Switch from xml.etree to lxml and cssselect.

poetry.lock

@@ -82,6 +82,14 @@ category = "dev"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
 
+[[package]]
+name = "cssselect"
+version = "1.1.0"
+description = "cssselect parses CSS3 Selectors and translates them to XPath 1.0"
+category = "main"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
+
 [[package]]
 name = "flake8"
 version = "3.9.1"
@@ -303,7 +311,7 @@ socks = ["PySocks (>=1.5.6,!=1.5.7,<2.0)"]
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.9"
-content-hash = "d43dc5e9f04655ee9faaa2e1fc46c006de7509945c4a0e6c4ea3990081f17d4e"
+content-hash = "8674071f4ee6a2bd084bc4aa02e2d3abaca72eeba749ee5ac67de9a8001ac8db"
 
 [metadata.files]
 appdirs = [
@@ -337,6 +345,10 @@ colorama = [
     {file = "colorama-0.4.4-py2.py3-none-any.whl", hash = "sha256:9f47eda37229f68eee03b24b9748937c7dc3868f906e8ba69fbcbdd3bc5dc3e2"},
     {file = "colorama-0.4.4.tar.gz", hash = "sha256:5941b2b48a20143d2267e95b1c2a7603ce057ee39fd88e7329b0c292aa16869b"},
 ]
+cssselect = [
+    {file = "cssselect-1.1.0-py2.py3-none-any.whl", hash = "sha256:f612ee47b749c877ebae5bb77035d8f4202c6ad0f0fc1271b3c18ad6c4468ecf"},
+    {file = "cssselect-1.1.0.tar.gz", hash = "sha256:f95f8dedd925fd8f54edb3d2dfb44c190d9d18512377d3c1e2388d16126879bc"},
+]
 flake8 = [
     {file = "flake8-3.9.1-py2.py3-none-any.whl", hash = "sha256:3b9f848952dddccf635be78098ca75010f073bfe14d2c6bda867154bea728d2a"},
     {file = "flake8-3.9.1.tar.gz", hash = "sha256:1aa8990be1e689d96c745c5682b687ea49f2e05a443aff1f8251092b0014e378"},

pyproject.toml

@@ -9,6 +9,7 @@ license = "MIT"
 python = "^3.9"
 requests = "^2.25.1"
 lxml = "^4.6.2"
+cssselect = "^1.1.0"
 
 [tool.poetry.dev-dependencies]
 pytest = "^6.2.2"

src/pricehist/sources/ecb.py

@@ -1,6 +1,7 @@
 from datetime import datetime, timedelta
 from decimal import Decimal
-from xml.etree import ElementTree
+from lxml import etree
+from lxml.cssselect import CSSSelector
 
 import requests
 
@@ -90,19 +91,16 @@ class ECB:
         response = requests.get(source_url)
         data = response.content
 
-        # TODO consider changing from xml.etree to lxml
-        root = ElementTree.fromstring(data)
-        namespaces = {
-            "default": "http://www.ecb.int/vocabulary/2002-08-01/eurofxref",
-            "gesmes": "http://www.gesmes.org/xml/2002-08-01",
-        }
+        root = etree.fromstring(data)
+        ns = {"default": "http://www.ecb.int/vocabulary/2002-08-01/eurofxref"}
+
         all_rows = []
-        for day in root.find("default:Cube", namespaces):
+        for day in CSSSelector("default|Cube[time]", ns)(root):
             date = day.attrib["time"]
-            rate_xpath = f"./*[@currency='{quote}']"
             # TODO what if it's not found for that day?
             # (some quotes aren't in the earliest data)
-            rate = Decimal(day.find(rate_xpath).attrib["rate"])
+            for row in CSSSelector(f"default|Cube[currency='{quote}']", ns)(day):
+                rate = Decimal(row.attrib["rate"])
                 all_rows.insert(0, (date, rate))
         selected = [
             Price(base, quote, d, r) for d, r in all_rows if d >= start and d <= end