Detecting images by pinging the server instead of relying on the url.

app/src/main/java/com/vitorpamplona/amethyst/model/UrlCachedPreviewer.kt

@@ -34,7 +34,7 @@ object UrlCachedPreviewer {
                         }
                     }
 
-                    val state = if (urlInfo.allFetchComplete() && urlInfo.url == url) {
+                    val state = if (urlInfo.fetchComplete() && urlInfo.url == url) {
                         UrlPreviewState.Loaded(urlInfo)
                     } else {
                         UrlPreviewState.Empty

app/src/main/java/com/vitorpamplona/amethyst/service/previews/BahaUrlPreview.kt

@@ -1,13 +1,9 @@
 package com.vitorpamplona.amethyst.service.previews
 
-import android.net.Uri
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
-import java.util.Locale
 
 class BahaUrlPreview(val url: String, var callback: IUrlPreviewCallback?) {
-    private val imageExtensionArray = arrayOf(".gif", ".png", ".jpg", ".jpeg", ".bmp", ".webp")
-
     suspend fun fetchUrlPreview(timeOut: Int = 30000) = withContext(Dispatchers.IO) {
         try {
             fetch(timeOut)
@@ -17,26 +13,7 @@ class BahaUrlPreview(val url: String, var callback: IUrlPreviewCallback?) {
     }
 
     private suspend fun fetch(timeOut: Int = 30000) {
-        lateinit var urlInfoItem: UrlInfoItem
-        if (checkIsImageUrl()) {
-            urlInfoItem = UrlInfoItem(url = url, image = url)
-        } else {
-            val document = getDocument(url, timeOut)
-            urlInfoItem = parseHtml(url, document)
-        }
-        callback?.onComplete(urlInfoItem)
-    }
-
-    private fun checkIsImageUrl(): Boolean {
-        val uri = Uri.parse(url)
-        var isImage = false
-        for (imageExtension in imageExtensionArray) {
-            if (uri.path != null && uri.path!!.toLowerCase(Locale.getDefault()).endsWith(imageExtension)) {
-                isImage = true
-                break
-            }
-        }
-        return isImage
+        callback?.onComplete(getDocument(url, timeOut))
     }
 
     fun cleanUp() {

app/src/main/java/com/vitorpamplona/amethyst/service/previews/UrlInfoItem.kt

@@ -1,14 +1,16 @@
 package com.vitorpamplona.amethyst.service.previews
 
 import androidx.compose.runtime.Immutable
+import okhttp3.MediaType
 import java.net.URL
 
 @Immutable
-data class UrlInfoItem(
+class UrlInfoItem(
     val url: String = "",
     val title: String = "",
     val description: String = "",
-    val image: String = ""
+    val image: String = "",
+    val mimeType: MediaType
 ) {
     val verifiedUrl = kotlin.runCatching { URL(url) }.getOrNull()
     val imageUrlFullPath =
@@ -18,6 +20,10 @@ data class UrlInfoItem(
             image
         }
 
+    fun fetchComplete(): Boolean {
+        return url.isNotEmpty() && image.isNotEmpty()
+    }
+
     fun allFetchComplete(): Boolean {
         return title.isNotEmpty() && description.isNotEmpty() && image.isNotEmpty()
     }

app/src/main/java/com/vitorpamplona/amethyst/service/previews/UrlPreviewUtils.kt

@@ -3,6 +3,8 @@ package com.vitorpamplona.amethyst.service.previews
 import com.vitorpamplona.amethyst.service.HttpClient
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import okhttp3.MediaType
+import okhttp3.MediaType.Companion.toMediaType
 import okhttp3.Request
 import org.jsoup.Jsoup
 import org.jsoup.nodes.Document
@@ -46,21 +48,31 @@ private val META_X_IMAGE = arrayOf(
 
 private const val CONTENT = "content"
 
-suspend fun getDocument(url: String, timeOut: Int = 30000): Document =
+suspend fun getDocument(url: String, timeOut: Int = 30000): UrlInfoItem =
     withContext(Dispatchers.IO) {
         val request: Request = Request.Builder().url(url).get().build()
-        val html = HttpClient.getHttpClient().newCall(request).execute().use {
+        HttpClient.getHttpClient().newCall(request).execute().use {
             if (it.isSuccessful) {
-                it.body.string()
+                val mimeType = it.headers.get("Content-Type")?.toMediaType()
+                    ?: throw IllegalArgumentException("Website returned unknown mimetype: ${it.headers.get("Content-Type")}")
+
+                if (mimeType.type == "text" && mimeType.subtype == "html") {
+                    val document = Jsoup.parse(it.body.string())
+                    parseHtml(url, document, mimeType)
+                } else if (mimeType.type == "image") {
+                    UrlInfoItem(url, image = url, mimeType = mimeType)
+                } else if (mimeType.type == "video") {
+                    UrlInfoItem(url, image = url, mimeType = mimeType)
+                } else {
+                    throw IllegalArgumentException("Website returned unknown encoding for previews: $mimeType")
+                }
             } else {
                 throw IllegalArgumentException("Website returned: " + it.code)
             }
         }
-
-        Jsoup.parse(html)
     }
 
-suspend fun parseHtml(url: String, document: Document): UrlInfoItem =
+suspend fun parseHtml(url: String, document: Document, type: MediaType): UrlInfoItem =
     withContext(Dispatchers.IO) {
         val metaTags = document.getElementsByTag(ELEMENT_TAG_META)
 
@@ -106,8 +118,8 @@ suspend fun parseHtml(url: String, document: Document): UrlInfoItem =
             }
 
             if (title.isNotEmpty() && description.isNotEmpty() && image.isNotEmpty()) {
-                return@withContext UrlInfoItem(url, title, description, image)
+                return@withContext UrlInfoItem(url, title, description, image, type)
             }
         }
-        return@withContext UrlInfoItem(url, title, description, image)
+        return@withContext UrlInfoItem(url, title, description, image, type)
     }

app/src/main/java/com/vitorpamplona/amethyst/ui/components/LoadUrlPreview.kt

@@ -2,6 +2,7 @@ package com.vitorpamplona.amethyst.ui.components
 
 import androidx.compose.animation.Crossfade
 import androidx.compose.animation.core.tween
+import androidx.compose.foundation.layout.Box
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
@@ -10,6 +11,8 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import com.vitorpamplona.amethyst.model.UrlCachedPreviewer
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.theme.HalfVertPadding
+import kotlinx.collections.immutable.persistentListOf
 
 @Composable
 fun LoadUrlPreview(url: String, urlText: String, accountViewModel: AccountViewModel) {
@@ -42,7 +45,17 @@ fun LoadUrlPreview(url: String, urlText: String, accountViewModel: AccountViewMo
         ) { state ->
             when (state) {
                 is UrlPreviewState.Loaded -> {
-                    UrlPreviewCard(url, state.previewInfo)
+                    if (state.previewInfo.mimeType.type == "image") {
+                        Box(modifier = HalfVertPadding) {
+                            ZoomableContentView(ZoomableUrlImage(url), persistentListOf(), roundedCorner = true, accountViewModel)
+                        }
+                    } else if (state.previewInfo.mimeType.type == "video") {
+                        Box(modifier = HalfVertPadding) {
+                            ZoomableContentView(ZoomableUrlVideo(url), persistentListOf(), roundedCorner = true, accountViewModel)
+                        }
+                    } else {
+                        UrlPreviewCard(url, state.previewInfo)
+                    }
                 }
 
                 else -> {