feat: Directory page UI improvements

These changes are needed to prepare for the Directory page UI improvements
implemented in ipfs/dir-index-html#37.

- update dir-index-html type structs
- emit gateway URL for root links
- emit CID of each directoryItem
- emit size of directory
- emit breadcrumbs

core/corehttp/gateway_handler.go

@@ -328,8 +328,20 @@ func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request
 			size = humanize.Bytes(uint64(s))
 		}
 
+		hash := ""
+		if r, err := i.api.ResolvePath(r.Context(), ipath.Join(resolvedPath, dirit.Name())); err == nil {
+			// Path may not be resolved. Continue anyways.
+			hash = r.Cid().String()
+		}
+
 		// See comment above where originalUrlPath is declared.
-		di := directoryItem{size, dirit.Name(), gopath.Join(originalUrlPath, dirit.Name())}
+		di := directoryItem{
+			Size:      size,
+			Name:      dirit.Name(),
+			Path:      gopath.Join(originalUrlPath, dirit.Name()),
+			Hash:      hash,
+			ShortHash: shortHash(hash),
+		}
 		dirListing = append(dirListing, di)
 	}
 	if dirit.Err() != nil {
@@ -359,14 +371,34 @@ func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request
 		}
 	}
 
+	size := "?"
+	if s, err := dir.Size(); err == nil {
+		// Size may not be defined/supported. Continue anyways.
+		size = humanize.Bytes(uint64(s))
+	}
+
 	hash := resolvedPath.Cid().String()
 
+	// Storage for gateway URL to be used when linking to other rootIDs. This
+	// will be blank unless subdomain resolution is being used for this request.
+	var gwURL string
+
+	// Get gateway hostname and build gateway URL.
+	if h, ok := r.Context().Value("gw-hostname").(string); ok {
+		gwURL = "//" + h
+	} else {
+		gwURL = ""
+	}
+
 	// See comment above where originalUrlPath is declared.
 	tplData := listingTemplateData{
-		Listing:  dirListing,
-		Path:     urlPath,
-		BackLink: backLink,
-		Hash:     hash,
+		GatewayURL:  gwURL,
+		Listing:     dirListing,
+		Size:        size,
+		Path:        urlPath,
+		Breadcrumbs: breadcrumbs(urlPath),
+		BackLink:    backLink,
+		Hash:        hash,
 	}
 
 	err = listingTemplate.Execute(w, tplData)

core/corehttp/gateway_indexPage.go

@@ -11,18 +11,51 @@ import (
 
 // structs for directory listing
 type listingTemplateData struct {
-	Listing  []directoryItem
-	Path     string
-	BackLink string
-	Hash     string
+	GatewayURL  string
+	Listing     []directoryItem
+	Size        string
+	Path        string
+	Breadcrumbs []breadcrumb
+	BackLink    string
+	Hash        string
 }
 
 type directoryItem struct {
-	Size string
+	Size      string
+	Name      string
+	Path      string
+	Hash      string
+	ShortHash string
+}
+
+type breadcrumb struct {
 	Name string
 	Path string
 }
 
+func breadcrumbs(path string) []breadcrumb {
+	var ret []breadcrumb
+	var pathParts = strings.Split(path, "/")
+	for i, pathPart := range pathParts {
+		if pathPart == "" {
+			continue
+		}
+		if pathPart == "ipfs" {
+			ret = append(ret, breadcrumb{Name: pathPart})
+		} else {
+			ret = append(ret, breadcrumb{
+				Name: pathPart,
+				Path: "/" + strings.Join(pathParts[1:i+1], "/"),
+			})
+		}
+	}
+	return ret
+}
+
+func shortHash(hash string) string {
+	return (hash[0:4] + "\u2026" + hash[len(hash)-4:])
+}
+
 var listingTemplate *template.Template
 
 func init() {

core/corehttp/hostname.go

@@ -141,6 +141,10 @@ func HostnameOption() ServeOption {
 			if gw, hostname, ns, rootID, ok := knownSubdomainDetails(r.Host, knownGateways); ok {
 				// Looks like we're using known subdomain gateway.
 
+				// Add gateway hostname context for linking to other root ids.
+				// Example: localhost/ipfs/{cid}
+				ctx := context.WithValue(r.Context(), "gw-hostname", hostname)
+
 				// Assemble original path prefix.
 				pathPrefix := "/" + ns + "/" + rootID
 
@@ -167,7 +171,7 @@ func HostnameOption() ServeOption {
 				r.URL.Path = pathPrefix + r.URL.Path
 
 				// Serve path request
-				childMux.ServeHTTP(w, r)
+				childMux.ServeHTTP(w, r.WithContext(ctx))
 				return
 			}
 			// We don't have a known gateway. Fallback on DNSLink lookup