implement New* routines for fetching and creating new feeds/pages.

Also includes routines for fetching gemini, http, and gopher resources.

TODO: add Update* routines to update existing feeds/pages.

fetch/fetch.go

@@ -0,0 +1,54 @@
+// Copyright (C) 2021 nytpu
+// SPDX-License-Identifier: AGPL-3.0-or-later
+// For more license details, see LICENSE or <https://www.gnu.org/licenses/agpl-3.0.html>.
+
+// package fetch implements routines for fetching gemini, gopher, and http
+// resources and parsing feed formats
+package fetch
+
+import (
+	"fmt"
+	"net/url"
+
+	"golang.nytpu.com/comitium/core"
+)
+
+// NewFeed will fetch and create a new core.Feed given any url
+func NewFeed(remoteURL *url.URL, title string) (*core.Feed, error) {
+	switch remoteURL.Scheme {
+	case "gemini":
+		return newGeminiFeed(remoteURL, title)
+	case "http", "https":
+		return newHTTPFeed(remoteURL, title)
+	case "gopher", "gophers":
+		return newGopherFeed(remoteURL, title)
+	default:
+		return nil, fmt.Errorf("Unsupported protocol '%s'", remoteURL.Scheme)
+	}
+}
+
+// NewPage will fetch and create a new core.Page given any url
+func NewPage(remoteURL *url.URL, title string) (*core.Page, error) {
+	switch remoteURL.Scheme {
+	case "gemini":
+		return newGeminiPage(remoteURL, title)
+	case "http", "https":
+		return newHTTPPage(remoteURL, title)
+	case "gopher", "gophers":
+		return newGopherPage(remoteURL, title)
+	default:
+		return nil, fmt.Errorf("Unsupported protocol '%s'", remoteURL.Scheme)
+	}
+}
+
+// UpdateFeed will check an existing core.Feed for updates
+func UpdateFeed(feed *core.Feed) error {
+	// TODO
+	return nil
+}
+
+// UpdatePage will check an existing core.Page for updages
+func UpdatePage(page *core.Page) error {
+	// TODO
+	return nil
+}