MinIO Haskell SDK API Reference

Initialize MinIO Client object.

MinIO - for public Play server

minioPlayCI :: ConnectInfo
minioPlayCI

AWS S3

awsCI :: ConnectInfo
awsCI { connectAccesskey = "your-access-key"
      , connectSecretkey = "your-secret-key"
      }

1. Connecting and running operations on the storage service

The Haskell MinIO SDK provides high-level functionality to perform
operations on a MinIO server or any AWS S3-like API compatible storage
service.

The ConnectInfo type

The ConnectInfo record-type contains connection information for a
particular server. It is recommended to construct the ConnectInfo
value using one of the several smart constructors provided by the
library, documented in the following subsections.

The library automatically discovers the region of a bucket by
default. This is especially useful with AWS, where buckets may be in
different regions. When performing an upload, download or other
operation, the library requests the service for the location of a
bucket and caches it for subsequent requests.

awsCI :: ConnectInfo

awsCI is a value that provides connection information for AWS
S3. Credentials can be supplied by overriding a couple of fields like
so:

awsConn = awsCI {
    connectAccessKey = "my-AWS-access-key"
  , connectSecretKey = "my-AWS-secret-key"
  }

awsWithRegionCI :: Region -> Bool -> ConnectInfo

This constructor allows to specify the initial region and a Boolean to
enable/disable the automatic region discovery behaviour.

The parameters in the expression awsWithRegion region autoDiscover are:

minioPlayCI :: ConnectInfo

This constructor provides connection and authentication information to
connect to the public MinIO Play server at
https://play.min.io/.

minioCI :: Text -> Int -> Bool -> ConnectInfo

Use to connect to a MinIO server.

The parameters in the expression minioCI host port isSecure are:

The ConnectInfo fields and Default instance

The following table shows the fields in the ConnectInfo record-type:

The def value of type ConnectInfo has all the above default
values.

The Minio Monad

This monad provides the required environment to perform requests
against a MinIO or other S3 API compatible server. It uses the
connection information from the ConnectInfo value provided to it. It
performs connection pooling, bucket location caching, error handling
and resource clean-up actions.

The runMinio function performs the provided action in the Minio
monad and returns a IO (Either MinioErr a) value:

{-# Language OverloadedStrings #-}

import Network.Minio

main :: IO ()
main = do
  result <- runMinio def $ do
    buckets <- listBuckets
    return $ length buckets

  case result of
    Left e -> putStrLn $ "Failed operation with error: " ++ show e
    Right n -> putStrLn $ show n ++ " bucket(s) found."

The above performs a listBuckets operation and returns the number of
buckets in the server. If there were any errors, they will be returned
as values of type MinioErr as a Left value.

2. Bucket operations

listBuckets :: Minio [BucketInfo]

Lists buckets.

Return Value

BucketInfo record type

makeBucket :: Bucket -> Maybe Region -> Minio ()

Create a new bucket. If the region is not specified, the region
specified by ConnectInfo is used.

Parameters

In the expression makeBucket bucketName region the arguments are:

Example

{-# Language OverloadedStrings #-}

main :: IO ()
main = do
    res <- runMinio minioPlayCI $ do
        makeBucket bucketName (Just "us-east-1")
    case res of
        Left err -> putStrLn $ "Failed to make bucket: " ++ (show res)
        Right _ -> putStrLn $ "makeBucket successful."

removeBucket :: Bucket -> Minio ()

Remove a bucket. The bucket must be empty or an error will be thrown.

Parameters

In the expression removeBucket bucketName the arguments are:

Example

{-# Language OverloadedStrings #-}

main :: IO ()
main = do
    res <- runMinio minioPlayCI $ do
        removeBucket "mybucket"

    case res of
        Left err -> putStrLn $ "Failed to remove bucket: " ++ (show res)
        Right _ -> putStrLn $ "removeBucket successful."

listObjects :: Bucket -> Maybe Text -> Bool -> C.ConduitM () ObjectInfo Minio ()

List objects in the given bucket, implements version 2 of AWS S3 API.

Parameters

In the expression listObjects bucketName prefix recursive the
arguments are:

Return Value

ObjectInfo record type

Example

{-# LANGUAGE OverloadedStrings #-}
import           Network.Minio

import           Conduit
import           Prelude


-- | The following example uses MinIO play server at
-- https://play.min.io.  The endpoint and associated
-- credentials are provided via the libary constant,
--
-- > minioPlayCI :: ConnectInfo
--

main :: IO ()
main = do
  let
    bucket = "test"

  -- Performs a recursive listing of all objects under bucket "test"
  -- on play.min.io.
  res <- runMinio minioPlayCI $
    runConduit $ listObjects bucket Nothing True .| mapM_C (\v -> (liftIO $ print v))
  print res

listObjectsV1 :: Bucket -> Maybe Text -> Bool -> C.ConduitM () ObjectInfo Minio ()

List objects in the given bucket, implements version 1 of AWS S3 API. This API
is provided for legacy S3 compatible object storage endpoints.

Parameters

In the expression listObjectsV1 bucketName prefix recursive the
arguments are:

Return Value

ObjectInfo record type

Example

{-# LANGUAGE OverloadedStrings #-}
import           Network.Minio

import           Conduit
import           Prelude


-- | The following example uses MinIO play server at
-- https://play.min.io.  The endpoint and associated
-- credentials are provided via the libary constant,
--
-- > minioPlayCI :: ConnectInfo
--

main :: IO ()
main = do
  let
    bucket = "test"

  -- Performs a recursive listing of all objects under bucket "test"
  -- on play.min.io.
  res <- runMinio minioPlayCI $
    runConduit $ listObjectsV1 bucket Nothing True .| mapM_C (\v -> (liftIO $ print v))
  print res

listIncompleteUploads :: Bucket -> Maybe Prefix -> Bool -> C.Producer Minio UploadInfo

List incompletely uploaded objects.

Parameters

In the expression listIncompleteUploads bucketName prefix recursive
the parameters are:

Return Value

UploadInfo record type

Example

{-# LANGUAGE OverloadedStrings #-}
import           Network.Minio

import           Conduit
import           Prelude

-- | The following example uses MinIO play server at
-- https://play.min.io.  The endpoint and associated
-- credentials are provided via the libary constant,
--
-- > minioPlayCI :: ConnectInfo
--

main :: IO ()
main = do
  let
    bucket = "test"

  -- Performs a recursive listing of incomplete uploads under bucket "test"
  -- on a local MinIO server.
  res <- runMinio minioPlayCI $
    runConduit $ listIncompleteUploads bucket Nothing True .| mapM_C (\v -> (liftIO $ print v))
  print res

3. Object operations

getObject :: Bucket -> Object -> GetObjectOptions -> Minio (C.ConduitM () ByteString Minio ())

Get an object from the S3 service, optionally object ranges can be provided as well.

Parameters

In the expression getObject bucketName objectName opts the parameters
are:

GetObjectOptions record type

Return Value

The return value can be incrementally read to process the contents of
the object.
| Return type | Description |
|:--------------------------------------------|:-----------------------------------------|
| Minio (C.ConduitM () ByteString Minio ()) | A Conduit source of ByteString values. |

Example

{-# LANGUAGE OverloadedStrings #-}
import           Network.Minio

import qualified Data.Conduit        as C
import qualified Data.Conduit.Binary as CB

import           Prelude

-- | The following example uses MinIO play server at
-- https://play.min.io.  The endpoint and associated
-- credentials are provided via the libary constant,
--
-- > minioPlayCI :: ConnectInfo
--

main :: IO ()
main = do
  let
      bucket = "my-bucket"
      object = "my-object"
  res <- runMinio minioPlayCI $ do
    src <- getObject bucket object def
    C.connect src $ CB.sinkFileCautious "/tmp/my-object"

  case res of
    Left e  -> putStrLn $ "getObject failed." ++ (show e)
    Right _ -> putStrLn "getObject succeeded."

putObject :: Bucket -> Object -> C.ConduitM () ByteString Minio () -> Maybe Int64 -> PutObjectOptions -> Minio ()

Uploads an object to a bucket in the service, from the given input
byte stream of optionally supplied length. Optionally you can also specify
additional metadata for the object.

Parameters

In the expression putObject bucketName objectName inputSrc the parameters
are:

Example

{-# LANGUAGE OverloadedStrings #-}
import           Network.Minio

import qualified Data.Conduit.Combinators as CC

import           Prelude

-- | The following example uses MinIO play server at
-- https://play.min.io.  The endpoint and associated
-- credentials are provided via the libary constant,
--
-- > minioPlayCI :: ConnectInfo
--

main :: IO ()
main = do
  let
      bucket = "test"
      object = "obj"
      localFile = "/etc/lsb-release"
      kb15 = 15 * 1024

  -- Eg 1. Upload a stream of repeating "a" using putObject with default options.
  res <- runMinio minioPlayCI $
    putObject bucket object (CC.repeat "a") (Just kb15) def
  case res of
    Left e   -> putStrLn $ "putObject failed." ++ show e
    Right () -> putStrLn "putObject succeeded."

fGetObject :: Bucket -> Object -> FilePath -> GetObjectOptions -> Minio ()

Downloads an object from a bucket in the service, to the given file

Parameters

In the expression fGetObject bucketName objectName inputFile the parameters
are:

GetObjectOptions record type

{-# Language OverloadedStrings #-}
import Network.Minio

import Data.Conduit (($$+-))
import Data.Conduit.Binary (sinkLbs)
import Prelude

-- | The following example uses MinIO play server at
-- https://play.min.io.  The endpoint and associated
-- credentials are provided via the libary constant,
--
-- > minioPlayCI :: ConnectInfo
--

main :: IO ()
main = do
  let
      bucket = "my-bucket"
      object = "my-object"
      localFile = "/etc/lsb-release"

  res <- runMinio minioPlayCI $ do
    src <- fGetObject bucket object localFile def
    (src $$+- sinkLbs)

  case res of
    Left e -> putStrLn $ "fGetObject failed." ++ (show e)
    Right _ -> putStrLn "fGetObject succeeded."

fPutObject :: Bucket -> Object -> FilePath -> Minio ()

Uploads an object to a bucket in the service, from the given file

Parameters

In the expression fPutObject bucketName objectName inputFile the parameters
are:

Example

{-# Language OverloadedStrings #-}
import Network.Minio
import qualified Data.Conduit.Combinators as CC

main :: IO ()
main = do
  let
    bucket = "mybucket"
    object = "myobject"
    localFile = "/etc/lsb-release"

  res <- runMinio minioPlayCI $ do
           fPutObject bucket object localFile

  case res of
    Left e -> putStrLn $ "Failed to fPutObject " ++ show bucket ++ "/" ++ show object
    Right _ -> putStrLn "fPutObject was successful"

copyObject :: DestinationInfo -> SourceInfo -> Minio ()

Copies content of an object from the service to another

Parameters

In the expression copyObject dstInfo srcInfo the parameters
are:

SourceInfo record type

Destination record type

Example

{-# Language OverloadedStrings #-}
import Network.Minio

main :: IO ()
main = do
  let
    bucket = "mybucket"
    object = "myobject"
    objectCopy = "obj-copy"

  res <- runMinio minioPlayCI $ do
           copyObject def { dstBucket = bucket, dstObject = objectCopy } def { srcBucket = bucket, srcObject = object }

  case res of
    Left e -> putStrLn $ "Failed to copyObject " ++ show bucket ++ show "/" ++ show object
    Right _ -> putStrLn "copyObject was successful"

removeObject :: Bucket -> Object -> Minio ()

Removes an object from the service

Parameters

In the expression removeObject bucketName objectName the parameters
are:

Example

{-# Language OverloadedStrings #-}
import Network.Minio

main :: IO ()
main = do
  let
    bucket = "mybucket"
    object = "myobject"

  res <- runMinio minioPlayCI $ do
           removeObject bucket object

  case res of
    Left e -> putStrLn $ "Failed to remove " ++ show bucket ++ "/" ++ show object
    Right _ -> putStrLn "Removed object successfully"

removeIncompleteUpload :: Bucket -> Object -> Minio ()

Removes an ongoing multipart upload of an object from the service

Parameters

In the expression removeIncompleteUpload bucketName objectName the parameters
are:

Example

{-# Language OverloadedStrings #-}
import Network.Minio

main :: IO ()
main = do
  let
    bucket = "mybucket"
    object = "myobject"

  res <- runMinio minioPlayCI $
           removeIncompleteUpload bucket object

  case res of
    Left _ -> putStrLn $ "Failed to remove " ++ show bucket ++ "/" ++ show object
    Right _ -> putStrLn "Removed incomplete upload successfully"

selectObjectContent :: Bucket -> Object -> SelectRequest -> Minio (ConduitT () EventMessage Minio ())

Removes an ongoing multipart upload of an object from the service

Parameters

In the expression selectObjectContent bucketName objectName selReq
the parameters are:

SelectRequest record

This record is created using selectRequest. Please refer to the Haddocks for further information.

Return Value

The return value can be used to read individual EventMessages in the response. Please refer to the Haddocks for further information.

Example

{-# Language OverloadedStrings #-}
import Network.Minio

import qualified Conduit              as C

main :: IO ()
main = do
  let
    bucket = "mybucket"
    object = "myobject"

  res <- runMinio minioPlayCI $ do
    let sr = selectRequest "Select * from s3object"
             defaultCsvInput defaultCsvOutput
    res <- selectObjectContent bucket object sr
    C.runConduit $ res C..| getPayloadBytes C..| C.stdoutC

  case res of
    Left _ -> putStrLn "Failed!"
    Right _ -> putStrLn "Success!"

bucketExists :: Bucket -> Minio Bool

Checks if a bucket exists.

Parameters

In the expression bucketExists bucketName the parameters are:

4. Presigned operations

presignedGetObjectUrl :: Bucket -> Object -> UrlExpiry -> Query -> RequestHeaders -> Minio ByteString

Generate a URL with authentication signature to GET (download) an
object. All extra query parameters and headers passed here will be
signed and are required when the generated URL is used. Query
parameters could be used to change the response headers sent by the
server. Headers can be used to set Etag match conditions among others.

For a list of possible request parameters and headers, please refer
to the GET object REST API AWS S3 documentation.

Parameters

In the expression presignedGetObjectUrl bucketName objectName expiry queryParams headers
the parameters are:

Return Value

Returns the generated URL - it will include authentication
information.

Example

{-# Language OverloadedStrings #-}

import Network.Minio
import qualified Data.ByteString.Char8 as B

main :: IO ()
main = do
  let
    bucket = "mybucket"
    object = "myobject"

  res <- runMinio minioPlayCI $ do
           -- Set a 7 day expiry for the URL
           presignedGetObjectUrl bucket object (7*24*3600) [] []

  -- Print the URL on success.
  putStrLn $ either
    (("Failed to generate URL: " ++) . show)
    B.unpack
    res

presignedPutObjectUrl :: Bucket -> Object -> UrlExpiry -> RequestHeaders -> Minio ByteString

Generate a URL with authentication signature to PUT (upload) an
object. Any extra headers if passed, are signed, and so they are
required when the URL is used to upload data. This could be used, for
example, to set user-metadata on the object.

For a list of possible headers to pass, please refer to the PUT object
REST API AWS S3 documentation.

Parameters

In the expression presignedPutObjectUrl bucketName objectName expiry headers
the parameters are:

Return Value

Returns the generated URL - it will include authentication
information.

Example

{-# Language OverloadedStrings #-}

import Network.Minio
import qualified Data.ByteString.Char8 as B

main :: IO ()
main = do
  let
    bucket = "mybucket"
    object = "myobject"

  res <- runMinio minioPlayCI $ do
           -- Set a 7 day expiry for the URL
           presignedPutObjectUrl bucket object (7*24*3600) [] []

  -- Print the URL on success.
  putStrLn $ either
    (("Failed to generate URL: " ++) . show)
    B.unpack
    res

presignedPostPolicy :: PostPolicy -> Minio (ByteString, HashMap Text ByteString)

Generate a presigned URL and POST policy to upload files via a POST
request. This is intended for browser uploads and generates form data
that should be submitted in the request.

The PostPolicy argument is created using the newPostPolicy function:

newPostPolicy :: UTCTime -> [PostPolicyCondition] -> Either PostPolicyError PostPolicy

In the expression newPostPolicy expirationTime conditions the parameters are:

The policy conditions are created using various helper functions -
please refer to the Haddocks for details.

Since conditions are validated by newPostPolicy it returns an
Either value.

Return Value

presignedPostPolicy returns a 2-tuple - the generated URL and a map
containing the form-data that should be submitted with the request.

Example

{-# Language OverloadedStrings #-}

import Network.Minio

import qualified Data.ByteString       as B
import qualified Data.ByteString.Char8 as Char8
import qualified Data.HashMap.Strict   as H
import qualified Data.Text.Encoding    as Enc
import qualified Data.Time             as Time

main :: IO ()
main = do
  now <- Time.getCurrentTime
  let
    bucket = "mybucket"
    object = "myobject"

    -- set an expiration time of 10 days
    expireTime = Time.addUTCTime (3600 * 24 * 10) now

    -- create a policy with expiration time and conditions - since the
    -- conditions are validated, newPostPolicy returns an Either value
    policyE = newPostPolicy expireTime
              [ -- set the object name condition
                ppCondKey "photos/my-object"
                -- set the bucket name condition
              , ppCondBucket "my-bucket"
                -- set the size range of object as 1B to 10MiB
              , ppCondContentLengthRange 1 (10*1024*1024)
                -- set content type as jpg image
              , ppCondContentType "image/jpeg"
                -- on success set the server response code to 200
              , ppCondSuccessActionStatus 200
              ]

  case policyE of
    Left err -> putStrLn $ show err
    Right policy -> do
      res <- runMinio minioPlayCI $ do
        (url, formData) <- presignedPostPolicy policy

        -- a curl command is output to demonstrate using the generated
        -- URL and form-data
        let
          formFn (k, v) = B.concat ["-F ", Enc.encodeUtf8 k, "=",
                                    "'", v, "'"]
          formOptions = B.intercalate " " $ map formFn $ H.toList formData


        return $ B.intercalate " " $
          ["curl", formOptions, "-F file=@/tmp/photo.jpg", url]

      case res of
        Left e -> putStrLn $ "post-policy error: " ++ (show e)
        Right cmd -> do
          putStrLn $ "Put a photo at /tmp/photo.jpg and run command:\n"

          -- print the generated curl command
          Char8.putStrLn cmd