69 lines
1.8 KiB
Go
69 lines
1.8 KiB
Go
package webseed
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import (
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"fmt"
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"net/http"
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"net/url"
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"strings"
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"github.com/anacrolix/torrent/metainfo"
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)
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type PathEscaper func(pathComps []string) string
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// Escapes path name components suitable for appending to a webseed URL. This works for converting
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// S3 object keys to URLs too.
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//
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// Contrary to the name, this actually does a QueryEscape, rather than a PathEscape. This works
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// better with most S3 providers.
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func EscapePath(pathComps []string) string {
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return defaultPathEscaper(pathComps)
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}
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func defaultPathEscaper(pathComps []string) string {
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var ret []string
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for _, comp := range pathComps {
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esc := url.PathEscape(comp)
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// S3 incorrectly escapes + in paths to spaces, so we add an extra encoding for that. This
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// seems to be handled correctly regardless of whether an endpoint uses query or path
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// escaping.
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esc = strings.ReplaceAll(esc, "+", "%2B")
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ret = append(ret, esc)
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}
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return strings.Join(ret, "/")
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}
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func trailingPath(
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infoName string,
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fileComps []string,
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pathEscaper PathEscaper,
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) string {
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if pathEscaper == nil {
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pathEscaper = defaultPathEscaper
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}
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return pathEscaper(append([]string{infoName}, fileComps...))
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}
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// Creates a request per BEP 19.
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func newRequest(
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url_ string, fileIndex int,
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info *metainfo.Info,
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offset, length int64,
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pathEscaper PathEscaper,
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) (*http.Request, error) {
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fileInfo := info.UpvertedFiles()[fileIndex]
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if strings.HasSuffix(url_, "/") {
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// BEP specifies that we append the file path. We need to escape each component of the path
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// for things like spaces and '#'.
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url_ += trailingPath(info.Name, fileInfo.Path, pathEscaper)
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}
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req, err := http.NewRequest(http.MethodGet, url_, nil)
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if err != nil {
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return nil, err
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}
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if offset != 0 || length != fileInfo.Length {
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req.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", offset, offset+length-1))
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}
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return req, nil
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}
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