Add translators from CAP to dict

Other systems we’re working with won’t easily be adapted to emit JSON
instead of CAP, so it’s less work for us to do that conversion.

This commit adds to code to parse the XML and turn it into a dict that
we can work with, including converting the polygon string into native
Python lists.

app/broadcast_message/translators.py

@@ -0,0 +1,31 @@
+from bs4 import BeautifulSoup
+
+
+def cap_xml_to_dict(cap_xml):
+    # This function assumes that it’s being passed valid CAP XML
+    cap = BeautifulSoup(cap_xml, "xml")
+    return {
+        "reference": cap.alert.identifier.text,
+        "category": cap.alert.info.category.text,
+        "expires": cap.alert.info.expires.text,
+        "content": cap.alert.info.description.text,
+        "areas": [
+            {
+                "name": area.areaDesc.text,
+                "polygons": [
+                    cap_xml_polygon_to_list(polygon.text)
+                    for polygon in area.find_all('polygon')
+                ]
+            }
+            for area in cap.alert.info.find_all('area')
+        ]
+    }
+
+
+def cap_xml_polygon_to_list(polygon_string):
+    return [
+        [
+            float(coordinate) for coordinate in pair.split(',')
+        ]
+        for pair in polygon_string.split(' ')
+    ]

requirements-app.txt

@@ -23,6 +23,7 @@ SQLAlchemy==1.3.22
 strict-rfc3339==0.7
 rfc3987==1.3.8
 cachetools==4.2.0
+beautifulsoup4==4.9.3
 
 notifications-python-client==5.7.1
 

requirements.txt

@@ -25,6 +25,7 @@ SQLAlchemy==1.3.22
 strict-rfc3339==0.7
 rfc3987==1.3.8
 cachetools==4.2.0
+beautifulsoup4==4.9.3
 
 notifications-python-client==5.7.1
 
@@ -42,14 +43,14 @@ alembic==1.4.3
 amqp==1.4.9
 anyjson==0.3.3
 attrs==20.3.0
-awscli==1.18.206
+awscli==1.18.215
 bcrypt==3.2.0
 billiard==3.3.0.23
 bleach==3.2.1
 blinker==1.4
 boto==2.49.0
-boto3==1.16.46
-botocore==1.19.46
+boto3==1.16.55
+botocore==1.19.55
 certifi==2020.12.5
 chardet==4.0.0
 click==7.1.2
@@ -60,19 +61,19 @@ flask-redis==0.4.0
 future==0.18.2
 geojson==2.5.0
 govuk-bank-holidays==0.8
-greenlet==0.4.17
+greenlet==1.0.0
 idna==2.10
-importlib-metadata==3.3.0
+importlib-metadata==3.4.0
 Jinja2==2.11.2
 jmespath==0.10.0
 kombu==3.0.37
-Mako==1.1.3
+Mako==1.1.4
 MarkupSafe==1.1.1
 mistune==0.8.4
 monotonic==1.5
 orderedset==2.0.3
 packaging==20.8
-phonenumbers==8.12.15
+phonenumbers==8.12.16
 pyasn1==0.4.8
 pycparser==2.20
 pyparsing==2.4.7
@@ -86,9 +87,10 @@ PyYAML==5.3.1
 redis==3.5.3
 requests==2.25.1
 rsa==4.5
-s3transfer==0.3.3
+s3transfer==0.3.4
 six==1.15.0
 smartypants==2.0.1
+soupsieve==2.1
 statsd==3.3.0
 typing-extensions==3.7.4.3
 urllib3==1.26.2