MinIO JavaScript Client SDK

For more complex upload requirements, use presignedPostPolicy(policy) to create a POST-based upload URL with specific restrictions. This requires creating a policy using minioClient.newPostPolicy() and applying constraints.

Workflow

1. Create a policy: const policy = minioClient.newPostPolicy()
2. Apply restrictions: Use methods like .setBucket(), .setKey(), .setExpires(), .setContentType(), or .setContentLengthRange() to define what the upload is allowed to do.
3. Generate URL and Form Data: const { postURL, formData } = await minioClient.presignedPostPolicy(policy)
4. Execute Upload: Use a client (like superagent) to POST the formData to the postURL.

Common Policy Methods

• setBucket(name): Restricts upload to a specific bucket.
• setKey(name): Restricts upload to a specific object name.
• setKeyStartsWith(prefix): Restricts object names to a specific prefix.
• setExpires(date): Sets the policy expiration date.
• setContentType(type): Restricts the allowed MIME type (e.g., 'text/plain').
• setContentDisposition(header): Sets the Content-Disposition header.
• setContentLengthRange(min, max): Restricts the file size in bytes.
• setUserMetaData(obj): Sets custom key-value metadata.

// 1. Create policy
const policy = minioClient.newPostPolicy()

// 2. Apply restrictions
policy.setBucket('mybucket')
policy.setKey('hello.txt')
policy.setContentType('text/plain')
policy.setContentLengthRange(1024, 1024 * 1024)

// 3. Generate URL and Form Data
const { postURL, formData } = await minioClient.presignedPostPolicy(policy)

// 4. Example upload using superagent
const req = superagent.post(postURL)
// Iterate through formData and attach to request...

The repository contains a comprehensive set of examples categorized by operation type. You can use these to understand how to implement specific features like bucket management, object manipulation, and presigned URLs.

Bucket Operations

• Listing buckets and objects (including v2 and metadata extensions)
• Bucket existence, creation, and removal
• Versioning, tagging, and lifecycle management
• Object lock, replication, and encryption configuration

File Object Operations

• fputObject: Uploading files from the local filesystem
• fGetObject: Downloading files to the local filesystem

Object Operations

• Standard CRUD: putObject, getObject, removeObject, statObject
• Advanced: copyObject, composeObject, selectObjectContent
• Metadata & Retention: Tagging, legal hold, and retention settings

Presigned Operations

• Generating presigned URLs for getObject and putObject
• Using presignedPostPolicy for secure uploads

Bucket Notification Operations

• Getting, setting, and removing bucket notifications
• Listening to bucket notifications (MinIO Extension)

Bucket Policy Operations

• Getting and setting bucket policies

To set up bucket notifications, you must define target configurations for the specific service you are using (SNS, SQS, or Lambda) and then add them to a NotificationConfig object.

Each target can be customized with:

• An Id via setId(id).
• Specific S3 events via addEvent(event).
• Key filters using addFilterPrefix(prefix) or addFilterSuffix(suffix).

Supported target types:

• TopicConfig: For Simple Notification Service (SNS).
• QueueConfig: For Simple Queue Service (SQS).
• CloudFunctionConfig: For Lambda functions.

import { 
  NotificationConfig, 
  TopicConfig, 
  QueueConfig, 
  CloudFunctionConfig 
} from 'minio';

const config = new NotificationConfig();

// Configure an SNS Topic target
const snsTarget = new TopicConfig('arn:aws:sns:us-east-1:123456789012:my-topic');
snsTarget.setId('my-sns-id');
snsTarget.addEvent('s3:ObjectCreated:*');
snsTarget.addFilterPrefix('uploads/');

// Configure an SQS Queue target
const queueTarget = new QueueConfig('arn:aws:sqs:us-east-1:123456789012:my-queue');
queueTarget.addFilterSuffix('.png');

// Add targets to the notification configuration
config.add(snsTarget);
config.add(queueTarget);