drone/internal/api/middleware/encode/encode.go

95 lines
3.2 KiB
Go

package encode
import (
"net/http"
"net/url"
"strings"
"github.com/rs/zerolog/log"
"github.com/harness/gitness/types"
)
// GitPathBefore wraps an http.HandlerFunc in a layer that encodes Paths coming as part of the GIT api
// (e.g. "space1/repo.git") before executing the provided http.HandlerFunc
// The first prefix that matches the URL.Path will be used during encoding.
func GitPathBefore(h http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
r, _ = pathTerminatedWithMarker(r, "", ".git", false)
h.ServeHTTP(w, r)
}
}
// TerminatedPathBefore wraps an http.HandlerFunc in a layer that encodes a terminated path (e.g. "/space1/space2/+")
// before executing the provided http.HandlerFunc. The first prefix that matches the URL.Path will
// be used during encoding.
func TerminatedPathBefore(prefixes []string, h http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
for _, p := range prefixes {
// IMPORTANT: define changed separately to avoid overshadowing r
var changed bool
if r, changed = pathTerminatedWithMarker(r, p, "/+", false); changed {
break
}
}
h.ServeHTTP(w, r)
}
}
// pathTerminatedWithMarker function encodes a path followed by a custom marker and returns a request with an
// updated URL.Path.
// A non-empty prefix can be provided to encode encode only after the prefix.
// It allows our Rest API to handle paths of the form "/spaces/space1/space2/+/authToken"
//
// Examples:
// Prefix: "" Path: "/space1/space2/+" => "/space1%2Fspace2"
// Prefix: "" Path: "/space1/space2.git" => "/space1%2Fspace2"
// Prefix: "/spaces" Path: "/spaces/space1/space2/+/authToken" => "/spaces/space1%2Fspace2/authToken".
func pathTerminatedWithMarker(r *http.Request, prefix string, marker string, keepMarker bool) (*http.Request, bool) {
// In case path doesn't start with prefix - nothing to encode
if len(r.URL.Path) < len(prefix) || r.URL.Path[0:len(prefix)] != prefix {
return r, false
}
originalSubPath := r.URL.Path[len(prefix):]
path, suffix, found := strings.Cut(originalSubPath, marker)
// If we don't find a marker - nothing to encode
if !found {
return r, false
}
// if marker was found - convert to escaped version (skip first character in case path starts with '/')
escapedPath := path[0:1] + strings.ReplaceAll(path[1:], types.PathSeparator, "%2F")
if keepMarker {
escapedPath += marker
}
updatedSubPath := escapedPath + suffix
// TODO: Proper Logging
log.Debug().Msgf(
"[Encode] prefix: '%s', marker: '%s', original: '%s', updated: '%s'.\n",
prefix,
marker,
originalSubPath,
updatedSubPath)
/*
* Return shallow clone with updated URL, similar to http.StripPrefix or earlier version of request.WithContext
* https://cs.opensource.google/go/go/+/refs/tags/go1.19:src/net/http/server.go;l=2138
* https://cs.opensource.google/go/go/+/refs/tags/go1.18:src/net/http/request.go;l=355
*
* http.StripPrefix initially changed the path only, but that was updated because of official recommendations:
* https://github.com/golang/go/issues/18952
*/
r2 := new(http.Request)
*r2 = *r
r2.URL = new(url.URL)
*r2.URL = *r.URL
r2.URL.Path = prefix + updatedSubPath
r2.URL.RawPath = ""
return r2, true
}