fix: add WithTempFile

Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>

file/getters.go

@@ -0,0 +1,23 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package file
+
+import "os"
+
+// GetName is the getter for the `Name` property of [os.File]
+func GetName(f *os.File) string {
+	return f.Name()
+}

io/file/file.go

@@ -0,0 +1,39 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package file
+
+import (
+	"io"
+	"os"
+
+	IO "github.com/IBM/fp-go/io"
+)
+
+// Close closes a closeable resource and ignores a potential error
+func Close[R io.Closer](r R) IO.IO[R] {
+	return IO.MakeIO[R](func() R {
+		r.Close() // #nosec: G104
+		return r
+	})
+}
+
+// Remove removes a resource and ignores a potential error
+func Remove(name string) IO.IO[string] {
+	return IO.MakeIO[string](func() string {
+		os.Remove(name) // #nosec: G104
+		return name
+	})
+}

ioeither/file/close.go

@@ -21,6 +21,7 @@ import (
 	IOE "github.com/IBM/fp-go/ioeither"
 )
 
+// onClose closes a closeable resource
 func onClose[R io.Closer](r R) IOE.IOEither[error, R] {
 	return IOE.TryCatchError(func() (R, error) {
 		return r, r.Close()

ioeither/file/file.go

@@ -24,14 +24,24 @@ import (
 var (
 	// Open opens a file for reading
 	Open = IOE.Eitherize1(os.Open)
+	// Create opens a file for writing
+	Create = IOE.Eitherize1(os.Create)
 	// ReadFile reads the context of a file
 	ReadFile = IOE.Eitherize1(os.ReadFile)
-	// WriteFile writes a data blob to a file
-	WriteFile = func(dstName string, perm os.FileMode) func([]byte) IOE.IOEither[error, []byte] {
-		return func(data []byte) IOE.IOEither[error, []byte] {
-			return IOE.TryCatchError(func() ([]byte, error) {
-				return data, os.WriteFile(dstName, data, perm)
-			})
-		}
-	}
 )
+
+// WriteFile writes a data blob to a file
+func WriteFile(dstName string, perm os.FileMode) func([]byte) IOE.IOEither[error, []byte] {
+	return func(data []byte) IOE.IOEither[error, []byte] {
+		return IOE.TryCatchError(func() ([]byte, error) {
+			return data, os.WriteFile(dstName, data, perm)
+		})
+	}
+}
+
+// Remove removes a file by name
+func Remove(name string) IOE.IOEither[error, string] {
+	return IOE.TryCatchError(func() (string, error) {
+		return name, os.Remove(name)
+	})
+}

ioeither/file/readall.go

@@ -29,7 +29,7 @@ func onReadAll[R io.Reader](r R) IOE.IOEither[error, []byte] {
 
 // ReadAll uses a generator function to create a stream, reads it and closes it
 func ReadAll[R io.ReadCloser](acquire IOE.IOEither[error, R]) IOE.IOEither[error, []byte] {
-	return IOE.WithResource[error, R, []byte](
+	return IOE.WithResource[[]byte](
 		acquire,
 		onClose[R])(
 		onReadAll[R],

ioeither/file/tempfile.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package file
+
+import (
+	"os"
+
+	FL "github.com/IBM/fp-go/file"
+	F "github.com/IBM/fp-go/function"
+	IO "github.com/IBM/fp-go/io"
+	IOF "github.com/IBM/fp-go/io/file"
+	IOE "github.com/IBM/fp-go/ioeither"
+)
+
+var (
+	// CreateTemp created a temp file with proper parametrization
+	CreateTemp = IOE.Eitherize2(os.CreateTemp)
+	// onCreateTempFile creates a temp file with sensible defaults
+	onCreateTempFile = CreateTemp("", "*")
+	// destroy handler
+	onReleaseTempFile = F.Flow4(
+		IOF.Close[*os.File],
+		IO.Map(FL.GetName),
+		IOE.FromIO[error, string],
+		IOE.Chain(Remove),
+	)
+)
+
+// WithTempFile creates a temporary file, then invokes a callback to create a resource based on the file, then close and remove the temp file
+func WithTempFile[A any](f func(*os.File) IOE.IOEither[error, A]) IOE.IOEither[error, A] {
+	return IOE.WithResource[A](onCreateTempFile, onReleaseTempFile)(f)
+}

ioeither/file/tempfile_test.go

@@ -0,0 +1,46 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package file
+
+import (
+	"os"
+	"testing"
+
+	E "github.com/IBM/fp-go/either"
+	F "github.com/IBM/fp-go/function"
+	IOE "github.com/IBM/fp-go/ioeither"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWithTempFile(t *testing.T) {
+
+	res := WithTempFile(onWriteAll[*os.File]([]byte("Carsten")))
+
+	assert.Equal(t, E.Of[error]([]byte("Carsten")), res())
+}
+
+func TestWithTempFileOnClosedFile(t *testing.T) {
+
+	res := WithTempFile(func(f *os.File) IOE.IOEither[error, []byte] {
+		return F.Pipe2(
+			f,
+			onWriteAll[*os.File]([]byte("Carsten")),
+			IOE.ChainFirst(F.Constant1[[]byte](onClose(f))),
+		)
+	})
+
+	assert.Equal(t, E.Of[error]([]byte("Carsten")), res())
+}

ioeither/file/write.go

@@ -34,7 +34,7 @@ func onWriteAll[W io.Writer](data []byte) func(w W) IOE.IOEither[error, []byte]
 func WriteAll[W io.WriteCloser](data []byte) func(acquire IOE.IOEither[error, W]) IOE.IOEither[error, []byte] {
 	onWrite := onWriteAll[W](data)
 	return func(onCreate IOE.IOEither[error, W]) IOE.IOEither[error, []byte] {
-		return IOE.WithResource[error, W, []byte](
+		return IOE.WithResource[[]byte](
 			onCreate,
 			onClose[W])(
 			onWrite,
@@ -43,8 +43,8 @@ func WriteAll[W io.WriteCloser](data []byte) func(acquire IOE.IOEither[error, W]
 }
 
 // Write uses a generator function to create a stream, writes data to it and closes it
-func Write[W io.WriteCloser, R any](acquire IOE.IOEither[error, W]) func(use func(W) IOE.IOEither[error, R]) IOE.IOEither[error, R] {
+func Write[R any, W io.WriteCloser](acquire IOE.IOEither[error, W]) func(use func(W) IOE.IOEither[error, R]) IOE.IOEither[error, R] {
-	return IOE.WithResource[error, W, R](
+	return IOE.WithResource[R](
 		acquire,
 		onClose[W])
 }

ioeither/ioeither.go

@@ -192,7 +192,7 @@ func ChainFirstIOK[E, A, B any](f func(A) I.IO[B]) func(IOEither[E, A]) IOEither
 }
 
 // WithResource constructs a function that creates a resource, then operates on it and then releases the resource
-func WithResource[E, R, A, ANY any](onCreate IOEither[E, R], onRelease func(R) IOEither[E, ANY]) func(func(R) IOEither[E, A]) IOEither[E, A] {
+func WithResource[A, E, R, ANY any](onCreate IOEither[E, R], onRelease func(R) IOEither[E, ANY]) func(func(R) IOEither[E, A]) IOEither[E, A] {
 	return G.WithResource[IOEither[E, A]](onCreate, onRelease)
 }