From 6760abd6fcd3d77400de4693f5d74fe739c07191 Mon Sep 17 00:00:00 2001
From: clsr <clsr@clsr.net>
Date: Sun, 27 Aug 2017 21:40:58 +0200
Subject: Add support for the draft/cnp-select and draft/cnm-selector

---
 fileserver.go | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 108 insertions(+), 10 deletions(-)

(limited to 'fileserver.go')

diff --git a/fileserver.go b/fileserver.go
index e1754a1..5145701 100644
--- a/fileserver.go
+++ b/fileserver.go
@@ -9,6 +9,7 @@ import (
 	"path"
 	"path/filepath"
 	"sort"
+	"strconv"
 	"strings"
 	"time"
 
@@ -21,7 +22,7 @@ func init() {
 	mime.AddExtensionType(".cnm", "text/cnm")
 }
 
-func listdir(w cnp.ResponseWriter, r *cnp.Request, root string, f *os.File, stat os.FileInfo) {
+func listDir(w cnp.ResponseWriter, r *cnp.Request, root string, f *os.File, stat os.FileInfo) {
 	if p := r.Path(); !strings.HasSuffix(p, "/") {
 		w.Response().SetIntent(cnp.IntentRedirect)
 		w.Response().SetLocation("", p+"/")
@@ -134,7 +135,7 @@ func open(dir, fpath string) (*os.File, error) {
 	return os.Open(filepath.Join(dir, filepath.FromSlash(path.Clean("/"+fpath))))
 }
 
-func getfile(dir, pth string, strict bool) (*os.File, os.FileInfo) {
+func getFile(dir, pth string, strict bool) (*os.File, os.FileInfo) {
 	var f *os.File
 	var err error
 	fnames := []string{pth}
@@ -172,7 +173,7 @@ func getfile(dir, pth string, strict bool) (*os.File, os.FileInfo) {
 		if !strings.HasSuffix(pth, "/") {
 			return nil, stat
 		}
-		f2, st2 := getfile(dir, pth+"index.cnm", true)
+		f2, st2 := getFile(dir, pth+"index.cnm", true)
 		if f2 != nil {
 			return f2, st2
 		}
@@ -180,10 +181,109 @@ func getfile(dir, pth string, strict bool) (*os.File, os.FileInfo) {
 	return f, stat
 }
 
+func byteSelect(w cnp.ResponseWriter, r *cnp.Request, f *os.File, stat os.FileInfo) {
+	size := stat.Size()
+	sel, selq := r.Select()
+	w.Response().SetSelect(sel, selq)
+	rej := cnp.ErrorRejected{Reason: "invalid byte selector"}
+
+	ss := strings.Split(selq, "-")
+	if len(ss) != 2 {
+		panic(rej)
+	}
+
+	ua := uint64(0)
+	var err error
+	if ss[0] != "" {
+		ua, err = strconv.ParseUint(ss[0], 10, 63)
+		if err != nil {
+			panic(rej)
+		}
+		f.Seek(int64(ua), os.SEEK_SET)
+	}
+
+	fr := io.Reader(f)
+	if ss[1] != "" {
+		var ub uint64
+		ub, err = strconv.ParseUint(ss[1], 10, 63)
+		if err != nil {
+			panic(rej)
+		}
+		fr = io.LimitReader(fr, int64(ub-ua))
+		if int64(ub) < size {
+			size = int64(ub)
+		}
+	}
+	size = size - int64(ua)
+	if size < 0 {
+		size = 0
+	}
+	w.Response().SetLength(size)
+
+	if _, err := io.Copy(w, fr); err != nil {
+		panic(err)
+	}
+}
+
+func cnmSelect(w cnp.ResponseWriter, r *cnp.Request, f *os.File, stat os.FileInfo) {
+	doc, err := cnm.ParseDocument(f)
+	if err != nil {
+		panic(err)
+	}
+
+	_, selq := r.Select()
+	sdoc, err := doc.Select(selq)
+	if err != nil {
+		panic(cnp.ErrorRejected{Reason: err.Error()})
+	}
+	if sdoc == nil {
+		return
+	}
+
+	if err = sdoc.Write(w); err != nil {
+		panic(err)
+	}
+}
+
+func serveFile(w cnp.ResponseWriter, r *cnp.Request, f *os.File, stat os.FileInfo, typ string) {
+	switch sel, _ := r.Select(); sel {
+	case "":
+		w.Response().SetLength(stat.Size())
+		if _, err := io.Copy(w, f); err != nil {
+			panic(err)
+		}
+		return
+
+	case "byte":
+		byteSelect(w, r, f, stat)
+		return
+
+	case "info":
+		resp := w.Response()
+		resp.SetLength(stat.Size())
+		var buf bytes.Buffer
+		resp.Write(&buf)
+		resp.Header = cnp.NewHeader(cnp.IntentOK, nil)
+		resp.SetLength(int64(buf.Len()))
+		if _, err := io.Copy(w, &buf); err != nil {
+			panic(err)
+		}
+		return
+
+	case "cnm":
+		if typ == "text/cnm" {
+			cnmSelect(w, r, f, stat)
+			return
+		}
+	}
+
+	panic(cnp.ErrorNotSupported{Reason: "unsupported selector"})
+}
+
 func server(addr, dir string) {
 	fmt.Printf("listening on %q, serving dir %q\n", addr, dir)
 	panic(cnp.ListenAndServe(addr, cnp.HandlerFunc(func(w cnp.ResponseWriter, r *cnp.Request) {
-		f, stat := getfile(dir, r.Path(), false)
+		f, stat := getFile(dir, r.Path(), false)
 		defer f.Close()
 
 		mtime := stat.ModTime().Truncate(time.Second)
@@ -191,7 +291,7 @@ func server(addr, dir string) {
 		w.Response().SetModified(mtime)
 		w.Response().SetTime(time.Now())
 		if stat.IsDir() {
-			listdir(w, r, dir, f, stat)
+			listDir(w, r, dir, f, stat)
 			return
 		}
 
@@ -203,13 +303,11 @@ func server(addr, dir string) {
 			return
 		}
 
-		w.Response().SetLength(stat.Size())
+		typ := guessType(f.Name())
 		w.Response().SetName(stat.Name())
-		w.Response().SetType(guessType(f.Name()))
+		w.Response().SetType(typ)
 
-		if _, err := io.Copy(w, f); err != nil {
-			panic(err)
-		}
+		serveFile(w, r, f, stat, typ)
 	})))
 }
 
-- 
cgit