webxdc (#2174)

* add new w30 APIs

* create the webview,
disable internet access,
inject deltachat.js

* connect deltachat to the webview

* promisify api

* use msgActionButton to start the w30 apps

* cleanup

- create observers in onCreate() to avoid memory leak,
- derive from WebViewActivity to easier deal with particularities
  and to saves >100 loc
- reorder some methods to reflect lifetimes

* make it more clear, which uri-part is 'domain' and which one is 'path'

* unify logging

* it is 'statusUpdate' not 'stateUpdate'; not sure if promise is needed at the end, we can readd that as needed, simple code for now

* use core implementation for status updates

* disable debugging enabled by default, streamline code

* use same name for InternalJSApi for both, js and java

* getStatusUpdates() always return an array

* call JSON.stringify() on payload

* fix typo, fix equal operator

* use shorter function names in js land

* adapt to new zipped w30 format

* load any file from w30 archives

* add fallback if getMimeTypeFromExtension() fails

* rename w30 to webxdc

* add selfName()

* return selfAddr() if selfName() is empty

* rename deltachat.js to webxdc.js

* observer correct event

* rename getBlobFromArchive() to getWebxdcBlob()

* show webxdc app name in title bar

* swap payload and descr in sendUpdate() (adapt to new core api)

* allow user-defined-texts for webxdc apps, make room for icon+name

* show webxdc icon and name in chats

* render webxdc drafts accordingly

* allow configuring drafts

* do not destroy webxdc-message to be sent out by removing it via setDraft(null)

* fix crash when replying to webxdc messages

* add webxdc messages to profile's document tab

* hide 'search menu' for webxdc apps

* show app summary beside app icon

* remove outdated comment

* add precautious WebView restrictions

* Update src/org/thoughtcrime/securesms/ConversationItem.java

Co-authored-by: Asiel Díaz Benítez <adbenitez@nauta.cu>

* Update src/org/thoughtcrime/securesms/ConversationItem.java

Co-authored-by: Asiel Díaz Benítez <adbenitez@nauta.cu>

* Update src/org/thoughtcrime/securesms/ConversationActivity.java

Co-authored-by: Hocuri <hocuri@gmx.de>

* Webxdc requires at least Android 5 Lollipop

see https://github.com/deltachat/deltachat-android/pull/2174#discussion_r785436874

* recognize .xdc files on android10

based on @Hocuri's findings in #2188

Co-authored-by: Simon Laux <mobile.info@simonlaux.de>
Co-authored-by: adbenitez <asieldbenitez@gmail.com>
Co-authored-by: Asiel Díaz Benítez <adbenitez@nauta.cu>
Co-authored-by: Hocuri <hocuri@gmx.de>

AndroidManifest.xml

@@ -277,6 +277,11 @@
               android:configChanges="touchscreen|keyboard|keyboardHidden|orientation|screenLayout|screenSize">
     </activity>
 
+    <activity android:name=".WebxdcActivity"
+              android:theme="@style/TextSecure.LightTheme"
+              android:configChanges="touchscreen|keyboard|keyboardHidden|orientation|screenLayout|screenSize">
+    </activity>
+
     <activity android:name=".FullMsgActivity"
         android:theme="@style/TextSecure.LightTheme"
         android:configChanges="touchscreen|keyboard|keyboardHidden|orientation|screenLayout|screenSize">

jni/dc_wrapper.c

@@ -86,6 +86,19 @@ static jstring jstring_new__(JNIEnv* env, const char* a)
 #define CTIMESTAMP(a) (((jlong)a)/((jlong)1000))
 
 
+static jbyteArray ptr2jbyteArray(JNIEnv *env, const void* ptr, size_t len) {
+    if (ptr == NULL || len <= 0) {
+        return NULL;
+    }
+    jbyteArray ret = (*env)->NewByteArray(env, len);
+    if (ret == NULL) {
+        return NULL;
+    }
+    (*env)->SetByteArrayRegion(env, ret, 0, len, (const jbyte*)ptr);
+    return ret;
+}
+
+
 static jintArray dc_array2jintArray_n_unref(JNIEnv *env, dc_array_t* ca)
 {
     /* takes a C-array of type dc_array_t and converts it it a Java-Array.
@@ -704,6 +717,26 @@ JNIEXPORT jint Java_com_b44t_messenger_DcContext_sendVideochatInvitation(JNIEnv
 }
 
 
+JNIEXPORT jboolean Java_com_b44t_messenger_DcContext_sendWebxdcStatusUpdate(JNIEnv *env, jobject obj, jint msg_id, jstring payload, jstring descr)
+{
+    CHAR_REF(payload);
+    CHAR_REF(descr);
+        jboolean ret = dc_send_webxdc_status_update(get_dc_context(env, obj), msg_id, payloadPtr, descrPtr) != 0;
+    CHAR_UNREF(descr);
+    CHAR_UNREF(payload);
+    return ret;
+}
+
+
+JNIEXPORT jstring Java_com_b44t_messenger_DcContext_getWebxdcStatusUpdates(JNIEnv *env, jobject obj, jint msg_id, jint status_update_id)
+{
+    char* temp = dc_get_webxdc_status_updates(get_dc_context(env, obj), msg_id, status_update_id);
+        jstring ret = JSTRING_NEW(temp);
+    dc_str_unref(temp);
+    return ret;
+}
+
+
 JNIEXPORT jint Java_com_b44t_messenger_DcContext_addDeviceMsg(JNIEnv *env, jobject obj, jstring label, jobject msg)
 {
     CHAR_REF(label);
@@ -1528,6 +1561,28 @@ JNIEXPORT jstring Java_com_b44t_messenger_DcMsg_getFilename(JNIEnv *env, jobject
 }
 
 
+JNIEXPORT jbyteArray Java_com_b44t_messenger_DcMsg_getWebxdcBlob(JNIEnv *env, jobject obj, jstring filename)
+{
+    jbyteArray ret = NULL;
+    CHAR_REF(filename)
+        size_t ptrSize = 0;
+        char* ptr = dc_msg_get_webxdc_blob(get_dc_msg(env, obj), filenamePtr, &ptrSize);
+        ret = ptr2jbyteArray(env, ptr, ptrSize);
+        dc_str_unref(ptr);
+    CHAR_UNREF(filename)
+    return ret;
+}
+
+
+JNIEXPORT jstring Java_com_b44t_messenger_DcMsg_getWebxdcInfoJson(JNIEnv *env, jobject obj)
+{
+    char* temp = dc_msg_get_webxdc_info(get_dc_msg(env, obj));
+        jstring ret =  JSTRING_NEW(temp);
+    dc_str_unref(temp);
+    return ret;
+}
+
+
 JNIEXPORT jboolean Java_com_b44t_messenger_DcMsg_isForwarded(JNIEnv *env, jobject obj)
 {
     return dc_msg_is_forwarded(get_dc_msg(env, obj))!=0;

res/layout/conversation_activity_attachment_editor_stub.xml

@@ -58,6 +58,17 @@
                 android:padding="8dp"
                 android:background="@drawable/message_bubble_background_sent_alone"/>
 
+        <org.thoughtcrime.securesms.components.WebxdcView
+                android:id="@+id/attachment_webxdc"
+                android:layout_width="230dp"
+                android:layout_height="wrap_content"
+                android:visibility="gone"
+                android:layout_marginTop="10dp"
+                android:layout_marginLeft="10dp"
+                android:layout_marginRight="10dp"
+                android:padding="8dp"
+                android:background="@drawable/message_bubble_background_sent_alone"/>
+
     </org.thoughtcrime.securesms.components.RemovableEditableMediaView>
 
 </FrameLayout>

res/layout/conversation_item_received.xml

@@ -143,6 +143,16 @@
                 android:layout_marginLeft="@dimen/message_bubble_horizontal_padding"
                 android:layout_marginRight="@dimen/message_bubble_horizontal_padding" />
 
+            <ViewStub
+                android:id="@+id/webxdc_view_stub"
+                android:layout="@layout/conversation_item_webxdc"
+                android:layout_width="210dp"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="@dimen/message_bubble_top_padding"
+                android:layout_marginBottom="@dimen/message_bubble_collapsed_footer_padding"
+                android:layout_marginLeft="@dimen/message_bubble_horizontal_padding"
+                android:layout_marginRight="@dimen/message_bubble_horizontal_padding" />
+
             <org.thoughtcrime.securesms.components.emoji.EmojiTextView
                 android:id="@+id/conversation_item_body"
                 android:layout_width="wrap_content"

res/layout/conversation_item_sent.xml

@@ -121,6 +121,16 @@
                 android:layout_marginLeft="@dimen/message_bubble_horizontal_padding"
                 android:layout_marginRight="@dimen/message_bubble_horizontal_padding" />
 
+            <ViewStub
+                android:id="@+id/webxdc_view_stub"
+                android:layout="@layout/conversation_item_webxdc"
+                android:layout_width="210dp"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="@dimen/message_bubble_top_padding"
+                android:layout_marginBottom="@dimen/message_bubble_collapsed_footer_padding"
+                android:layout_marginLeft="@dimen/message_bubble_horizontal_padding"
+                android:layout_marginRight="@dimen/message_bubble_horizontal_padding" />
+
             <org.thoughtcrime.securesms.components.emoji.EmojiTextView
                 android:id="@+id/conversation_item_body"
                 android:layout_width="wrap_content"

res/layout/conversation_item_webxdc.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<org.thoughtcrime.securesms.components.WebxdcView
+        xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto"
+        xmlns:tools="http://schemas.android.com/tools"
+        android:id="@+id/webxdc_view"
+        android:layout_width="210dp"
+        android:layout_height="wrap_content"
+        android:visibility="gone"
+        tools:visibility="visible"/>

res/layout/webxdc_view.xml

@@ -0,0 +1,55 @@
+<?xml version="1.0" encoding="utf-8"?>
+<merge xmlns:android="http://schemas.android.com/apk/res/android"
+       xmlns:tools="http://schemas.android.com/tools"
+       xmlns:app="http://schemas.android.com/apk/res-auto"
+       tools:context="org.thoughtcrime.securesms.components.WebxdcView">
+
+        <LinearLayout android:id="@+id/webxdc_container"
+                      android:layout_width="fill_parent"
+                      android:layout_height="wrap_content"
+                      android:clickable="false"
+                      android:focusable="false"
+                      android:gravity="center_vertical"
+                      android:orientation="horizontal">
+
+            <androidx.appcompat.widget.AppCompatImageView
+                android:id="@+id/webxdc_icon"
+                android:layout_marginTop="2dp"
+                android:layout_width="72dp"
+                android:layout_height="72dp"
+                android:scaleType="fitCenter"
+                app:srcCompat="@drawable/ic_chevron_up"/>
+
+            <LinearLayout android:layout_width="match_parent"
+                          android:layout_height="wrap_content"
+                          android:layout_marginTop="2dp"
+                          android:layout_marginLeft="6dp"
+                          android:layout_marginStart="6dp"
+                          android:orientation="vertical"
+                          android:focusable="false"
+                          android:clickable="false">
+
+                <TextView android:id="@+id/webxdc_app_name"
+                          android:layout_width="match_parent"
+                          android:layout_height="wrap_content"
+                          style="@style/Signal.Text.Body"
+                          android:singleLine="true"
+                          android:maxLines="1"
+                          android:clickable="false"
+                          android:ellipsize="end"
+                          android:textColor="?conversation_item_incoming_text_primary_color"
+                          android:textStyle="bold"
+                          tools:text="Great App"/>
+
+                <TextView android:id="@+id/webxdc_subtitle"
+                          android:layout_width="wrap_content"
+                          android:layout_height="wrap_content"
+                          android:maxLines="1"
+                          android:ellipsize="end"
+                          style="@style/Signal.Text.Caption"
+                          android:clickable="false"
+                          android:textColor="?conversation_item_incoming_text_primary_color"
+                          tools:text="24kb"/>
+            </LinearLayout>
+        </LinearLayout>
+</merge>

res/raw/webxdc.js

@@ -0,0 +1,26 @@
+window.webxdc = (() => {
+  var update_listener = () => {};
+
+  window.__webxdcUpdate = (updateId) => {
+    var updates = JSON.parse(InternalJSApi.getStatusUpdates(updateId));
+    if (updates.length === 1) {
+      update_listener(updates[0]);
+    }
+  };
+
+  return {
+    selfAddr: () => InternalJSApi.selfAddr(),
+
+    selfName: () => InternalJSApi.selfName(),
+
+    setUpdateListener: (cb) => (update_listener = cb),
+
+    getAllUpdates: () => {
+      return JSON.parse(InternalJSApi.getStatusUpdates(0));
+    },
+
+    sendUpdate: (payload, descr) => {
+      InternalJSApi.sendStatusUpdate(JSON.stringify(payload), descr);
+    },
+  };
+})();

src/com/b44t/messenger/DcContext.java

@@ -27,6 +27,7 @@ public class DcContext {
     public final static int DC_EVENT_SECUREJOIN_JOINER_PROGRESS  = 2061;
     public final static int DC_EVENT_CONNECTIVITY_CHANGED        = 2100;
     public final static int DC_EVENT_SELFAVATAR_CHANGED          = 2110;
+    public final static int DC_EVENT_WEBXDC_STATUS_UPDATE        = 2120;
 
     public final static int DC_IMEX_EXPORT_SELF_KEYS = 1;
     public final static int DC_IMEX_IMPORT_SELF_KEYS = 2;
@@ -195,6 +196,8 @@ public class DcContext {
     public native int          sendMsg              (int chat_id, DcMsg msg);
     public native int          sendTextMsg          (int chat_id, String text);
     public native int          sendVideochatInvitation(int chat_id);
+    public native boolean      sendWebxdcStatusUpdate(int msg_id, String payload, String descr);
+    public native String       getWebxdcStatusUpdates(int msg_id, int status_update_id);
     public native int          addDeviceMsg         (String label, DcMsg msg);
     public native boolean      wasDeviceMsgEverAdded(String label);
     public DcLot               checkQr              (String qr) { return new DcLot(checkQrCPtr(qr)); }

src/com/b44t/messenger/DcMsg.java

@@ -1,5 +1,8 @@
 package com.b44t.messenger;
 
+import org.json.JSONException;
+import org.json.JSONObject;
+
 import java.io.File;
 import java.util.Set;
 
@@ -15,12 +18,14 @@ public class DcMsg {
     public final static int DC_MSG_VIDEO = 50;
     public final static int DC_MSG_FILE = 60;
     public final static int DC_MSG_VIDEOCHAT_INVITATION = 70;
+    public final static int DC_MSG_WEBXDC = 80;
 
     public final static int DC_STATE_UNDEFINED =  0;
     public final static int DC_STATE_IN_FRESH = 10;
     public final static int DC_STATE_IN_NOTICED = 13;
     public final static int DC_STATE_IN_SEEN = 16;
     public final static int DC_STATE_OUT_PREPARING = 18;
+    public final static int DC_STATE_OUT_DRAFT = 19;
     public final static int DC_STATE_OUT_PENDING = 20;
     public final static int DC_STATE_OUT_ERROR = 24;
     public final static int DC_STATE_OUT_DELIVERED = 26;
@@ -110,6 +115,15 @@ public class DcMsg {
     public native String  getFilemime        ();
     public native String  getFilename        ();
     public native long    getFilebytes       ();
+    public native byte[]  getWebxdcBlob      (String filename);
+    public JSONObject     getWebxdcInfo      () {
+      try {
+        return new JSONObject(getWebxdcInfoJson());
+      } catch(Exception e) {
+        e.printStackTrace();
+        return new JSONObject();
+      }
+    }
     public native boolean isForwarded        ();
     public native boolean isInfo             ();
     public native boolean isSetupMessage     ();
@@ -206,4 +220,5 @@ public class DcMsg {
     private native long getSummaryCPtr  (long chatCPtr);
     private native void setQuoteCPtr    (long quoteCPtr);
     private native long getQuotedMsgCPtr ();
+    private native String getWebxdcInfoJson ();
 };

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -46,6 +46,7 @@ import android.view.View.OnFocusChangeListener;
 import android.view.View.OnKeyListener;
 import android.view.WindowManager;
 import android.view.inputmethod.EditorInfo;
+import android.webkit.MimeTypeMap;
 import android.widget.ImageButton;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
@@ -836,6 +837,9 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
       case DcMsg.DC_MSG_VIDEO:
         setMedia(uri, MediaType.VIDEO).addListener(listener);
         break;
+      case DcMsg.DC_MSG_WEBXDC:
+        setMedia(draft, MediaType.DOCUMENT).addListener(listener);
+        break;
       default:
         setMedia(uri, MediaType.DOCUMENT).addListener(listener);
         break;
@@ -1012,7 +1016,11 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
       return new SettableFuture<>(false);
     }
 
-    return attachmentManager.setMedia(glideRequests, uri, mediaType, 0, 0);
+    return attachmentManager.setMedia(glideRequests, uri, null, mediaType, 0, 0, chatId);
+  }
+
+  private ListenableFuture<Boolean> setMedia(DcMsg msg, @NonNull MediaType mediaType) {
+    return attachmentManager.setMedia(glideRequests, Uri.fromFile(new File(msg.getFile())), msg, mediaType, 0, 0, chatId);
   }
 
   private void addAttachmentContactInfo(Intent data) {
@@ -1029,7 +1037,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
     return dcChat.getVisibility() == DcChat.DC_CHAT_VISIBILITY_ARCHIVED;
   }
 
-  private String getRealPathFromAttachment(Attachment attachment) {
+  public static String getRealPathFromAttachment(Context context, Attachment attachment) {
     try {
       // get file in the blobdir as `<blobdir>/<name>[-<uniqueNumber>].<ext>`
       String filename = attachment.getFileName();
@@ -1045,11 +1053,11 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
           filename = filename.substring(0, i);
         }
       }
-      String path = DcHelper.getBlobdirFile(dcContext, filename, ext);
+      String path = DcHelper.getBlobdirFile(DcHelper.getContext(context), filename, ext);
 
       // copy content to this file
       if(path!=null) {
-        InputStream inputStream = PartAuthority.getAttachmentStream(this, attachment.getDataUri());
+        InputStream inputStream = PartAuthority.getAttachmentStream(context, attachment.getDataUri());
         OutputStream outputStream = new FileOutputStream(path);
         Util.copy(inputStream, outputStream);
       }
@@ -1095,29 +1103,30 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
       }
 
       try {
-        List<Attachment> attachments = slideDeck.asAttachments();
+        if (slideDeck.getWebxdctDraftId() != 0) {
-        for (Attachment attachment : attachments) {
+          msg = dcContext.getDraft(chatId);
-          String contentType = attachment.getContentType();
+        } else {
-          if (MediaUtil.isImageType(contentType) && slideDeck.getDocumentSlide()==null) {
+          List<Attachment> attachments = slideDeck.asAttachments();
-            msg = new DcMsg(dcContext,
+          for (Attachment attachment : attachments) {
-                    MediaUtil.isGif(contentType) ? DcMsg.DC_MSG_GIF : DcMsg.DC_MSG_IMAGE);
+            String contentType = attachment.getContentType();
-            msg.setDimension(attachment.getWidth(), attachment.getHeight());
+            if (MediaUtil.isImageType(contentType) && slideDeck.getDocumentSlide() == null) {
+              msg = new DcMsg(dcContext,
+                MediaUtil.isGif(contentType) ? DcMsg.DC_MSG_GIF : DcMsg.DC_MSG_IMAGE);
+              msg.setDimension(attachment.getWidth(), attachment.getHeight());
+            } else if (MediaUtil.isAudioType(contentType)) {
+              msg = new DcMsg(dcContext,
+                attachment.isVoiceNote() ? DcMsg.DC_MSG_VOICE : DcMsg.DC_MSG_AUDIO);
+            } else if (MediaUtil.isVideoType(contentType) && slideDeck.getDocumentSlide() == null) {
+              msg = new DcMsg(dcContext, DcMsg.DC_MSG_VIDEO);
+              recompress = DcMsg.DC_MSG_VIDEO;
+            } else {
+              msg = new DcMsg(dcContext, DcMsg.DC_MSG_FILE);
+            }
+            String path = getRealPathFromAttachment(this, attachment);
+            msg.setFile(path, null);
           }
-          else if (MediaUtil.isAudioType(contentType)) {
-            msg = new DcMsg(dcContext,
-                attachment.isVoiceNote()? DcMsg.DC_MSG_VOICE : DcMsg.DC_MSG_AUDIO);
-          }
-          else if (MediaUtil.isVideoType(contentType) && slideDeck.getDocumentSlide()==null) {
-            msg = new DcMsg(dcContext, DcMsg.DC_MSG_VIDEO);
-            recompress = DcMsg.DC_MSG_VIDEO;
-          }
-          else {
-            msg = new DcMsg(dcContext, DcMsg.DC_MSG_FILE);
-          }
-          String path = getRealPathFromAttachment(attachment);
-          msg.setFile(path, null);
-          msg.setText(body);
         }
+        msg.setText(body);
       }
       catch(Exception e) {
         e.printStackTrace();
@@ -1140,7 +1149,12 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
         DcMsg msg = (DcMsg)param[0];
         Integer recompress = (Integer)param[1];
         if (action==ACTION_SEND_OUT) {
-          dcContext.setDraft(dcChat.getId(), null);
+
+          // for WEBXDC, drafts are just sent out as is.
+          // for preparations and other cases, cleanup draft soon.
+          if (msg.getType() != DcMsg.DC_MSG_WEBXDC) {
+            dcContext.setDraft(dcChat.getId(), null);
+          }
 
           if(msg!=null)
           {
@@ -1369,7 +1383,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
   private void sendSticker(@NonNull Uri uri, String contentType) {
     Attachment attachment = new UriAttachment(uri, null, contentType,
       AttachmentDatabase.TRANSFER_PROGRESS_STARTED, 0, 0, 0, null, null, false);
-    String path = getRealPathFromAttachment(attachment);
+    String path = getRealPathFromAttachment(this, attachment);
 
     Optional<QuoteModel> quote = inputPanel.getQuote();
     inputPanel.clearQuote();

src/org/thoughtcrime/securesms/ConversationItem.java

@@ -48,6 +48,7 @@ import org.thoughtcrime.securesms.components.ConversationItemFooter;
 import org.thoughtcrime.securesms.components.ConversationItemThumbnail;
 import org.thoughtcrime.securesms.components.DocumentView;
 import org.thoughtcrime.securesms.components.QuoteView;
+import org.thoughtcrime.securesms.components.WebxdcView;
 import org.thoughtcrime.securesms.components.emoji.EmojiTextView;
 import org.thoughtcrime.securesms.connect.DcHelper;
 import org.thoughtcrime.securesms.mms.AudioSlide;
@@ -107,6 +108,7 @@ public class ConversationItem extends BaseConversationItem
   private @NonNull  Stub<ConversationItemThumbnail> mediaThumbnailStub;
   private @NonNull  Stub<AudioView>                 audioViewStub;
   private @NonNull  Stub<DocumentView>              documentViewStub;
+  private @NonNull  Stub<WebxdcView>                webxdcViewStub;
   private           Stub<BorderlessImageView>       stickerStub;
   private @Nullable EventListener                   eventListener;
 
@@ -139,6 +141,7 @@ public class ConversationItem extends BaseConversationItem
     this.mediaThumbnailStub      = new Stub<>(findViewById(R.id.image_view_stub));
     this.audioViewStub           = new Stub<>(findViewById(R.id.audio_view_stub));
     this.documentViewStub        = new Stub<>(findViewById(R.id.document_view_stub));
+    this.webxdcViewStub          = new Stub<>(findViewById(R.id.webxdc_view_stub));
     this.stickerStub             = new Stub<>(findViewById(R.id.sticker_view_stub));
     this.groupSenderHolder       =            findViewById(R.id.group_sender_holder);
     this.quoteView               =            findViewById(R.id.quote_view);
@@ -289,6 +292,11 @@ public class ConversationItem extends BaseConversationItem
       documentViewStub.get().setFocusable(!shouldInterceptClicks(messageRecord) && batchSelected.isEmpty());
       documentViewStub.get().setClickable(batchSelected.isEmpty());
     }
+
+    if (webxdcViewStub.resolved()) {
+      webxdcViewStub.get().setFocusable(!shouldInterceptClicks(messageRecord) && batchSelected.isEmpty());
+      webxdcViewStub.get().setClickable(batchSelected.isEmpty());
+    }
   }
 
   private boolean hasAudio(DcMsg messageRecord) {
@@ -313,9 +321,14 @@ public class ConversationItem extends BaseConversationItem
     return hasThumbnail(messageRecord) &&
 	   !hasAudio(messageRecord)    &&
 	   !hasDocument(messageRecord) &&
+	   !hasWebxdc(messageRecord) &&
 	   !hasSticker(messageRecord);
   }
 
+  private boolean hasWebxdc(DcMsg dcMsg) {
+    return dcMsg.getType()==DcMsg.DC_MSG_WEBXDC;
+  }
+
   private boolean hasDocument(DcMsg dcMsg) {
     return dcMsg.getType()==DcMsg.DC_MSG_FILE && !dcMsg.isSetupMessage();
   }
@@ -361,6 +374,17 @@ public class ConversationItem extends BaseConversationItem
           passthroughClickListener.onClick(view);
         }
       });
+    } else if (messageRecord.getType() == DcMsg.DC_MSG_WEBXDC) {
+      msgActionButton.setVisibility(View.VISIBLE);
+      msgActionButton.setEnabled(true);
+      msgActionButton.setText("Start…");
+      msgActionButton.setOnClickListener(view -> {
+        if (batchSelected.isEmpty()) {
+          WebxdcActivity.openWebxdcActivity(getContext(), messageRecord);
+        } else {
+          passthroughClickListener.onClick(view);
+        }
+      });
     }
     else if (messageRecord.hasHtml()) {
       msgActionButton.setVisibility(View.VISIBLE);
@@ -401,6 +425,7 @@ public class ConversationItem extends BaseConversationItem
       audioViewStub.get().setVisibility(View.VISIBLE);
       if (mediaThumbnailStub.resolved()) mediaThumbnailStub.get().setVisibility(View.GONE);
       if (documentViewStub.resolved())   documentViewStub.get().setVisibility(View.GONE);
+      if (webxdcViewStub.resolved())     webxdcViewStub.get().setVisibility(View.GONE);
       if (stickerStub.resolved())        stickerStub.get().setVisibility(View.GONE);
 
       //noinspection ConstantConditions
@@ -422,6 +447,7 @@ public class ConversationItem extends BaseConversationItem
       documentViewStub.get().setVisibility(View.VISIBLE);
       if (mediaThumbnailStub.resolved()) mediaThumbnailStub.get().setVisibility(View.GONE);
       if (audioViewStub.resolved())      audioViewStub.get().setVisibility(View.GONE);
+      if (webxdcViewStub.resolved())     webxdcViewStub.get().setVisibility(View.GONE);
       if (stickerStub.resolved())        stickerStub.get().setVisibility(View.GONE);
 
       //noinspection ConstantConditions
@@ -433,10 +459,26 @@ public class ConversationItem extends BaseConversationItem
       ViewUtil.updateLayoutParams(groupSenderHolder, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
       footer.setVisibility(VISIBLE);
     }
+    else if (hasWebxdc(messageRecord)) {
+      webxdcViewStub.get().setVisibility(View.VISIBLE);
+      if (mediaThumbnailStub.resolved()) mediaThumbnailStub.get().setVisibility(View.GONE);
+      if (audioViewStub.resolved())      audioViewStub.get().setVisibility(View.GONE);
+      if (documentViewStub.resolved())   documentViewStub.get().setVisibility(View.GONE);
+      if (stickerStub.resolved())        stickerStub.get().setVisibility(View.GONE);
+
+      webxdcViewStub.get().setWebxdc(messageRecord);
+      webxdcViewStub.get().setWebxdcClickListener(new ThumbnailClickListener());
+      webxdcViewStub.get().setOnLongClickListener(passthroughClickListener);
+
+      ViewUtil.updateLayoutParams(bodyText, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
+      ViewUtil.updateLayoutParams(groupSenderHolder, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
+      footer.setVisibility(VISIBLE);
+    }
     else if (hasThumbnail(messageRecord)) {
       mediaThumbnailStub.get().setVisibility(View.VISIBLE);
       if (audioViewStub.resolved())    audioViewStub.get().setVisibility(View.GONE);
       if (documentViewStub.resolved()) documentViewStub.get().setVisibility(View.GONE);
+      if (webxdcViewStub.resolved())   webxdcViewStub.get().setVisibility(View.GONE);
       if (stickerStub.resolved())        stickerStub.get().setVisibility(View.GONE);
 
       Slide slide = MediaUtil.getSlideForMsg(context, messageRecord);
@@ -473,6 +515,7 @@ public class ConversationItem extends BaseConversationItem
       stickerStub.get().setVisibility(View.VISIBLE);
       if (audioViewStub.resolved())      audioViewStub.get().setVisibility(View.GONE);
       if (documentViewStub.resolved())   documentViewStub.get().setVisibility(View.GONE);
+      if (webxdcViewStub.resolved())     webxdcViewStub.get().setVisibility(View.GONE);
       if (mediaThumbnailStub.resolved()) mediaThumbnailStub.get().setVisibility(View.GONE);
 
       bodyBubble.setBackgroundColor(Color.TRANSPARENT);
@@ -492,6 +535,7 @@ public class ConversationItem extends BaseConversationItem
       if (mediaThumbnailStub.resolved()) mediaThumbnailStub.get().setVisibility(View.GONE);
       if (audioViewStub.resolved())      audioViewStub.get().setVisibility(View.GONE);
       if (documentViewStub.resolved())   documentViewStub.get().setVisibility(View.GONE);
+      if (webxdcViewStub.resolved())     webxdcViewStub.get().setVisibility(View.GONE);
 
       ViewUtil.updateLayoutParams(bodyText, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
       ViewUtil.updateLayoutParams(groupSenderHolder, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
@@ -725,6 +769,8 @@ public class ConversationItem extends BaseConversationItem
     public void onClick(final View v, final Slide slide) {
       if (shouldInterceptClicks(messageRecord) || !batchSelected.isEmpty()) {
         performClick();
+      } else if (messageRecord.getType() == DcMsg.DC_MSG_WEBXDC) {
+        WebxdcActivity.openWebxdcActivity(context, messageRecord);
       } else if (MediaPreviewActivity.isTypeSupported(slide) && slide.getUri() != null) {
         Intent intent = new Intent(context, MediaPreviewActivity.class);
         intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

src/org/thoughtcrime/securesms/ProfileDocumentsFragment.java

@@ -103,7 +103,7 @@ public class ProfileDocumentsFragment
 
   @Override
   public Loader<BucketedThreadMediaLoader.BucketedThreadMedia> onCreateLoader(int i, Bundle bundle) {
-    return new BucketedThreadMediaLoader(getContext(), chatId, DcMsg.DC_MSG_FILE, DcMsg.DC_MSG_AUDIO, 0);
+    return new BucketedThreadMediaLoader(getContext(), chatId, DcMsg.DC_MSG_FILE, DcMsg.DC_MSG_AUDIO, DcMsg.DC_MSG_WEBXDC);
   }
 
   @Override

src/org/thoughtcrime/securesms/WebViewActivity.java

@@ -9,11 +9,14 @@ import android.util.Log;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
+import android.webkit.WebResourceRequest;
+import android.webkit.WebResourceResponse;
 import android.webkit.WebView;
 import android.webkit.WebViewClient;
 import android.widget.ImageView;
 import android.widget.Toast;
 
+import androidx.annotation.RequiresApi;
 import androidx.appcompat.widget.SearchView;
 import androidx.webkit.WebSettingsCompat;
 import androidx.webkit.WebViewFeature;
@@ -75,6 +78,26 @@ public class WebViewActivity extends PassphraseRequiredActionBarActivity
         // if we come over really useful things, we should allow that explicitly.
         return true;
       }
+
+      @Override
+      @SuppressWarnings("deprecation")
+      public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
+        WebResourceResponse res = interceptRequest(url);
+        if (res!=null) {
+          return res;
+        }
+        return super.shouldInterceptRequest(view, url);
+      }
+
+      @Override
+      @RequiresApi(21)
+      public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
+        WebResourceResponse res = interceptRequest(request.getUrl().toString());
+        if (res!=null) {
+          return res;
+        }
+        return super.shouldInterceptRequest(view, request);
+      }
     });
     webView.setFindListener(this);
 
@@ -245,6 +268,10 @@ public class WebViewActivity extends PassphraseRequiredActionBarActivity
     }
   }
 
+  protected WebResourceResponse interceptRequest(String url) {
+    return null;
+  }
+
   @Override
   public void onActivityResult(int reqCode, int resultCode, final Intent data) {
     super.onActivityResult(reqCode, resultCode, data);

src/org/thoughtcrime/securesms/WebxdcActivity.java

@@ -0,0 +1,172 @@
+package org.thoughtcrime.securesms;
+
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Build;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.util.Log;
+import android.view.Menu;
+import android.webkit.JavascriptInterface;
+import android.webkit.MimeTypeMap;
+import android.webkit.WebResourceResponse;
+import android.webkit.WebSettings;
+import android.widget.Toast;
+
+import androidx.annotation.NonNull;
+
+import com.b44t.messenger.DcContext;
+import com.b44t.messenger.DcEvent;
+import com.b44t.messenger.DcMsg;
+
+import org.json.JSONObject;
+import org.thoughtcrime.securesms.connect.DcEventCenter;
+import org.thoughtcrime.securesms.connect.DcHelper;
+import org.thoughtcrime.securesms.util.Util;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+
+public class WebxdcActivity extends WebViewActivity implements DcEventCenter.DcEventDelegate  {
+  private static final String TAG = WebxdcActivity.class.getSimpleName();
+  private static final String INTERNAL_SCHEMA = "webxdc";
+  private static final String INTERNAL_DOMAIN = "local.app";
+  private DcContext dcContext;
+  private DcMsg dcAppMsg;
+
+  public static void openWebxdcActivity(Context context, DcMsg instance) {
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+      Intent intent =new Intent(context, WebxdcActivity.class);
+      intent.putExtra("appMessageId", instance.getId());
+      context.startActivity(intent);
+    } else {
+      Toast.makeText(context, "At least Android 5.0 (Lollipop) required for Webxdc.", Toast.LENGTH_LONG).show();
+    }
+  }
+
+  @Override
+  protected void onCreate(Bundle state, boolean ready) {
+    super.onCreate(state, ready);
+    DcEventCenter eventCenter = DcHelper.getEventCenter(WebxdcActivity.this.getApplicationContext());
+    eventCenter.addObserver(DcContext.DC_EVENT_WEBXDC_STATUS_UPDATE, this);
+    
+    Bundle b = getIntent().getExtras();
+    int appMessageId = b.getInt("appMessageId");
+
+    this.dcContext = DcHelper.getContext(getApplicationContext());
+    this.dcAppMsg = this.dcContext.getMsg(appMessageId);
+
+    WebSettings webSettings = webView.getSettings();
+    webSettings.setJavaScriptEnabled(true);
+    webSettings.setAllowFileAccess(false);
+    webSettings.setBlockNetworkLoads(true);
+    webSettings.setAllowContentAccess(false);
+    webSettings.setGeolocationEnabled(false);
+    webSettings.setAllowFileAccessFromFileURLs(false);
+    webSettings.setAllowUniversalAccessFromFileURLs(false);
+    webView.addJavascriptInterface(new InternalJSApi(), "InternalJSApi");
+
+    webView.loadUrl(INTERNAL_SCHEMA + "://" + INTERNAL_DOMAIN + "/index.html");
+
+    Util.runOnAnyBackgroundThread(() -> {
+      JSONObject info = this.dcAppMsg.getWebxdcInfo();
+      Util.runOnMain(() -> {
+        try {
+          getSupportActionBar().setTitle(info.getString("name"));
+        } catch (Exception e) {
+          e.printStackTrace();
+        }
+      });
+    });
+  }
+
+  @Override
+  protected void onDestroy() {
+    DcHelper.getEventCenter(this.getApplicationContext()).removeObservers(this);
+    super.onDestroy();
+  }
+
+  @Override
+  public boolean onPrepareOptionsMenu(Menu menu) {
+    // do not call super.onPrepareOptionsMenu() as the default "Search" menu is not needed
+    return true;
+  }
+
+  @Override
+  protected void openOnlineUrl(String url) {
+    Toast.makeText(this, "Please embed needed resources.", Toast.LENGTH_LONG).show();
+  }
+
+  @Override
+  protected WebResourceResponse interceptRequest(String rawUrl) {
+    Log.i(TAG, "interceptRequest: " + rawUrl);
+    try {
+      if (rawUrl == null) {
+        throw new Exception("no url specified");
+      }
+      String path = Uri.parse(rawUrl).getPath();
+      if (path.equalsIgnoreCase("/webxdc.js")) {
+        InputStream targetStream = getResources().openRawResource(R.raw.webxdc);
+        return new WebResourceResponse("text/javascript", "UTF-8", targetStream);
+      } else {
+        byte[] blob = this.dcAppMsg.getWebxdcBlob(path);
+        if (blob == null) {
+          throw new Exception("\"" + path + "\" not found");
+        }
+        String ext = MimeTypeMap.getFileExtensionFromUrl(path);
+        String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(ext);
+        if (mimeType == null) {
+          switch (ext) {
+            case "js": mimeType = "text/javascript"; break;
+            default:   mimeType = "application/octet-stream"; Log.i(TAG, "unknown mime type for " + rawUrl); break;
+          }
+        }
+        String encoding = mimeType.startsWith("text/")? "UTF-8" : null;
+        InputStream targetStream = new ByteArrayInputStream(blob);
+        return new WebResourceResponse(mimeType, encoding, targetStream);
+      }
+    } catch (Exception e) {
+      e.printStackTrace();
+      InputStream targetStream = new ByteArrayInputStream(("Webxdc Request Error: " + e.getMessage()).getBytes());
+      return new WebResourceResponse("text/plain", "UTF-8", targetStream);
+    }
+  }
+
+  @Override
+  public void handleEvent(@NonNull DcEvent event) {
+    int eventId = event.getId();
+    if ((eventId == DcContext.DC_EVENT_WEBXDC_STATUS_UPDATE && event.getData1Int() == dcAppMsg.getId())) {
+      Log.i(TAG, "handleEvent");
+      webView.loadUrl("javascript:window.__webxdcUpdate(" + event.getData2Int() + ");");
+    }
+  }
+
+  class InternalJSApi {
+    @JavascriptInterface
+    public String selfAddr() {
+      return WebxdcActivity.this.dcContext.getConfig("addr");
+    }
+
+    @JavascriptInterface
+    public String selfName() {
+      String name = WebxdcActivity.this.dcContext.getConfig("displayname");
+      if (TextUtils.isEmpty(name)) {
+        name = selfAddr();
+      }
+      return name;
+    }
+
+    @JavascriptInterface
+    public boolean sendStatusUpdate(String payload, String descr) {
+      Log.i(TAG, "sendStatusUpdate");
+      return WebxdcActivity.this.dcContext.sendWebxdcStatusUpdate(WebxdcActivity.this.dcAppMsg.getId(), payload, descr);
+    }
+
+    @JavascriptInterface
+    public String getStatusUpdates(int statusUpdateId) {
+      Log.i(TAG, "getStatusUpdates");
+      return WebxdcActivity.this.dcContext.getWebxdcStatusUpdates(WebxdcActivity.this.dcAppMsg.getId(), statusUpdateId);
+    }
+  }
+}

src/org/thoughtcrime/securesms/components/WebxdcView.java

@@ -0,0 +1,102 @@
+package org.thoughtcrime.securesms.components;
+
+
+import android.content.Context;
+
+import androidx.annotation.AttrRes;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.appcompat.widget.AppCompatImageView;
+
+import android.graphics.drawable.Drawable;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.FrameLayout;
+import android.widget.TextView;
+
+import com.b44t.messenger.DcMsg;
+
+import org.json.JSONObject;
+import org.thoughtcrime.securesms.R;
+import org.thoughtcrime.securesms.mms.DocumentSlide;
+import org.thoughtcrime.securesms.mms.SlideClickListener;
+import org.thoughtcrime.securesms.util.Util;
+
+import java.io.ByteArrayInputStream;
+
+public class WebxdcView extends FrameLayout {
+
+  private static final String TAG = WebxdcView.class.getSimpleName();
+
+  private final @NonNull AppCompatImageView icon;
+  private final @NonNull TextView           appName;
+  private final @NonNull TextView           appSubtitle;
+
+  private @Nullable SlideClickListener viewListener;
+
+  public WebxdcView(@NonNull Context context) {
+    this(context, null);
+  }
+
+  public WebxdcView(@NonNull Context context, @Nullable AttributeSet attrs) {
+    this(context, attrs, 0);
+  }
+
+  public WebxdcView(@NonNull Context context, @Nullable AttributeSet attrs, @AttrRes int defStyleAttr) {
+    super(context, attrs, defStyleAttr);
+    inflate(context, R.layout.webxdc_view, this);
+
+    this.icon        = findViewById(R.id.webxdc_icon);
+    this.appName     = findViewById(R.id.webxdc_app_name);
+    this.appSubtitle = findViewById(R.id.webxdc_subtitle);
+  }
+
+  public void setWebxdcClickListener(@Nullable SlideClickListener listener) {
+    this.viewListener = listener;
+  }
+
+  public void setWebxdc(final @NonNull DcMsg dcMsg)
+  {
+    try {
+      JSONObject info = dcMsg.getWebxdcInfo();
+      setOnClickListener(new OpenClickedListener(getContext(), dcMsg));
+
+      // icon
+      byte[] blob = dcMsg.getWebxdcBlob(info.getString("icon"));
+      if (blob == null) {
+        throw new Exception("webxdc icon not found");
+      }
+      ByteArrayInputStream is = new ByteArrayInputStream(blob);
+      Drawable drawable = Drawable.createFromStream(is, "icon");
+      icon.setImageDrawable(drawable);
+
+      // name
+      appName.setText(info.getString("name"));
+
+      // subtitle
+      String summary = info.optString("summary");
+      if (summary.isEmpty()) {
+        summary = Util.getPrettyFileSize(dcMsg.getFilebytes()) + " Webxdc";
+      }
+      appSubtitle.setText(summary);
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  private class OpenClickedListener implements View.OnClickListener {
+    private final @NonNull DocumentSlide slide;
+
+    private OpenClickedListener(Context context, @NonNull DcMsg dcMsg) {
+      this.slide = new DocumentSlide(context, dcMsg);
+    }
+
+    @Override
+    public void onClick(View v) {
+      if (viewListener != null) {
+        viewListener.onClick(v, slide);
+      }
+    }
+  }
+
+}

src/org/thoughtcrime/securesms/mms/AttachmentManager.java

@@ -38,17 +38,25 @@ import android.widget.Toast;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
+import com.b44t.messenger.DcContext;
+import com.b44t.messenger.DcMsg;
+
 import org.thoughtcrime.securesms.ApplicationContext;
+import org.thoughtcrime.securesms.ConversationActivity;
 import org.thoughtcrime.securesms.MediaPreviewActivity;
 import org.thoughtcrime.securesms.R;
 import org.thoughtcrime.securesms.ShareLocationDialog;
+import org.thoughtcrime.securesms.WebxdcActivity;
 import org.thoughtcrime.securesms.attachments.Attachment;
+import org.thoughtcrime.securesms.attachments.UriAttachment;
 import org.thoughtcrime.securesms.audio.AudioSlidePlayer;
 import org.thoughtcrime.securesms.components.AudioView;
 import org.thoughtcrime.securesms.components.DocumentView;
 import org.thoughtcrime.securesms.components.RemovableEditableMediaView;
 import org.thoughtcrime.securesms.components.ThumbnailView;
+import org.thoughtcrime.securesms.components.WebxdcView;
 import org.thoughtcrime.securesms.connect.DcHelper;
+import org.thoughtcrime.securesms.database.AttachmentDatabase;
 import org.thoughtcrime.securesms.geolocation.DcLocationManager;
 import org.thoughtcrime.securesms.permissions.Permissions;
 import org.thoughtcrime.securesms.providers.PersistentBlobProvider;
@@ -84,6 +92,7 @@ public class AttachmentManager {
   private ThumbnailView              thumbnail;
   private AudioView                  audioView;
   private DocumentView               documentView;
+  private WebxdcView                 webxdcView;
   //private SignalMapView              mapView;
 
   private @NonNull  List<Uri>       garbage = new LinkedList<>();
@@ -104,6 +113,7 @@ public class AttachmentManager {
       this.thumbnail          = ViewUtil.findById(root, R.id.attachment_thumbnail);
       this.audioView          = ViewUtil.findById(root, R.id.attachment_audio);
       this.documentView       = ViewUtil.findById(root, R.id.attachment_document);
+      this.webxdcView         = ViewUtil.findById(root, R.id.attachment_webxdc);
       //this.mapView            = ViewUtil.findById(root, R.id.attachment_location);
       this.removableMediaView = ViewUtil.findById(root, R.id.removable_media_view);
 
@@ -113,6 +123,7 @@ public class AttachmentManager {
       int incomingBubbleColor = ThemeUtil.getThemedColor(context, R.attr.conversation_item_incoming_bubble_color);
       audioView.getBackground().setColorFilter(incomingBubbleColor, PorterDuff.Mode.MULTIPLY);
       documentView.getBackground().setColorFilter(incomingBubbleColor, PorterDuff.Mode.MULTIPLY);
+      webxdcView.getBackground().setColorFilter(incomingBubbleColor, PorterDuff.Mode.MULTIPLY);
     }
 
   }
@@ -220,9 +231,11 @@ public class AttachmentManager {
   @SuppressLint("StaticFieldLeak")
   public ListenableFuture<Boolean> setMedia(@NonNull final GlideRequests glideRequests,
                                             @NonNull final Uri uri,
+                                            @Nullable final DcMsg msg,
                                             @NonNull final MediaType mediaType,
                                                      final int width,
-                                                     final int height)
+                                                     final int height,
+                                                     final int chatId)
   {
     inflateStub();
 
@@ -238,10 +251,13 @@ public class AttachmentManager {
       @Override
       protected @Nullable Slide doInBackground(Void... params) {
         try {
-          if (PartAuthority.isLocalUri(uri)) {
+          if (msg != null && msg.getType() == DcMsg.DC_MSG_WEBXDC) {
+            return new DocumentSlide(context, msg);
+          }
+          else if (PartAuthority.isLocalUri(uri)) {
             return getManuallyCalculatedSlideInfo(uri, width, height);
           } else {
-            Slide result = getContentResolverSlideInfo(uri, width, height);
+            Slide result = getContentResolverSlideInfo(uri, width, height, chatId);
 
             if (result == null) return getManuallyCalculatedSlideInfo(uri, width, height);
             else                return result;
@@ -291,8 +307,17 @@ public class AttachmentManager {
             removableMediaView.display(audioView, false);
             result.set(true);
           } else if (slide.hasDocument()) {
-            documentView.setDocument((DocumentSlide) slide);
+            if (slide.isWebxdcDocument()) {
-            removableMediaView.display(documentView, false);
+              DcMsg instance = msg != null ? msg : DcHelper.getContext(context).getMsg(slide.dcMsgId);
+              webxdcView.setWebxdc(instance);
+              webxdcView.setWebxdcClickListener((v, s) -> {
+                WebxdcActivity.openWebxdcActivity(context, instance);
+              });
+              removableMediaView.display(webxdcView, false);
+            } else {
+              documentView.setDocument((DocumentSlide) slide);
+              removableMediaView.display(documentView, false);
+            }
             result.set(true);
           } else {
             Attachment attachment = slide.asAttachment();
@@ -304,7 +329,7 @@ public class AttachmentManager {
         }
       }
 
-      private @Nullable Slide getContentResolverSlideInfo(Uri uri, int width, int height) {
+      private @Nullable Slide getContentResolverSlideInfo(Uri uri, int width, int height, int chatId) {
         Cursor cursor = null;
         long   start  = System.currentTimeMillis();
 
@@ -323,7 +348,7 @@ public class AttachmentManager {
             }
 
             Log.w(TAG, "remote slide with size " + fileSize + " took " + (System.currentTimeMillis() - start) + "ms");
-            return mediaType.createSlide(context, uri, fileName, mimeType, fileSize, width, height);
+            return mediaType.createSlide(context, uri, fileName, mimeType, fileSize, width, height, chatId);
           }
         } finally {
           if (cursor != null) cursor.close();
@@ -367,7 +392,7 @@ public class AttachmentManager {
         }
 
         Log.w(TAG, "local slide with size " + mediaSize + " took " + (System.currentTimeMillis() - start) + "ms");
-        return mediaType.createSlide(context, uri, fileName, mimeType, mediaSize, width, height);
+        return mediaType.createSlide(context, uri, fileName, mimeType, mediaSize, width, height, chatId);
       }
     }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
 
@@ -598,7 +623,8 @@ public class AttachmentManager {
                                       @Nullable String mimeType,
                                                 long    dataSize,
                                                 int     width,
-                                                int     height)
+                                                int     height,
+                                                int     chatId)
     {
       if (mimeType == null) {
         mimeType = "application/octet-stream";
@@ -609,7 +635,20 @@ public class AttachmentManager {
       case GIF:      return new GifSlide(context, uri, dataSize, width, height);
       case AUDIO:    return new AudioSlide(context, uri, dataSize, false, fileName);
       case VIDEO:    return new VideoSlide(context, uri, dataSize);
-      case DOCUMENT: return new DocumentSlide(context, uri, mimeType, dataSize, fileName);
+      case DOCUMENT:
+        // We have to special-case Webxdc slides: The user can interact with them as soon as a draft
+        // is set. Therefore we need to create a DcMsg already now.
+        if (fileName != null && fileName.endsWith(".xdc")) {
+          DcContext dcContext = DcHelper.getContext(context);
+          DcMsg msg = new DcMsg(dcContext, DcMsg.DC_MSG_WEBXDC);
+          Attachment attachment = new UriAttachment(uri, null, MediaUtil.WEBXDC, AttachmentDatabase.TRANSFER_PROGRESS_STARTED, 0, 0, 0, fileName, null, false);
+          String path = ConversationActivity.getRealPathFromAttachment(context, attachment);
+          msg.setFile(path, MediaUtil.WEBXDC);
+          dcContext.setDraft(chatId, msg);
+          return new DocumentSlide(context, msg);
+        } else {
+          return new DocumentSlide(context, uri, mimeType, dataSize, fileName);
+        }
       default:       throw  new AssertionError("unrecognized enum");
       }
     }

src/org/thoughtcrime/securesms/mms/DocumentSlide.java

@@ -13,10 +13,12 @@ import org.thoughtcrime.securesms.attachments.DcAttachment;
 import org.thoughtcrime.securesms.util.StorageUtil;
 
 public class DocumentSlide extends Slide {
+  private int dcMsgType = DcMsg.DC_MSG_UNDEFINED;
 
   public DocumentSlide(Context context, DcMsg dcMsg) {
     super(context, new DcAttachment(dcMsg));
     dcMsgId = dcMsg.getId();
+    dcMsgType = dcMsg.getType();
   }
 
   public DocumentSlide(@NonNull Context context, @NonNull Uri uri,
@@ -31,4 +33,8 @@ public class DocumentSlide extends Slide {
     return true;
   }
 
+  @Override
+  public boolean isWebxdcDocument() {
+    return dcMsgType == DcMsg.DC_MSG_WEBXDC;
+  }
 }

src/org/thoughtcrime/securesms/mms/Slide.java

@@ -94,6 +94,10 @@ public abstract class Slide {
     return false;
   }
 
+  public boolean isWebxdcDocument() {
+    return false;
+  }
+
   public boolean hasLocation() {
     return false;
   }

src/org/thoughtcrime/securesms/mms/SlideDeck.java

@@ -19,6 +19,8 @@ package org.thoughtcrime.securesms.mms;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
+import com.b44t.messenger.DcMsg;
+
 import org.thoughtcrime.securesms.attachments.Attachment;
 
 import java.util.LinkedList;
@@ -72,4 +74,14 @@ public class SlideDeck {
 
     return null;
   }
+
+  // Webxdc requires draft-ids to be used; this function returns the previously used draft-id, if any.
+  public int getWebxdctDraftId() {
+    for (Slide slide: slides) {
+      if (slide.isWebxdcDocument()) {
+        return slide.dcMsgId;
+      }
+    }
+    return 0;
+  }
 }

src/org/thoughtcrime/securesms/util/MediaUtil.java

@@ -47,6 +47,7 @@ public class MediaUtil {
   public static final String AUDIO_UNSPECIFIED = "audio/*";
   public static final String VIDEO_UNSPECIFIED = "video/*";
   public static final String OCTET             = "application/octet-stream";
+  public static final String WEBXDC            = "application/webxdc+zip";
 
 
   public static Slide getSlideForMsg(Context context, DcMsg dcMsg) {
@@ -62,7 +63,8 @@ public class MediaUtil {
     } else if (dcMsg.getType() == DcMsg.DC_MSG_AUDIO
             || dcMsg.getType() == DcMsg.DC_MSG_VOICE) {
       slide = new AudioSlide(context, dcMsg);
-    } else if (dcMsg.getType() == DcMsg.DC_MSG_FILE) {
+    } else if (dcMsg.getType() == DcMsg.DC_MSG_FILE
+            || dcMsg.getType() == DcMsg.DC_MSG_WEBXDC) {
       slide = new DocumentSlide(context, dcMsg);
     }
 
@@ -259,6 +261,8 @@ public class MediaUtil {
         return "aac";
       case IMAGE_WEBP:
         return "webp";
+      case WEBXDC:
+        return "xdc";
     }
     return null;
   }