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package disk
import (
"context"
"errors"
"fmt"
"io"
"io/fs"
"net/http"
"os"
"strconv"
"strings"
"time"
"github.com/prometheus/client_golang/prometheus"
"gitlab.com/gitlab-org/labkit/errortracking"
"gitlab.com/gitlab-org/gitlab-pages/internal/httperrors"
"gitlab.com/gitlab-org/gitlab-pages/internal/logging"
"gitlab.com/gitlab-org/gitlab-pages/internal/redirects"
"gitlab.com/gitlab-org/gitlab-pages/internal/serving"
"gitlab.com/gitlab-org/gitlab-pages/internal/serving/disk/symlink"
"gitlab.com/gitlab-org/gitlab-pages/internal/vfs"
vfsServing "gitlab.com/gitlab-org/gitlab-pages/internal/vfs/serving"
)
// Reader is a disk access driver
type Reader struct {
fileSizeMetric *prometheus.HistogramVec
vfs vfs.VFS
}
// Show the user some validation messages for their _redirects file
func (reader *Reader) serveRedirectsStatus(h serving.Handler, redirects *redirects.Redirects) {
h.Writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
h.Writer.Header().Set("X-Content-Type-Options", "nosniff")
h.Writer.WriteHeader(http.StatusOK)
fmt.Fprintln(h.Writer, redirects.Status())
}
// tryRedirects returns true if it successfully handled request
func (reader *Reader) tryRedirects(h serving.Handler) bool {
ctx := h.Request.Context()
root, err := reader.vfs.Root(ctx, h.LookupPath.Path, h.LookupPath.SHA256)
if err != nil {
return handleRootError(err, h)
}
r := redirects.ParseRedirects(ctx, root)
rewrittenURL, status, err := r.Rewrite(h.Request.URL)
if err != nil {
if err != redirects.ErrNoRedirect {
// We assume that rewrite failure is not fatal
// and we only capture the error
errortracking.Capture(err, errortracking.WithRequest(h.Request), errortracking.WithStackTrace())
}
return false
}
if status == http.StatusOK {
h.SubPath = strings.TrimPrefix(rewrittenURL.Path, h.LookupPath.Prefix)
return reader.tryFile(h)
}
http.Redirect(h.Writer, h.Request, rewrittenURL.Path, status)
return true
}
// tryFile returns true if it successfully handled request
func (reader *Reader) tryFile(h serving.Handler) bool {
ctx := h.Request.Context()
root, err := reader.vfs.Root(ctx, h.LookupPath.Path, h.LookupPath.SHA256)
if err != nil {
return handleRootError(err, h)
}
fullPath, err := reader.resolvePath(ctx, root, h.SubPath)
request := h.Request
urlPath := request.URL.Path
if locationError, _ := err.(*locationDirectoryError); locationError != nil {
if endsWithSlash(urlPath) {
fullPath, err = reader.resolvePath(ctx, root, h.SubPath, "index.html")
} else {
http.Redirect(h.Writer, h.Request, redirectPath(h.Request), http.StatusFound)
return true
}
}
if locationError, _ := err.(*locationFileNoExtensionError); locationError != nil {
fullPath, err = reader.resolvePath(ctx, root, strings.TrimSuffix(h.SubPath, "/")+".html")
}
if err != nil {
// We assume that this is mostly missing file type of the error
// and additional handlers should try to process the request
return false
}
// Serve status of `_redirects` under `_redirects`
// We check if the final resolved path is `_redirects` after symlink traversal
if fullPath == redirects.ConfigFile {
if os.Getenv("FF_ENABLE_REDIRECTS") != "false" {
r := redirects.ParseRedirects(ctx, root)
reader.serveRedirectsStatus(h, r)
return true
}
h.Writer.WriteHeader(http.StatusForbidden)
return true
}
return reader.serveFile(ctx, h.Writer, h.Request, root, fullPath, h.LookupPath.HasAccessControl)
}
func redirectPath(request *http.Request) string {
url := *request.URL
// This ensures that path starts with `//<host>/`
url.Scheme = ""
url.Host = request.Host
url.Path = strings.TrimPrefix(url.Path, "/") + "/"
return strings.TrimSuffix(url.String(), "?")
}
func (reader *Reader) tryNotFound(h serving.Handler) bool {
ctx := h.Request.Context()
root, err := reader.vfs.Root(ctx, h.LookupPath.Path, h.LookupPath.SHA256)
if err != nil {
return handleRootError(err, h)
}
page404, err := reader.resolvePath(ctx, root, "404.html")
if err != nil {
// We assume that this is mostly missing file type of the error
// and additional handlers should try to process the request
return false
}
err = reader.serveCustomFile(ctx, h.Writer, h.Request, http.StatusNotFound, root, page404)
if err != nil {
// Handle context.Canceled error as not exist https://gitlab.com/gitlab-org/gitlab-pages/-/issues/669
if errors.Is(err, context.Canceled) {
logging.LogRequest(h.Request).WithError(err).Warn("user cancelled request")
return false
}
httperrors.Serve500WithRequest(h.Writer, h.Request, "serveCustomFile", err)
return true
}
return true
}
// Resolve the HTTP request to a path on disk, converting requests for
// directories to requests for index.html inside the directory if appropriate.
func (reader *Reader) resolvePath(ctx context.Context, root vfs.Root, subPath ...string) (string, error) {
// Don't use filepath.Join as cleans the path,
// where we want to traverse full path as supplied by user
// (including ..)
testPath := strings.Join(subPath, "/")
fullPath, err := symlink.EvalSymlinks(ctx, root, testPath)
if err != nil {
if endsWithoutHTMLExtension(testPath) {
return "", &locationFileNoExtensionError{
FullPath: fullPath,
}
}
return "", err
}
fi, err := root.Lstat(ctx, fullPath)
if err != nil {
return "", err
}
// The requested path is a directory, so try index.html via recursion
if fi.IsDir() {
return "", &locationDirectoryError{
FullPath: fullPath,
RelativePath: testPath,
}
}
// The file exists, but is not a supported type to serve. Perhaps a block
// special device or something else that may be a security risk.
if !fi.Mode().IsRegular() {
return "", fmt.Errorf("%s: is not a regular file", fullPath)
}
return fullPath, nil
}
func (reader *Reader) serveFile(ctx context.Context, w http.ResponseWriter, r *http.Request, root vfs.Root, origPath string, accessControl bool) bool {
fullPath := reader.handleContentEncoding(ctx, w, r, root, origPath)
file, err := root.Open(ctx, fullPath)
if err != nil {
httperrors.Serve500WithRequest(w, r, "root.Open", err)
return true
}
defer file.Close()
fi, err := root.Lstat(ctx, fullPath)
if err != nil {
httperrors.Serve500WithRequest(w, r, "root.Lstat", err)
return true
}
if !accessControl {
// Set caching headers
w.Header().Set("Cache-Control", "max-age=600")
w.Header().Set("Expires", time.Now().Add(10*time.Minute).Format(time.RFC1123))
}
contentType, err := reader.detectContentType(ctx, root, origPath)
if err != nil {
httperrors.Serve500WithRequest(w, r, "detectContentType", err)
return true
}
w.Header().Set("Content-Type", contentType)
reader.fileSizeMetric.WithLabelValues(reader.vfs.Name()).Observe(float64(fi.Size()))
// Support vfs.SeekableFile if available (uncompressed files)
if rs, ok := file.(vfs.SeekableFile); ok {
http.ServeContent(w, r, origPath, fi.ModTime(), rs)
} else {
w.Header().Set("Content-Length", strconv.FormatInt(fi.Size(), 10))
vfsServing.ServeCompressedFile(w, r, fi.ModTime(), file)
}
return true
}
func (reader *Reader) serveCustomFile(ctx context.Context, w http.ResponseWriter, r *http.Request, code int, root vfs.Root, origPath string) error {
fullPath := reader.handleContentEncoding(ctx, w, r, root, origPath)
// Open and serve content of file
file, err := root.Open(ctx, fullPath)
if err != nil {
return err
}
defer file.Close()
fi, err := root.Lstat(ctx, fullPath)
if err != nil {
return err
}
contentType, err := reader.detectContentType(ctx, root, origPath)
if err != nil {
return err
}
reader.fileSizeMetric.WithLabelValues(reader.vfs.Name()).Observe(float64(fi.Size()))
w.Header().Set("Content-Type", contentType)
w.Header().Set("Content-Length", strconv.FormatInt(fi.Size(), 10))
w.WriteHeader(code)
if r.Method != "HEAD" {
_, err := io.CopyN(w, file, fi.Size())
return err
}
return nil
}
func handleRootError(err error, h serving.Handler) bool {
if err == nil {
return false
}
if errors.Is(err, fs.ErrNotExist) {
return false
}
if errors.Is(err, context.Canceled) {
// Handle context.Canceled error as not found exist https://gitlab.com/gitlab-org/gitlab-pages/-/issues/669
httperrors.Serve404(h.Writer)
return true
}
httperrors.Serve500WithRequest(h.Writer, h.Request, "vfs.Root", err)
return true
}
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