rendering images in the messenger

features/messenger/src/main/kotlin/app/dapk/st/messenger/DecryptingFetcher.kt

@@ -0,0 +1,64 @@
+package app.dapk.st.messenger
+
+import android.util.Base64
+import app.dapk.st.matrix.sync.RoomEvent
+import coil.bitmap.BitmapPool
+import coil.decode.DataSource
+import coil.decode.Options
+import coil.fetch.FetchResult
+import coil.fetch.Fetcher
+import coil.fetch.SourceResult
+import coil.size.Size
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okio.Buffer
+import java.security.MessageDigest
+import javax.crypto.Cipher
+import javax.crypto.spec.IvParameterSpec
+import javax.crypto.spec.SecretKeySpec
+
+private const val CRYPTO_BUFFER_SIZE = 32 * 1024
+private const val CIPHER_ALGORITHM = "AES/CTR/NoPadding"
+private const val SECRET_KEY_SPEC_ALGORITHM = "AES"
+private const val MESSAGE_DIGEST_ALGORITHM = "SHA-256"
+
+class DecryptingFetcher : Fetcher<RoomEvent.Image> {
+
+    private val http = OkHttpClient()
+
+    override suspend fun fetch(pool: BitmapPool, data: RoomEvent.Image, size: Size, options: Options): FetchResult {
+        val keys = data.imageMeta.keys!!
+        val key = Base64.decode(keys.k.replace('-', '+').replace('_', '/'), Base64.DEFAULT)
+        val initVectorBytes = Base64.decode(keys.iv, Base64.DEFAULT)
+
+        val decryptCipher = Cipher.getInstance(CIPHER_ALGORITHM)
+        val secretKeySpec = SecretKeySpec(key, SECRET_KEY_SPEC_ALGORITHM)
+        val ivParameterSpec = IvParameterSpec(initVectorBytes)
+        decryptCipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec)
+
+        val messageDigest = MessageDigest.getInstance(MESSAGE_DIGEST_ALGORITHM)
+
+        var read: Int
+        val d = ByteArray(CRYPTO_BUFFER_SIZE)
+        var decodedBytes: ByteArray
+
+        val response = http.newCall(Request.Builder().url(data.imageMeta.url).build()).execute()
+        val outputStream = Buffer()
+
+        response.body()?.let {
+            it.byteStream().use {
+                read = it.read(d)
+                while (read != -1) {
+                    messageDigest.update(d, 0, read)
+                    decodedBytes = decryptCipher.update(d, 0, read)
+                    outputStream.write(decodedBytes)
+                    read = it.read(d)
+                }
+            }
+        }
+        return SourceResult(outputStream, null, DataSource.NETWORK)
+    }
+
+    override fun key(data: RoomEvent.Image) = data.imageMeta.url
+
+}

features/messenger/src/main/kotlin/app/dapk/st/messenger/MessengerActivity.kt

@@ -9,10 +9,10 @@ import androidx.activity.compose.setContent
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.material.Surface
 import androidx.compose.ui.Modifier
-import app.dapk.st.design.components.SmallTalkTheme
 import app.dapk.st.core.DapkActivity
 import app.dapk.st.core.module
 import app.dapk.st.core.viewModel
+import app.dapk.st.design.components.SmallTalkTheme
 import app.dapk.st.matrix.common.RoomId
 import kotlinx.parcelize.Parcelize
 

features/messenger/src/main/kotlin/app/dapk/st/messenger/MessengerScreen.kt

@@ -1,5 +1,6 @@
 package app.dapk.st.messenger
 
+import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
 import androidx.compose.foundation.border
 import androidx.compose.foundation.layout.*
@@ -179,16 +180,9 @@ private fun LazyItemScope.Image(self: UserId, message: RoomEvent.Image, wasPrevi
                         isNotSelf = false,
                         wasPreviousMessageSameSender = wasPreviousMessageSameSender
                     ) {
-                        Text(message.imageMeta.url)
+                        Box {
-                        androidx.compose.foundation.Image(
+                            MessageImage(message)
-                            painter = rememberImagePainter(
+                        }
-                                data = message.imageMeta.url,
-                            ),
-                            contentDescription = null,
-                            modifier = Modifier
-                                .size(100.dp)
-                                .align(Alignment.Center)
-                        )
                     }
                 }
             }
@@ -200,25 +194,29 @@ private fun LazyItemScope.Image(self: UserId, message: RoomEvent.Image, wasPrevi
                     isNotSelf = true,
                     wasPreviousMessageSameSender = wasPreviousMessageSameSender
                 ) {
-                    Text(message.imageMeta.url)
+                    Box {
-                    androidx.compose.foundation.Image(
+                        MessageImage(message)
-                        painter = rememberImagePainter(
-                            data = message.imageMeta.url,
-                            builder = {
-
                     }
-                        ),
-                        contentDescription = null,
-                        modifier = Modifier
-                            .size(100.dp)
-                            .align(Alignment.Center)
-                    )
                 }
             }
         }
     }
 }
 
+@Composable
+private fun MessageImage(message: RoomEvent.Image) {
+    val width = with(LocalDensity.current) { message.imageMeta.width.toDp() }
+    val height = with(LocalDensity.current) { message.imageMeta.height.toDp() }
+
+    Image(
+        modifier = Modifier.size(width, height),
+        painter = rememberImagePainter(
+            data = message,
+            builder = { fetcher(DecryptingFetcher()) }
+        ),
+        contentDescription = null,
+    )
+}
 
 @Composable
 private fun LazyItemScope.Message(self: UserId, message: Message, wasPreviousMessageSameSender: Boolean) {

matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/RoomState.kt

@@ -93,7 +93,18 @@ sealed class RoomEvent {
             @SerialName("width") val width: Int,
             @SerialName("height") val height: Int,
             @SerialName("url") val url: String,
+            @SerialName("keys") val keys: Keys?,
+        ) {
+
+            @Serializable
+            data class Keys(
+                @SerialName("k") val k: String,
+                @SerialName("iv") val iv: String,
+                @SerialName("v") val v: String,
+                @SerialName("hashes") val hashes: Map<String, String>,
             )
+
+        }
     }
 
 }

matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/request/ApiSyncResponse.kt

@@ -459,7 +459,8 @@ internal sealed class ApiTimelineEvent {
 
             @Serializable
             data class Image(
-                @SerialName("file") val file: File,
+                @SerialName("url") val url: MxUrl? = null,
+                @SerialName("file") val file: File? = null,
                 @SerialName("info") val info: Info,
                 @SerialName("m.relates_to") override val relation: Relation? = null,
                 @SerialName("msgtype") val messageType: String = "m.image",
@@ -468,14 +469,24 @@ internal sealed class ApiTimelineEvent {
                 @Serializable
                 data class File(
                     @SerialName("url") val url: MxUrl,
+                    @SerialName("iv") val iv: String,
+                    @SerialName("v") val v: String,
+                    @SerialName("hashes") val hashes: Map<String, String>,
+                    @SerialName("key") val key: Key,
+                ) {
+
+                    @Serializable
+                    data class Key(
+                        @SerialName("k") val k: String,
                     )
 
+                }
+
                 @Serializable
                 internal data class Info(
                     @SerialName("h") val height: Int,
                     @SerialName("w") val width: Int,
                 )
-
             }
 
             @Serializable
@@ -553,10 +564,7 @@ internal object ApiTimelineMessageContentDeserializer : KSerializer<ApiTimelineE
         val element = decoder.decodeJsonElement()
         return when (element.jsonObject["msgtype"]?.jsonPrimitive?.content) {
             "m.text" -> ApiTimelineEvent.TimelineMessage.Content.Text.serializer().deserialize(decoder)
-            "m.image" -> when (element.jsonObject["file"]) {
+            "m.image" -> ApiTimelineEvent.TimelineMessage.Content.Image.serializer().deserialize(decoder)
-                null -> ApiTimelineEvent.TimelineMessage.Content.Ignored
-                else -> ApiTimelineEvent.TimelineMessage.Content.Image.serializer().deserialize(decoder)
-            }
             else -> {
                 println(element)
                 ApiTimelineEvent.TimelineMessage.Content.Ignored

matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/room/RoomEventsDecrypter.kt

@@ -37,7 +37,8 @@ internal class RoomEventsDecrypter(
                         imageMeta = RoomEvent.Image.ImageMeta(
                             width = content.info.width,
                             height = content.info.height,
-                            url = content.file?.url?.convertMxUrToUrl(userCredentials.homeServer) ?: ""
+                            url = content.file?.url?.convertMxUrToUrl(userCredentials.homeServer) ?: content.url!!.convertMxUrToUrl(userCredentials.homeServer),
+                            keys = content.file?.let { RoomEvent.Image.ImageMeta.Keys(it.key.k, it.iv, it.v, it.hashes) }
                         ),
                         encryptedContent = null,
                     )

matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/sync/RoomEventFactory.kt

@@ -47,7 +47,8 @@ internal class RoomEventFactory(
         return RoomEvent.Image.ImageMeta(
             content.info.width,
             content.info.height,
-            content.file?.url?.convertMxUrToUrl(userCredentials.homeServer)
+            content.file?.url?.convertMxUrToUrl(userCredentials.homeServer) ?: content.url!!.convertMxUrToUrl(userCredentials.homeServer),
+            keys = content.file?.let { RoomEvent.Image.ImageMeta.Keys(it.key.k, it.iv, it.v, it.hashes) }
         )
     }
 }