Allow null user_id and provide partial Webhooks (#675)

* Added IllegalStateException when trying to use newClient() on a Webhook with no token
* improved docs, made Webhook extend IFakeable, and added more exceptions

src/main/java/net/dv8tion/jda/core/audit/AuditLogEntry.java

@@ -20,13 +20,17 @@
 import net.dv8tion.jda.core.entities.Guild;
 import net.dv8tion.jda.core.entities.ISnowflake;
 import net.dv8tion.jda.core.entities.User;
+import net.dv8tion.jda.core.entities.Webhook;
 import net.dv8tion.jda.core.entities.impl.GuildImpl;
 import net.dv8tion.jda.core.entities.impl.UserImpl;
+import net.dv8tion.jda.core.entities.impl.WebhookImpl;
 import net.dv8tion.jda.core.utils.Checks;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import javax.annotation.Nullable;
 
 /**
  * Single entry for an {@link net.dv8tion.jda.core.requests.restaction.pagination.AuditLogPaginationAction
@@ -41,20 +45,22 @@ public class AuditLogEntry implements ISnowflake
     protected final long targetId;
     protected final GuildImpl guild;
     protected final UserImpl user;
+    protected final WebhookImpl webhook;
     protected final String reason;
 
     protected final Map<String, AuditLogChange> changes;
     protected final Map<String, Object> options;
     protected final ActionType type;
 
-    public AuditLogEntry(ActionType type, long id, long targetId, GuildImpl guild, UserImpl user, String reason,
-                         Map<String, AuditLogChange> changes, Map<String, Object> options)
+    public AuditLogEntry(ActionType type, long id, long targetId, GuildImpl guild, UserImpl user, WebhookImpl webhook, 
+                        String reason, Map<String, AuditLogChange> changes, Map<String, Object> options)
     {
         this.type = type;
         this.id = id;
         this.targetId = targetId;
         this.guild = guild;
         this.user = user;
+        this.webhook = webhook;
         this.reason = reason;
         this.changes = changes != null && !changes.isEmpty()
                 ? Collections.unmodifiableMap(changes)
@@ -93,6 +99,17 @@ public String getTargetId()
     {
         return Long.toUnsignedString(targetId);
     }
+
+    /**
+     * The {@link net.dv8tion.jda.core.entities.Webhook Webhook} that the target id of this audit-log entry refers to
+     * 
+     * @return Possibly-null Webhook instance
+     */
+    @Nullable
+    public Webhook getWebhook()
+    {
+        return webhook;
+    }
 
     /**
      * The {@link net.dv8tion.jda.core.entities.Guild Guild} this audit-log entry refers to
@@ -108,8 +125,9 @@ public Guild getGuild()
      * The {@link net.dv8tion.jda.core.entities.User User} responsible
      * for this action.
      *
-     * @return The User instance
+     * @return Possibly-null User instance
      */
+    @Nullable
     public User getUser()
     {
         return user;
@@ -120,6 +138,7 @@ public User getUser()
      *
      * @return Possibly-null reason String
      */
+    @Nullable
     public String getReason()
     {
         return reason;
@@ -157,6 +176,7 @@ public Map<String, AuditLogChange> getChanges()
      *
      * @return Possibly-null value corresponding to the specified key
      */
+    @Nullable
     public AuditLogChange getChangeByKey(final AuditLogKey key)
     {
         return key == null ? null : getChangeByKey(key.getKey());
@@ -171,6 +191,7 @@ public AuditLogChange getChangeByKey(final AuditLogKey key)
      *
      * @return Possibly-null value corresponding to the specified key
      */
+    @Nullable
     public AuditLogChange getChangeByKey(final String key)
     {
         return changes.get(key);
@@ -231,6 +252,7 @@ public Map<String, Object> getOptions()
      *
      * @return Possibly-null value corresponding to the specified key
      */
+    @Nullable
     @SuppressWarnings("unchecked")
     public <T> T getOptionByName(String name)
     {
@@ -252,6 +274,7 @@ public <T> T getOptionByName(String name)
      *
      * @return Possibly-null value corresponding to the specified option constant
      */
+    @Nullable
     public <T> T getOption(AuditLogOption option)
     {
         Checks.notNull(option, "Option");

src/main/java/net/dv8tion/jda/core/entities/EntityBuilder.java

@@ -485,9 +485,9 @@ public void createGuildVoiceStatePass(GuildImpl guildObj, JSONArray voiceStates)
         }
     }
 
-    public User createFakeUser(JSONObject user, boolean modifyCache) { return createUser(user, true, modifyCache); }
-    public User createUser(JSONObject user)     { return createUser(user, false, true); }
-    private User createUser(JSONObject user, boolean fake, boolean modifyCache)
+    public UserImpl createFakeUser(JSONObject user, boolean modifyCache) { return createUser(user, true, modifyCache); }
+    public UserImpl createUser(JSONObject user)     { return createUser(user, false, true); }
+    private UserImpl createUser(JSONObject user, boolean fake, boolean modifyCache)
     {
         final long id = user.getLong("id");
         UserImpl userObj;
@@ -1157,7 +1157,7 @@ public PermissionOverride createPermissionOverride(JSONObject override, Channel
         return permOverride.setAllow(allow).setDeny(deny);
     }
 
-    public Webhook createWebhook(JSONObject object)
+    public WebhookImpl createWebhook(JSONObject object)
     {
         final long id = object.getLong("id");
         final long guildId = object.getLong("guild_id");
@@ -1179,17 +1179,25 @@ public Webhook createWebhook(JSONObject object)
                     .put("avatar", avatar);
         User defaultUser = createFakeUser(fakeUser, false);
 
-        JSONObject ownerJson = object.getJSONObject("user");
-        final long userId = ownerJson.getLong("id");
-
-        User owner = api.getUserById(userId);
-        if (owner == null)
+        JSONObject ownerJson = object.optJSONObject("user");
+        User owner = null;
+
+        if (ownerJson != null)
         {
-            ownerJson.put("id", userId);
-            owner = createFakeUser(ownerJson, false);
-        }
+            final long userId = ownerJson.getLong("id");
 
-        return new WebhookImpl(channel, id).setToken(token).setOwner(channel.getGuild().getMember(owner)).setUser(defaultUser);
+            owner = api.getUserById(userId);
+            if (owner == null)
+            {
+                ownerJson.put("id", userId);
+                owner = createFakeUser(ownerJson, false);
+            }
+        }
+
+        return new WebhookImpl(channel, id)
+                .setToken(token)
+                .setOwner(owner == null ? null : channel.getGuild().getMember(owner))
+                .setUser(defaultUser);
     }
 
     public Relationship createRelationship(JSONObject relationshipJson)
@@ -1366,7 +1374,7 @@ public AuthorizedApplication createAuthorizedApplication(JSONObject object)
         return new AuthorizedApplicationImpl(api, authId, description, iconId, id, name, scopes);
     }
 
-    public AuditLogEntry createAuditLogEntry(GuildImpl guild, JSONObject entryJson, JSONObject userJson)
+    public AuditLogEntry createAuditLogEntry(GuildImpl guild, JSONObject entryJson, JSONObject userJson, JSONObject webhookJson)
     {
         final long targetId = Helpers.optLong(entryJson, "target_id", 0);
         final long id = entryJson.getLong("id");
@@ -1375,7 +1383,8 @@ public AuditLogEntry createAuditLogEntry(GuildImpl guild, JSONObject entryJson,
         final JSONObject options = entryJson.isNull("options") ? null : entryJson.getJSONObject("options");
         final String reason = entryJson.optString("reason", null);
 
-        final UserImpl user = (UserImpl) createFakeUser(userJson, false);
+        final UserImpl user = userJson == null ? null : createFakeUser(userJson, false);
+        final WebhookImpl webhook = webhookJson == null ? null : createWebhook(webhookJson);
         final Set<AuditLogChange> changesList;
         final ActionType type = ActionType.from(typeKey);
 
@@ -1398,7 +1407,7 @@ public AuditLogEntry createAuditLogEntry(GuildImpl guild, JSONObject entryJson,
         CaseInsensitiveMap<String, Object> optionMap = options != null
                 ? new CaseInsensitiveMap<>(options.toMap()) : null;
 
-        return new AuditLogEntry(type, id, targetId, guild, user, reason, changeMap, optionMap);
+        return new AuditLogEntry(type, id, targetId, guild, user, webhook, reason, changeMap, optionMap);
     }
 
     public AuditLogChange createAuditLogChange(JSONObject change)

src/main/java/net/dv8tion/jda/core/entities/Webhook.java

@@ -23,13 +23,14 @@
 import net.dv8tion.jda.webhook.WebhookClientBuilder;
 
 import javax.annotation.CheckReturnValue;
+import javax.annotation.Nullable;
 
 /**
  * An object representing Webhooks in Discord
  *
  * @since  3.0
  */
-public interface Webhook extends ISnowflake
+public interface Webhook extends ISnowflake, IFakeable
 {
 
     /**
@@ -57,11 +58,12 @@ public interface Webhook extends ISnowflake
     TextChannel getChannel();
 
     /**
-     * The owner of this Webhook.
+     * The owner of this Webhook. This will be null for fake Webhooks, such as those retrieved from Audit Logs.
      *
-     * @return A {@link net.dv8tion.jda.core.entities.Member Member} instance
-     *         representing the owner of this Webhook
+     * @return Possibly-null {@link net.dv8tion.jda.core.entities.Member Member} instance
+     *         representing the owner of this Webhook.
      */
+    @Nullable
     Member getOwner();
 
     /**
@@ -96,15 +98,19 @@ public interface Webhook extends ISnowflake
      * The execute token for this Webhook.
      * <br>This can be used to modify/delete/execute
      * this Webhook.
+     * 
+     * <p><b>Note: Fake Webhooks, such as those retrieved from Audit Logs, do not contain a token</b>
      *
      * @return The execute token for this Webhook
      */
+    @Nullable
     String getToken();
 
     /**
      * The {@code POST} route for this Webhook.
      * <br>This contains the {@link #getToken() token} and {@link #getId() id}
-     * of this Webhook.
+     * of this Webhook. Fake Webhooks without tokens (such as those retrieved from Audit Logs)
+     * will return a URL without a token.
      *
      * <p>The route returned by this method does not need permission checks
      * to be executed.
@@ -122,6 +128,9 @@ public interface Webhook extends ISnowflake
     /**
      * Deletes this Webhook.
      *
+     * @throws IllegalStateException 
+     *         if the Webhook is fake, such as the Webhooks retrieved from Audit Logs
+     * 
      * @return {@link net.dv8tion.jda.core.requests.restaction.AuditableRestAction AuditableRestAction}
      *         <br>The rest action to delete this Webhook.
      */
@@ -135,6 +144,9 @@ public interface Webhook extends ISnowflake
      * @throws net.dv8tion.jda.core.exceptions.InsufficientPermissionException
      *         If the currently logged in account does not have {@link net.dv8tion.jda.core.Permission#MANAGE_WEBHOOKS Permission.MANAGE_WEBHOOKS}
      *
+     * @throws IllegalStateException 
+     *         if the Webhook is fake, such as the Webhooks retrieved from Audit Logs
+     * 
      * @return The {@link net.dv8tion.jda.core.managers.WebhookManager WebhookManager} for this Webhook
      */
     WebhookManager getManager();
@@ -160,6 +172,9 @@ public interface Webhook extends ISnowflake
      *
      * <p><b><u>Remember to close the WebhookClient once you don't need it anymore to free resources!</u></b>
      *
+     * @throws IllegalStateException 
+     *         if the Webhook is fake, such as the Webhooks retrieved from Audit Logs
+     * 
      * @return The new WebhookClientBuilder
      */
     WebhookClientBuilder newClient();

src/main/java/net/dv8tion/jda/core/entities/impl/WebhookImpl.java

@@ -99,12 +99,15 @@ public String getToken()
     @Override
     public String getUrl()
     {
-        return Requester.DISCORD_API_PREFIX + "webhooks/" + getId() + "/" + getToken();
+        return Requester.DISCORD_API_PREFIX + "webhooks/" + getId() + (getToken() == null ? "" : "/" + getToken());
     }
 
     @Override
     public AuditableRestAction<Void> delete()
     {
+        if (isFake())
+            throw new IllegalStateException("Fake Webhooks (such as those retrieved from Audit Logs) "
+                    + "cannot be used for deletion!");
         Route.CompiledRoute route = Route.Webhooks.DELETE_TOKEN_WEBHOOK.compile(getId(), token);
         return new AuditableRestAction<Void>(getJDA(), route)
         {
@@ -122,6 +125,9 @@ protected void handleResponse(Response response, Request<Void> request)
     @Override
     public WebhookManager getManager()
     {
+        if (isFake())
+            throw new IllegalStateException("Fake Webhooks (such as those retrieved from Audit Logs) "
+                    + "cannot provide a WebhookManager!");
         WebhookManager mng = manager;
         if (mng == null)
         {
@@ -155,6 +161,9 @@ public net.dv8tion.jda.core.managers.WebhookManagerUpdatable getManagerUpdatable
     @Override
     public WebhookClientBuilder newClient()
     {
+        if (isFake())
+            throw new IllegalStateException("Fake Webhooks (such as those retrieved from Audit Logs) "
+                    + "cannot be used to create a WebhookClient!");
         return new WebhookClientBuilder(id, token);
     }
 
@@ -164,6 +173,12 @@ public long getIdLong()
         return id;
     }
 
+    @Override
+    public boolean isFake()
+    {
+        return token == null;
+    }
+
     /* -- Impl Setters -- */
 
     public WebhookImpl setOwner(Member member)

src/main/java/net/dv8tion/jda/core/requests/restaction/pagination/AuditLogPaginationAction.java

@@ -29,6 +29,7 @@
 import net.dv8tion.jda.core.requests.Request;
 import net.dv8tion.jda.core.requests.Response;
 import net.dv8tion.jda.core.requests.Route;
+import net.dv8tion.jda.core.utils.Helpers;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
@@ -193,6 +194,7 @@ protected void handleResponse(Response response, Request<List<AuditLogEntry>> re
 
         JSONObject obj = response.getObject();
         JSONArray users = obj.getJSONArray("users");
+        JSONArray webhooks = obj.getJSONArray("webhooks");
         JSONArray entries = obj.getJSONArray("audit_log_entries");
 
         List<AuditLogEntry> list = new ArrayList<>(entries.length());
@@ -204,13 +206,22 @@ protected void handleResponse(Response response, Request<List<AuditLogEntry>> re
             JSONObject user = users.getJSONObject(i);
             userMap.put(user.getLong("id"), user);
         }
+
+        TLongObjectMap<JSONObject> webhookMap = new TLongObjectHashMap<>();
+        for (int i = 0; i < webhooks.length(); i++)
+        {
+            JSONObject webhook = webhooks.getJSONObject(i);
+            webhookMap.put(webhook.getLong("id"), webhook);
+        }
+
         for (int i = 0; i < entries.length(); i++)
         {
             try
             {
                 JSONObject entry = entries.getJSONObject(i);
-                JSONObject user = userMap.get(entry.getLong("user_id"));
-                AuditLogEntry result = builder.createAuditLogEntry((GuildImpl) guild, entry, user);
+                JSONObject user = userMap.get(Helpers.optLong(entry, "user_id", 0));
+                JSONObject webhook = webhookMap.get(Helpers.optLong(entry, "target_id", 0));
+                AuditLogEntry result = builder.createAuditLogEntry((GuildImpl) guild, entry, user, webhook);
                 list.add(result);
                 if (this.useCache)
                     this.cached.add(result);