diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d46b935ef8551c032ebe3610432c0217fe1803f..f1155cf743510f0e7e276497f5150d58fb5c8735 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.1.4
+
+- support presignedPostPolicy
+
## 0.1.3
- support presignedGetObject and presignedPutObject
diff --git a/README.md b/README.md
index cc0c02b08b19f8ed0b4cce50b0ba71274eb03782..9454ad94774ef4902b8cdd4390e19d6f0a08c02e 100644
--- a/README.md
+++ b/README.md
@@ -2,18 +2,18 @@ This is the _unofficial_ MinIO Dart Client SDK that provides simple APIs to acce
## API
-| Bucket operations | Object operations | Presigned operations | Bucket Policy & Notification operations |
-|-------------------------|-------------------------|-----------------------|-------------------------------------------|
-| [makeBucket] | [getObject] | [presignedUrl] | getBucketNotification |
-| [listBuckets] | [getPartialObject] | [presignedGetObject] | setBucketNotification |
-| [bucketExists] | [fGetObject] | [presignedPutObject] | removeAllBucketNotification |
-| [removeBucket] | [putObject] | presignedPostPolicy | getBucketPolicy |
-| [listObjects] | [fPutObject] | | setBucketPolicy |
-| [listObjectsV2] | [copyObject] | | listenBucketNotification |
-| [listIncompleteUploads] | [statObject] | | |
-| | [removeObject] | | |
-| | [removeObjects] | | |
-| | [removeIncompleteUpload]| | |
+| Bucket operations | Object operations | Presigned operations | Bucket Policy & Notification operations |
+|-------------------------|--------------------------|----------------------|-----------------------------------------|
+| [makeBucket] | [getObject] | [presignedUrl] | getBucketNotification |
+| [listBuckets] | [getPartialObject] | [presignedGetObject] | setBucketNotification |
+| [bucketExists] | [fGetObject] | [presignedPutObject] | removeAllBucketNotification |
+| [removeBucket] | [putObject] | [presignedPostPolicy]| listenBucketNotification |
+| [listObjects] | [fPutObject] | | getBucketPolicy |
+| [listObjectsV2] | [copyObject] | | setBucketPolicy |
+| [listIncompleteUploads] | [statObject] | | |
+| | [removeObject] | | |
+| | [removeObjects] | | |
+| | [removeIncompleteUpload] | | |
## Usage
@@ -95,4 +95,5 @@ MIT
[presignedUrl]: https://pub.dev/documentation/minio/latest/minio/Minio/presignedUrl.html
[presignedGetObject]: https://pub.dev/documentation/minio/latest/minio/Minio/presignedGetObject.html
[presignedPutObject]: https://pub.dev/documentation/minio/latest/minio/Minio/presignedPutObject.html
+[presignedPostPolicy]: https://pub.dev/documentation/minio/latest/minio/Minio/presignedPostPolicy.html
diff --git a/lib/src/minio.dart b/lib/src/minio.dart
index b2baeaa4ab17e619d79418e97108f11120b9699f..0772893058046c6261f725ef28a49634859cd742 100644
--- a/lib/src/minio.dart
+++ b/lib/src/minio.dart
@@ -641,6 +641,60 @@ class Minio {
);
}
+ /// presignedPostPolicy can be used in situations where we want more control on the upload than what
+ /// presignedPutObject() provides. i.e Using presignedPostPolicy we will be able to put policy restrictions
+ /// on the object's `name` `bucket` `expiry` `Content-Type`
+ Future presignedPostPolicy(PostPolicy postPolicy) async {
+ if (_client.anonymous) {
+ throw MinioAnonymousRequestError(
+ 'Presigned POST policy cannot be generated for anonymous requests');
+ }
+
+ final region = await getBucketRegion(postPolicy.formData['bucket']);
+ var date = DateTime.now().toUtc();
+ var dateStr = makeDateLong(date);
+
+ if (postPolicy.policy['expiration'] == null) {
+ // 'expiration' is mandatory field for S3.
+ // Set default expiration date of 7 days.
+ var expires = DateTime.now().toUtc();
+ expires.add(Duration(days: 7));
+ postPolicy.setExpires(expires);
+ }
+
+ postPolicy.policy['conditions'].push(['eq', r'$x-amz-date', dateStr]);
+ postPolicy.formData['x-amz-date'] = dateStr;
+
+ postPolicy.policy['conditions']
+ .push(['eq', r'$x-amz-algorithm', 'AWS4-HMAC-SHA256']);
+ postPolicy.formData['x-amz-algorithm'] = 'AWS4-HMAC-SHA256';
+
+ postPolicy.policy['conditions'].push(
+ ['eq', r'$x-amz-credential', accessKey + '/' + getScope(region, date)]);
+ postPolicy.formData['x-amz-credential'] =
+ accessKey + '/' + getScope(region, date);
+
+ if (sessionToken != null) {
+ postPolicy.policy['conditions']
+ .push(['eq', r'$x-amz-security-token', sessionToken]);
+ }
+
+ final policyBase64 = jsonBase64(postPolicy.policy);
+ postPolicy.formData['policy'] = policyBase64;
+
+ final signature =
+ postPresignSignatureV4(region, date, secretKey, policyBase64);
+
+ postPolicy.formData['x-amz-signature'] = signature;
+ final url = _client
+ .getBaseRequest('POST', postPolicy.formData['bucket'], null, region,
+ null, null, null)
+ .url;
+ var portStr = (port == 80 || port == 443 || port == null) ? '' : ':$port';
+ var urlStr = '${url.scheme}://${url.host}${portStr}${url.path}';
+ return PostPolicyResult(postURL: urlStr, formData: postPolicy.formData);
+ }
+
/// Generate a presigned URL for PUT.
/// Using this URL, the browser can upload to S3 only with the specified object name.
///
diff --git a/lib/src/minio_models.dart b/lib/src/minio_models.dart
index a1e27adc6b12e282f2a785d34a20fdf58613160c..382e6dac985941aeea13dba3b48fe59e2b6626af 100644
--- a/lib/src/minio_models.dart
+++ b/lib/src/minio_models.dart
@@ -1,4 +1,5 @@
import 'package:minio/models.dart';
+import 'package:minio/src/minio_errors.dart';
import 'package:xml/xml.dart';
class ListObjectsChunk {
@@ -113,3 +114,71 @@ class StatObjectResult {
final DateTime lastModified;
final Map<String, String> metaData;
}
+
+/// Build PostPolicy object that can be signed by presignedPostPolicy
+class PostPolicy {
+ final policy = <String, dynamic>{
+ 'conditions': [],
+ };
+
+ final formData = <String, String>{};
+
+ /// set expiration date
+ void setExpires(DateTime date) {
+ if (date == null) {
+ throw MinioInvalidDateError('Invalid date : cannot be null');
+ }
+ policy['expiration'] = date.toIso8601String();
+ }
+
+ /// set object name
+ void setKey(String object) {
+ MinioInvalidObjectNameError.check(object);
+ policy['conditions'].add(['eq', r'$key', object]);
+ formData['key'] = object;
+ }
+
+ /// set object name prefix, i.e policy allows any keys with this prefix
+ void setKeyStartsWith(String prefix) {
+ MinioInvalidPrefixError.check(prefix);
+ policy['conditions'].push(['starts-with', r'$key', prefix]);
+ formData['key'] = prefix;
+ }
+
+ /// set bucket name
+ void setBucket(bucket) {
+ MinioInvalidBucketNameError.check(bucket);
+ policy['conditions'].push(['eq', r'$bucket', bucket]);
+ formData['bucket'] = bucket;
+ }
+
+ /// set Content-Type
+ void setContentType(String type) {
+ if (type == null) {
+ throw MinioError('content-type cannot be null');
+ }
+ policy['conditions'].push(['eq', r'$Content-Type', type]);
+ formData['Content-Type'] = type;
+ }
+
+ /// set minimum/maximum length of what Content-Length can be.
+ void setContentLengthRange(int min, int max) {
+ if (min > max) {
+ throw MinioError('min cannot be more than max');
+ }
+ if (min < 0) {
+ throw MinioError('min should be > 0');
+ }
+ if (max < 0) {
+ throw MinioError('max should be > 0');
+ }
+ policy['conditions'].push(['content-length-range', min, max]);
+ }
+}
+
+class PostPolicyResult {
+ PostPolicyResult({this.postURL, this.formData});
+
+ final String postURL;
+ final Map<String, String> formData;
+}
diff --git a/lib/src/minio_sign.dart b/lib/src/minio_sign.dart
index c2313d6ea0b94d681f275fb30f90212a19c3af33..fee400cc21e89a3403460989de53fb0a96a7629e 100644
--- a/lib/src/minio_sign.dart
+++ b/lib/src/minio_sign.dart
@@ -146,3 +146,14 @@ String presignSignatureV4(
return presignedUrl;
}
+
+// calculate the signature of the POST policy
+String postPresignSignatureV4(
+ String region,
+ DateTime date,
+ String secretKey,
+ String policyBase64,
+) {
+ final signingKey = getSigningKey(date, region, secretKey);
+ return sha256HmacHex(policyBase64, signingKey);
+}
diff --git a/lib/src/utils.dart b/lib/src/utils.dart
index 8b586e3a5e58f5e1175faa1404dcf80d893c550c..f52f794e179a4ed24812c8db44f30628e93ac55e 100644
--- a/lib/src/utils.dart
+++ b/lib/src/utils.dart
@@ -31,6 +31,10 @@ String md5Base64(String source) {
return base64.encode(md5digest);
}
+String jsonBase64(Map<String, dynamic> jsonObject) {
+ return base64.encode(utf8.encode(json.encode(jsonObject)));
+}
+
XmlElement getNodeProp(XmlElement xml, String name) {
final result = xml.findElements(name);
return result.isNotEmpty ? result.first : null;
diff --git a/pubspec.yaml b/pubspec.yaml
index a7b8128f303115f68dae345ef40aeeae736f616f..1d2accc84f39945a3e789b4d11159c2479e93afa 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
name: minio
description: Unofficial MinIO Dart Client SDK that provides simple APIs to access any Amazon S3 compatible object storage server.
-version: 0.1.3
+version: 0.1.4
homepage: https://github.com/xtyxtyx/minio-dart
issue_tracker: https://github.com/xtyxtyx/minio-dart/issues