使用处理后台上载的AWSS3TransferUtility

import AWSS3

    let transferUtility = AWSS3TransferUtility.default()
    //In order to customize the header information, we use the AWSS3TransferUtilityUploadExpression class
    let expression = AWSS3TransferUtilityUploadExpression()

    //We want our file to be publicly available by default
    expression.setValue("public-read", forRequestParameter: "x-amz-acl")

    //Copy the custom Meta information into the expression
    transferUtility.uploadFile(uploadRequest.body, bucket: uploadRequest.bucket ?? "", key: uploadRequest.key ?? "", contentType: uploadRequest.contentType ?? "", expression: expression) { (task, error) in }

不要忘记在应用程序委托中添加以下代码

func application(_ application: UIApplication, handleEventsForBackgroundURLSession identifier: String, completionHandler: @escaping () -> Void) {
    /*
     Store the completion handler.
     */
    AWSS3TransferUtility.interceptApplication(application, handleEventsForBackgroundURLSession: identifier, completionHandler: completionHandler)
}