From e2e053e3227a39a8962c12ae694a6ac5bd52bf8f Mon Sep 17 00:00:00 2001
From: Raghu Rajagopalan <raghu.rajagopalan@gmail.com>
Date: Fri, 20 Apr 2018 16:55:49 +0530
Subject: [PATCH] feat(cmd): allow reading input from stdin

---
 cmd/libasciidoc/root_cmd.go      | 12 +++++++---
 cmd/libasciidoc/root_cmd_test.go | 38 ++++++++++++++++++++++++++++++--
 2 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/cmd/libasciidoc/root_cmd.go b/cmd/libasciidoc/root_cmd.go
index c3d84973..effe3a2e 100644
--- a/cmd/libasciidoc/root_cmd.go
+++ b/cmd/libasciidoc/root_cmd.go
@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"os"
 
 	"github.com/bytesparadise/libasciidoc"
 	"github.com/bytesparadise/libasciidoc/renderer"
@@ -16,11 +17,16 @@ func NewRootCmd() *cobra.Command {
 		Use:   "libasciidoc",
 		Short: "libasciidoc is a tool to generate an html output from an asciidoc file",
 		RunE: func(cmd *cobra.Command, args []string) error {
+			var err error
 			if cmd.Flag("source").Value.String() == "" {
 				return fmt.Errorf("flag 'source' is required")
 			}
-			source := cmd.Flag("source").Value.String()
-			_, err := libasciidoc.ConvertFileToHTML(context.Background(), source, cmd.OutOrStdout(), renderer.IncludeHeaderFooter(true)) //renderer.IncludeHeaderFooter(true)
+			if cmd.Flag("source").Value.String() == "-" {
+				_, err = libasciidoc.ConvertToHTML(context.Background(), os.Stdin, cmd.OutOrStdout(), renderer.IncludeHeaderFooter(true))
+			} else {
+				source := cmd.Flag("source").Value.String()
+				_, err = libasciidoc.ConvertFileToHTML(context.Background(), source, cmd.OutOrStdout(), renderer.IncludeHeaderFooter(true)) //renderer.IncludeHeaderFooter(true)
+			}
 			if err != nil {
 				return err
 			}
@@ -28,6 +34,6 @@ func NewRootCmd() *cobra.Command {
 		},
 	}
 	flags := rootCmd.Flags()
-	flags.StringVarP(&source, "source", "s", "", "the path to the asciidoc source to process")
+	flags.StringVarP(&source, "source", "s", "", "the path to the asciidoc source to process. Use '-' for reading from stdin")
 	return rootCmd
 }
diff --git a/cmd/libasciidoc/root_cmd_test.go b/cmd/libasciidoc/root_cmd_test.go
index 9e64f8a5..a8886b51 100644
--- a/cmd/libasciidoc/root_cmd_test.go
+++ b/cmd/libasciidoc/root_cmd_test.go
@@ -2,15 +2,20 @@ package main_test
 
 import (
 	"bytes"
+	"io/ioutil"
+	"log"
+	"os"
 	"testing"
 
 	main "github.com/bytesparadise/libasciidoc/cmd/libasciidoc"
 	"github.com/stretchr/testify/require"
-)
 
-import . "github.com/onsi/ginkgo"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
 
 var _ = Describe("root cmd", func() {
+	RegisterFailHandler(Fail)
 
 	It("ok", func() {
 		// given
@@ -37,6 +42,35 @@ var _ = Describe("root cmd", func() {
 		require.Error(GinkgoT(), err)
 	})
 
+	It("should process stdin", func() {
+		// given
+		root := main.NewRootCmd()
+		buf := new(bytes.Buffer)
+		root.SetOutput(buf)
+		content := "some content"
+		tmpfile, err := ioutil.TempFile("", "example")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		defer os.Remove(tmpfile.Name()) // clean up
+
+		if _, err := tmpfile.Write([]byte(content)); err != nil {
+			log.Fatal(err)
+		}
+		tmpfile.Seek(0, 0)
+		oldstdin := os.Stdin
+		os.Stdin = tmpfile
+		defer func() { os.Stdin = oldstdin }()
+
+		root.SetArgs([]string{"-s", "-"})
+		// when
+		err = root.Execute()
+		GinkgoT().Logf("command output: %v", buf.String())
+		Expect(buf.String()).To(ContainSubstring(content))
+		require.NoError(GinkgoT(), err)
+		require.NotEmpty(GinkgoT(), buf)
+	})
 })
 
 func TestRootCommand(t *testing.T) {