MultipartWritable - adding an extension-implied content type (expecte…

…d by Azure file upload)

openai-client/src/main/scala/io/cequence/openaiscala/service/ws/MultipartWritable.scala

@@ -19,6 +19,27 @@ object MultipartWritable {
     val CONTENT_TYPE = "content-type"
   }
 
+  private val fileExtensionContentTypeMap = Map(
+    "txt" -> "text/plain",
+    "csv" -> "text/csv",
+    "json" -> "application/json",
+    "xml" -> "application/xml",
+    "pdf" -> "application/pdf",
+    "zip" -> "application/zip",
+    "tar" -> "application/x-tar",
+    "gz" -> "application/x-gzip",
+    "ogg" -> "application/ogg",
+    "mp3" -> "audio/mpeg",
+    "wav" -> "audio/x-wav",
+    "mp4" -> "video/mp4",
+    "webm" -> "video/webm",
+    "png" -> "image/png",
+    "jpg" -> "image/jpeg",
+    "jpeg" -> "image/jpeg",
+    "gif" -> "image/gif",
+    "svg" -> "image/svg+xml"
+  )
+
   /**
    * `Writeable` for `MultipartFormData`.
    */
@@ -45,13 +66,21 @@ object MultipartWritable {
 
     def filePartHeader(file: FilePart) = {
       val name = s""""${file.key}""""
-      val filename = s""""${file.headerFileName.getOrElse(file.path)}""""
-      val contentType = file.contentType.map { ct =>
+      val filenameAux = file.headerFileName.getOrElse(file.path)
+      val filenamePart = s""""${filenameAux}""""
+
+      val contentTypeAux = file.contentType.orElse {
+        val extension = filenameAux.split('.').last
+        // Azure expects an explicit content type for files
+        fileExtensionContentTypeMap.get(extension)
+      }
+
+      val contentTypePart = contentTypeAux.map { ct =>
         s"${HttpHeaderNames.CONTENT_TYPE}: $ct\r\n"
       }.getOrElse("")
 
       encode(
-        s"--$boundary\r\n${HttpHeaderNames.CONTENT_DISPOSITION}: form-data; name=$name; filename=$filename\r\n$contentType\r\n"
+        s"--$boundary\r\n${HttpHeaderNames.CONTENT_DISPOSITION}: form-data; name=$name; filename=$filenamePart\r\n$contentTypePart\r\n"
       )
     }