feat: implement per-request caching for DNS resolution

Author: jakejarvis

server/services/dns.ts

@@ -1,5 +1,6 @@
 import { eq } from "drizzle-orm";
 import { after } from "next/server";
+import { cache } from "react";
 import { isCloudflareIp } from "@/lib/cloudflare";
 import { USER_AGENT } from "@/lib/constants/app";
 import { db } from "@/lib/db/client";
@@ -70,7 +71,16 @@ function buildDohUrl(
   return url;
 }
 
-export async function resolveAll(domain: string): Promise<DnsResolveResult> {
+/**
+ * Resolve all DNS record types for a domain with Postgres caching.
+ *
+ * Wrapped in React's cache() for per-request deduplication during SSR,
+ * ensuring multiple services can query DNS without triggering duplicate
+ * lookups to DoH providers.
+ */
+export const resolveAll = cache(async function resolveAll(
+  domain: string,
+): Promise<DnsResolveResult> {
   console.debug(`[dns] start ${domain}`);
 
   const providers = providerOrderForLookup(domain);
@@ -396,7 +406,7 @@ export async function resolveAll(domain: string): Promise<DnsResolveResult> {
   throw new Error(
     `All DoH providers failed for ${registrable}: ${String(lastError)}`,
   );
-}
+});
 
 async function resolveTypeWithProvider(
   domain: string,

server/services/hosting.ts

@@ -1,6 +1,7 @@
 import { eq } from "drizzle-orm";
 import { alias } from "drizzle-orm/pg-core";
 import { after } from "next/server";
+import { cache } from "react";
 import { db } from "@/lib/db/client";
 import { findDomainByName } from "@/lib/db/repos/domains";
 import { upsertHosting } from "@/lib/db/repos/hosting";
@@ -25,7 +26,16 @@ import { resolveAll } from "@/server/services/dns";
 import { probeHeaders } from "@/server/services/headers";
 import { lookupIpMeta } from "@/server/services/ip";
 
-export async function detectHosting(domain: string): Promise<Hosting> {
+/**
+ * Detect hosting, email, and DNS providers for a domain with Postgres caching.
+ *
+ * Wrapped in React's cache() for per-request deduplication during SSR,
+ * ensuring multiple components can query hosting without triggering duplicate
+ * fetches of DNS and headers data.
+ */
+export const detectHosting = cache(async function detectHosting(
+  domain: string,
+): Promise<Hosting> {
   console.debug(`[hosting] start ${domain}`);
 
   // Only support registrable domains (no subdomains, IPs, or invalid TLDs)
@@ -275,4 +285,4 @@ export async function detectHosting(domain: string): Promise<Hosting> {
     `[hosting] ok ${registrable} hosting=${hostingName} email=${emailName} dns=${dnsName}`,
   );
   return info;
-}
+});

server/services/ip.ts

@@ -1,4 +1,15 @@
-export async function lookupIpMeta(ip: string): Promise<{
+import { cache } from "react";
+
+/**
+ * Lookup IP metadata including geolocation and ownership information.
+ *
+ * Wrapped in React's cache() for per-request deduplication during SSR,
+ * ensuring multiple services can query the same IP without triggering
+ * duplicate API calls to the upstream provider.
+ */
+export const lookupIpMeta = cache(async function lookupIpMeta(
+  ip: string,
+): Promise<{
   geo: {
     city: string;
     region: string;
@@ -94,4 +105,4 @@ export async function lookupIpMeta(ip: string): Promise<{
       },
     };
   }
-}
+});