EditProjectForm(FlaskForm):
     contact_email = StringField(_("Email"), validators=[DataRequired(), Email()])
     project_history = BooleanField(_("Enable project history"))
     ip_recording = BooleanField(_("Use IP tracking for project history"))
+    currency_helper = CurrencyConverter()
+    default_currency = SelectField(
+        _("Default Currency"),
+        choices=[
+            (currency_name, currency_name)
+            for currency_name in currency_helper.get_currencies()
+        ],
+        validators=[DataRequired()],
+    )
 
     @property
     def logging_preference(self):
@@ -112,6 +154,7 @@ class EditProjectForm(FlaskForm):
             password=generate_password_hash(self.password.data),
             contact_email=self.contact_email.data,
             logging_preference=self.logging_preference,
+            default_currency=self.default_currency.data,
         )
         return project
 
@@ -125,6 +168,7 @@ class EditProjectForm(FlaskForm):
 
         project.contact_email = self.contact_email.data
         project.logging_preference = self.logging_preference
+        project.default_currency = self.default_currency.data
 
         return project
 
@@ -199,6 +243,15 @@ class BillForm(FlaskForm):
     what = StringField(_("What?"), validators=[DataRequired()])
     payer = SelectField(_("Payer"), validators=[DataRequired()], coerce=int)
     amount = CalculatorStringField(_("Amount paid"), validators=[DataRequired()])
+    currency_helper = CurrencyConverter()
+    original_currency = SelectField(
+        _("Currency"),
+        choices=[
+            (currency_name, currency_name)
+            for currency_name in currency_helper.get_currencies()
+        ],
+        validators=[DataRequired()],
+    )
     external_link = URLField(
         _("External link"),
         validators=[Optional()],
@@ -217,6 +270,10 @@ class BillForm(FlaskForm):
         bill.external_link = self.external_link.data
         bill.date = self.date.data
         bill.owers = [Person.query.get(ower, project) for ower in self.payed_for.data]
+        bill.original_currency = self.original_currency.data
+        bill.converted_amount = self.currency_helper.exchange_currency(
+            bill.amount, bill.original_currency, project.default_currency
+        )
         return bill
 
     def fake_form(self, bill, project):
@@ -226,6 +283,10 @@ class BillForm(FlaskForm):
         bill.external_link = ""
         bill.date = self.date
         bill.owers = [Person.query.get(ower, project) for ower in self.payed_for]
+        bill.original_currency = CurrencyConverter.default
+        bill.converted_amount = self.currency_helper.exchange_currency(
+            bill.amount, bill.original_currency, project.default_currency
+        )
 
         return bill
 
@@ -234,6 +295,7 @@ class BillForm(FlaskForm):
         self.amount.data = bill.amount
         self.what.data = bill.what
         self.external_link.data = bill.external_link
+        self.original_currency.data = bill.original_currency
         self.date.data = bill.date
         self.payed_for.data = [int(ower.id) for ower in bill.owers]
 

ihatemoney/migrations/versions/927ed575acbd_add_currencies.py

@@ -0,0 +1,73 @@
+"""Add currencies
+
+Revision ID: 927ed575acbd
+Revises: cb038f79982e
+Create Date: 2020-04-25 14:49:41.136602
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = "927ed575acbd"
+down_revision = "cb038f79982e"
+
+from alembic import op
+import sqlalchemy as sa
+from ihatemoney.currency_convertor import CurrencyConverter
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column("bill", sa.Column("converted_amount", sa.Float(), nullable=True))
+    op.add_column(
+        "bill",
+        sa.Column(
+            "original_currency",
+            sa.String(length=3),
+            server_default=CurrencyConverter.default,
+            nullable=True,
+        ),
+    )
+    op.add_column(
+        "bill_version",
+        sa.Column("converted_amount", sa.Float(), autoincrement=False, nullable=True),
+    )
+    op.add_column(
+        "bill_version",
+        sa.Column(
+            "original_currency", sa.String(length=3), autoincrement=False, nullable=True
+        ),
+    )
+    op.add_column(
+        "project",
+        sa.Column(
+            "default_currency",
+            sa.String(length=3),
+            server_default=CurrencyConverter.default,
+            nullable=True,
+        ),
+    )
+    op.add_column(
+        "project_version",
+        sa.Column(
+            "default_currency", sa.String(length=3), autoincrement=False, nullable=True
+        ),
+    )
+    # ### end Alembic commands ###
+    op.execute(
+        """
+    UPDATE bill
+    SET converted_amount = amount
+    WHERE converted_amount IS NULL
+    """
+    )
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column("project_version", "default_currency")
+    op.drop_column("project", "default_currency")
+    op.drop_column("bill_version", "original_currency")
+    op.drop_column("bill_version", "converted_amount")
+    op.drop_column("bill", "original_currency")
+    op.drop_column("bill", "converted_amount")
+    # ### end Alembic commands ###

ihatemoney/models.py

@@ -71,6 +71,7 @@ class Project(db.Model):
     members = db.relationship("Person", backref="project")
 
     query_class = ProjectQuery
+    default_currency = db.Column(db.String(3))
 
     @property
     def _to_serialize(self):
@@ -80,6 +81,7 @@ class Project(db.Model):
             "contact_email": self.contact_email,
             "logging_preference": self.logging_preference.value,
             "members": [],
+            "default_currency": self.default_currency,
         }
 
         balance = self.balance
@@ -128,7 +130,10 @@ class Project(db.Model):
             {
                 "member": member,
                 "paid": sum(
-                    [bill.amount for bill in self.get_member_bills(member.id).all()]
+                    [
+                        bill.converted_amount
+                        for bill in self.get_member_bills(member.id).all()
+                    ]
                 ),
                 "spent": sum(
                     [
@@ -151,7 +156,7 @@ class Project(db.Model):
         """
         monthly = defaultdict(lambda: defaultdict(float))
         for bill in self.get_bills().all():
-            monthly[bill.date.year][bill.date.month] += bill.amount
+            monthly[bill.date.year][bill.date.month] += bill.converted_amount
         return monthly
 
     @property
@@ -432,6 +437,9 @@ class Bill(db.Model):
     what = db.Column(db.UnicodeText)
     external_link = db.Column(db.UnicodeText)
 
+    original_currency = db.Column(db.String(3))
+    converted_amount = db.Column(db.Float)
+
     archive = db.Column(db.Integer, db.ForeignKey("archive.id"))
 
     @property
@@ -445,9 +453,11 @@ class Bill(db.Model):
             "creation_date": self.creation_date,
             "what": self.what,
             "external_link": self.external_link,
+            "original_currency": self.original_currency,
+            "converted_amount": self.converted_amount,
         }
 
-    def pay_each(self):
+    def pay_each_default(self, amount):
         """Compute what each share has to pay"""
         if self.owers:
             weights = (
@@ -455,13 +465,16 @@ class Bill(db.Model):
                 .join(billowers, Bill)
                 .filter(Bill.id == self.id)
             ).scalar()
-            return self.amount / weights
+            return amount / weights
         else:
             return 0
 
     def __str__(self):
         return self.what
 
+    def pay_each(self):
+        return self.pay_each_default(self.converted_amount)
+
     def __repr__(self):
         return (
             f"<Bill of {self.amount} from {self.payer} for "

ihatemoney/run.py

@@ -10,6 +10,7 @@ from werkzeug.middleware.proxy_fix import ProxyFix
 
 from ihatemoney import default_settings
 from ihatemoney.api.v1 import api as apiv1
+from ihatemoney.currency_convertor import CurrencyConverter
 from ihatemoney.models import db
 from ihatemoney.utils import (
     IhmJSONEncoder,
@@ -137,6 +138,9 @@ def create_app(
     # Configure the a, root="main"pplication
     setup_database(app)
 
+    # Setup Currency Cache
+    CurrencyConverter()
+
     mail = Mail()
     mail.init_app(app)
     app.mail = mail

ihatemoney/templates/forms.html

@@ -75,6 +75,7 @@
     {{ input(form.name) }}
     {{ input(form.password) }}
     {{ input(form.contact_email) }}
+    {{ input(form.default_currency) }}
     {% if not home %}
     {{ submit(form.submit, home=True) }}
     {% endif %}
@@ -96,6 +97,7 @@
         </div>
     </div>
 
+    {{ input(form.default_currency) }}
     <div class="actions">
         <button class="btn btn-primary">{{ _("Edit the project") }}</button>
         <a id="delete-project" style="color:red; margin-left:10px; cursor:pointer; ">{{ _("delete") }}</a>
@@ -122,6 +124,9 @@
     {{ input(form.what, inline=True) }}
     {{ input(form.payer, inline=True, class="form-control custom-select") }}
     {{ input(form.amount, inline=True) }}
+    {% if not form.original_currency.render_kw %}
+        {{ input(form.original_currency, inline=True) }}
+    {% endif %}
     {{ input(form.external_link, inline=True) }}
 
     <div class="form-group row">

ihatemoney/templates/list_bills.html

@@ -111,7 +111,19 @@
         <div class="clearfix"></div>
 
         <table id="bill_table" class="col table table-striped table-hover table-responsive-sm">
-            <thead><tr><th>{{ _("When?") }}</th><th>{{ _("Who paid?") }}</<th><th>{{ _("For what?") }}</th><th>{{ _("For whom?") }}</th><th>{{ _("How much?") }}</th><th>{{ _("Actions") }}</th></tr></thead>
+            <thead>
+                <tr><th>{{ _("When?") }}
+                </th><th>{{ _("Who paid?") }}   
+                </th><th>{{ _("For what?") }}
+                </th><th>{{ _("For whom?") }}
+                </th><th>{{ _("How much?") }}
+                {% if g.project.default_currency != "No Currency" %}
+                  </th><th>{{ _("Amount in ") }}{{ g.project.default_currency }}
+                {%- else -%}
+                  </th><th>{{ _("Amount") }}
+                {% endif %}
+                </th><th>{{ _("Actions") }}</th></tr>
+            </thead>
         <tbody>
         {% for bill in bills.items %}
         <tr owers="{{bill.owers|join(',','id')}}" payer="{{bill.payer.id}}">
@@ -130,7 +142,14 @@
                 {%- else -%}
                 {{ bill.owers|join(', ', 'name') }}
                 {%- endif %}</td>
-                <td>{{ "%0.2f"|format(bill.amount) }} ({{ "%0.2f"|format(bill.pay_each()) }} {{ _("each") }})</td>
+                <td>
+                    {% if bill.original_currency != "No Currency" %}
+                        {{ "%0.2f"|format(bill.amount) }} {{bill.original_currency}} ({{ "%0.2f"|format(bill.pay_each_default(bill.amount)) }} {{bill.original_currency}} {{ _(" each") }})
+                    {%- else -%}
+                        {{ "%0.2f"|format(bill.amount) }} ({{ "%0.2f"|format(bill.pay_each_default(bill.amount)) }} {{ _(" each") }})
+                    {% endif %}
+                </td>
+                <td>{{ "%0.2f"|format(bill.converted_amount) }}</td>
                 <td class="bill-actions">
                     <a class="edit" href="{{ url_for(".edit_bill", bill_id=bill.id) }}" title="{{ _("edit") }}">{{ _('edit') }}</a>
                     <a class="delete" href="{{ url_for(".delete_bill", bill_id=bill.id) }}" title="{{ _("delete") }}">{{ _('delete') }}</a>

ihatemoney/tests/tests.py

@@ -6,7 +6,7 @@ import json
 import os
 from time import sleep
 import unittest
-from unittest.mock import patch
+from unittest.mock import patch, MagicMock
 
 from flask import session
 from flask_testing import TestCase
@@ -15,6 +15,7 @@ from werkzeug.security import check_password_hash, generate_password_hash
 
 from ihatemoney import history, models, utils
 from ihatemoney.manage import DeleteProject, GenerateConfig, GeneratePasswordHash
+from ihatemoney.currency_convertor import CurrencyConverter
 from ihatemoney.run import create_app, db, load_configuration
 from ihatemoney.versioning import LoggingMode
 
@@ -59,6 +60,7 @@ class BaseTestCase(TestCase):
                 "id": name,
                 "password": name,
                 "contact_email": f"{name}@notmyidea.org",
+                "default_currency": "USD",
             },
         )
 
@@ -68,6 +70,7 @@ class BaseTestCase(TestCase):
             name=str(name),
             password=generate_password_hash(name),
             contact_email=f"{name}@notmyidea.org",
+            default_currency="USD",
         )
         models.db.session.add(project)
         models.db.session.commit()
@@ -254,6 +257,7 @@ class BudgetTestCase(IhatemoneyTestCase):
                     "id": "raclette",
                     "password": "party",
                     "contact_email": "raclette@notmyidea.org",
+                    "default_currency": "USD",
                 },
             )
 
@@ -273,6 +277,7 @@ class BudgetTestCase(IhatemoneyTestCase):
                     "id": "raclette",  # already used !
                     "password": "party",
                     "contact_email": "raclette@notmyidea.org",
+                    "default_currency": "USD",
                 },
             )
 
@@ -290,6 +295,7 @@ class BudgetTestCase(IhatemoneyTestCase):
                     "id": "raclette",
                     "password": "party",
                     "contact_email": "raclette@notmyidea.org",
+                    "default_currency": "USD",
                 },
             )
 
@@ -310,6 +316,7 @@ class BudgetTestCase(IhatemoneyTestCase):
                     "id": "raclette",
                     "password": "party",
                     "contact_email": "raclette@notmyidea.org",
+                    "default_currency": "USD",
                 },
             )
 
@@ -329,6 +336,7 @@ class BudgetTestCase(IhatemoneyTestCase):
                     "id": "raclette",
                     "password": "party",
                     "contact_email": "raclette@notmyidea.org",
+                    "default_currency": "USD",
                 },
             )
 
@@ -841,6 +849,7 @@ class BudgetTestCase(IhatemoneyTestCase):
             "contact_email": "alexis@notmyidea.org",
             "password": "didoudida",
             "logging_preference": LoggingMode.ENABLED.value,
+            "default_currency": "USD",
         }
 
         resp = self.client.post("/raclette/edit", data=new_data, follow_redirects=True)
@@ -849,6 +858,7 @@ class BudgetTestCase(IhatemoneyTestCase):
 
         self.assertEqual(project.name, new_data["name"])
         self.assertEqual(project.contact_email, new_data["contact_email"])
+        self.assertEqual(project.default_currency, new_data["default_currency"])
         self.assertTrue(check_password_hash(project.password, new_data["password"]))
 
         # Editing a project with a wrong email address should fail
@@ -1099,6 +1109,7 @@ class BudgetTestCase(IhatemoneyTestCase):
                 "payer": 1,
                 "payed_for": [1, 2, 3, 4],
                 "amount": "10.0",
+                "original_currency": "USD",
             },
         )
 
@@ -1110,6 +1121,7 @@ class BudgetTestCase(IhatemoneyTestCase):
                 "payer": 2,
                 "payed_for": [1, 3],
                 "amount": "200",
+                "original_currency": "USD",
             },
         )
 
@@ -1121,6 +1133,7 @@ class BudgetTestCase(IhatemoneyTestCase):
                 "payer": 3,
                 "payed_for": [2],
                 "amount": "13.33",
+                "original_currency": "USD",
             },
         )
 
@@ -1425,6 +1438,7 @@ class APITestCase(IhatemoneyTestCase):
                 "id": id,
                 "password": password,
                 "contact_email": contact,
+                "default_currency": "USD",
             },
         )
 
@@ -1486,6 +1500,7 @@ class APITestCase(IhatemoneyTestCase):
                 "id": "raclette",
                 "password": "raclette",
                 "contact_email": "not-an-email",
+                "default_currency": "USD",
             },
         )
 
@@ -1514,6 +1529,7 @@ class APITestCase(IhatemoneyTestCase):
             "members": [],
             "name": "raclette",
             "contact_email": "raclette@notmyidea.org",
+            "default_currency": "USD",
             "id": "raclette",
             "logging_preference": 1,
         }
@@ -1525,6 +1541,7 @@ class APITestCase(IhatemoneyTestCase):
             "/api/projects/raclette",
             data={
                 "contact_email": "yeah@notmyidea.org",
+                "default_currency": "USD",
                 "password": "raclette",
                 "name": "The raclette party",
                 "project_history": "y",
@@ -1542,6 +1559,7 @@ class APITestCase(IhatemoneyTestCase):
         expected = {
             "name": "The raclette party",
             "contact_email": "yeah@notmyidea.org",
+            "default_currency": "USD",
             "members": [],
             "id": "raclette",
             "logging_preference": 1,
@@ -1554,6 +1572,7 @@ class APITestCase(IhatemoneyTestCase):
             "/api/projects/raclette",
             data={
                 "contact_email": "yeah@notmyidea.org",
+                "default_currency": "USD",
                 "password": "tartiflette",
                 "name": "The raclette party",
             },
@@ -1776,6 +1795,8 @@ class APITestCase(IhatemoneyTestCase):
             "amount": 25.0,
             "date": "2011-08-10",
             "id": 1,
+            "converted_amount": 25.0,
+            "original_currency": "USD",
             "external_link": "https://raclette.fr",
         }
 
@@ -1845,6 +1866,8 @@ class APITestCase(IhatemoneyTestCase):
             "amount": 25.0,
             "date": "2011-09-10",
             "external_link": "https://raclette.fr",
+            "converted_amount": 25.0,
+            "original_currency": "USD",
             "id": 1,
         }
 
@@ -1922,6 +1945,8 @@ class APITestCase(IhatemoneyTestCase):
                 "date": "2011-08-10",
                 "id": id,
                 "external_link": "",
+                "original_currency": "USD",
+                "converted_amount": expected_amount,
             }
 
             got = json.loads(req.data.decode("utf-8"))
@@ -2064,6 +2089,8 @@ class APITestCase(IhatemoneyTestCase):
             "date": "2011-08-10",
             "id": 1,
             "external_link": "",
+            "converted_amount": 25.0,
+            "original_currency": "USD",
         }
         got = json.loads(req.data.decode("utf-8"))
         self.assertEqual(
@@ -2106,6 +2133,7 @@ class APITestCase(IhatemoneyTestCase):
             "id": "raclette",
             "name": "raclette",
             "logging_preference": 1,
+            "default_currency": "USD",
         }
 
         self.assertStatus(200, req)
@@ -2850,5 +2878,23 @@ class HistoryTestCase(IhatemoneyTestCase):
         self.assertEqual(len(history_list), 6)
 
 
+class TestCurrencyConverter(unittest.TestCase):
+    converter = CurrencyConverter()
+    mock_data = {"USD": 1, "EUR": 0.8115}
+    converter.get_rates = MagicMock(return_value=mock_data)
+
+    def test_only_one_instance(self):
+        one = id(CurrencyConverter())
+        two = id(CurrencyConverter())
+        self.assertEqual(one, two)
+
+    def test_get_currencies(self):
+        self.assertCountEqual(self.converter.get_currencies(), ["USD", "EUR"])
+
+    def test_exchange_currency(self):
+        result = self.converter.exchange_currency(100, "USD", "EUR")
+        self.assertEqual(result, 81.15)
+
+
 if __name__ == "__main__":
     unittest.main()

ihatemoney/web.py

@@ -37,10 +37,10 @@ from sqlalchemy_continuum import Operation
 from werkzeug.exceptions import NotFound
 from werkzeug.security import check_password_hash, generate_password_hash
 
+from ihatemoney.currency_convertor import CurrencyConverter
 from ihatemoney.forms import (
     AdminAuthenticationForm,
     AuthenticationForm,
-    EditProjectForm,
     InviteForm,
     MemberForm,
     PasswordReminder,
@@ -48,6 +48,7 @@ from ihatemoney.forms import (
     ResetPasswordForm,
     UploadForm,
     get_billform_for,
+    get_editprojectform_for,
 )
 from ihatemoney.history import get_history, get_history_queries
 from ihatemoney.models import Bill, LoggingMode, Person, Project, db
@@ -376,7 +377,7 @@ def reset_password():
 
 @main.route("/<project_id>/edit", methods=["GET", "POST"])
 def edit_project():
-    edit_form = EditProjectForm()
+    edit_form = get_editprojectform_for(g.project)
     import_form = UploadForm()
     # Import form
     if import_form.validate_on_submit():
@@ -391,6 +392,18 @@ def edit_project():
     # Edit form
     if edit_form.validate_on_submit():
         project = edit_form.update(g.project)
+        # Update converted currency
+        if project.default_currency != CurrencyConverter.default:
+            for bill in project.get_bills():
+
+                if bill.original_currency == CurrencyConverter.default:
+                    bill.original_currency = project.default_currency
+
+                bill.converted_amount = CurrencyConverter().exchange_currency(
+                    bill.amount, bill.original_currency, project.default_currency
+                )
+                db.session.add(bill)
+
         db.session.add(project)
         db.session.commit()
 
@@ -478,6 +491,7 @@ def import_project(file, project):
         form.date = parse(b["date"])
         form.payer = id_dict[b["payer_name"]]
         form.payed_for = owers_id
+        form.original_currency = b.get("original_currency")
 
         db.session.add(form.fake_form(bill, project))
 
@@ -543,6 +557,7 @@ def demo():
             name="demonstration",
             password=generate_password_hash("demo"),
             contact_email="demo@notmyidea.org",
+            default_currency="EUR",
         )
         db.session.add(project)
         db.session.commit()

setup.cfg

@@ -23,6 +23,7 @@ include_package_data = True
 zip_safe = False
 install_requires =
     blinker==1.4
+    cachetools==4.1.0
     debts==0.5
     email_validator==1.0.5
     Flask-Babel==1.0.0
@@ -37,6 +38,7 @@ install_requires =
     Flask==1.1.2
     itsdangerous==1.1.0
     Jinja2==2.11.2
+    requests==2.22.0
     SQLAlchemy-Continuum==1.3.9
 
 [options.extras_require]