content type renamed to media type to be more in line with MIME spec

src/commonMain/kotlin/ContentType.kt → src/commonMain/kotlin/MediaType.kt

@@ -18,8 +18,11 @@ package com.xemantic.ai.file.magic
 
 import kotlinx.io.files.Path
 
+/**
+ * A subset of MIME types and associated type detectors.
+ */
 @OptIn(ExperimentalUnsignedTypes::class)
-public enum class ContentType(
+public enum class MediaType(
   public val mime: String,
   private val detect: (ByteArray) -> Boolean
 ) {
@@ -36,7 +39,7 @@ public enum class ContentType(
 
   GIF(
     mime = "image/gif",
-    detect = { it.startsWith("GIF87", "GIF89") }
+    detect = { it.startsWith("GIF87") || it.startsWith("GIF89") }
   ),
 
   WEBP(
@@ -53,7 +56,7 @@ public enum class ContentType(
 
     public fun detect(
       bytes: ByteArray
-    ): ContentType? = entries.find {
+    ): MediaType? = entries.find {
       it.detect(bytes)
     }
 
@@ -62,18 +65,18 @@ public enum class ContentType(
 }
 
 public fun ByteArray.startsWith(
-  vararg values: String
-): Boolean = values.any {
-  (size >= it.length)
-      && sliceArray(0 ..< it.length)
-        .contentEquals(it.encodeToByteArray())
-}
+  data: String
+): Boolean = (size >= data.length)
+      && sliceArray(0 ..< data.length)
+        .contentEquals(data.encodeToByteArray())
 
 @OptIn(ExperimentalUnsignedTypes::class)
 public fun ByteArray.startsWith(
   vararg bytes: UByte
-): Boolean = size >= bytes.size && sliceArray(0 ..< bytes.size).toUByteArray().contentEquals(bytes)
+): Boolean = (size >= bytes.size)
+    && sliceArray(0 ..< bytes.size)
+      .toUByteArray().contentEquals(bytes)
 
-public fun ByteArray.detectContentType(): ContentType? = ContentType.detect(this)
+public fun ByteArray.detectMediaType(): MediaType? = MediaType.detect(this)
 
-public fun Path.detectContentType(): ContentType? = toBytes().detectContentType()
+public fun Path.detectMediaType(): MediaType? = readBytes().detectMediaType()

src/commonMain/kotlin/Paths.kt

@@ -22,7 +22,7 @@ import kotlinx.io.files.SystemFileSystem
 import kotlinx.io.readByteArray
 import kotlinx.io.readString
 
-public fun Path.toBytes(): ByteArray = SystemFileSystem.source(
+public fun Path.readBytes(): ByteArray = SystemFileSystem.source(
   this
 ).buffered().use {
   it.readByteArray()

src/commonTest/kotlin/MediaTypeTest.kt

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2024 Kazimierz Pogoda / Xemantic
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.xemantic.ai.file.magic
+
+import com.xemantic.ai.file.magic.test.MINIMAL_GIF
+import com.xemantic.ai.file.magic.test.MINIMAL_JPEG
+import com.xemantic.ai.file.magic.test.MINIMAL_PDF
+import com.xemantic.ai.file.magic.test.MINIMAL_PNG
+import com.xemantic.ai.file.magic.test.MINIMAL_WEBP
+import com.xemantic.ai.file.magic.test.isBrowserTest
+import com.xemantic.ai.file.magic.test.testDataDir
+import com.xemantic.kotlin.test.assert
+import kotlinx.io.files.Path
+import kotlin.test.Test
+
+class MediaTypeTest {
+
+  @Test
+  fun `Should detect MediaTypes`() {
+    assert(byteArrayOf().detectMediaType() == null)
+    assert("foo".encodeToByteArray().detectMediaType() == null)
+    assert(MINIMAL_PDF.detectMediaType() == MediaType.PDF)
+    assert(MINIMAL_JPEG.detectMediaType() == MediaType.JPEG)
+    assert(MINIMAL_PNG.detectMediaType() == MediaType.PNG)
+    assert(MINIMAL_WEBP.detectMediaType() == MediaType.WEBP)
+    assert(MINIMAL_GIF.detectMediaType() == MediaType.GIF)
+  }
+
+  @Test
+  fun `Should detect MediaTypes of Paths`() {
+    if (isBrowserTest) return // we don't have file access in the browser, but we do have with node.js
+    assert(Path(testDataDir, "minimal.gif").detectMediaType() == MediaType.GIF)
+    assert(Path(testDataDir, "minimal.jpeg").detectMediaType() == MediaType.JPEG)
+    assert(Path(testDataDir, "minimal.pdf").detectMediaType() == MediaType.PDF)
+    assert(Path(testDataDir, "minimal.png").detectMediaType() == MediaType.PNG)
+    assert(Path(testDataDir, "minimal.webp").detectMediaType() == MediaType.WEBP)
+  }
+
+  @Test
+  fun `Should not detect MediaTypes of a Path with empty file`() {
+    if (isBrowserTest) return // we don't have file access in the browser, but we do have with node.js
+    assert(Path(testDataDir, "zero.txt").detectMediaType() == null)
+  }
+
+}