3PID authentication (#60)

Fix for #49

src/main/java/io/kamax/mxisd/backend/memory/MemoryIdentityStore.java

@@ -0,0 +1,111 @@
+/*
+ * mxisd - Matrix Identity Server Daemon
+ * Copyright (C) 2018 Maxime Dor
+ *
+ * https://www.kamax.io/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.mxisd.backend.memory;
+
+import io.kamax.matrix.MatrixID;
+import io.kamax.matrix.ThreePid;
+import io.kamax.matrix._MatrixID;
+import io.kamax.mxisd.UserIdType;
+import io.kamax.mxisd.auth.provider.AuthenticatorProvider;
+import io.kamax.mxisd.auth.provider.BackendAuthResult;
+import io.kamax.mxisd.config.MatrixConfig;
+import io.kamax.mxisd.config.memory.MemoryIdentityConfig;
+import io.kamax.mxisd.config.memory.MemoryStoreConfig;
+import io.kamax.mxisd.config.memory.MemoryThreePid;
+import io.kamax.mxisd.lookup.SingleLookupReply;
+import io.kamax.mxisd.lookup.SingleLookupRequest;
+import io.kamax.mxisd.lookup.ThreePidMapping;
+import io.kamax.mxisd.lookup.provider.IThreePidProvider;
+import org.apache.commons.lang.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+
+@Component
+public class MemoryIdentityStore implements AuthenticatorProvider, IThreePidProvider {
+
+    private final Logger logger = LoggerFactory.getLogger(MemoryIdentityStore.class);
+
+    private final MatrixConfig mxCfg;
+    private final MemoryStoreConfig cfg;
+
+    @Autowired
+    public MemoryIdentityStore(MatrixConfig mxCfg, MemoryStoreConfig cfg) {
+        this.mxCfg = mxCfg;
+        this.cfg = cfg;
+    }
+
+    public Optional<MemoryIdentityConfig> findByUsername(String username) {
+        return cfg.getIdentities().stream().filter(id -> StringUtils.equals(id.getUsername(), username)).findFirst();
+    }
+
+    @Override
+    public boolean isEnabled() {
+        return cfg.isEnabled();
+    }
+
+    @Override
+    public boolean isLocal() {
+        return true;
+    }
+
+    @Override
+    public int getPriority() {
+        return Integer.MAX_VALUE;
+    }
+
+    @Override
+    public Optional<SingleLookupReply> find(SingleLookupRequest request) {
+        logger.info("Performing lookup {} of type {}", request.getThreePid(), request.getType());
+        ThreePid req = new ThreePid(request.getType(), request.getThreePid());
+        for (MemoryIdentityConfig id : cfg.getIdentities()) {
+            for (MemoryThreePid threepid : id.getThreepids()) {
+                if (req.equals(new ThreePid(threepid.getMedium(), threepid.getAddress()))) {
+                    return Optional.of(new SingleLookupReply(request, new MatrixID(id.getUsername(), mxCfg.getDomain())));
+                }
+            }
+        }
+
+        return Optional.empty();
+    }
+
+    @Override
+    public List<ThreePidMapping> populate(List<ThreePidMapping> mappings) {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public BackendAuthResult authenticate(_MatrixID mxid, String password) {
+        return findByUsername(mxid.getLocalPart()).map(id -> {
+            if (!StringUtils.equals(id.getUsername(), mxid.getLocalPart())) {
+                return BackendAuthResult.failure();
+            } else {
+                return BackendAuthResult.success(mxid.getId(), UserIdType.MatrixID, "");
+            }
+        }).orElseGet(BackendAuthResult::failure);
+    }
+
+}

src/main/java/io/kamax/mxisd/config/memory/MemoryIdentityConfig.java

@@ -0,0 +1,59 @@
+/*
+ * mxisd - Matrix Identity Server Daemon
+ * Copyright (C) 2018 Maxime Dor
+ *
+ * https://www.kamax.io/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.mxisd.config.memory;
+
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Component
+public class MemoryIdentityConfig {
+
+    private String username;
+    private String password;
+    private List<MemoryThreePid> threepids = new ArrayList<>();
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public List<MemoryThreePid> getThreepids() {
+        return threepids;
+    }
+
+    public void setThreepids(List<MemoryThreePid> threepids) {
+        this.threepids = threepids;
+    }
+
+}

src/main/java/io/kamax/mxisd/config/memory/MemoryStoreConfig.java

@@ -0,0 +1,51 @@
+/*
+ * mxisd - Matrix Identity Server Daemon
+ * Copyright (C) 2018 Maxime Dor
+ *
+ * https://www.kamax.io/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.mxisd.config.memory;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+import java.util.List;
+
+@Configuration
+@ConfigurationProperties("memory")
+public class MemoryStoreConfig {
+
+    private boolean enabled;
+    private List<MemoryIdentityConfig> identities;
+
+    public boolean isEnabled() {
+        return enabled;
+    }
+
+    public void setEnabled(boolean enabled) {
+        this.enabled = enabled;
+    }
+
+    public List<MemoryIdentityConfig> getIdentities() {
+        return identities;
+    }
+
+    public void setIdentities(List<MemoryIdentityConfig> identities) {
+        this.identities = identities;
+    }
+
+}

src/main/java/io/kamax/mxisd/config/memory/MemoryThreePid.java

@@ -0,0 +1,47 @@
+/*
+ * mxisd - Matrix Identity Server Daemon
+ * Copyright (C) 2018 Maxime Dor
+ *
+ * https://www.kamax.io/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.mxisd.config.memory;
+
+import org.springframework.stereotype.Component;
+
+@Component
+public class MemoryThreePid {
+
+    private String medium;
+    private String address;
+
+    public String getMedium() {
+        return medium;
+    }
+
+    public void setMedium(String medium) {
+        this.medium = medium;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+
+}

src/main/java/io/kamax/mxisd/controller/DefaultExceptionHandler.java

@@ -54,6 +54,16 @@ public class DefaultExceptionHandler {
         return gson.toJson(obj);
     }
 
+    @ExceptionHandler(RemoteLoginException.class)
+    public String handle(HttpServletRequest request, HttpServletResponse response, RemoteLoginException e) {
+        if (e.getErrorBodyMsgResp() != null) {
+            response.setStatus(e.getStatus());
+            log.info("Request {} {} - Error {}: {}", request.getMethod(), request.getRequestURL(), e.getErrorCode(), e.getError());
+            return gson.toJson(e.getErrorBodyMsgResp());
+        }
+        return handleGeneric(request, response, e);
+    }
+
     @ExceptionHandler(InternalServerError.class)
     public String handle(HttpServletRequest request, HttpServletResponse response, InternalServerError e) {
         if (StringUtils.isNotBlank(e.getInternalReason())) {

src/main/java/io/kamax/mxisd/controller/auth/v1/AuthController.java

@@ -20,15 +20,27 @@
 
 package io.kamax.mxisd.controller.auth.v1;
 
-import com.google.gson.Gson;
-import com.google.gson.JsonElement;
-import com.google.gson.JsonObject;
+import com.google.gson.*;
+import com.google.i18n.phonenumbers.NumberParseException;
+import com.google.i18n.phonenumbers.PhoneNumberUtil;
+import com.google.i18n.phonenumbers.Phonenumber;
 import io.kamax.mxisd.auth.AuthManager;
 import io.kamax.mxisd.auth.UserAuthResult;
 import io.kamax.mxisd.controller.auth.v1.io.CredentialsValidationResponse;
+import io.kamax.mxisd.dns.ClientDnsOverwrite;
 import io.kamax.mxisd.exception.JsonMemberNotFoundException;
+import io.kamax.mxisd.exception.RemoteLoginException;
+import io.kamax.mxisd.lookup.strategy.LookupStrategy;
 import io.kamax.mxisd.util.GsonParser;
 import io.kamax.mxisd.util.GsonUtil;
+import io.kamax.mxisd.util.RestClientUtils;
+import org.apache.commons.lang.StringUtils;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.client.utils.URIBuilder;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.util.EntityUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -39,13 +51,18 @@ import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RestController;
 
 import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
+import java.net.URI;
 
 @RestController
 @CrossOrigin
 @RequestMapping(produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
 public class AuthController {
 
+    // TODO export into SDK
+    private static final String logV1Url = "/_matrix/client/r0/login";
+
     private Logger log = LoggerFactory.getLogger(AuthController.class);
 
     private Gson gson = GsonUtil.build();
@@ -54,6 +71,23 @@ public class AuthController {
     @Autowired
     private AuthManager mgr;
 
+    @Autowired
+    private LookupStrategy strategy;
+
+    @Autowired
+    private ClientDnsOverwrite dns;
+
+    @Autowired
+    private CloseableHttpClient client;
+
+    private String resolveProxyUrl(HttpServletRequest req) {
+        URI target = URI.create(req.getRequestURL().toString());
+        URIBuilder builder = dns.transform(target);
+        String urlToLogin = builder.toString();
+        log.info("Proxy resolution: {} to {}", target.toString(), urlToLogin);
+        return urlToLogin;
+    }
+
     @RequestMapping(value = "/_matrix-internal/identity/v1/check_credentials", method = RequestMethod.POST)
     public String checkCredentials(HttpServletRequest req) {
         try {
@@ -84,4 +118,112 @@ public class AuthController {
         }
     }
 
+    @RequestMapping(value = logV1Url, method = RequestMethod.GET)
+    public String getLogin(HttpServletRequest req, HttpServletResponse res) {
+        try (CloseableHttpResponse hsResponse = client.execute(new HttpGet(resolveProxyUrl(req)))) {
+            res.setStatus(hsResponse.getStatusLine().getStatusCode());
+            return EntityUtils.toString(hsResponse.getEntity());
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @RequestMapping(value = logV1Url, method = RequestMethod.POST)
+    public String login(HttpServletRequest req) {
+        try {
+            JsonObject reqJsonObject = parser.parse(req.getInputStream());
+
+            // find 3PID in main object
+            GsonUtil.findPrimitive(reqJsonObject, "medium").ifPresent(medium -> {
+                GsonUtil.findPrimitive(reqJsonObject, "address").ifPresent(address -> {
+                    log.info("Login request with medium '{}' and address '{}'", medium.getAsString(), address.getAsString());
+                    strategy.findLocal(medium.getAsString(), address.getAsString()).ifPresent(lookupDataOpt -> {
+                        reqJsonObject.addProperty("user", lookupDataOpt.getMxid().getLocalPart());
+                        reqJsonObject.remove("medium");
+                        reqJsonObject.remove("address");
+                    });
+                });
+            });
+
+            // find 3PID in 'identifier' object
+            GsonUtil.findObj(reqJsonObject, "identifier").ifPresent(identifier -> {
+                GsonUtil.findPrimitive(identifier, "type").ifPresent(type -> {
+
+                    if (StringUtils.equals(type.getAsString(), "m.id.thirdparty")) {
+                        GsonUtil.findPrimitive(identifier, "medium").ifPresent(medium -> {
+                            GsonUtil.findPrimitive(identifier, "address").ifPresent(address -> {
+                                log.info("Login request with medium '{}' and address '{}'", medium.getAsString(), address.getAsString());
+                                strategy.findLocal(medium.getAsString(), address.getAsString()).ifPresent(lookupDataOpt -> {
+                                    identifier.addProperty("type", "m.id.user");
+                                    identifier.addProperty("user", lookupDataOpt.getMxid().getLocalPart());
+                                    identifier.remove("medium");
+                                    identifier.remove("address");
+                                });
+                            });
+                        });
+                    }
+
+                    if (StringUtils.equals(type.getAsString(), "m.id.phone")) {
+                        GsonUtil.findPrimitive(identifier, "number").ifPresent(number -> {
+                            GsonUtil.findPrimitive(identifier, "country").ifPresent(country -> {
+                                log.info("Login request with phone '{}'-'{}'", country.getAsString(), number.getAsString());
+                                try {
+                                    PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance();
+                                    Phonenumber.PhoneNumber phoneNumber = phoneUtil.parse(number.getAsString(), country.getAsString());
+                                    String canon_phoneNumber = phoneUtil.format(phoneNumber, PhoneNumberUtil.PhoneNumberFormat.E164).replace("+", "");
+                                    String medium = "msisdn";
+                                    strategy.findLocal(medium, canon_phoneNumber).ifPresent(lookupDataOpt -> {
+                                        identifier.addProperty("type", "m.id.user");
+                                        identifier.addProperty("user", lookupDataOpt.getMxid().getLocalPart());
+                                        identifier.remove("country");
+                                        identifier.remove("number");
+                                    });
+                                } catch (NumberParseException e) {
+                                    throw new RuntimeException(e);
+                                }
+                            });
+                        });
+                    }
+                });
+            });
+
+            // invoke 'login' on homeserver
+            HttpPost httpPost = RestClientUtils.post(resolveProxyUrl(req), gson, reqJsonObject);
+            try (CloseableHttpResponse httpResponse = client.execute(httpPost)) {
+                // check http status
+                int status = httpResponse.getStatusLine().getStatusCode();
+                log.info("http status = {}", status);
+                if (status != 200) {
+                    // try to get possible json error message from response
+                    // otherwise just get returned plain error message
+                    String errcode = String.valueOf(httpResponse.getStatusLine().getStatusCode());
+                    String error = EntityUtils.toString(httpResponse.getEntity());
+                    if (httpResponse.getEntity() != null) {
+                        try {
+                            JsonObject bodyJson = new JsonParser().parse(error).getAsJsonObject();
+                            if (bodyJson.has("errcode")) {
+                                errcode = bodyJson.get("errcode").getAsString();
+                            }
+                            if (bodyJson.has("error")) {
+                                error = bodyJson.get("error").getAsString();
+                            }
+                            throw new RemoteLoginException(status, errcode, error, bodyJson);
+                        } catch (JsonSyntaxException e) {
+                            log.warn("Response body is not JSON");
+                        }
+                    }
+                    throw new RemoteLoginException(status, errcode, error);
+                }
+
+                /// return response
+                JsonObject respJsonObject = parser.parseOptional(httpResponse).get();
+                return gson.toJson(respJsonObject);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
 }

src/main/java/io/kamax/mxisd/directory/DirectoryManager.java

@@ -38,7 +38,6 @@ import org.apache.http.client.methods.HttpPost;
 import org.apache.http.client.utils.URIBuilder;
 import org.apache.http.entity.ContentType;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClients;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -59,14 +58,15 @@ public class DirectoryManager {
     private List<IDirectoryProvider> providers;
 
     private ClientDnsOverwrite dns;
-    private CloseableHttpClient client;
     private Gson gson;
 
+    @Autowired
+    private CloseableHttpClient client;
+
     @Autowired
     public DirectoryManager(DirectoryConfig cfg, List<IDirectoryProvider> providers, ClientDnsOverwrite dns) {
         this.cfg = cfg;
         this.dns = dns;
-        this.client = HttpClients.custom().setUserAgent("mxisd").build(); //FIXME centralize
         this.gson = GsonUtil.build();
         this.providers = providers.stream().filter(IDirectoryProvider::isEnabled).collect(Collectors.toList());
 

src/main/java/io/kamax/mxisd/exception/RemoteLoginException.java

@@ -0,0 +1,43 @@
+/*
+ * mxisd - Matrix Identity Server Daemon
+ * Copyright (C) 2017 Maxime Dor
+ *
+ * https://max.kamax.io/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.mxisd.exception;
+
+
+import com.google.gson.JsonObject;
+
+public class RemoteLoginException extends MatrixException {
+
+    private JsonObject errorBodyMsgResp;
+
+    public RemoteLoginException(int status, String errorCode, String error) {
+        super(status, errorCode, error);
+        this.errorBodyMsgResp = null;
+    }
+
+    public RemoteLoginException(int status, String errorCode, String error, JsonObject errorBodyMsgResp) {
+        super(status, errorCode, error);
+        this.errorBodyMsgResp = errorBodyMsgResp;
+    }
+
+    public JsonObject getErrorBodyMsgResp() {
+        return errorBodyMsgResp;
+    }
+}

src/main/java/io/kamax/mxisd/lookup/strategy/RecursivePriorityLookupStrategy.java

@@ -159,6 +159,8 @@ public class RecursivePriorityLookupStrategy implements LookupStrategy {
         for (IThreePidProvider provider : providers) {
             Optional<SingleLookupReply> lookupDataOpt = provider.find(request);
             if (lookupDataOpt.isPresent()) {
+                log.info("Found 3PID mapping: {medium: '{}', address: '{}', mxid: '{}'}",
+                        request.getType(), request.getThreePid(), lookupDataOpt.get().getMxid().getId());
                 return lookupDataOpt;
             }
         }
@@ -169,9 +171,13 @@ public class RecursivePriorityLookupStrategy implements LookupStrategy {
                         (!cfg.getBridge().getRecursiveOnly() || isAllowedForRecursive(request.getRequester()))
                 ) {
             log.info("Using bridge failover for lookup");
-            return bridge.find(request);
+            Optional<SingleLookupReply> lookupDataOpt = bridge.find(request);
+            log.info("Found 3PID mapping: {medium: '{}', address: '{}', mxid: '{}'}",
+                    request.getThreePid(), request.getId(), lookupDataOpt.get().getMxid().getId());
+            return lookupDataOpt;
         }
 
+        log.info("No 3PID mapping found");
         return Optional.empty();
     }
 

src/main/java/io/kamax/mxisd/spring/CloseableHttpClientFactory.java

@@ -0,0 +1,36 @@
+/*
+ * mxisd - Matrix Identity Server Daemon
+ * Copyright (C) 2018 Kamax Sàrl
+ *
+ * https://www.kamax.io/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.mxisd.spring;
+
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class CloseableHttpClientFactory {
+
+    @Bean
+    public CloseableHttpClient getClient() {
+        return HttpClients.custom().setUserAgent("mxisd").build();
+    }
+
+}

src/main/java/io/kamax/mxisd/util/GsonUtil.java

@@ -20,9 +20,9 @@
 
 package io.kamax.mxisd.util;
 
-import com.google.gson.FieldNamingPolicy;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
+import com.google.gson.*;
+
+import java.util.Optional;
 
 public class GsonUtil {
 
@@ -30,4 +30,16 @@ public class GsonUtil {
         return new GsonBuilder().setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES).create();
     }
 
+    public static Optional<JsonElement> findElement(JsonObject o, String key) {
+        return Optional.ofNullable(o.get(key));
+    }
+
+    public static Optional<JsonObject> findObj(JsonObject o, String key) {
+        return findElement(o, key).map(el -> el.isJsonObject() ? el.getAsJsonObject() : null);
+    }
+
+    public static Optional<JsonPrimitive> findPrimitive(JsonObject o, String key) {
+        return findElement(o, key).map(el -> el.isJsonPrimitive() ? el.getAsJsonPrimitive() : null);
+    }
+
 }