*: prepare for time comparison with remote

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

cmd/sl-feeds/main.go

@@ -35,13 +35,42 @@ func main() {
 	app.Action = func(c *cli.Context) error {
 		if c.Bool("sample-config") {
 			c := Config{
-				Dest: "./public_html/feeds/",
+				Dest: "$HOME/public_html/feeds/",
+				Mirrors: []Mirror{
+					Mirror{
+						URL: "http://slackware.osuosl.org/",
+						Releases: []string{
+							"slackware-14.0",
+							"slackware-14.1",
+							"slackware-14.2",
+							"slackware-current",
+							"slackware64-14.0",
+							"slackware64-14.1",
+							"slackware64-14.2",
+							"slackware64-current",
+						},
+					},
+					Mirror{
+						URL: "http://ftp.arm.slackware.com/slackwarearm/",
+						Releases: []string{
+							"slackwarearm-14.1",
+							"slackwarearm-14.2",
+							"slackwarearm-current",
+						},
+					},
+				},
 			}
 			toml.NewEncoder(os.Stdout).Encode(c)
 			return nil
 		}
 
-		fmt.Println(config.Dest)
+		fmt.Println(os.ExpandEnv(config.Dest))
+		/*
+			for each mirror in Mirrors
+				if there is not a $release.RSS file, then fetch the whole ChangeLog
+				if there is a $release.RSS file, then stat the file and only fetch remote if it is newer than the local RSS file
+				if the remote returns any error (404, 503, etc) then print a warning but continue
+		*/
 		return nil
 	}
 
@@ -67,5 +96,11 @@ func main() {
 }
 
 type Config struct {
-	Dest string
+	Dest    string
+	Mirrors []Mirror
+}
+
+type Mirror struct {
+	URL      string
+	Releases []string
 }

fetch/fetch.go

@@ -13,10 +13,38 @@ type Repo struct {
 	URL string
 }
 
+func (r Repo) head(file string) (*http.Response, error) {
+	return http.Head(r.URL + "/" + file)
+}
 func (r Repo) get(file string) (*http.Response, error) {
 	return http.Get(r.URL + "/" + file)
 }
 
+func (r Repo) NewerChangeLog(than time.Time) (e []changelog.Entry, mtime time.Time, err error) {
+	resp, err := r.head("ChangeLog.txt")
+	if err != nil {
+		return nil, time.Unix(0, 0), err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, time.Unix(0, 0), fmt.Errorf("%d status from %s", resp.StatusCode, resp.Request.URL)
+	}
+
+	mtime, err = http.ParseTime(resp.Header.Get("last-modified"))
+	if err != nil {
+		return nil, time.Unix(0, 0), err
+	}
+
+	if mtime.After(than) {
+		return r.ChangeLog()
+	}
+	return nil, time.Unix(0, 0), NotNewer
+}
+
+// NotNewer is a status error usage to indicate that the remote file is not newer
+var NotNewer = fmt.Errorf("Remote file is not newer than provided time")
+
 // ChangeLog fetches the ChangeLog.txt for this remote Repo, along with the
 // last-modified (for comparisons).
 func (r Repo) ChangeLog() (e []changelog.Entry, mtime time.Time, err error) {