Moving OpenGraph parser to commons

amethyst/src/main/java/com/vitorpamplona/amethyst/service/previews/HtmlParser.kt

@@ -20,6 +20,7 @@
  */
 package com.vitorpamplona.amethyst.service.previews
 
+import com.vitorpamplona.amethyst.commons.preview.HtmlCharsetParser
 import com.vitorpamplona.amethyst.commons.preview.MetaTag
 import com.vitorpamplona.amethyst.commons.preview.MetaTagsParser
 import kotlinx.coroutines.Dispatchers
@@ -31,10 +32,6 @@ import java.nio.charset.Charset
 
 class HtmlParser {
     companion object {
-        val ATTRIBUTE_VALUE_CHARSET = "charset"
-        val ATTRIBUTE_VALUE_HTTP_EQUIV = "http-equiv"
-        val CONTENT = "content"
-
         // taken from okhttp
         private val UNICODE_BOMS =
             Options.of(
@@ -49,25 +46,30 @@ class HtmlParser {
                 // UTF-32LE
                 "ffff0000".decodeHex(),
             )
-
-        private val RE_CONTENT_TYPE_CHARSET = Regex("""charset=([^;]+)""")
     }
 
     suspend fun parseHtml(
         source: BufferedSource,
         type: Charset?,
+    ): Sequence<MetaTag> =
+        parseHtml(
+            source.readByteArray(),
+            type ?: source.readBomAsCharset(),
+        )
+
+    suspend fun parseHtml(
+        bodyBytes: ByteArray,
+        type: Charset?,
     ): Sequence<MetaTag> =
         withContext(Dispatchers.IO) {
             // sniff charset from Content-Type header or BOM
-            val sniffedCharset = type ?: source.readBomAsCharset()
+            if (type != null) {
-            if (sniffedCharset != null) {
+                val content = bodyBytes.toString(type)
-                val content = source.readByteArray().toString(sniffedCharset)
                 return@withContext MetaTagsParser.parse(content)
             }
 
             // if sniffing was failed, detect charset from content
-            val bodyBytes = source.readByteArray()
+            val charset = HtmlCharsetParser.detectCharset(bodyBytes)
-            val charset = detectCharset(bodyBytes)
             val content = bodyBytes.toString(charset)
             return@withContext MetaTagsParser.parse(content)
         }
@@ -82,29 +84,4 @@ class HtmlParser {
             -1 -> null
             else -> throw AssertionError()
         }
-
-    private fun detectCharset(bodyBytes: ByteArray): Charset {
-        // try to detect charset from meta tags parsed from first 1024 bytes of body
-        val firstPart = String(bodyBytes, 0, 1024, Charset.forName("utf-8"))
-        val metaTags = MetaTagsParser.parse(firstPart)
-        metaTags.forEach { meta ->
-            val charsetAttr = meta.attr(ATTRIBUTE_VALUE_CHARSET)
-            if (charsetAttr.isNotEmpty()) {
-                runCatching { Charset.forName(charsetAttr) }.getOrNull()?.let {
-                    return it
-                }
-            }
-            if (meta.attr(ATTRIBUTE_VALUE_HTTP_EQUIV).lowercase() == "content-type") {
-                RE_CONTENT_TYPE_CHARSET
-                    .find(meta.attr(CONTENT))
-                    ?.let {
-                        runCatching { Charset.forName(it.groupValues[1]) }.getOrNull()
-                    }?.let {
-                        return it
-                    }
-            }
-        }
-        // defaults to UTF-8
-        return Charset.forName("utf-8")
-    }
 }

amethyst/src/main/java/com/vitorpamplona/amethyst/service/previews/UrlPreview.kt

@@ -20,6 +20,8 @@
  */
 package com.vitorpamplona.amethyst.service.previews
 
+import com.vitorpamplona.amethyst.commons.preview.OpenGraphParser
+import com.vitorpamplona.amethyst.commons.preview.UrlInfoItem
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/UrlPreviewCard.kt

@@ -40,7 +40,7 @@ import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.style.TextOverflow
 import coil3.compose.AsyncImage
 import com.vitorpamplona.amethyst.R
-import com.vitorpamplona.amethyst.service.previews.UrlInfoItem
+import com.vitorpamplona.amethyst.commons.preview.UrlInfoItem
 import com.vitorpamplona.amethyst.ui.stringRes
 import com.vitorpamplona.amethyst.ui.theme.DoubleVertSpacer
 import com.vitorpamplona.amethyst.ui.theme.MaxWidthWithHorzPadding

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/UrlPreviewState.kt

@@ -21,7 +21,7 @@
 package com.vitorpamplona.amethyst.ui.components
 
 import androidx.compose.runtime.Immutable
-import com.vitorpamplona.amethyst.service.previews.UrlInfoItem
+import com.vitorpamplona.amethyst.commons.preview.UrlInfoItem
 
 @Immutable
 sealed class UrlPreviewState {

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/markdown/RenderContentAsMarkdown.kt

@@ -39,9 +39,9 @@ import com.halilibo.richtext.commonmark.CommonMarkdownParseOptions
 import com.halilibo.richtext.commonmark.CommonmarkAstNodeParser
 import com.halilibo.richtext.markdown.BasicMarkdown
 import com.halilibo.richtext.ui.material3.RichText
+import com.vitorpamplona.amethyst.commons.preview.UrlInfoItem
 import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.UrlCachedPreviewer
-import com.vitorpamplona.amethyst.service.previews.UrlInfoItem
 import com.vitorpamplona.amethyst.ui.components.UrlPreviewState
 import com.vitorpamplona.amethyst.ui.navigation.navs.EmptyNav
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/preview/HtmlCharsetParser.kt

@@ -0,0 +1,56 @@
+/**
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.preview
+
+import java.nio.charset.Charset
+
+object HtmlCharsetParser {
+    val ATTRIBUTE_VALUE_CHARSET = "charset"
+    val ATTRIBUTE_VALUE_HTTP_EQUIV = "http-equiv"
+    val CONTENT = "content"
+
+    private val RE_CONTENT_TYPE_CHARSET = Regex("""charset=([^;]+)""")
+
+    fun detectCharset(bodyBytes: ByteArray): Charset {
+        // try to detect charset from meta tags parsed from first 1024 bytes of body
+        val firstPart = String(bodyBytes, 0, 1024, Charset.forName("utf-8"))
+        val metaTags = MetaTagsParser.parse(firstPart)
+        metaTags.forEach { meta ->
+            val charsetAttr = meta.attr(ATTRIBUTE_VALUE_CHARSET)
+            if (charsetAttr.isNotEmpty()) {
+                runCatching { Charset.forName(charsetAttr) }.getOrNull()?.let {
+                    return it
+                }
+            }
+            if (meta.attr(ATTRIBUTE_VALUE_HTTP_EQUIV).lowercase() == "content-type") {
+                RE_CONTENT_TYPE_CHARSET
+                    .find(meta.attr(CONTENT))
+                    ?.let {
+                        runCatching { Charset.forName(it.groupValues[1]) }.getOrNull()
+                    }?.let {
+                        return it
+                    }
+            }
+        }
+        // defaults to UTF-8
+        return Charset.forName("utf-8")
+    }
+}

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/preview/OpenGraphParser.kt

@@ -18,9 +18,7 @@
  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
-package com.vitorpamplona.amethyst.service.previews
+package com.vitorpamplona.amethyst.commons.preview
-
-import com.vitorpamplona.amethyst.commons.preview.MetaTag
 
 class OpenGraphParser {
     class Result(

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/preview/UrlInfoItem.kt

@@ -18,7 +18,7 @@
  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
-package com.vitorpamplona.amethyst.service.previews
+package com.vitorpamplona.amethyst.commons.preview
 
 import androidx.compose.runtime.Immutable
 import java.net.URL
@@ -31,7 +31,7 @@ class UrlInfoItem(
     val image: String = "",
     val mimeType: String,
 ) {
-    val verifiedUrl = kotlin.runCatching { URL(url) }.getOrNull()
+    val verifiedUrl = runCatching { URL(url) }.getOrNull()
     val imageUrlFullPath =
         if (image.startsWith("/")) {
             URL(verifiedUrl, image).toString()