Implement support for preprocess command

config.go

@@ -1,11 +1,8 @@
 package main
 
 import (
-	"log"
 	"os"
-	"os/exec"
 	"path"
-	"strings"
 	"text/template"
 
 	"github.com/BurntSushi/toml"
@@ -25,28 +22,14 @@ type Task struct {
 	InputExt    string `toml:"input_ext"`    // input file extension
 	OutputExt   string `toml:"output_ext"`   // output file extension
 	TemplateExt string `toml:"template_ext"` // template file extension
+	PreProcess  string `toml:"preprocess"`   // preprocess command
 	PostProcess string `toml:"postprocess"`  // postprocess command
 	StaticDir   string `toml:"static_dir"`   // static file directory
 	OutputDir   string `toml:"output_dir"`   // output directory
 }
 
-func (t Task) Format(p *Page) (string, []byte) {
+func (t Task) OutputPath(pagePath string) string {
-	path := path.Join(p.Path, "index"+t.OutputExt)
+	return path.Join(pagePath, "index"+t.OutputExt)
-
-	// Run a custom command.
-	if t.PostProcess != "" {
-		split := strings.Split(t.PostProcess, " ")
-		cmd := exec.Command(split[0], split[1:]...)
-		cmd.Stdin = strings.NewReader(p.Content)
-		cmd.Stderr = os.Stderr
-		output, err := cmd.Output()
-		if err != nil {
-			log.Fatal(err)
-		}
-		return path, output
-	}
-
-	return path, []byte(p.Content)
 }
 
 // LoadConfig loads the configuration from the provided path.

dir.go

@@ -2,8 +2,11 @@ package main
 
 import (
 	"bytes"
+	"io"
 	"io/ioutil"
+	"log"
 	"os"
+	"os/exec"
 	pathpkg "path"
 	"sort"
 	"strings"
@@ -19,10 +22,6 @@ type Dir struct {
 	Dirs    []*Dir  // Subdirectories.
 	index   *Page   // The index page.
 	feed    []byte  // Atom feed.
-
-	inputExt    string // input file extension
-	outputExt   string // output file extension
-	templateExt string // template file extension
 }
 
 // NewDir returns a new Dir with the given path.
@@ -37,8 +36,12 @@ func NewDir(path string) *Dir {
 	}
 }
 
-// read reads from a directory and indexes the files and directories within it.
+// Read reads from a directory and indexes the files and directories within it.
-func (d *Dir) read(srcDir string, path string) error {
+func (d *Dir) Read(srcDir string, task *Task) error {
+	return d.read(srcDir, "", task)
+}
+
+func (d *Dir) read(srcDir, path string, task *Task) error {
 	entries, err := ioutil.ReadDir(pathpkg.Join(srcDir, path))
 	if err != nil {
 		return err
@@ -53,20 +56,21 @@ func (d *Dir) read(srcDir string, path string) error {
 		if entry.IsDir() {
 			// Gather directory data
 			dir := NewDir(path)
-			dir.inputExt = d.inputExt
+			if err := dir.read(srcDir, path, task); err != nil {
-			dir.outputExt = d.outputExt
-			dir.templateExt = d.templateExt
-			if err := dir.read(srcDir, path); err != nil {
 				return err
 			}
 			d.Dirs = append(d.Dirs, dir)
-		} else {
+		} else if ext := pathpkg.Ext(name); ext == task.InputExt {
 			srcPath := pathpkg.Join(srcDir, path)
 			content, err := ioutil.ReadFile(srcPath)
 			if err != nil {
 				return err
 			}
-			if ext := pathpkg.Ext(name); ext == d.inputExt {
+
+			if cmd := task.PreProcess; cmd != "" {
+				content = RunProcessCmd(cmd, bytes.NewReader(content))
+			}
+
 			// Gather page data
 			if strings.TrimSuffix(name, ext) == "index" {
 				d.index = NewPage(d.Path, content)
@@ -77,27 +81,26 @@ func (d *Dir) read(srcDir string, path string) error {
 			}
 		}
 	}
-	}
 	return nil
 }
 
-// manipulate processes and manipulates the directory's contents.
+// Process processes the directory's contents.
-func (d *Dir) manipulate(cfg *Config) error {
+func (d *Dir) Process(cfg *Config, task *Task) error {
-	if d.templateExt != "" {
+	if task.TemplateExt != "" {
 		// Create index
 		if d.index != nil {
 			var b strings.Builder
-			tmpl := cfg.Templates.FindTemplate(d.Path, "index"+d.templateExt)
+			tmpl := cfg.Templates.FindTemplate(d.Path, "index"+task.TemplateExt)
 			if err := tmpl.Execute(&b, d); err != nil {
 				return err
 			}
 			d.index.Content = b.String()
 		}
 
-		// Manipulate pages
+		// Process pages
 		for i := range d.Pages {
 			var b strings.Builder
-			tmpl := cfg.Templates.FindTemplate(d.Path, "page"+d.templateExt)
+			tmpl := cfg.Templates.FindTemplate(d.Path, "page"+task.TemplateExt)
 			if err := tmpl.Execute(&b, d.Pages[i]); err != nil {
 				return err
 			}
@@ -129,22 +132,17 @@ func (d *Dir) manipulate(cfg *Config) error {
 		d.feed = b.Bytes()
 	}
 
-	// Manipulate subdirectories
+	// Process subdirectories
 	for _, d := range d.Dirs {
-		if err := d.manipulate(cfg); err != nil {
+		if err := d.Process(cfg, task); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
-// Format represents an output format.
+// Write writes the directory's contents to the provided destination path.
-type Format interface {
+func (d *Dir) Write(dstDir string, task *Task) error {
-	Format(*Page) (path string, content []byte)
-}
-
-// write writes the Dir to the provided destination path.
-func (d *Dir) write(dstDir string, format Format) error {
 	// Create the directory
 	dirPath := pathpkg.Join(dstDir, d.Path)
 	if err := os.MkdirAll(dirPath, 0755); err != nil {
@@ -152,31 +150,23 @@ func (d *Dir) write(dstDir string, format Format) error {
 	}
 
 	// Write pages
-	for _, page := range d.Pages {
+	pages := d.Pages
-		path, content := format.Format(page)
+	if d.index != nil {
-		dstPath := pathpkg.Join(dstDir, path)
+		pages = append(pages, d.index)
-		dir := pathpkg.Dir(dstPath)
-		os.MkdirAll(dir, 0755)
-		f, err := os.Create(dstPath)
-		if err != nil {
-			return err
-		}
-		if _, err := f.Write(content); err != nil {
-			return err
 	}
+	for _, page := range pages {
+		path := task.OutputPath(page.Path)
+		var content []byte
+		if cmd := task.PostProcess; cmd != "" {
+			content = RunProcessCmd(cmd, strings.NewReader(page.Content))
+		} else {
+			content = []byte(page.Content)
 		}
 
-	// Write the index file
-	if d.index != nil {
-		path, content := format.Format(d.index)
 		dstPath := pathpkg.Join(dstDir, path)
 		dir := pathpkg.Dir(dstPath)
 		os.MkdirAll(dir, 0755)
-		f, err := os.Create(dstPath)
+		if err := os.WriteFile(dstPath, content, 0644); err != nil {
-		if err != nil {
-			return err
-		}
-		if _, err := f.Write(content); err != nil {
 			return err
 		}
 	}
@@ -186,18 +176,14 @@ func (d *Dir) write(dstDir string, format Format) error {
 		const path = "atom.xml"
 		dstPath := pathpkg.Join(dstDir, path)
 		os.MkdirAll(dstDir, 0755)
-		f, err := os.Create(dstPath)
+		if err := os.WriteFile(dstPath, d.feed, 0644); err != nil {
-		if err != nil {
-			return err
-		}
-		if _, err := f.Write(d.feed); err != nil {
 			return err
 		}
 	}
 
 	// Write subdirectories
 	for _, dir := range d.Dirs {
-		dir.write(dstDir, format)
+		dir.Write(dstDir, task)
 	}
 	return nil
 }
@@ -212,3 +198,16 @@ func (d *Dir) sort() {
 		d.sort()
 	}
 }
+
+// RunProcessCmd runs a process command.
+func RunProcessCmd(command string, input io.Reader) []byte {
+	split := strings.Split(command, " ")
+	cmd := exec.Command(split[0], split[1:]...)
+	cmd.Stdin = input
+	cmd.Stderr = os.Stderr
+	output, err := cmd.Output()
+	if err != nil {
+		log.Fatal(err)
+	}
+	return output
+}

main.go

@@ -86,21 +86,18 @@ func runAll(cfg *Config) error {
 }
 
 func runTask(cfg *Config, task *Task) error {
-	// Load content
+	// Read content
 	dir := NewDir("")
-	dir.inputExt = task.InputExt
+	if err := dir.Read("content", task); err != nil {
-	dir.outputExt = task.OutputExt
-	dir.templateExt = task.TemplateExt
-	if err := dir.read("content", ""); err != nil {
 		return err
 	}
 	dir.sort()
-	// Manipulate content
+	// Process content
-	if err := dir.manipulate(cfg); err != nil {
+	if err := dir.Process(cfg, task); err != nil {
 		return err
 	}
 	// Write content
-	if err := dir.write(task.OutputDir, task); err != nil {
+	if err := dir.Write(task.OutputDir, task); err != nil {
 		return err
 	}
 	// Copy static files