How to upload image to s3 bucket in flutter

About flutter:

Flutter is an open-source UI software development kit (SDK) that was primarily created by Google. It is used to develop cross-platform applications for Android, iOS, Linux, macOS, Windows, and the web from a single codebase. 

1. About multipart request.

Using the HTTP package in flutter, we will able to send only string, int, list,date and double data-types. If you want to send images/videos/files to the server then we use multipart requests for that.

2. Code. 

2.1)Creating Project in  Flutter

2.1.1) open android studio and click on file > new >new flutter project

After that you need to provide some basic details about your project like project name, description organization, etc then hit the finish button. It will create a new project in Flutter.

2.1.2) open new pubspec.yaml file and install plugin(required).

2.1.3)  http package

2.1)code for Multipart Request

  uploadToS3 (image)async{

  Try{

  var postUri = Uri.parse("${postImageToS3}"); /// url

  var request = http.MultipartRequest("POST", postUri);

  Map<String, String> headers = { "access-token": "$ {dataStorage.read("authToken")}"}; /// header

  request.headers.addAll(headers);

  request.files.add(

      await http.MultipartFile.fromPath('file', image)); /// file that you need to send s3

  var response = await request.send();

  var responsed = await http.Response.fromStream(response);

  final responseData = json.decode(responsed.body);

  if (response.statusCode == 200) {

 /// if response.statuscode is 200 then you will get a image id from aws 

    var imagedetails= jsonDecode(responsed.body);

    /// s3 image id 

    print(imagedetails["imageId"]);

  }

  else if (response.statusCode == 401) {

    Get.off(() => LoginScreen());

  }

  else if (response.statusCode == 400) {

    log("errorCode ${response.statusCode}");

    Get.rawSnackbar(

      message: "Error in upLoading Image",

      snackPosition: SnackPosition.BOTTOM,

      snackStyle: SnackStyle.GROUNDED,

      backgroundColor: Colors.red

    );

  }

  else if (response.statusCode == 500) {

   Get.rawSnackbar(

        message: "Something Went Wrong from Server",

        snackPosition: SnackPosition.BOTTOM,

        margin: EdgeInsets.zero,

        snackStyle: SnackStyle.GROUNDED,

        backgroundColor: Colors.red);

  }

 } on SocketException {

   Get.rawSnackbar(

       message: "Internet Exception",

       snackPosition: SnackPosition.BOTTOM,

       margin: EdgeInsets.zero,

       snackStyle: SnackStyle.GROUNDED,

       backgroundColor: Colors.red);

 } catch (e) {

   Get.rawSnackbar(

       message: " $e Error Occured",

       snackPosition: SnackPosition.BOTTOM,

       margin: EdgeInsets.zero,

       snackStyle: SnackStyle.GROUNDED,

       backgroundColor: Colors.red);

 } finally {

 }

}

/// simple pass image to above method then it will allow you to upload image to s3 then get image id from aws on 200 response