torrent/webseed/request.go

75 lines
2.1 KiB
Go

package webseed
import (
"fmt"
"net/http"
"net/url"
"path"
"strings"
"github.com/anacrolix/torrent/metainfo"
)
// Escapes path name components suitable for appending to a webseed URL. This works for converting
// S3 object keys to URLs too.
// Contrary to the name, this actually does a QueryEscape, rather than a
// PathEscape. This works better with most S3 providers. You can use
// EscapePathWithCustomEncoding for a custom encoding.
func EscapePath(pathComps []string) string {
return escapePath(pathComps, nil)
}
func escapePath(pathComps []string, encodeUrl func(string) string) string {
if encodeUrl == nil {
encodeUrl = url.QueryEscape
}
return path.Join(
func() (ret []string) {
for _, comp := range pathComps {
ret = append(ret, encodeUrl(comp))
}
return
}()...,
)
}
func trailingPath(infoName string, fileComps []string, encodeUrl func(string) string) string {
return escapePath(append([]string{infoName}, fileComps...), encodeUrl)
}
// Creates a request per BEP 19.
func NewRequest(url_ string, fileIndex int, info *metainfo.Info, offset, length int64) (*http.Request, error) {
return newRequest(url_, fileIndex, info, offset, length, nil)
}
func NewRequestWithCustomUrlEncoding(
url_ string, fileIndex int,
info *metainfo.Info,
offset, length int64,
encodeUrl func(string) string,
) (*http.Request, error) {
return newRequest(url_, fileIndex, info, offset, length, encodeUrl)
}
func newRequest(
url_ string, fileIndex int,
info *metainfo.Info,
offset, length int64,
encodeUrl func(string) string,
) (*http.Request, error) {
fileInfo := info.UpvertedFiles()[fileIndex]
if strings.HasSuffix(url_, "/") {
// BEP specifies that we append the file path. We need to escape each component of the path
// for things like spaces and '#'.
url_ += trailingPath(info.Name, fileInfo.Path, encodeUrl)
}
req, err := http.NewRequest(http.MethodGet, url_, nil)
if err != nil {
return nil, err
}
if offset != 0 || length != fileInfo.Length {
req.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", offset, offset+length-1))
}
return req, nil
}