Import source: handler/fs/fs

Import the existing local project snapshot. This commit organizes existing files; it does not represent newly developed functionality.

handler/fs/fs.go

@@ -0,0 +1,84 @@
+package fs
+
+import (
+	"io"
+	"path"
+	"reactor-crw"
+)
+
+// PathResolver defines a simple interface to resolve path for content
+// before saving it.
+type pathResolver interface {
+	// CreateFolder creates a new folder in the "current" dir. The current
+	// directory is specified in Config.SavePath provided by a user. If dir
+	// with such name already exists it'll skip creation step.
+	CreateFolder(name string) error
+
+	// CreateFile creates a new file for downloaded content in the directory
+	// created by the CreateFolder function and returns the corresponding
+	// io.WriteCloser. If a file with such a name already exists then it'll
+	// be overwritten.
+	CreateFile(name string) (io.WriteCloser, error)
+
+	// Remove removes a file or folder by its name. If provided path does not
+	// exist it'll be skipped.
+	Remove(name string)
+}
+
+// FileSaver defines ContentHandler implementation that will download content
+// and save it to the host's file system. It resolves the corresponding file
+// path with PathResolver.
+type FileSaver struct {
+	pr pathResolver
+	t  reactor_crw.Transport
+}
+
+// NewFileSaver creates a new FileSaver instance along with a new folder that
+// will act as a context for a new instance. All files will be processed within
+// this new folder.
+func NewFileSaver(pr pathResolver, t reactor_crw.Transport, baseFolder string) (*FileSaver, error) {
+	err := pr.CreateFolder(baseFolder)
+	if err != nil {
+		return nil, err
+	}
+
+	return &FileSaver{
+		pr: pr,
+		t:  t,
+	}, nil
+}
+
+// Process downloads content by the corresponding URL by making an HTTP request
+// and saves the result to the file system. In case of error during saving the
+// content the corresponding file will be deleted from the file system.
+func (f *FileSaver) Process(url string, progress chan<- int, e chan<- error) {
+	defer func() {
+		progress <- 1
+	}()
+
+	data, err := f.t.FetchData(url)
+	if err != nil {
+		e <- err
+		return
+	}
+
+	defer func(b io.ReadCloser) {
+		_ = b.Close()
+	}(data)
+
+	file, err := f.pr.CreateFile(path.Base(url))
+	if err != nil {
+		e <- err
+		return
+	}
+
+	defer func(f io.WriteCloser) {
+		_ = f.Close()
+	}(file)
+
+	_, err = io.Copy(file, data)
+	if err != nil {
+		f.pr.Remove(path.Base(url))
+		e <- err
+	}
+}

handler/fs/fs_test.go

@@ -0,0 +1,130 @@
+//go:build unit
+// +build unit
+
+package fs_test
+
+import (
+	"errors"
+	"io"
+	"io/ioutil"
+	"os"
+	"reactor-crw/handler/fs"
+	"testing"
+
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
+)
+
+type pathResolverMock struct {
+	mock.Mock
+}
+
+func (m *pathResolverMock) CreateFolder(name string) error {
+	args := m.Called(name)
+	return args.Error(0)
+}
+
+func (m *pathResolverMock) CreateFile(name string) (io.WriteCloser, error) {
+	args := m.Called(name)
+	return args.Get(0).(io.WriteCloser), args.Error(1)
+}
+
+func (m *pathResolverMock) Remove(name string) {
+	_ = m.Called(name)
+}
+
+type transportMock struct {
+	mock.Mock
+}
+
+func (m *transportMock) FetchData(url string) (io.ReadCloser, error) {
+	args := m.Called(url)
+	return args.Get(0).(io.ReadCloser), args.Error(1)
+}
+
+func TestNewFileSaver(t *testing.T) {
+	pr := pathResolverMock{}
+	trp := transportMock{}
+
+	t.Log("Given the need to create a file saver handler.")
+	{
+		t.Log("When baseFolder is incorrect.")
+		{
+			pr.On("CreateFolder", "baseFolder").Return(errors.New("error"))
+			_, err := fs.NewFileSaver(&pr, &trp, "baseFolder")
+			require.Error(t, err, "Expected an error during create folder")
+			pr.ExpectedCalls = []*mock.Call{}
+		}
+
+		t.Log("When all data correct.")
+		{
+			pr.On("CreateFolder", "baseFolder").Return(nil)
+			_, err := fs.NewFileSaver(&pr, &trp, "baseFolder")
+			require.NoError(t, err, "Wasn't expected an error on new creating file saver")
+		}
+	}
+}
+
+func TestFileSaver_Process(t *testing.T) {
+	tmlFile, _ := ioutil.TempFile(os.TempDir(), "file-title.txt")
+
+	pr := pathResolverMock{}
+	pr.On("CreateFolder", "baseFolder").Return(nil)
+	pr.On("Remove", mock.Anything)
+
+	trp := transportMock{}
+
+	p := make(chan int, 1)
+	e := make(chan error, 1)
+
+	fileSaver, _ := fs.NewFileSaver(&pr, &trp, "baseFolder")
+
+	t.Log("Given the need to process data.")
+	{
+		t.Log("When transport returns an error.")
+		{
+			trp.On("FetchData", "file-title.txt").Return(tmlFile, errors.New("error")).Once()
+
+			fileSaver.Process("file-title.txt", p, e)
+			require.Error(t, <-e, "Expected an error during create file")
+			<-p
+		}
+
+		t.Log("When path resolver returns an error.")
+		{
+			trp.On("FetchData", "file-title.txt").Return(tmlFile, nil).Once()
+			pr.On("CreateFile", "file-title.txt").Return(tmlFile, errors.New("error")).Once()
+
+			fileSaver.Process("file-title.txt", p, e)
+			require.Error(t, <-e, "Expected an error during create file")
+			<-p
+		}
+
+		t.Log("When cannot save the data.")
+		{
+			trp.On("FetchData", "file-title.txt").Return(tmlFile, nil).Once()
+			pr.On("CreateFile", "file-title.txt").Return(tmlFile, nil).Once()
+			pr.On("Remove", mock.Anything)
+
+			fileSaver.Process("file-title.txt", p, e)
+			require.Error(t, <-e, "Expected an error file copying")
+			<-p
+		}
+
+		t.Log("When all data correct.")
+		{
+			tmlFile, _ = ioutil.TempFile(os.TempDir(), "new-file-title.txt")
+
+			trp.On("FetchData", "new-file-title.txt").Return(tmlFile, nil).Once()
+			pr.On("CreateFile", "new-file-title.txt").Return(tmlFile, nil).Once()
+
+			fileSaver.Process("new-file-title.txt", p, e)
+			select {
+			case err := <-e:
+				require.NoError(t, err, "Wasn't expected an error on new file process")
+			case <-p:
+				return
+			}
+		}
+	}
+}