cmd/htpacker now split into its own module

cmd/htpacker/yaml.go

@@ -0,0 +1,172 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/lwithers/htpack/cmd/htpacker/packer"
+	"github.com/spf13/cobra"
+	yaml "gopkg.in/yaml.v2"
+)
+
+var yamlCmd = &cobra.Command{
+	Use:   "yaml",
+	Short: "Build YAML spec from list of files/dirs",
+	Long: `Generates a YAML specification from a list of files and directories.
+The specification is suitable for passing to pack.
+
+File names will be mapped as follows:
+ • if you specify a file, it will appear be served as "/filename";
+ • if you specify a directory, its contents will be merged into "/", such that a
+   directory with contents "a", "b", and "c/d" will cause entries "/a", "/b" and
+   "/c/d" to be served.
+`,
+	RunE: func(c *cobra.Command, args []string) error {
+		if len(args) == 0 {
+			return errors.New("must specify one or more files/directories")
+		}
+
+		// convert "out" to absolute path, in case we need to chdir
+		out, err := c.Flags().GetString("out")
+		if err != nil {
+			return err
+		}
+		out, err = filepath.Abs(out)
+		if err != nil {
+			return err
+		}
+
+		// chdir if required
+		chdir, err := c.Flags().GetString("chdir")
+		if err != nil {
+			return err
+		}
+		if chdir != "" {
+			if err = os.Chdir(chdir); err != nil {
+				return err
+			}
+		}
+
+		if err := MakeYaml(args, out); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		return nil
+	},
+}
+
+func init() {
+	yamlCmd.Flags().StringP("out", "O", "",
+		"Output filename")
+	yamlCmd.MarkFlagRequired("out")
+	yamlCmd.Flags().StringP("chdir", "C", "",
+		"Change to directory before searching for input files")
+}
+
+func MakeYaml(args []string, out string) error {
+	ftp, err := filesFromList(args)
+	if err != nil {
+		return err
+	}
+
+	raw, err := yaml.Marshal(ftp)
+	if err != nil {
+		return fmt.Errorf("failed to marshal %T to YAML: %v", ftp, err)
+	}
+
+	return ioutil.WriteFile(out, raw, 0666)
+}
+
+func filesFromList(args []string) (packer.FilesToPack, error) {
+	ftp := make(packer.FilesToPack)
+
+	// NB: we don't use filepath.Walk since:
+	//  (a) we don't care about lexical order; just do it quick
+	//  (b) we want to dereference symlinks
+	for _, arg := range args {
+		if err := filesFromListR(arg, arg, ftp); err != nil {
+			return nil, err
+		}
+	}
+	return ftp, nil
+}
+
+func filesFromListR(prefix, arg string, ftp packer.FilesToPack) error {
+	f, err := os.Open(arg)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	fi, err := f.Stat()
+	if err != nil {
+		return err
+	}
+
+	switch {
+	case fi.Mode().IsDir():
+		// readdir
+		fnames, err := f.Readdirnames(0) // 0 ⇒ everything
+		if err != nil {
+			return err
+		}
+		for _, fname := range fnames {
+			fullname := filepath.Join(arg, fname)
+			if err = filesFromListR(prefix, fullname, ftp); err != nil {
+				return err
+			}
+		}
+		return nil
+
+	case fi.Mode().IsRegular():
+		// sniff content type
+		buf := make([]byte, 512)
+		n, err := f.Read(buf)
+		if err != nil {
+			return err
+		}
+		buf = buf[:n]
+		ctype := http.DetectContentType(buf)
+
+		// augmented rules for JS / CSS / etc.
+		switch {
+		case strings.HasPrefix(ctype, "text/plain"):
+			switch filepath.Ext(arg) {
+			case ".css":
+				ctype = "text/css"
+			case ".js":
+				ctype = "application/javascript"
+			case ".json":
+				ctype = "application/json"
+			}
+
+		case strings.HasPrefix(ctype, "text/xml"):
+			switch filepath.Ext(arg) {
+			case ".svg":
+				ctype = "image/svg+xml"
+			}
+		}
+
+		// pack
+		srvName := strings.TrimPrefix(arg, prefix)
+		if srvName == "" {
+			srvName = filepath.Base(arg)
+		}
+		if !strings.HasPrefix(srvName, "/") {
+			srvName = "/" + srvName
+		}
+		ftp[srvName] = packer.FileToPack{
+			Filename:    arg,
+			ContentType: ctype,
+		}
+		return nil
+
+	default:
+		return fmt.Errorf("%s: not file/dir (mode %x)", arg, fi.Mode())
+	}
+}