Merge pull request #2971 from vitorpamplona/claude/add-nowhere-links-LPMnM

Add Nowhere link detection and branded card rendering

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParser.kt

@@ -332,9 +332,15 @@ class RichTextParser {
             }
         }
 
-        if (urls.withoutScheme.contains(word)) return SchemelessUrlSegment(word)
+        if (urls.withoutScheme.contains(word)) {
+            parseNowhereLink(word)?.let { return it }
+            return SchemelessUrlSegment(word)
+        }
 
-        if (urls.withScheme.contains(word)) return LinkSegment(word)
+        if (urls.withScheme.contains(word)) {
+            parseNowhereLink(word)?.let { return it }
+            return LinkSegment(word)
+        }
 
         if (urls.emails.contains(word)) return EmailSegment(word)
 
@@ -529,6 +535,29 @@ class RichTextParser {
         }
 
         fun isUrlWithoutScheme(url: String) = noProtocolUrlValidator.matches(url)
+
+        // Nowhere links (https://github.com/5t34k/nowhere) encode an entire mini-site in the URL
+        // fragment. Servers never see the fragment, so OpenGraph previews return nothing useful
+        // (and hostednowhere.com 403s scrapers). Detect them by host + presence of a fragment
+        // so the renderer can show a branded card instead of falling through to LoadUrlPreview.
+        private val nowhereHosts = listOf("nowhr.xyz", "hostednowhere.com")
+
+        fun parseNowhereLink(word: String): NowhereLinkSegment? {
+            val afterScheme =
+                when {
+                    word.startsWith("https://", ignoreCase = true) -> word.substring(8)
+                    word.startsWith("http://", ignoreCase = true) -> word.substring(7)
+                    else -> word
+                }
+            val slash = afterScheme.indexOf('/')
+            if (slash < 0) return null
+            val host = afterScheme.substring(0, slash).lowercase()
+            if (host !in nowhereHosts) return null
+            val hash = afterScheme.indexOf('#', slash)
+            if (hash < 0) return null
+            val pathSegment = afterScheme.substring(slash + 1, hash).substringBefore('/').takeIf { it.isNotEmpty() }
+            return NowhereLinkSegment(word, host, pathSegment)
+        }
     }
 }
 

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParserSegments.kt

@@ -158,6 +158,13 @@ class SchemelessUrlSegment(
     segment: String,
 ) : Segment(segment)
 
+@Immutable
+class NowhereLinkSegment(
+    segment: String,
+    val host: String,
+    val tool: String?,
+) : Segment(segment)
+
 @Immutable
 class RegularTextSegment(
     segment: String,

commons/src/commonTest/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParserTest.kt

@@ -4400,6 +4400,52 @@ class RichTextParserTest {
             }
     }
 
+    @Test
+    fun testNowhereLinkInTheMiddleOfAPost() {
+        val text = "Check out my store https://nowhr.xyz/s#bYxNC4JAEEDRX7LbpcsirR9F1MW0jRDLPsEOMZaHinJTCzOl right now"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment } as? NowhereLinkSegment
+        assertEquals("https://nowhr.xyz/s#bYxNC4JAEEDRX7LbpcsirR9F1MW0jRDLPsEOMZaHinJTCzOl", nowhere?.segmentText)
+        assertEquals("nowhr.xyz", nowhere?.host)
+        assertEquals("s", nowhere?.tool)
+    }
+
+    @Test
+    fun testHostedNowhereSchemelessLink() {
+        val text = "see hostednowhere.com/m#bYxNAB end"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment } as? NowhereLinkSegment
+        assertEquals("hostednowhere.com/m#bYxNAB", nowhere?.segmentText)
+        assertEquals("hostednowhere.com", nowhere?.host)
+        assertEquals("m", nowhere?.tool)
+    }
+
+    @Test
+    fun testNowhereLinkWithLargeBase64UrlFragment() {
+        // Real nowhere links can be kilobytes long (a full store catalogue or forum thread
+        // base64url-encoded). Verify both UrlDetector capture and our classifier survive a
+        // ~5KB fragment containing every base64url-legal character (A-Z, a-z, 0-9, -, _).
+        val alphabet = ('A'..'Z').joinToString("") + ('a'..'z').joinToString("") + ('0'..'9').joinToString("") + "-_"
+        val payload = (0 until 80).joinToString("") { alphabet }
+        val url = "https://nowhr.xyz/s#$payload"
+        val text = "look at this big store $url and reply"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment } as? NowhereLinkSegment
+        assertEquals(url, nowhere?.segmentText)
+        assertEquals(payload.length, nowhere?.segmentText?.substringAfter('#')?.length)
+        assertEquals("nowhr.xyz", nowhere?.host)
+        assertEquals("s", nowhere?.tool)
+    }
+
+    @Test
+    fun testPlainNowhereHostWithoutFragmentStaysAsLink() {
+        // No fragment => not a nowhere site, fall through to LinkSegment.
+        val text = "Visit https://hostednowhere.com/manage to manage"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment }
+        assertEquals(null, nowhere)
+    }
+
     private fun printStateForDebug(state: RichTextViewerState) {
         state.paragraphs.forEach { paragraph ->
             paragraph.words.forEach { seg ->

commons/src/jvmTest/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParserNowhereJvmTest.kt

@@ -0,0 +1,55 @@
+/*
+ * 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.richtext
+
+import com.vitorpamplona.amethyst.commons.model.EmptyTagList
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class RichTextParserNowhereJvmTest {
+    @Test
+    fun realWorldNowhereStoreLinkRoundtripsThroughTheParser() {
+        // Verbatim from a real Nostr note ("Works, thanks!\n\nhttps://nowhr.xyz/s#..."): a
+        // published nowhr.xyz store catalogue with a ~5KB base64url fragment. Kept as a
+        // resource so the URL isn't subject to source-editor truncation.
+        val url =
+            this::class.java
+                .classLoader!!
+                .getResourceAsStream("richtext/realNowhereStoreUrl.txt")!!
+                .bufferedReader()
+                .readText()
+                .trim()
+
+        assertTrue(url.startsWith("https://nowhr.xyz/s#"), "resource lost its prefix")
+        assertTrue(url.length > 5000, "resource shorter than expected: ${url.length}")
+
+        val text = "Works, thanks!\n\n$url"
+
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment } as? NowhereLinkSegment
+
+        assertEquals(url, nowhere?.segmentText)
+        assertEquals("nowhr.xyz", nowhere?.host)
+        assertEquals("s", nowhere?.tool)
+        assertTrue(state.urlSet.withScheme.contains(url), "url not in detected withScheme set")
+    }
+}