Add --symbols option, implement for ECB.

src/pricehist/cli.py

@@ -50,10 +50,15 @@ def cmd_source(args):
         first_output = wrapper.wrap(first)
         wrapper.initial_indent = subsequent_indent
         rest_output = sum([wrapper.wrap(line) for line in rest], [])
-        # TODO use str.splitlines()?
+        output = "\n".join(first_output + rest_output)
-        print("\n".join(first_output + rest_output))
+        if output != "":
+            print(output)
 
-    source = sources.by_id[args.identifier]
+    source = sources.by_id[args.identifier]()
+
+    if args.symbols:
+        print("\n".join(source.symbols()))
+    else:
         key_width = 11
         output_width = shutil.get_terminal_size().columns
 
@@ -62,8 +67,6 @@ def cmd_source(args):
         print_field("Description", source.description(), key_width, output_width)
         print_field("URL", source.source_url(), key_width, output_width, force=False)
         print_field("Notes", source.notes(), key_width, output_width)
-    print_field("Bases", ", ".join(source.bases()), key_width, output_width)
-    print_field("Quotes", ", ".join(source.quotes()), key_width, output_width)
 
 
 def cmd_fetch(args):
@@ -157,6 +160,7 @@ def build_parser():
     source_parser = subparsers.add_parser(
         "source",
         help="show source details",
+        usage="pricehist source SOURCE [-h] [-s]",
         formatter_class=formatter,
     )
     source_parser.add_argument(
@@ -166,6 +170,12 @@ def build_parser():
         choices=sources.by_id.keys(),
         help="the source identifier",
     )
+    source_parser.add_argument(
+        "-s",
+        "--symbols",
+        action="store_true",
+        help="list available symbols",
+    )
 
     fetch_parser = subparsers.add_parser(
         "fetch",

src/pricehist/sources/ecb.py

@@ -28,68 +28,23 @@ class ECB:
     def notes():
         return ""
 
-    @staticmethod
+    def symbols(self):
-    def bases():
+        data = self._raw_data(more_than_90_days=True)
-        return ["EUR"]
+        root = etree.fromstring(data)
-
+        nodes = root.cssselect("[currency]")
-    @staticmethod
+        currencies = sorted(set([n.attrib["currency"] for n in nodes]))
-    def quotes():
+        pairs = [f"EUR/{c}" for c in currencies]
-        return [
+        return pairs
-            "AUD",
-            "BGN",
-            "BRL",
-            "CAD",
-            "CHF",
-            "CNY",
-            "CZK",
-            "DKK",
-            "GBP",
-            "HKD",
-            "HRK",
-            "HUF",
-            "IDR",
-            "ILS",
-            "INR",
-            "ISK",
-            "JPY",
-            "KRW",
-            "MXN",
-            "MYR",
-            "NOK",
-            "NZD",
-            "PHP",
-            "PLN",
-            "RON",
-            "RUB",
-            "SEK",
-            "SGD",
-            "THB",
-            "TRY",
-            "USD",
-            "ZAR",
-        ]
 
     def fetch(self, pair, type, start, end):
         base, quote = pair.split("/")
-        if base not in self.bases():
-            exit(f"Invalid base {base}")
-        if quote not in self.quotes():
-            exit(f"Invalid quote {quote}")
 
         min_start = "1999-01-04"
         if start < min_start:
             exit(f"start {start} too early. Minimum is {min_start}")
 
         almost_90_days_ago = str(datetime.now().date() - timedelta(days=85))
-        url_base = "https://www.ecb.europa.eu/stats/eurofxref"
+        data = self._raw_data(start > almost_90_days_ago)
-        if start > almost_90_days_ago:
-            source_url = f"{url_base}/eurofxref-hist-90d.xml"  # last 90 days
-        else:
-            source_url = f"{url_base}/eurofxref-hist.xml"  # since 1999
-
-        response = requests.get(source_url)
-        data = response.content
-
         root = etree.fromstring(data)
 
         all_rows = []
@@ -105,3 +60,13 @@ class ECB:
         ]
 
         return selected
+
+    def _raw_data(self, more_than_90_days=False):
+        url_base = "https://www.ecb.europa.eu/stats/eurofxref"
+        if more_than_90_days:
+            source_url = f"{url_base}/eurofxref-hist.xml"  # since 1999
+        else:
+            source_url = f"{url_base}/eurofxref-hist-90d.xml"  # last 90 days
+
+        response = requests.get(source_url)
+        return response.content