new consumer

consumer/src/lookup.ts

@@ -0,0 +1,42 @@
+import fs from 'fs';
+
+const ipsData = JSON.parse(fs.readFileSync('./dist/ipv4-db.json', 'utf8'));
+const countriesData = JSON.parse(fs.readFileSync('./dist/countries-db.json', 'utf8'));
+
+function inRange(ip: string, cidr: string) {
+    const [subnet, mask] = cidr.split('/');
+    const ipBytes = ip.split('.').map(Number);
+    const subnetBytes = subnet.split('.').map(Number);
+
+    const ipInt = (ipBytes[0] << 24) | (ipBytes[1] << 16) | (ipBytes[2] << 8) | ipBytes[3];
+    const subnetInt = (subnetBytes[0] << 24) | (subnetBytes[1] << 16) | (subnetBytes[2] << 8) | subnetBytes[3];
+
+    const maskInt = 0xffffffff << (32 - parseInt(mask));
+
+    return (ipInt & maskInt) === (subnetInt & maskInt);
+}
+
+function getCountryFromId(id: number) {
+    for (const country of countriesData) {
+        if (country[0] == id) {
+            return country;
+        }
+    }
+}
+
+export function lookup(ip: string) {
+    try {
+        const startPiece = parseInt(ip.split('.')[0]);
+        for (const target of ipsData) {
+            const matchingStartPiece = target[0] == startPiece;
+            if (!matchingStartPiece) continue;
+            if (!inRange(ip, target[1])) continue;
+            const country = getCountryFromId(target[2]);
+            return [country[1], country[2]];
+        }
+        return ['??', '??'];
+    } catch (ex) {
+        console.error('ERROR DURING LOOKUP', ex);
+        return ['??', '??'];
+    }
+}