cmd/scriggo: add the build command to build a template

cmd/scriggo/build.go

@@ -0,0 +1,182 @@
+// Copyright 2024 The Scriggo Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/open2b/scriggo"
+	"github.com/open2b/scriggo/native"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/extension"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/renderer/html"
+)
+
+// build the template.
+func build(dir, o string) error {
+
+	start := time.Now()
+
+	srcDir := dir
+	if srcDir == "" {
+		srcDir = "."
+	}
+
+	publicDir := "public"
+	if o != "" {
+		st, err := os.Stat(o)
+		if !errors.Is(err, fs.ErrNotExist) {
+			if err != nil {
+				return fmt.Errorf("cannot stat output directory %q: %s", o, err)
+			}
+			if !st.IsDir() {
+				return fmt.Errorf("path %q exists but is not a directory", o)
+			}
+		}
+		publicDir = o
+	}
+	publicDir, err := filepath.Abs(publicDir)
+	if err != nil {
+		return err
+	}
+
+	dstDir, err := os.MkdirTemp(filepath.Dir(publicDir), "public-temp-*")
+	if err != nil {
+		return err
+	}
+	defer func() {
+		err = os.RemoveAll(dstDir)
+		if err != nil {
+			log.Print(err)
+		}
+	}()
+
+	md := goldmark.New(
+		goldmark.WithRendererOptions(html.WithUnsafe()),
+		goldmark.WithParserOptions(parser.WithAutoHeadingID()),
+		goldmark.WithExtensions(extension.GFM),
+		goldmark.WithExtensions(extension.Footnote))
+
+	buildOptions := &scriggo.BuildOptions{
+		Globals: make(native.Declarations, len(globals)+1),
+		MarkdownConverter: func(src []byte, out io.Writer) error {
+			return md.Convert(src, out)
+		},
+	}
+	for n, v := range globals {
+		buildOptions.Globals[n] = v
+	}
+
+	srcFS := os.DirFS(srcDir)
+
+	dstBase := filepath.Base(dstDir)
+	publicBase := filepath.Base(publicDir)
+
+	err = fs.WalkDir(srcFS, ".", func(name string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if name[0] == '.' {
+			return nil
+		}
+		// If it is a directory with the same base name as the public directory name,
+		// skip it if it is effectively the public directory. It is considered the public
+		// directory if the corresponding destination temporary directory also exists.
+		if name == publicBase && d.IsDir() {
+			st, err := srcFS.(fs.StatFS).Stat(dstBase)
+			if !errors.Is(err, fs.ErrNotExist) {
+				if err != nil {
+					return err
+				}
+				if st.IsDir() {
+					return fs.SkipAll
+				}
+			}
+		}
+		// If it is the destination temporary directory, skip it.
+		if name == dstBase && d.IsDir() {
+			return fs.SkipAll
+		}
+		if d.IsDir() {
+			return os.MkdirAll(filepath.Join(dstDir, name), 0700)
+		}
+		ext := filepath.Ext(name)
+		switch ext {
+		case ".html":
+			var dir string
+			if p := strings.Index(name, "/"); p > 0 {
+				dir = name[0:p]
+			}
+			switch dir {
+			case "imports", "layouts", "partials":
+				return nil
+			}
+			fallthrough
+		case ".md":
+			fpath := strings.TrimSuffix(name, ext)
+			buildOptions.Globals["filepath"] = fpath
+			template, err := scriggo.BuildTemplate(srcFS, name, buildOptions)
+			if err != nil {
+				return err
+			}
+			name := filepath.Join(dstDir, fpath) + ".html"
+			fi, err := os.OpenFile(name, os.O_WRONLY|os.O_CREATE, 0600)
+			if err != nil {
+				return err
+			}
+			err = template.Run(fi, nil, nil)
+			if err == nil {
+				err = fi.Close()
+			}
+		default:
+			src, err := srcFS.Open(name)
+			if err != nil {
+				return err
+			}
+			name := filepath.Join(dstDir, name)
+			err = os.MkdirAll(filepath.Dir(name), 0700)
+			if err != nil {
+				return err
+			}
+			dst, err := os.OpenFile(name, os.O_WRONLY|os.O_CREATE, 0600)
+			if err != nil {
+				return err
+			}
+			_, err = io.Copy(dst, src)
+			if err == nil {
+				_ = src.Close()
+				err = dst.Close()
+			}
+		}
+		return err
+	})
+	if err != nil {
+		return err
+	}
+
+	err = os.RemoveAll(publicDir)
+	if err != nil {
+		return err
+	}
+	err = os.Rename(dstDir, publicDir)
+	if err != nil {
+		return err
+	}
+
+	buildTime := time.Since(start)
+	_, _ = fmt.Fprintf(os.Stderr, "Build took %s\n", buildTime)
+
+	return nil
+}

cmd/scriggo/help.go

@@ -20,6 +20,9 @@ The commands are:
     serve       run a web server and serve the template rooted at the current
                 directory
 
+    build       generate static files from the template rooted at the current 
+                directory, writing them to './public' by default
+
     init        initialize an interpreter for Go programs
 
     import      generate the source for an importer used by Scriggo to import 
@@ -40,6 +43,40 @@ Additional help topics:
 
 `
 
+const helpBuild = `
+usage: scriggo build [-o output] [dir]
+
+Build processes the template rooted at the current directory and writes the
+generated files to the 'public' directory by default. If the 'public' directory
+already exists, it is deleted along with all its content before writing the new
+files. If a directory 'dir' is specified, the template rooted at that directory
+is built instead of the current directory.
+
+Non-template files, such as CSS and JavaScript, are copied as-is.
+
+For example:
+
+    scriggo build
+
+generates a static version of the template rooted at the current directory,
+processing all template files (e.g., HTML, Markdown) and generating their final
+output in the 'public' directory. Non-template files from the source directory,
+such as stylesheets and scripts, are copied without modification, resulting in a
+complete static site ready for deployment.
+
+The -o flag allows specifying an alternative output directory instead of the
+default 'public'.
+
+Examples:
+
+	scriggo build src
+
+	scriggo build -o ../public
+
+	scriggo build -o /var/www site
+
+`
+
 const helpInit = `
 usage: scriggo init [dir]
 

cmd/scriggo/main.go

@@ -114,6 +114,9 @@ var commandsHelp = map[string]func(){
 			`The report includes useful system information.`,
 		)
 	},
+	"build": func() {
+		txtToHelp(helpBuild)
+	},
 	"import": func() {
 		txtToHelp(helpImport)
 	},
@@ -155,6 +158,25 @@ var commands = map[string]func(){
 		fmt.Fprintf(os.Stdout, "If you encountered an issue, report it at:\n\n\thttps://github.com/open2b/scriggo/issues/new\n\n")
 		exit(0)
 	},
+	"build": func() {
+		flag.Usage = commandsHelp["build"]
+		o := flag.String("o", "", "write the resulting files to the named directory instead of './public'.")
+		flag.Parse()
+		var dir string
+		switch n := len(flag.Args()); n {
+		case 0:
+		case 1:
+			dir = flag.Arg(0)
+		default:
+			flag.Usage()
+			exitError(`bad number of arguments`)
+		}
+		err := build(dir, *o)
+		if err != nil {
+			exitError("%s", err)
+		}
+		exit(0)
+	},
 	"init": func() {
 		flag.Usage = commandsHelp["init"]
 		f := flag.String("f", "", "path of the Scriggofile.")