Use github.com/google/shlex to parse commands

Implements: https://todo.sr.ht/~adnano/kiln/21

funcs.go

@@ -5,6 +5,8 @@ import (
 	"path"
 	"reflect"
 	"strings"
+
+	"github.com/google/shlex"
 )
 
 // funcs returns functions for use in templates.
@@ -56,7 +58,11 @@ func (_strings) TrimSuffix(a, b string) string        { return strings.TrimSuffi
 
 func executeString(command, input string) (string, error) {
 	var b strings.Builder
-	if err := execute(command, strings.NewReader(input), &b); err != nil {
+	cmd, err := shlex.Split(command)
+	if err != nil {
+		return "", err
+	}
+	if err := execute(cmd, strings.NewReader(input), &b); err != nil {
 		return "", err
 	}
 	return b.String(), nil

go.mod

@@ -3,6 +3,7 @@ module kiln
 go 1.16
 
 require (
+	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/pelletier/go-toml v1.9.0
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )

go.sum

@@ -1,3 +1,5 @@
+github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
+github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
 github.com/pelletier/go-toml v1.9.0 h1:NOd0BRdOKpPf0SxkL3HxSQOG7rNh+4kl6PHcBPFs7Q0=
 github.com/pelletier/go-toml v1.9.0/go.mod h1:u1nR/EPcESfeI/szUZKdtJ0xRNbUoANCkoOuaOx1Y+c=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

page.go

@@ -120,7 +120,7 @@ func (p *Page) _read(srcDir, path string, task *Task, cfg *Site) error {
 				content = bytes.TrimLeft(content, "\r\n")
 			}
 
-			if cmd, ok := task.Preprocess[strings.TrimPrefix(ext, ".")]; ok {
+			if cmd, ok := task.preprocess[strings.TrimPrefix(ext, ".")]; ok {
 				var buf bytes.Buffer
 				if err := execute(cmd, bytes.NewReader(content), &buf); err != nil {
 					return err
@@ -275,7 +275,7 @@ func (p *Page) write(dstDir string, task *Task) error {
 
 func (p *Page) writeTo(dstPath string, task *Task) error {
 	var content []byte
-	if cmd := task.Postprocess; cmd != "" {
+	if cmd := task.postprocess; cmd != nil {
 		var buf bytes.Buffer
 		if err := execute(cmd, strings.NewReader(p.Content), &buf); err != nil {
 			return err
@@ -331,9 +331,11 @@ func sortPages(pages []*Page) {
 }
 
 // execute runs a command.
-func execute(command string, input io.Reader, output io.Writer) error {
-	split := strings.Split(command, " ")
-	cmd := exec.Command(split[0], split[1:]...)
+func execute(command []string, input io.Reader, output io.Writer) error {
+	if len(command) == 0 {
+		return nil
+	}
+	cmd := exec.Command(command[0], command[1:]...)
 	cmd.Stdin = input
 	cmd.Stderr = os.Stderr
 	cmd.Stdout = output

site.go

@@ -6,6 +6,7 @@ import (
 	"text/template"
 	"time"
 
+	"github.com/google/shlex"
 	"github.com/pelletier/go-toml"
 )
 
@@ -33,6 +34,8 @@ type Task struct {
 	URL         string            `toml:"url"`
 	UglyURLs    bool              `toml:"ugly_urls"`
 	Feeds       []Feed            `toml:"feeds"`
+	preprocess  map[string][]string
+	postprocess []string
 	feeds       map[string][]Feed
 }
 
@@ -92,13 +95,30 @@ func LoadSite(config string) (*Site, error) {
 		return nil, err
 	}
 
-	// Populate task feeds map
 	for _, task := range site.Tasks {
+		// Populate feeds
 		task.feeds = map[string][]Feed{}
 		for _, feed := range task.Feeds {
 			dir := feed.InputDir
 			task.feeds[dir] = append(task.feeds[dir], feed)
 		}
+
+		// Parse commands
+		task.preprocess = map[string][]string{}
+		for path := range task.Preprocess {
+			preprocess, err := shlex.Split(task.Preprocess[path])
+			if err != nil {
+				return nil, err
+			}
+			task.preprocess[path] = preprocess
+		}
+		if task.Postprocess != "" {
+			postprocess, err := shlex.Split(task.Postprocess)
+			if err != nil {
+				return nil, err
+			}
+			task.postprocess = postprocess
+		}
 	}
 
 	return site, nil