RDAP: Allow domain and nameserver queries with no initial string under certain circumstances

Up to now, our search wildcard rules have been that there must be an initial string of at least two characters. If a wildcard is present after that, it can optionally be followed by a suffix specifying the TLD (for domains) or domain (for nameservers). So domain queries can look like:

example.tld
ex*
ex*.tld

and nameserver queries can look like:

ns1.example.tld
ns*.example.tld
ns*

But you can't do a domain query for *.tld, nor a nameserver query for *.example.tld. It would be nice to support such queries, and the presence of a valid TLD or domain makes them relatively efficient. This CL relaxes the restrictions to allow wildcards with no initial string if the suffix is present. For nameservers, the suffix must be a valid domain in the system, to avoid having to loop through all nameservers.

A side effect of the changes is to fix a shortcoming in the logic which caused wildcard nameserver searches to fail if the specified domain suffix referred to an external domain.

Entity searches are not affected, since they do not support suffixes.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=159856563

java/google/registry/rdap/RdapNameserverSearchAction.java

@@ -80,7 +80,11 @@ public class RdapNameserverSearchAction extends RdapActionBase {
     return PATH;
   }
 
-  /** Parses the parameters and calls the appropriate search function. */
+  /**
+   * Parses the parameters and calls the appropriate search function.
+   *
+   * <p>The RDAP spec allows nameserver search by either name or IP address.
+   */
   @Override
   public ImmutableMap<String, Object> getJsonObjectForResource(
       String pathSearchString, boolean isHeadRequest, String linkBase) {
@@ -135,39 +139,51 @@ public class RdapNameserverSearchAction extends RdapActionBase {
           ImmutableList.of(
               rdapJsonFormatter.makeRdapJsonForHost(
                   hostResource, false, rdapLinkBase, rdapWhoisServer, now, OutputDataType.FULL)));
-    // Handle queries with a wildcard, but no suffix. There are no pending deletes for hosts, so we
-    // can call queryUndeleted.
-    } else if (partialStringQuery.getSuffix() == null) {
-      return makeSearchResults(
-          // Add 1 so we can detect truncation.
-          queryUndeleted(
-                  HostResource.class,
-                  "fullyQualifiedHostName",
-                  partialStringQuery,
-                  rdapResultSetMaxSize + 1)
-              .list(),
-          now);
-    // Handle queries with a wildcard and a suffix. In this case, it is more efficient to do things
-    // differently. We use the suffix to look up the domain, then loop through the subordinate hosts
-    // looking for matches.
+    // Handle queries with a wildcard.
     } else {
-      DomainResource domainResource =
-          loadByForeignKey(DomainResource.class, partialStringQuery.getSuffix(), now);
-      if (domainResource == null) {
-        throw new NotFoundException("No domain found for specified nameserver suffix");
-      }
-      ImmutableList.Builder<HostResource> hostListBuilder = new ImmutableList.Builder<>();
-      for (String fqhn : ImmutableSortedSet.copyOf(domainResource.getSubordinateHosts())) {
-        // We can't just check that the host name starts with the initial query string, because then
-        // the query ns.exam*.example.com would match against nameserver ns.example.com.
-        if (partialStringQuery.matches(fqhn)) {
-          HostResource hostResource = loadByForeignKey(HostResource.class, fqhn, now);
-          if (hostResource != null) {
-            hostListBuilder.add(hostResource);
+      // If there is a suffix, it should be a domain. If it happens to be a domain that we manage,
+      // we can look up the domain and look through the subordinate hosts. This is more efficient,
+      // and lets us permit wildcard searches with no initial string.
+      if (partialStringQuery.getSuffix() != null) {
+        DomainResource domainResource =
+            loadByForeignKey(DomainResource.class, partialStringQuery.getSuffix(), now);
+        ImmutableList.Builder<HostResource> hostListBuilder = new ImmutableList.Builder<>();
+        if (domainResource != null) {
+          for (String fqhn : ImmutableSortedSet.copyOf(domainResource.getSubordinateHosts())) {
+            // We can't just check that the host name starts with the initial query string, because
+            // then the query ns.exam*.example.com would match against nameserver ns.example.com.
+            if (partialStringQuery.matches(fqhn)) {
+              HostResource hostResource = loadByForeignKey(HostResource.class, fqhn, now);
+              if (hostResource != null) {
+                hostListBuilder.add(hostResource);
+              }
+            }
+          }
+        } else {
+          // If we don't recognize the domain, call queryUndeleted and filter.
+          // TODO(mountford): figure out how to size this correctly
+          for (HostResource hostResource :
+              queryUndeleted(
+                  HostResource.class, "fullyQualifiedHostName", partialStringQuery, 1000)) {
+            if (partialStringQuery.matches(hostResource.getFullyQualifiedHostName())) {
+              hostListBuilder.add(hostResource);
+            }
           }
         }
+        return makeSearchResults(hostListBuilder.build(), now);
+      // Handle queries with a wildcard, but no suffix. There are no pending deletes for hosts, so
+      // we can call queryUndeleted.
+      } else {
+        return makeSearchResults(
+            // Add 1 so we can detect truncation.
+            queryUndeleted(
+                    HostResource.class,
+                    "fullyQualifiedHostName",
+                    partialStringQuery,
+                    rdapResultSetMaxSize + 1)
+                .list(),
+            now);
       }
-      return makeSearchResults(hostListBuilder.build(), now);
     }
   }