Allow setting the filename properly of the file field in the multip…

…art upload. This allows us to work out the type of the uploaded file more easily in the streaming upload context on the API server, where other metadata may not be available at the time that the upload part is processed.

api.go

@@ -303,8 +303,17 @@ func (api *CacophonyAPI) UploadVideo(r io.Reader, data map[string]interface{}) (
 	if _, ok := data["type"]; !ok {
 		data["type"] = "thermalRaw"
 	}
+
 	data["fileHash"] = hash
 
+	filename := "file"
+	value, exists := data["filename"]
+	if exists {
+		if value, ok := value.(string); ok {
+			filename = value
+		}
+	}
+
 	// JSON encoded "data" parameter.
 	dataBuf, err := json.Marshal(data)
 	if err != nil {
@@ -315,7 +324,7 @@ func (api *CacophonyAPI) UploadVideo(r io.Reader, data map[string]interface{}) (
 	}
 
 	// Add the file as a new MIME part.
-	fw, err := w.CreateFormFile("file", "file")
+	fw, err := w.CreateFormFile("file", filename)
 	if err != nil {
 		return 0, err
 	}