Linting.

README.md

@@ -156,7 +156,7 @@ cp sample-custom_blacklist.txt ./data/custom_blacklist.txt
 
 The source database of banned IPs isn't perfect. You may determine that
 there's an IP address you want to ban this is not found in `ipsum.txt`.
-Also, the `ipsum.txt` file only contains IP addesses, and you may want
+Also, the `ipsum.txt` file only contains IP addresses, and you may want
 to ban an entire subnet. The custom blacklist allows you to capture
 specific IP addresses or subnets (in [CIDR][def] format), one per line,
 that you want to block. Some of your custom blacklist IPs may be found
@@ -174,24 +174,24 @@ blacklisted IPs, save a copy of it somewhere outside the repository.*
 When you're done, the `~/banip/data` directory should look like this:
 
 ```text
-├── data
-│   ├── custom_blacklist.txt (optional)
-│   ├── custom_whitelist.txt (optional)
-│   ├── geolite (required)
-│   │   ├── COPYRIGHT.txt
-│   │   ├── GeoLite2-Country-Blocks-IPv4.csv
-│   │   ├── GeoLite2-Country-Blocks-IPv6.csv
-│   │   ├── GeoLite2-Country-Locations-de.csv
-│   │   ├── GeoLite2-Country-Locations-en.csv
-│   │   ├── GeoLite2-Country-Locations-es.csv
-│   │   ├── GeoLite2-Country-Locations-fr.csv
-│   │   ├── GeoLite2-Country-Locations-ja.csv
-│   │   ├── GeoLite2-Country-Locations-pt-BR.csv
-│   │   ├── GeoLite2-Country-Locations-ru.csv
-│   │   ├── GeoLite2-Country-Locations-zh-CN.csv
-│   │   └── LICENSE.txt
-│   ├── ipsum.txt (required)
-│   └── targets.txt (required)
+data
+├── custom_blacklist.txt (optional)
+├── custom_whitelist.txt (optional)
+├── geolite (required)
+│   ├── COPYRIGHT.txt
+│   ├── GeoLite2-Country-Blocks-IPv4.csv
+│   ├── GeoLite2-Country-Blocks-IPv6.csv
+│   ├── GeoLite2-Country-Locations-de.csv
+│   ├── GeoLite2-Country-Locations-en.csv
+│   ├── GeoLite2-Country-Locations-es.csv
+│   ├── GeoLite2-Country-Locations-fr.csv
+│   ├── GeoLite2-Country-Locations-ja.csv
+│   ├── GeoLite2-Country-Locations-pt-BR.csv
+│   ├── GeoLite2-Country-Locations-ru.csv
+│   ├── GeoLite2-Country-Locations-zh-CN.csv
+│   └── LICENSE.txt
+├── ipsum.txt (required)
+└── targets.txt (required)
 ```
 
 ## Running

src/banip/__main__.py

@@ -24,13 +24,13 @@ def main() -> None:
     )
 
     subparsers = parser.add_subparsers(title="Commands")
-    msg = """Check to see if a single IP address is found in the
-    blacklist. Run \"banip check -h" for more."""
-    subparser_check = subparsers.add_parser(name="check", help=msg)
     msg = """Create a list of banned (blacklisted) client IP addresses
     to be used with a proxy server (like HAProxy) to block network
     access from those clients. Run \"banip build -h" for more."""
     subparser_build = subparsers.add_parser(name="build", help=msg)
+    msg = """Check to see if a single IP address is found in the
+    blacklist. Run \"banip check -h" for more."""
+    subparser_check = subparsers.add_parser(name="check", help=msg)
 
     msg = """Output file that will contain the generated list of
     blacklisted IP addresses. If not provided, results will be saved to

src/banip/build_list.py

@@ -218,14 +218,20 @@ def banned_ips(args: Namespace) -> None:
         for ip in D[key]:
             args.outfile.write(f"{format(ip)}\n")
 
-    now = dt.now().strftime("%Y-%m-%d %H:%M:%S")
-    args.outfile.write("\n# ------------custom entries -------------\n")
-    args.outfile.write(f"# Added on: {now}\n")
-    args.outfile.write("# ----------------------------------------\n\n")
-
+    custom_present = False
     for key in c_keys:
-        for chunk in D[key]:
-            args.outfile.write(f"{format(chunk)}\n")
+        if len(D[key]) > 0:
+            custom_present = True
+            break
+
+    if custom_present:
+        now = dt.now().strftime("%Y-%m-%d %H:%M:%S")
+        args.outfile.write("\n# ------------custom entries -------------\n")
+        args.outfile.write(f"# Added on: {now}\n")
+        args.outfile.write("# ----------------------------------------\n\n")
+        for key in c_keys:
+            for chunk in D[key]:
+                args.outfile.write(f"{format(chunk)}\n")
 
     # Save a copy of the generated IP blacklist to
     # ./data/ip_blacklist.txt. This will be used when running banip to

src/banip/utilities.py

@@ -234,7 +234,7 @@ def tag_networks() -> None:
                 country_id = countries_D[int(net[2])]
             ipv6_D[ipa.IPv6Network(net[0])] = country_id
 
-    print("\nGenerating files...", end="")
+    print("\nGenerating interim build products...", end="")
     keys_4 = list(ipv4_D.keys())
     keys_6 = list(ipv6_D.keys())
     keys_4.sort()
@@ -298,18 +298,40 @@ def check_ip(ip: str) -> None:
 def ip_in_network(
     ip: Any,
     networks: list[Any],
-    start: int,
-    finish: int,
+    first: int,
+    last: int,
 ) -> bool:
-    """Do this."""
-    if start > finish:
+    """Check if a single IP is in a list of networks.
+
+    This is a recursive binary search across a list of networks (either
+    all IPv4 or all IPv6) to see if a single IP address is contained in
+    any of the networks.
+
+    Parameters
+    ----------
+    ip : Any
+        This will be either an IPv4 or IPv6 address, in ip_address()
+        format.
+    networks : list[Any]
+        This is a homogenous list of networks. The type of items in the
+        list with be either IPv4Network or IPv6Network.
+    first : int
+        The starting index in the binary search.
+    last : int
+        The ending index in the binary search.
+
+    Returns
+    -------
+    bool
+        True if ip is in any of the networks in the list; False
+        otherwise.
+    """
+    if first > last:
         return False
-    mid = (start + finish) // 2
-    # print(type(ip), type(networks[mid]))
-    if ip in networks[mid]:
+    mid = (first + last) // 2
+    clients = ipa.ip_network(networks[mid])
+    if ip in clients:
         return True
-    inner_edge = ipa.ip_network(networks[mid])[0]
-    if ip < inner_edge:
-        return ip_in_network(ip, networks, start, mid - 1)
-    else:
-        return ip_in_network(ip, networks, mid + 1, finish)
+    if ip < clients[0]:
+        return ip_in_network(ip, networks, first, mid - 1)
+    return ip_in_network(ip, networks, mid + 1, last)