add FileExists

internal/transport/buffer.go

@@ -0,0 +1,116 @@
+// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.
+
+package transport
+
+import (
+_	"errors"
+	"path/filepath"
+	"io"
+	"os"
+	"net/url"
+	"strings"
+	"fmt"
+	"compress/gzip"
+)
+
+type Buffer struct {
+	uri *url.URL
+	path string
+	exttype string
+	fileext string
+	readHandle *os.File
+	writeHandle *os.File
+	gzip bool
+	gzipWriter io.WriteCloser
+	gzipReader io.ReadCloser
+}
+
+func NewBuffer(u *url.URL) (b *Buffer, err error) {
+	b = &Buffer{
+		uri: u,
+		path: filepath.Join(u.Hostname(), u.RequestURI()),
+	}
+	b.extension()
+	b.DetectGzip()
+
+	if b.path == "" || b.path == "-" {
+		b.readHandle = os.Stdin
+		b.writeHandle = os.Stdout
+	} else {
+		if b.readHandle, err = os.OpenFile(b.Path(), os.O_RDWR|os.O_CREATE, 0644); err != nil {
+			return
+		}
+		b.writeHandle = b.readHandle
+	}
+
+	if b.Gzip() {
+		b.gzipWriter = gzip.NewWriter(b.writeHandle)
+		if b.gzipReader, err = gzip.NewReader(b.readHandle); err != nil {
+			return
+		}
+	}
+	return
+}
+
+func (b *Buffer) extension() {
+	elements := strings.Split(b.path, ".")
+	numberOfElements := len(elements)
+	if numberOfElements > 2 {
+		b.exttype = elements[numberOfElements - 2]
+		b.fileext = elements[numberOfElements - 1]
+	}
+	b.exttype = elements[numberOfElements - 1]
+}
+
+func (b *Buffer) DetectGzip() {
+	b.gzip = (b.uri.Query().Get("gzip") == "true" || b.fileext == "gz") 
+}
+
+func (b *Buffer) URI() *url.URL {
+	return b.uri
+}
+
+func (b *Buffer) Path() string {
+	return b.path
+}
+
+func (b *Buffer) Signature() (documentSignature string) {
+	if signatureResp, signatureErr := os.Open(fmt.Sprintf("%s.sig", b.uri.String())); signatureErr == nil {
+		defer signatureResp.Close()
+		readSignatureBody, readSignatureErr := io.ReadAll(signatureResp)
+		if readSignatureErr == nil {
+			documentSignature = string(readSignatureBody)
+		} else {
+			panic(readSignatureErr)
+		}
+	} else {
+		panic(signatureErr)
+	}
+	return documentSignature
+}
+
+func (b *Buffer) ContentType() string {
+	return b.exttype
+}
+
+func (b *Buffer) SetGzip(gzip bool) {
+	b.gzip = gzip
+}
+
+func (b *Buffer) Gzip() bool {
+	return b.gzip
+}
+
+func (b *Buffer) Reader() io.ReadCloser {
+	if b.Gzip() {
+		return b.gzipReader
+	}
+	return b.readHandle
+}
+
+func (b *Buffer) Writer() io.WriteCloser {
+	if b.Gzip() {
+		return b.gzipWriter
+	}
+	return b.writeHandle
+}

internal/transport/buffer_test.go

@@ -0,0 +1,39 @@
+// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.
+
+package transport
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+	"fmt"
+	"os"
+	"net/url"
+	"path/filepath"
+)
+
+var TransportBufferTestFile = fmt.Sprintf("%s/foo", TempDir)
+
+func TestNewTransportBufferReader(t *testing.T) {
+	path := fmt.Sprintf("%s/foo", TempDir)
+	u, e := url.Parse(fmt.Sprintf("file://%s", path))
+	assert.Nil(t, e)
+
+	writeErr := os.WriteFile(path, []byte("test"), 0644)
+	assert.Nil(t, writeErr)
+
+	file, err := NewBuffer(u)
+	assert.Nil(t, err)
+	assert.Equal(t, file.Path(), path)
+}
+
+func TestNewTransportBufferReaderExtension(t *testing.T) {
+	u, e := url.Parse(fmt.Sprintf("file://%s.yaml", TransportBufferTestFile))
+	assert.Nil(t, e)
+
+	b := &Buffer{
+		uri: u,
+		path: filepath.Join(u.Hostname(), u.RequestURI()),
+	}
+	b.extension()
+	assert.Equal(t, b.exttype, "yaml")
+}

internal/transport/file.go

@@ -25,10 +25,19 @@ type File struct {
 	gzipReader io.ReadCloser
 }
 
+func FilePath(u *url.URL) string {
+	return filepath.Join(u.Hostname(), u.RequestURI())
+}
+
+func FileExists(u *url.URL) bool {
+	_, err := os.Stat(FilePath(u))
+	return err == nil
+}
+
 func NewFile(u *url.URL) (f *File, err error) {
 	f = &File {
 		uri: u,
-		path: filepath.Join(u.Hostname(), u.RequestURI()),
+		path: FilePath(u),
 	}
 	f.extension()
 	f.DetectGzip()
@@ -55,11 +64,13 @@ func NewFile(u *url.URL) (f *File, err error) {
 func (f *File) extension() {
 	elements := strings.Split(f.path, ".")
 	numberOfElements := len(elements)
+	if numberOfElements > 1 {
 		if numberOfElements > 2 {
 			f.exttype = elements[numberOfElements - 2]
 			f.fileext = elements[numberOfElements - 1]
 		}
 		f.exttype = elements[numberOfElements - 1]
+	}
 }
 
 func (f *File) DetectGzip() {
@@ -90,6 +101,9 @@ func (f *File) Signature() (documentSignature string) {
 }
 
 func (f *File) ContentType() string {
+	if f.uri.Scheme != "file" {
+		return f.uri.Scheme
+	}
 	return f.exttype
 }
 

internal/transport/http.go

@@ -33,6 +33,10 @@ type HTTP struct {
 	Client *http.Client
 }
 
+func HTTPExists(u *url.URL) bool {
+	return false
+}
+
 func (b BufferCloser) Close() error {
 	if b.stream != nil {
 		return b.stream.Close()

internal/transport/transport.go

@@ -27,6 +27,7 @@ type Reader struct {
 	uri *url.URL
 	handle Handler
 	stream io.ReadCloser
+	exists func() bool
 }
 
 func NewReader(u *url.URL) (reader *Reader, e error) {
@@ -39,8 +40,9 @@ func NewReader(u *url.URL) (reader *Reader, e error) {
 		fallthrough
 	default:
 		reader.handle, e = NewFile(u)
+		reader.exists = func() bool { return FileExists(u) }
 	}
-	reader.stream = reader.handle.Reader()
+	reader.SetStream(reader.handle.Reader())
 	return
 }
 
@@ -56,6 +58,7 @@ type Writer struct {
 	uri *url.URL
 	handle Handler
 	stream io.WriteCloser
+	exists func() bool
 }
 
 func NewWriter(u *url.URL) (writer *Writer, e error) {
@@ -68,8 +71,9 @@ func NewWriter(u *url.URL) (writer *Writer, e error) {
 		fallthrough
 	default:
 		writer.handle, e = NewFile(u)
+		writer.exists = func() bool { return FileExists(u) }
 	}
-	writer.stream = writer.handle.Writer()
+	writer.SetStream(writer.handle.Writer())
 	return writer, e
 }
 
@@ -81,6 +85,25 @@ func NewWriterURI(uri string) (writer *Writer, e error) {
 	return
 }
 
+func ExistsURI(uri string) bool {
+	var u *url.URL
+	u, _ = url.Parse(uri)
+	return Exists(u)
+}
+
+func Exists(u *url.URL) bool {
+	switch u.Scheme {
+	case "http", "https":
+		return HTTPExists(u)
+	case "file":
+		fallthrough
+	default:
+		return FileExists(u)
+	}
+}
+
+func (r *Reader) Exists() bool { return r.exists() }
+
 func (r *Reader) Read(b []byte) (int, error) {
 	return r.stream.Read(b)
 }
@@ -101,8 +124,13 @@ func (r *Reader) Signature() string {
 	return r.handle.Signature()
 }
 
+func (r *Reader) SetStream(s io.ReadCloser) {
+	r.stream = s
+}
 
 
+func (w *Writer) Exists() bool { return w.exists() }
+
 func (w *Writer) Write(b []byte) (int, error) {
 	return w.stream.Write(b)
 }
@@ -122,3 +150,7 @@ func (w *Writer) Gzip() bool {
 func (w *Writer) Signature() string {
 	return w.handle.Signature()
 }
+
+func (w *Writer) SetStream(s io.WriteCloser) {
+	w.stream = s
+}

internal/transport/transport_test.go

@@ -52,13 +52,32 @@ func TestTransportReaderContentType(t *testing.T) {
 	u, e := url.Parse(fmt.Sprintf("file://%s", path))
 	assert.Nil(t, e)
 
+	assert.False(t, Exists(u))
 	writeErr := os.WriteFile(path, []byte(testFileResourceDoc), 0644)
 
 	assert.Nil(t, writeErr)
 
 	reader, err := NewReader(u)
 	assert.Nil(t, err)
+	assert.True(t, reader.Exists())
 	assert.NotNil(t, reader)
 
 	assert.Equal(t, reader.ContentType(), "yaml")
 }
+
+func TestTransportWriter(t *testing.T) {
+	path := fmt.Sprintf("%s/writefoo", TempDir)
+	u, e := url.Parse(fmt.Sprintf("file://%s", path))
+	assert.Nil(t, e)
+
+	assert.False(t, Exists(u))
+	writer, err := NewWriter(u)
+	assert.Nil(t, err)
+	defer writer.Close()
+	assert.NotNil(t, writer)
+	assert.True(t, writer.Exists())
+	_, writeErr := writer.Write([]byte("testdata"))
+	assert.Nil(t, writeErr)
+	assert.FileExists(t, path)
+	
+}