From 10f9126cb6b686e0bbc48c772686206463891620 Mon Sep 17 00:00:00 2001
From: Maxime Dor <max@kamax.io>
Date: Sun, 11 Mar 2018 18:28:48 +0100
Subject: [PATCH] Better federation auto-discovery - Use the new status check
 endpoint at /_matrix/identity/api/v1 - Enforce DNS SRV existence before
 asking remote server for data

---
 .../mxisd/matrix/IdentityServerUtils.java     | 62 +++++++------------
 1 file changed, 24 insertions(+), 38 deletions(-)

diff --git a/src/main/java/io/kamax/mxisd/matrix/IdentityServerUtils.java b/src/main/java/io/kamax/mxisd/matrix/IdentityServerUtils.java
index 7dbaef8..77cc18e 100644
--- a/src/main/java/io/kamax/mxisd/matrix/IdentityServerUtils.java
+++ b/src/main/java/io/kamax/mxisd/matrix/IdentityServerUtils.java
@@ -22,9 +22,6 @@ import java.util.Optional;
 // FIXME placeholder, this must go in matrix-java-sdk for 1.0
 public class IdentityServerUtils {
 
-    public static final String THREEPID_TEST_MEDIUM = "email";
-    public static final String THREEPID_TEST_ADDRESS = "mxisd-email-forever-unknown@forever-invalid.kamax.io";
-
     private static Logger log = LoggerFactory.getLogger(IdentityServerUtils.class);
     private static JsonParser parser = new JsonParser();
 
@@ -35,9 +32,7 @@ public class IdentityServerUtils {
 
         try {
             // FIXME use Apache HTTP client
-            HttpURLConnection rootSrvConn = (HttpURLConnection) new URL(
-                    remote + "/_matrix/identity/api/v1/lookup?medium=" + THREEPID_TEST_MEDIUM + "&address=" + THREEPID_TEST_ADDRESS
-            ).openConnection();
+            HttpURLConnection rootSrvConn = (HttpURLConnection) new URL(remote + "/_matrix/identity/api/v1/").openConnection();
             // TODO turn this into a configuration property
             rootSrvConn.setConnectTimeout(2000);
 
@@ -53,11 +48,6 @@ public class IdentityServerUtils {
                 return false;
             }
 
-            if (el.getAsJsonObject().has("address")) {
-                log.debug("IS {} did not send back a JSON object for single 3PID lookup");
-                return false;
-            }
-
             return true;
         } catch (IllegalArgumentException | IOException | JsonParseException e) {
             log.info("{} is not a usable Identity Server: {}", remote, e.getMessage());
@@ -84,39 +74,35 @@ public class IdentityServerUtils {
 
             List<SRVRecord> srvRecords = new ArrayList<>();
             Record[] records = new Lookup(lookupDns, Type.SRV).run();
-            if (records != null) {
-                for (Record record : records) {
-                    log.info("Record: {}", record.toString());
-                    if (record.getType() == Type.SRV) {
-                        if (record instanceof SRVRecord) {
-                            srvRecords.add((SRVRecord) record);
-                        } else {
-                            log.warn("We requested SRV records but we got {} instead!", record.getClass().getName());
-                        }
-                    } else {
-                        log.warn("We request SRV type records but we got type #{} instead!", record.getType());
-                    }
-                }
-                srvRecords.sort(Comparator.comparingInt(SRVRecord::getPriority));
+            if (records == null || records.length == 0) {
+                log.info("No SRV record for {}", lookupDns);
+                return Optional.empty();
+            }
 
-                for (SRVRecord srvRecord : srvRecords) {
-                    String baseUrl = "https://" + srvRecord.getTarget().toString(true) + ":" + srvRecord.getPort();
+            for (Record record : records) {
+                log.info("Record: {}", record.toString());
+                if (record.getType() == Type.SRV) {
+                    if (record instanceof SRVRecord) {
+                        srvRecords.add((SRVRecord) record);
+                    } else {
+                        log.warn("We requested SRV records but we got {} instead!", record.getClass().getName());
+                    }
+                } else {
+                    log.warn("We request SRV type records but we got type #{} instead!", record.getType());
+                }
+            }
+            srvRecords.sort(Comparator.comparingInt(SRVRecord::getPriority));
+
+            for (SRVRecord srvRecord : srvRecords) {
+                String baseUrl = "https://" + srvRecord.getTarget().toString(true) + ":" + srvRecord.getPort();
+                if (isUsable(baseUrl)) {
                     log.info("Found Identity Server for domain {} at {}", domainOrUrl, baseUrl);
                     return Optional.of(baseUrl);
                 }
-            } else {
-                log.info("No SRV record for {}", lookupDns);
             }
 
-            log.info("Performing basic lookup using domain name {}", domainOrUrl);
-            String baseUrl = "https://" + domainOrUrl;
-            if (isUsable(baseUrl)) {
-                log.info("Found Identity Server for domain {} at {}", domainOrUrl, baseUrl);
-                return Optional.of(baseUrl);
-            } else {
-                log.info("{} is not a usable Identity Server", baseUrl);
-                return Optional.empty();
-            }
+            log.info("Found no Identity server for domain {} at {}");
+            return Optional.empty();
         } catch (TextParseException e) {
             log.warn(domainOrUrl + " is not a valid domain name");
             return Optional.empty();