download: gzip support

download.go

@@ -0,0 +1,66 @@
+package archive
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"time"
+)
+
+func (this *ArchiveServer) serveDownload(w http.ResponseWriter) {
+	w.Header().Set(`Content-Type`, `application/octet-stream`)
+	w.Header().Set(`Content-Disposition`, `download; filename="chat-archive-`+time.Now().Format("20060102030405")+`.tar.gz"`)
+	w.WriteHeader(200)
+
+	gzw := gzip.NewWriter(w)
+	defer gzw.Close()
+
+	t := tar.NewWriter(gzw)
+	defer t.Close()
+
+	for i, ls := range this.cfg.Logs {
+
+		slug, _ := this.bestSlugFor(&this.cfg.Logs[i])
+
+		limit := ls.LatestDate().Next() // one off the end
+		for ympair := ls.EarliestDate(); !ympair.Equals(limit); ympair = ympair.Next() {
+
+			fname, err := this.LogFile(&ls, ympair)
+			if err != nil {
+				continue // no log exists for this ym
+			}
+
+			fi, err := os.Stat(fname)
+			if err != nil {
+				continue
+			}
+
+			fh, err := os.Open(fname)
+			if err != nil {
+				continue // can't open this log file
+			}
+
+			tHdr, _ := tar.FileInfoHeader(fi, "")
+			tHdr.Name = fmt.Sprintf(`/%s/%d-%02d.log`, slug, ympair.Year, ympair.Month)
+			t.WriteHeader(tHdr)
+
+			func() {
+				defer fh.Close()
+
+				_, err := io.Copy(t, fh)
+				if err != nil {
+					log.Printf("Error while archiving file '%s': %s", fname, err.Error())
+					return
+				}
+			}()
+
+			t.Flush()
+		}
+
+	}
+
+}