Draft: Serve custom page when directory listing is disabled

loophole · Feb 24, 2022 · 9b5738e · 9b5738e
1 parent b5d9ea4
commit 9b5738e
Show file tree

Hide file tree

Showing 4 changed files with 149 additions and 35 deletions.
diff --git a/go.mod b/go.mod
@@ -1,6 +1,6 @@
 module github.com/loophole/cli
 
-go 1.14
+go 1.16
 
 require (
 	github.com/abbot/go-http-auth v0.4.0

diff --git a/internal/pkg/customfilesystem/customfilesystem.go b/internal/pkg/customfilesystem/customfilesystem.go
@@ -0,0 +1,75 @@
+//necessary bits and pieces for being able to serve e.g. the custom notification html
+// without needing to create files in the users folders
+package customfilesystem
+
+import (
+	"bytes"
+	"errors"
+	"io/fs"
+	"net/http"
+	"path/filepath"
+)
+
+var DirectoryListingDisabledPage = []byte("<!DOCTYPE html><html><body><img src=\"https://raw.githubusercontent.com/loophole/website/master/static/img/logo.png\" alt=\"https://raw.githubusercontent.com/loophole/website/master/static/img/logo.png\" class=\"transparent shrinkToFit\" width=\"400\" height=\"88\"><p>Directory index listing has been disabled. Please enter the path of a file.</p></body></html>")
+
+type CustomFileSystem struct {
+	FS http.FileSystem
+}
+
+//the file cannot be reused since it's io.Reader can only be read from once,
+// so we need a reusable way to create it
+func writeDirectoryListingDisabledPageFile(pageFile *MyFile) {
+	*pageFile = MyFile{
+		Reader: bytes.NewReader(DirectoryListingDisabledPage),
+		mif: myFileInfo{
+			name: "customIndex.html",
+			data: DirectoryListingDisabledPage,
+		},
+	}
+}
+
+func (cfs CustomFileSystem) Open(path string) (http.File, error) {
+	f, err := _Open(path, cfs)
+
+	if err != nil {
+		var pathErrorInstance error = &fs.PathError{
+			Err: errors.New(""),
+		}
+		if errors.As(err, &pathErrorInstance) {
+			return nil, err
+		}
+		var pageFile *MyFile = &MyFile{}
+		writeDirectoryListingDisabledPageFile(pageFile)
+		return pageFile, nil
+	}
+	return f, nil
+}
+
+//if there is an elegant way to integrate the following into the function above without
+// using labeled breaks or adding even more control structures let me know
+func _Open(path string, cfs CustomFileSystem) (http.File, error) {
+	f, err := cfs.FS.Open(path)
+	if err != nil {
+		if path == "/" {
+			var pageFile *MyFile = &MyFile{}
+			writeDirectoryListingDisabledPageFile(pageFile)
+			return pageFile, nil
+		}
+		return nil, err
+	}
+
+	s, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+
+	if s.IsDir() {
+		index := filepath.Join(path, "index.html")
+		if _, err := cfs.FS.Open(index); err != nil {
+			var pageFile *MyFile = &MyFile{}
+			writeDirectoryListingDisabledPageFile(pageFile)
+			return pageFile, nil
+		}
+	}
+	return f, nil
+}
diff --git a/internal/pkg/customfilesystem/file.go b/internal/pkg/customfilesystem/file.go
@@ -0,0 +1,44 @@
+//taken from https://stackoverflow.com/questions/52697277/simples-way-to-make-a-byte-into-a-virtual-file-object-in-golang
+package customfilesystem
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"time"
+)
+
+type File interface {
+	io.Closer
+	io.Reader
+	io.Seeker
+	Readdir(count int) ([]os.FileInfo, error)
+	Stat() (os.FileInfo, error)
+}
+
+type myFileInfo struct {
+	name string
+	data []byte
+}
+
+func (mif myFileInfo) Name() string       { return mif.name }
+func (mif myFileInfo) Size() int64        { return int64(len(mif.data)) }
+func (mif myFileInfo) Mode() os.FileMode  { return 0444 }        // Read for all
+func (mif myFileInfo) ModTime() time.Time { return time.Time{} } // Return anything
+func (mif myFileInfo) IsDir() bool        { return false }
+func (mif myFileInfo) Sys() interface{}   { return nil }
+
+type MyFile struct {
+	*bytes.Reader
+	mif myFileInfo
+}
+
+func (mf *MyFile) Close() error { return nil } // Noop, nothing to do
+
+func (mf *MyFile) Readdir(count int) ([]os.FileInfo, error) {
+	return nil, nil // We are not a directory but a single file
+}
+
+func (mf *MyFile) Stat() (os.FileInfo, error) {
+	return mf.mif, nil
+}
diff --git a/internal/pkg/httpserver/httpserver.go b/internal/pkg/httpserver/httpserver.go
@@ -1,16 +1,18 @@
 package httpserver
 
 import (
+	"bytes"
 	"crypto/tls"
 	"fmt"
 	"net/http"
 	"net/http/httputil"
 	"net/url"
-	"path/filepath"
+	"time"
 
 	auth "github.com/abbot/go-http-auth"
 	"github.com/loophole/cli/config"
 	lm "github.com/loophole/cli/internal/app/loophole/models"
+	cfs "github.com/loophole/cli/internal/pkg/customfilesystem"
 	"github.com/loophole/cli/internal/pkg/urlmaker"
 	"golang.org/x/crypto/bcrypt"
 	"golang.org/x/net/webdav"
@@ -20,34 +22,6 @@ const (
 	logoURL = "https://raw.githubusercontent.com/loophole/website/master/static/img/logo.png"
 )
 
-type customFileSystem struct {
-	fs http.FileSystem
-}
-
-func (cfs customFileSystem) Open(path string) (http.File, error) {
-	f, err := cfs.fs.Open(path)
-	if err != nil {
-		return nil, err
-	}
-
-	s, err := f.Stat()
-	if err != nil {
-		return nil, err
-	}
-	if s.IsDir() {
-		index := filepath.Join(path, "index.html")
-		if _, err := cfs.fs.Open(index); err != nil {
-			closeErr := f.Close()
-			if closeErr != nil {
-				return nil, err
-			}
-			return nil, err
-		}
-	}
-
-	return f, nil
-}
-
 type ServerBuilder interface {
 	WithSiteID(string) ServerBuilder
 	WithDomain(string) ServerBuilder
@@ -206,18 +180,39 @@ func (ssb *staticServerBuilder) WithBasicAuth(username string, password string)
 	return ssb
 }
 
+func serveDirectoryListingNotification(w http.ResponseWriter, req *http.Request) {
+	customPageSeeker := bytes.NewReader(cfs.DirectoryListingDisabledPage)
+	http.ServeContent(w, req, "name", time.Now(), customPageSeeker)
+}
+
+//this could break desktop but I haven't been able to figure out another way yet
+var fsHandler http.Handler = nil
+var fsHandlerIsCustom = false
+
+//handler functions may only take these arguments, so we need variables outside of it to make it's behaviour conditional
+func conditionalHandler(w http.ResponseWriter, req *http.Request) {
+	if req.URL.Path == "/" && fsHandlerIsCustom {
+		serveDirectoryListingNotification(w, req)
+	} else {
+		fsHandler.ServeHTTP(w, req)
+	}
+}
+
 func (ssb *staticServerBuilder) Build() (*http.Server, error) {
-	var fs http.Handler
 	if config.Config.Display.DisableDirectoryListing {
-		fs = http.FileServer(customFileSystem{http.Dir(ssb.directory)})
+		fsHandler = http.FileServer(cfs.CustomFileSystem{
+			FS: http.Dir(ssb.directory),
+		})
+		fsHandlerIsCustom = true
 	} else {
-		fs = http.FileServer(http.Dir(ssb.directory))
+		fsHandler = http.FileServer(http.Dir(ssb.directory))
+		fsHandlerIsCustom = false
 	}
 
 	var server *http.Server
 
 	if ssb.basicAuthEnabled {
-		handler, err := getBasicAuthHandler(ssb.serverBuilder.siteID, ssb.serverBuilder.domain, ssb.basicAuthUsername, ssb.basicAuthPassword, fs.ServeHTTP)
+		handler, err := getBasicAuthHandler(ssb.serverBuilder.siteID, ssb.serverBuilder.domain, ssb.basicAuthUsername, ssb.basicAuthPassword, conditionalHandler)
 		if err != nil {
 			return nil, err
 		}
@@ -228,7 +223,7 @@ func (ssb *staticServerBuilder) Build() (*http.Server, error) {
 		}
 	} else {
 		server = &http.Server{
-			Handler:   fs,
+			Handler:   http.HandlerFunc(conditionalHandler),
 			TLSConfig: getTLSConfig(ssb.serverBuilder.siteID, ssb.serverBuilder.domain),
 		}
 	}