Merge pull request #3035 from greenart7c3/claude/epic-newton-OZLCC

Use URL SHA for Blossom bridge, not imeta hash

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

@@ -42,7 +42,6 @@ fun MediaUrlContent.toCoilModel(useLocalBlossomBridge: Boolean): String =
     bridgeUrl(
         url = url,
         useBridge = useLocalBlossomBridge,
-        explicitHash = hash,
         mimeType = mimeType,
         authorPubKey = authorPubKey,
         skipBridge = this is MediaUrlVideo && isLiveStream,
@@ -95,7 +94,6 @@ const val DEFAULT_LOCAL_CACHE_BASE = "http://127.0.0.1:24242"
 private fun bridgeUrl(
     url: String,
     useBridge: Boolean,
-    explicitHash: String?,
     mimeType: String?,
     authorPubKey: String?,
     skipBridge: Boolean,
@@ -105,19 +103,15 @@ private fun bridgeUrl(
     if (!url.startsWith("http://", ignoreCase = true) && !url.startsWith("https://", ignoreCase = true)) return url
 
     // The local Blossom cache fetches `<xs>/<sha>.<ext>` on miss per BUD-01,
-    // which only works when the upstream URL is itself BUD-01 layout. For
-    // non-BUD-01 URLs (e.g. https://i.nostr.build/M5AwJ.gif) the imeta `x`
-    // hash identifies the blob but the upstream server doesn't host it at
-    // /<sha>.<ext>, so trusting only `explicitHash` would point the cache
-    // at a 404. Require the sha to be in the URL path before bridging.
-    val urlSha = extractSha256FromUrlPath(url) ?: return url
-
-    // Prefer the imeta hash when it's a valid sha256 (authoritative casing),
-    // otherwise fall back to what was parsed from the URL.
-    val sha = explicitHash?.lowercase()?.takeIf { sha256HexRegex.matches(it) } ?: urlSha
+    // which only works when the upstream URL is itself BUD-01 layout — the
+    // file at `<xs>/<sha>.<ext>` is the one named in the URL path, not the
+    // imeta `x` hash (which on resizing CDNs may identify a different blob
+    // than the URL filename, e.g. `x` = post-resize, `ox` = original).
+    // Always use the URL's sha; never trust the imeta override.
+    val sha = extractSha256FromUrlPath(url) ?: return url
 
     val ext = guessExtension(url, mimeType)
-    val serverBase = extractServerBase(url, urlSha) ?: return url
+    val serverBase = extractServerBase(url, sha) ?: return url
 
     val authors =
         authorPubKey

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

@@ -255,4 +255,19 @@ class MediaUrlContentExtTest {
         val image = MediaUrlImage(url = url, hash = null)
         assertEquals(url, image.toCoilModel(useLocalBlossomBridge = true))
     }
+
+    @Test
+    fun bridgeOnUsesUrlShaNotImetaWhenTheyDiffer() {
+        // On resizing CDNs the imeta `x` (post-resize) can differ from the
+        // `ox` (original) embedded in the URL. The upstream file is named
+        // after the URL's sha, so the cache request must use that — using
+        // the imeta `x` would point xs= at a non-existent path on miss.
+        val urlSha = "f24026b7281e598973a775adefb1b9a13b9f037a94ac98dd48ccc91b83f4b7b3"
+        val imetaX = "6932a918de1bfae3bf6611794ff54dd677013d22b760a9212117a0bd9079badf"
+        val image = MediaUrlImage(url = "https://image.nostr.build/$urlSha.png", hash = imetaX)
+        assertEquals(
+            "blossom:$urlSha.png?xs=https://image.nostr.build",
+            image.toCoilModel(useLocalBlossomBridge = true),
+        )
+    }
 }