[#137] Add index page support

Signed-off-by: Nikita Zinkevich <n.zinkevich@yadro.com>

internal/handler/browse.go

@@ -0,0 +1,157 @@
+package handler
+
+import (
+	"html/template"
+	"net/url"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-http-gw/internal/data"
+	"git.frostfs.info/TrueCloudLab/frostfs-http-gw/utils"
+	"github.com/docker/go-units"
+	"github.com/valyala/fasthttp"
+	"go.uber.org/zap"
+)
+
+const (
+	dateFormat   = "02-01-2006 15:04"
+	attrOID      = "OID"
+	attrCreated  = "Created"
+	attrFileName = "FileName"
+	attrSize     = "Size"
+)
+
+type (
+	BrowsePageData struct {
+		BucketName,
+		Prefix string
+		Objects []ResponseObject
+	}
+	ResponseObject struct {
+		OID      string
+		Created  string
+		FileName string
+		Size     string
+		IsDir    bool
+	}
+)
+
+func parseTimestamp(tstamp string) (time.Time, error) {
+	millis, err := strconv.ParseInt(tstamp, 10, 64)
+	if err != nil {
+		return time.Time{}, err
+	}
+
+	return time.UnixMilli(millis), nil
+}
+
+func NewResponseObject(nodes map[string]string) ResponseObject {
+	return ResponseObject{
+		OID:      nodes[attrOID],
+		Created:  nodes[attrCreated],
+		FileName: nodes[attrFileName],
+		Size:     nodes[attrSize],
+		IsDir:    nodes[attrOID] == "",
+	}
+}
+
+func formatTimestamp(strdate string) string {
+	date, err := parseTimestamp(strdate)
+	if err != nil || date.IsZero() {
+		return ""
+	}
+
+	return date.Format(dateFormat)
+}
+
+func formatSize(strsize string) string {
+	size, err := strconv.ParseFloat(strsize, 64)
+	if err != nil {
+		return "0B"
+	}
+	return units.HumanSize(size)
+}
+
+func parentDir(prefix string) string {
+	index := strings.LastIndex(prefix, "/")
+	if index == -1 {
+		return prefix
+	}
+	return prefix[index:]
+}
+
+func trimPrefix(encPrefix string) string {
+	prefix, err := url.PathUnescape(encPrefix)
+	if err != nil {
+		return ""
+	}
+	slashIndex := strings.LastIndex(prefix, "/")
+	if slashIndex == -1 {
+		return ""
+	}
+	return prefix[:slashIndex]
+}
+
+func urlencode(prefix, filename string) string {
+	var res strings.Builder
+	path := filename
+	if prefix != "" {
+		path = strings.Join([]string{prefix, filename}, "/")
+	}
+	prefixParts := strings.Split(path, "/")
+	for _, prefixPart := range prefixParts {
+		prefixPart = "/" + url.PathEscape(prefixPart)
+		if prefixPart == "/." || prefixPart == "/.." {
+			prefixPart = url.PathEscape(prefixPart)
+		}
+		res.WriteString(prefixPart)
+	}
+
+	return res.String()
+}
+
+func (h *Handler) browseObjects(c *fasthttp.RequestCtx, bucketInfo *data.BucketInfo, prefix string) {
+	log := h.log.With(zap.String("bucket", bucketInfo.Name))
+	ctx := utils.GetContextFromRequest(c)
+	nodes, err := h.listObjects(ctx, bucketInfo, prefix)
+	if err != nil {
+		logAndSendBucketError(c, log, err)
+		return
+	}
+
+	respObjects := make([]ResponseObject, len(nodes))
+
+	for i, node := range nodes {
+		respObjects[i] = NewResponseObject(node)
+	}
+
+	sort.Slice(respObjects, func(i, j int) bool {
+		if respObjects[i].IsDir == respObjects[j].IsDir {
+			return respObjects[i].FileName < respObjects[j].FileName
+		}
+		return respObjects[i].IsDir
+	})
+	indexTemplate := h.config.IndexPageTemplate()
+
+	tmpl, err := template.New("index").Funcs(template.FuncMap{
+		"formatTimestamp": formatTimestamp,
+		"formatSize":      formatSize,
+		"trimPrefix":      trimPrefix,
+		"urlencode":       urlencode,
+		"parentDir":       parentDir,
+	}).Parse(indexTemplate)
+	if err != nil {
+		logAndSendBucketError(c, log, err)
+		return
+	}
+	if err = tmpl.Execute(c, &BrowsePageData{
+		BucketName: bucketInfo.Name,
+		Prefix:     prefix,
+		Objects:    respObjects,
+	}); err != nil {
+		logAndSendBucketError(c, log, err)
+		return
+	}
+}