map nyaa://q=X to https://nyaa.si/.../

src/feeds/http.go

@@ -49,7 +49,12 @@ func (feed Feed) ShouldExecute() (bool, error) {
 }
 
 func (feed Feed) Fetch(ctx context.Context) (Items, error) {
-	resp, err := proxyFetch(ctx, feed.Version.URL)
+	u, err := feed.FetchURL()
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := proxyFetch(ctx, u.String())
 	if err != nil {
 		return nil, err
 	}
@@ -132,3 +137,32 @@ func proxyFetch(ctx context.Context, u string) (string, error) {
 
 	return string(b), nil
 }
+
+func (feed Feed) FetchURL() (*url.URL, error) {
+	u, err := url.Parse(feed.Version.URL)
+	if err != nil {
+		return nil, err
+	}
+
+	switch u.Scheme {
+	case "nyaa": // `nyaa://?q=A B` to `https://nyaa.si/?page=rss&q=A%20B&c=0_0&f=0`
+		q := u.Query()
+		if q.Get("q") == "" {
+			return nil, fmt.Errorf("invalid nyaa:// (%s): no ?q", feed.Version.URL)
+		}
+
+		q.Set("page", "rss")
+		q.Set("c", "0_0")
+		q.Set("f", "0")
+
+		u.RawQuery = q.Encode()
+		u.Scheme = "https"
+		u.Host = "nyaa.si"
+		u.Path = "/"
+	case "http", "https":
+	default:
+		return nil, fmt.Errorf("not impl mapping %s:// to url", u.Scheme)
+	}
+
+	return u, nil
+}

src/feeds/http_test.go

@@ -74,3 +74,24 @@ func TestFeedFetch(t *testing.T) {
 		t.Errorf("expected\n\t%+v but got \n\t%+v", expect, items[0])
 	}
 }
+
+func TestFeedFetchURL(t *testing.T) {
+	cases := map[string]string{
+		"http://host/path?k=v":  "http://host/path?k=v",
+		"https://host/path?k=v": "https://host/path?k=v",
+		"nyaa://?q=a b&u=c d":   "https://nyaa.si/?c=0_0&f=0&page=rss&q=a+b&u=c+d",
+	}
+
+	for given, want := range cases {
+		given := given
+		want := want
+		t.Run(given, func(t *testing.T) {
+			f := feeds.Feed{}
+			f.Version.URL = given
+			got, _ := f.FetchURL()
+			if got := got.String(); got != want {
+				t.Errorf("expected %q but got %q", want, got)
+			}
+		})
+	}
+}