Gogs
commit
c9508770a9
@ -0,0 +1,314 @@ |
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package comments |
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|
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import ( |
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"bytes" |
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"crypto/subtle" |
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"encoding/json" |
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"fmt" |
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"html/template" |
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"io" |
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"net/http" |
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"strconv" |
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"sync" |
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"time" |
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|
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"github.com/peterbourgon/diskv" |
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) |
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|
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type Comment struct { |
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Name, Text string |
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IP string |
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Date time.Time |
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Spam bool |
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} |
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|
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func MarshalJSON(c Comment) ([]byte, error) { |
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buf := new(bytes.Buffer) |
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err := json.NewEncoder(buf).Encode(c) |
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return buf.Bytes(), err |
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} |
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|
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func UnmarshalJSON(b []byte) (Comment, error) { |
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var c Comment |
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err := json.NewDecoder(bytes.NewBuffer(b)).Decode(&c) |
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return c, err |
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} |
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|
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func Default() *Service { |
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return WithStorage(NewDiskv("comments")) |
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} |
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func WithStorage(storage Storage) *Service { |
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return &Service{Storage: storage} |
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} |
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type Service struct { |
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Storage Storage |
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Password string |
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} |
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type Storage interface { |
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Store(post string, c Comment) error |
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Retreive(post string) ([]Comment, error) |
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ReadAll(post string) (io.Reader, error) |
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} |
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func (cs *Service) User(r *http.Request) (string, bool) { |
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if cs.Password == "" { |
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return "", true |
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} |
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user, providedPass, ok := r.BasicAuth() |
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if ok && subtle.ConstantTimeCompare([]byte(cs.Password), []byte(providedPass)) == 1 { |
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return user, true |
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} |
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return "", false |
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} |
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func (cs *Service) ServeComments(post string, w http.ResponseWriter, r *http.Request) error { |
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user, allowed := cs.User(r) |
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if !allowed { |
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fmt.Fprintf(w, "<a href='/login'>click here to enter your name and the comments password</a>") |
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w.WriteHeader(401) |
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return nil |
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} |
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|
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if r.Method == "POST" { |
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return cs.Comment(post, Comment{ |
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Name: user, |
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Text: readCommentText(r), |
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IP: r.RemoteAddr, |
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Date: time.Now(), |
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}) |
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} |
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|
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w.Header().Set("Content-Type", "text/html") |
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_, err := cs.WriteHTML(post, w) |
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if err != nil { |
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return err |
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} |
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return nil |
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} |
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func readCommentText(r *http.Request) string { |
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comment := struct{ Text string }{} |
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json.NewDecoder(r.Body).Decode(&comment) |
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return comment.Text |
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} |
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|
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func (cs *Service) Comment(post string, c Comment) error { |
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return cs.Storage.Store(post, c) |
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} |
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func (cs *Service) Load(post string) ([]Comment, error) { |
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return cs.Storage.Retreive(post) |
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} |
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func (cs *Service) WriteHTML(post string, w io.Writer) (int64, error) { |
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buf := &bytes.Buffer{} |
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tmpl := template.Must(template.New("").Parse( |
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`<style> |
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comment { |
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margin: 10px 0; |
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} |
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comment, comment name, comment text { |
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display: block; |
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} |
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comment name::after { |
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content: " says:"; |
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} |
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comment text { |
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margin-left: 5px; |
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padding-left: 5px; |
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border-left: 2px solid gray; |
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} |
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</style> |
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{{range .}}{{ if .Text }}<comment> |
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<name>{{.Name}}</name> |
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<text>{{.Text}}</text> |
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</comment> |
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{{end}}{{end}} |
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<form onsubmit="submitComment(event)"> |
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<p> |
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<div> |
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<label for="comment">post a comment:</label> |
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</div> |
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<div> |
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<textarea placeholder="comment..." name="comment"></textarea> |
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</div> |
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<div> |
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<button type="submit">post</button> |
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</div> |
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</p> |
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</form>`)) |
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comments, err := cs.Load(post) |
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if err != nil { |
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return 0, err |
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} |
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err = tmpl.Execute(buf, comments) |
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if err != nil { |
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return 0, err |
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} |
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return io.Copy(w, buf) |
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} |
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func (cs *Service) WriteJSON(post string, w io.Writer) (int64, error) { |
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r, err := cs.Storage.ReadAll(post) |
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if err != nil { |
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return 0, err |
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} |
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return io.Copy(w, r) |
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} |
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type diskvStorage struct { |
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*diskv.Diskv |
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keyMtx sync.Mutex |
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keyLastKnown int64 |
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} |
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func (d *diskvStorage) nextKey(post string) (string, error) { |
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d.keyMtx.Lock() |
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defer d.keyMtx.Unlock() |
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prefix := post + "-" |
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lastKey := prefix |
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keys := d.KeysPrefix(prefix, nil) |
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for key := range keys { |
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lastKey = key |
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} |
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if lastKey == prefix { |
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return prefix + "1", nil |
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} |
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minusPrefix := lastKey[len(prefix):] |
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lastIdx, err := strconv.Atoi(minusPrefix) |
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if err != nil { |
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return "", fmt.Errorf("comment key %q seems malformed", lastKey) |
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} |
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key := prefix + fmt.Sprint(lastIdx+1) |
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err = d.WriteStream(key, &bytes.Buffer{}, true) |
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return key, err |
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} |
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func (d *diskvStorage) Store(post string, c Comment) error { |
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b, err := MarshalJSON(c) |
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if err != nil { |
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return fmt.Errorf("error marshaling comment for storage: %v", err) |
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} |
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key, err := d.nextKey(post) |
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if err != nil { |
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return fmt.Errorf("error recording comment: %v", err) |
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} |
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err = d.Write(key, b) |
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if err != nil { |
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return fmt.Errorf("error writing comment to storage: %v", err) |
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} |
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return nil |
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} |
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type multiReadCloser struct { |
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rcs []io.ReadCloser |
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} |
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func (mrc *multiReadCloser) Read(b []byte) (int, error) { |
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if len(mrc.rcs) == 0 { |
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return 0, io.EOF |
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} |
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n, err := mrc.rcs[0].Read(b) |
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if n == len(b) { // we read enough
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return n, err |
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} |
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for (err == nil || err == io.EOF) && len(mrc.rcs) > 1 { |
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var n2 int |
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closeErr := mrc.rcs[0].Close() |
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if closeErr != nil { |
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return n, closeErr |
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} |
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mrc.rcs = mrc.rcs[1:] |
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n2, err = mrc.rcs[0].Read(b[n:]) |
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n += n2 |
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} |
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return n, err |
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} |
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func (mrc *multiReadCloser) Close() error { |
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var err error |
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for _, rc := range mrc.rcs { |
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err2 := rc.Close() |
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if err2 != nil { |
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err = err2 |
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} |
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} |
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if err != nil { |
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return err |
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} |
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return nil |
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} |
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func (d *diskvStorage) ReadAll(post string) (io.Reader, error) { |
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prefix := post + "-" |
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var rcs []io.ReadCloser |
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keys := d.KeysPrefix(prefix, nil) |
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for key := range keys { |
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rc, err := d.ReadStream(key, false) |
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if err != nil { |
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return nil, err |
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} |
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rcs = append(rcs, rc) |
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} |
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return &multiReadCloser{rcs}, nil |
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} |
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func (d *diskvStorage) Retreive(post string) ([]Comment, error) { |
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var comments []Comment |
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r, err := d.ReadAll(post) |
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if err != nil { |
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return comments, fmt.Errorf("error reading comment from storage: %v", err) |
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} |
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dec := json.NewDecoder(r) |
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for dec.More() { |
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comment := Comment{} |
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err := dec.Decode(&comment) |
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if err != nil { |
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return comments, fmt.Errorf("error unmarshaling comment: %v", err) |
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} |
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comments = append(comments, comment) |
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} |
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return comments, nil |
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} |
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func NewDiskv(path string) Storage { |
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return &diskvStorage{ |
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Diskv: diskv.New(diskv.Options{ |
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BasePath: path, |
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CacheSizeMax: 1024 * 1024, |
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}), |
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} |
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} |
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