First commit

reader/feed/parser.go

@@ -0,0 +1,82 @@
+// Copyright 2017 Frédéric Guillot. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+package feed
+
+import (
+	"bytes"
+	"encoding/xml"
+	"errors"
+	"github.com/miniflux/miniflux2/helper"
+	"github.com/miniflux/miniflux2/model"
+	"github.com/miniflux/miniflux2/reader/feed/atom"
+	"github.com/miniflux/miniflux2/reader/feed/json"
+	"github.com/miniflux/miniflux2/reader/feed/rss"
+	"io"
+	"strings"
+	"time"
+
+	"golang.org/x/net/html/charset"
+)
+
+const (
+	FormatRss     = "rss"
+	FormatAtom    = "atom"
+	FormatJson    = "json"
+	FormatUnknown = "unknown"
+)
+
+func DetectFeedFormat(data io.Reader) string {
+	defer helper.ExecutionTime(time.Now(), "[Feed:DetectFeedFormat]")
+
+	var buffer bytes.Buffer
+	tee := io.TeeReader(data, &buffer)
+
+	decoder := xml.NewDecoder(tee)
+	decoder.CharsetReader = charset.NewReaderLabel
+
+	for {
+		token, _ := decoder.Token()
+		if token == nil {
+			break
+		}
+
+		if element, ok := token.(xml.StartElement); ok {
+			switch element.Name.Local {
+			case "rss":
+				return FormatRss
+			case "feed":
+				return FormatAtom
+			}
+		}
+	}
+
+	if strings.HasPrefix(strings.TrimSpace(buffer.String()), "{") {
+		return FormatJson
+	}
+
+	return FormatUnknown
+}
+
+func parseFeed(data io.Reader) (*model.Feed, error) {
+	defer helper.ExecutionTime(time.Now(), "[Feed:ParseFeed]")
+
+	var buffer bytes.Buffer
+	io.Copy(&buffer, data)
+
+	reader := bytes.NewReader(buffer.Bytes())
+	format := DetectFeedFormat(reader)
+	reader.Seek(0, io.SeekStart)
+
+	switch format {
+	case FormatAtom:
+		return atom.Parse(reader)
+	case FormatRss:
+		return rss.Parse(reader)
+	case FormatJson:
+		return json.Parse(reader)
+	default:
+		return nil, errors.New("Unsupported feed format")
+	}
+}