uploadFile static method

Future<String?> uploadFile({ required String accessKey, required String secretKey, required String bucket, required File file, String? key, String destDir = '', String region = 'us-east-2', ACL acl = ACL.public_read, String? filename, String contentType = 'binary/octet-stream', Map<String, String>? metadata, })

Upload a file, returning the file's public URL on success.

Implementation

static Future<String?> uploadFile({
  /// AWS access key
  required String accessKey,

  /// AWS secret key
  required String secretKey,

  /// The name of the S3 storage bucket to upload  to
  required String bucket,

  /// The file to upload
  required File file,

  /// The key to save this file as. Will override destDir and filename if set.
  String? key,

  /// The path to upload the file to (e.g. "uploads/public"). Defaults to the root "directory"
  String destDir = '',

  /// The AWS region. Must be formatted correctly, e.g. us-west-1
  String region = 'us-east-2',

  /// Access control list enables you to manage access to bucket and objects
  /// For more information visit [https://docs.aws.amazon.com/AmazonS3/latest/userguide/acl-overview.html]
  ACL acl = ACL.public_read,

  /// The filename to upload as. If null, defaults to the given file's current filename.
  String? filename,

  /// The content-type of file to upload. defaults to binary/octet-stream.
  String contentType = 'binary/octet-stream',

  /// Additional metadata to be attached to the upload
  Map<String, String>? metadata,
}) async {
  final endpoint = 'https://$bucket.s3.$region.amazonaws.com';

  var uploadKey;

  if (key != null) {
    uploadKey = key;
  } else if (destDir.isNotEmpty) {
    uploadKey = '$destDir/${filename ?? path.basename(file.path)}';
  } else {
    uploadKey = '${filename ?? path.basename(file.path)}';
  }

  final stream = http.ByteStream(Stream.castFrom(file.openRead()));
  final length = await file.length();

  final uri = Uri.parse(endpoint);
  final req = http.MultipartRequest("POST", uri);
  final multipartFile = http.MultipartFile('file', stream, length,
      filename: path.basename(file.path));

  // Convert metadata to AWS-compliant params before generating the policy.
  final metadataParams = _convertMetadataToParams(metadata);

  // Generate pre-signed policy.
  final policy = Policy.fromS3PresignedPost(
    uploadKey,
    bucket,
    accessKey,
    15,
    length,
    acl,
    region: region,
    metadata: metadataParams,
  );

  final signingKey =
      SigV4.calculateSigningKey(secretKey, policy.datetime, region, 's3');
  final signature = SigV4.calculateSignature(signingKey, policy.encode());

  req.files.add(multipartFile);
  req.fields['key'] = policy.key;
  req.fields['acl'] = aclToString(acl);
  req.fields['X-Amz-Credential'] = policy.credential;
  req.fields['X-Amz-Algorithm'] = 'AWS4-HMAC-SHA256';
  req.fields['X-Amz-Date'] = policy.datetime;
  req.fields['Policy'] = policy.encode();
  req.fields['X-Amz-Signature'] = signature;
  req.fields['Content-Type'] = contentType;

  // If metadata isn't null, add metadata params to the request.
  if (metadata != null) {
    req.fields.addAll(metadataParams);
  }

  try {
    final res = await req.send();

    if (res.statusCode == 204) return '$endpoint/$uploadKey';
  } catch (e) {
    print('Failed to upload to AWS, with exception:');
    print(e);
    return null;
  }
}