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Simplify feed parser and format detection

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- Avoid doing multiple buffer copies
- Move parser and format detection logic to its own package
This commit is contained in:
Frédéric Guillot 2018-10-14 11:46:41 -07:00
parent d5ff4191b6
commit 5870f04260
11 changed files with 229 additions and 221 deletions
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20
http/client/response.go
View file

@ -6,6 +6,7 @@ package client // import "miniflux.app/http/client"
import (
"io"
"io/ioutil"
"mime"
"strings"
@ -56,23 +57,32 @@ func (r *Response) IsModified(etag, lastModified string) bool {
return true
}
// NormalizeBodyEncoding make sure the body is encoded in UTF-8.
// EnsureUnicodeBody makes sure the body is encoded in UTF-8.
//
// If a charset other than UTF-8 is detected, we convert the document to UTF-8.
// This is used by the scraper and feed readers.
//
// Do not forget edge cases:
// - Some non-utf8 feeds specify encoding only in Content-Type, not in XML document.
func (r *Response) NormalizeBodyEncoding() (io.Reader, error) {
func (r *Response) EnsureUnicodeBody() error {
_, params, err := mime.ParseMediaType(r.ContentType)
if err == nil {
if enc, found := params["charset"]; found {
enc = strings.ToLower(enc)
if enc != "utf-8" && enc != "utf8" && enc != "" {
logger.Debug("[NormalizeBodyEncoding] Convert body to UTF-8 from %s", enc)
return charset.NewReader(r.Body, r.ContentType)
logger.Debug("[EnsureUnicodeBody] Convert body to utf-8 from %s", enc)
r.Body, err = charset.NewReader(r.Body, r.ContentType)
if err != nil {
return err
}
}
}
}
return r.Body, nil
return nil
}
// String returns the response body as string.
func (r *Response) String() string {
bytes, _ := ioutil.ReadAll(r.Body)
return string(bytes)
}

2
reader/feed/doc.go
View file

@ -4,7 +4,7 @@
/*
Package feed provides a generic feed parser that abstracts all different formats.
Package feed handles feed updates and creation.
*/
package feed // import "miniflux.app/reader/feed"

11
reader/feed/handler.go
View file

@ -14,6 +14,7 @@ import (
"miniflux.app/logger"
"miniflux.app/model"
"miniflux.app/reader/icon"
"miniflux.app/reader/parser"
"miniflux.app/reader/processor"
"miniflux.app/storage"
"miniflux.app/timer"
@ -67,12 +68,11 @@ func (h *Handler) CreateFeed(userID, categoryID int64, url string, crawler bool,
return nil, errors.NewLocalizedError(errDuplicate, response.EffectiveURL)
}
body, err := response.NormalizeBodyEncoding()
if err != nil {
if err := response.EnsureUnicodeBody(); err != nil {
return nil, errors.NewLocalizedError(errEncoding, err)
}
subscription, feedErr := parseFeed(body)
subscription, feedErr := parser.ParseFeed(response.String())
if feedErr != nil {
return nil, feedErr
}
@ -183,12 +183,11 @@ func (h *Handler) RefreshFeed(userID, feedID int64) error {
return err
}
body, err := response.NormalizeBodyEncoding()
if err != nil {
if err := response.EnsureUnicodeBody(); err != nil {
return errors.NewLocalizedError(errEncoding, err)
}
subscription, parseErr := parseFeed(body)
subscription, parseErr := parser.ParseFeed(response.String())
if parseErr != nil {
originalFeed.ParsingErrorCount++
originalFeed.ParsingErrorMsg = parseErr.Localize(printer)

118
reader/feed/parser.go
View file

@ -1,118 +0,0 @@
// 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 "miniflux.app/reader/feed"
import (
"bytes"
"encoding/xml"
"io"
"strings"
"time"
"miniflux.app/errors"
"miniflux.app/logger"
"miniflux.app/model"
"miniflux.app/reader/atom"
"miniflux.app/reader/encoding"
"miniflux.app/reader/json"
"miniflux.app/reader/rdf"
"miniflux.app/reader/rss"
"miniflux.app/timer"
)
// List of feed formats.
const (
FormatRDF = "rdf"
FormatRSS = "rss"
FormatAtom = "atom"
FormatJSON = "json"
FormatUnknown = "unknown"
)
// DetectFeedFormat detect feed format from input data.
func DetectFeedFormat(r io.Reader) string {
defer timer.ExecutionTime(time.Now(), "[Feed:DetectFeedFormat]")
var buffer bytes.Buffer
tee := io.TeeReader(r, &buffer)
decoder := xml.NewDecoder(tee)
decoder.CharsetReader = encoding.CharsetReader
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
case "RDF":
return FormatRDF
}
}
}
if strings.HasPrefix(strings.TrimSpace(buffer.String()), "{") {
return FormatJSON
}
return FormatUnknown
}
func parseFeed(r io.Reader) (*model.Feed, *errors.LocalizedError) {
defer timer.ExecutionTime(time.Now(), "[Feed:ParseFeed]")
var buffer bytes.Buffer
size, _ := io.Copy(&buffer, r)
if size == 0 {
return nil, errors.NewLocalizedError(errEmptyFeed)
}
str := stripInvalidXMLCharacters(buffer.String())
reader := strings.NewReader(str)
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)
case FormatRDF:
return rdf.Parse(reader)
default:
return nil, errors.NewLocalizedError("Unsupported feed format")
}
}
func stripInvalidXMLCharacters(input string) string {
return strings.Map(func(r rune) rune {
if isInCharacterRange(r) {
return r
}
logger.Debug("Strip invalid XML characters: %U", r)
return -1
}, input)
}
// Decide whether the given rune is in the XML Character Range, per
// the Char production of http://www.xml.com/axml/testaxml.htm,
// Section 2.2 Characters.
func isInCharacterRange(r rune) (inrange bool) {
return r == 0x09 ||
r == 0x0A ||
r == 0x0D ||
r >= 0x20 && r <= 0xDF77 ||
r >= 0xE000 && r <= 0xFFFD ||
r >= 0x10000 && r <= 0x10FFFF
}

10
reader/parser/doc.go Normal file
View file

@ -0,0 +1,10 @@
// Copyright 2018 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 parser provides a generic feed parser that abstract all different formats.
*/
package parser // import "miniflux.app/reader/parser"

51
reader/parser/format.go Normal file
View file

@ -0,0 +1,51 @@
// Copyright 2018 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 parser // import "miniflux.app/reader/parser"
import (
"encoding/xml"
"strings"
"miniflux.app/reader/encoding"
)
// List of feed formats.
const (
FormatRDF = "rdf"
FormatRSS = "rss"
FormatAtom = "atom"
FormatJSON = "json"
FormatUnknown = "unknown"
)
// DetectFeedFormat tries to guess the feed format from input data.
func DetectFeedFormat(data string) string {
if strings.HasPrefix(strings.TrimSpace(data), "{") {
return FormatJSON
}
decoder := xml.NewDecoder(strings.NewReader(data))
decoder.CharsetReader = encoding.CharsetReader
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
case "RDF":
return FormatRDF
}
}
}
return FormatUnknown
}

70
reader/parser/format_test.go Normal file
View file

@ -0,0 +1,70 @@
// Copyright 2018 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 parser // import "miniflux.app/reader/parser"
import (
"testing"
)
func TestDetectRDF(t *testing.T) {
data := `<?xml version="1.0"?><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://my.netscape.com/rdf/simple/0.9/"></rdf:RDF>`
format := DetectFeedFormat(data)
if format != FormatRDF {
t.Errorf(`Wrong format detected: %q instead of %q`, format, FormatRDF)
}
}
func TestDetectRSS(t *testing.T) {
data := `<?xml version="1.0"?><rss version="2.0"><channel></channel></rss>`
format := DetectFeedFormat(data)
if format != FormatRSS {
t.Errorf(`Wrong format detected: %q instead of %q`, format, FormatRSS)
}
}
func TestDetectAtom(t *testing.T) {
data := `<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom"></feed>`
format := DetectFeedFormat(data)
if format != FormatAtom {
t.Errorf(`Wrong format detected: %q instead of %q`, format, FormatAtom)
}
}
func TestDetectAtomWithISOCharset(t *testing.T) {
data := `<?xml version="1.0" encoding="ISO-8859-15"?><feed xmlns="http://www.w3.org/2005/Atom"></feed>`
format := DetectFeedFormat(data)
if format != FormatAtom {
t.Errorf(`Wrong format detected: %q instead of %q`, format, FormatAtom)
}
}
func TestDetectJSON(t *testing.T) {
data := `
{
"version" : "https://jsonfeed.org/version/1",
"title" : "Example"
}
`
format := DetectFeedFormat(data)
if format != FormatJSON {
t.Errorf(`Wrong format detected: %q instead of %q`, format, FormatJSON)
}
}
func TestDetectUnknown(t *testing.T) {
data := `
<!DOCTYPE html> <html> </html>
`
format := DetectFeedFormat(data)
if format != FormatUnknown {
t.Errorf(`Wrong format detected: %q instead of %q`, format, FormatUnknown)
}
}

58
reader/parser/parser.go Normal file
View file

@ -0,0 +1,58 @@
// Copyright 2018 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 parser // import "miniflux.app/reader/parser"
import (
"strings"
"miniflux.app/errors"
"miniflux.app/logger"
"miniflux.app/model"
"miniflux.app/reader/atom"
"miniflux.app/reader/json"
"miniflux.app/reader/rdf"
"miniflux.app/reader/rss"
)
// ParseFeed analyzes the input data and returns a normalized feed object.
func ParseFeed(data string) (*model.Feed, *errors.LocalizedError) {
data = stripInvalidXMLCharacters(data)
switch DetectFeedFormat(data) {
case FormatAtom:
return atom.Parse(strings.NewReader(data))
case FormatRSS:
return rss.Parse(strings.NewReader(data))
case FormatJSON:
return json.Parse(strings.NewReader(data))
case FormatRDF:
return rdf.Parse(strings.NewReader(data))
default:
return nil, errors.NewLocalizedError("Unsupported feed format")
}
}
func stripInvalidXMLCharacters(input string) string {
return strings.Map(func(r rune) rune {
if isInCharacterRange(r) {
return r
}
logger.Debug("Strip invalid XML characters: %U", r)
return -1
}, input)
}
// Decide whether the given rune is in the XML Character Range, per
// the Char production of http://www.xml.com/axml/testaxml.htm,
// Section 2.2 Characters.
func isInCharacterRange(r rune) (inrange bool) {
return r == 0x09 ||
r == 0x0A ||
r == 0x0D ||
r >= 0x20 && r <= 0xDF77 ||
r >= 0xE000 && r <= 0xFFFD ||
r >= 0x10000 && r <= 0x10FFFF
}

76
reader/feed/parser_test.go → reader/parser/parser_test.go
View file

@ -2,74 +2,12 @@
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
package feed // import "miniflux.app/reader/feed"
package parser // import "miniflux.app/reader/parser"
import (
"bytes"
"testing"
)
func TestDetectRDF(t *testing.T) {
data := `<?xml version="1.0"?><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://my.netscape.com/rdf/simple/0.9/"></rdf:RDF>`
format := DetectFeedFormat(bytes.NewBufferString(data))
if format != FormatRDF {
t.Errorf("Wrong format detected: %s instead of %s", format, FormatRDF)
}
}
func TestDetectRSS(t *testing.T) {
data := `<?xml version="1.0"?><rss version="2.0"><channel></channel></rss>`
format := DetectFeedFormat(bytes.NewBufferString(data))
if format != FormatRSS {
t.Errorf("Wrong format detected: %s instead of %s", format, FormatRSS)
}
}
func TestDetectAtom(t *testing.T) {
data := `<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom"></feed>`
format := DetectFeedFormat(bytes.NewBufferString(data))
if format != FormatAtom {
t.Errorf("Wrong format detected: %s instead of %s", format, FormatAtom)
}
}
func TestDetectAtomWithISOCharset(t *testing.T) {
data := `<?xml version="1.0" encoding="ISO-8859-15"?><feed xmlns="http://www.w3.org/2005/Atom"></feed>`
format := DetectFeedFormat(bytes.NewBufferString(data))
if format != FormatAtom {
t.Errorf("Wrong format detected: %s instead of %s", format, FormatAtom)
}
}
func TestDetectJSON(t *testing.T) {
data := `
{
"version" : "https://jsonfeed.org/version/1",
"title" : "Example"
}
`
format := DetectFeedFormat(bytes.NewBufferString(data))
if format != FormatJSON {
t.Errorf("Wrong format detected: %s instead of %s", format, FormatJSON)
}
}
func TestDetectUnknown(t *testing.T) {
data := `
<!DOCTYPE html> <html> </html>
`
format := DetectFeedFormat(bytes.NewBufferString(data))
if format != FormatUnknown {
t.Errorf("Wrong format detected: %s instead of %s", format, FormatUnknown)
}
}
func TestParseAtom(t *testing.T) {
data := `<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
@ -92,7 +30,7 @@ func TestParseAtom(t *testing.T) {
</feed>`
feed, err := parseFeed(bytes.NewBufferString(data))
feed, err := ParseFeed(data)
if err != nil {
t.Error(err)
}
@ -118,7 +56,7 @@ func TestParseRSS(t *testing.T) {
</channel>
</rss>`
feed, err := parseFeed(bytes.NewBufferString(data))
feed, err := ParseFeed(data)
if err != nil {
t.Error(err)
}
@ -147,7 +85,7 @@ func TestParseRDF(t *testing.T) {
</item>
</rdf:RDF>`
feed, err := parseFeed(bytes.NewBufferString(data))
feed, err := ParseFeed(data)
if err != nil {
t.Error(err)
}
@ -177,7 +115,7 @@ func TestParseJson(t *testing.T) {
]
}`
feed, err := parseFeed(bytes.NewBufferString(data))
feed, err := ParseFeed(data)
if err != nil {
t.Error(err)
}
@ -200,14 +138,14 @@ func TestParseUnknownFeed(t *testing.T) {
</html>
`
_, err := parseFeed(bytes.NewBufferString(data))
_, err := ParseFeed(data)
if err == nil {
t.Error("ParseFeed must returns an error")
}
}
func TestParseEmptyFeed(t *testing.T) {
_, err := parseFeed(bytes.NewBufferString(""))
_, err := ParseFeed("")
if err == nil {
t.Error("ParseFeed must returns an error")
}

13
reader/scraper/scraper.go
View file

@ -18,7 +18,7 @@ import (
"github.com/PuerkitoBio/goquery"
)
// Fetch downloads a web page a returns relevant contents.
// Fetch downloads a web page and returns relevant contents.
func Fetch(websiteURL, rules, userAgent string) (string, error) {
clt := client.New(websiteURL)
if userAgent != "" {
@ -38,8 +38,7 @@ func Fetch(websiteURL, rules, userAgent string) (string, error) {
return "", fmt.Errorf("scraper: this resource is not a HTML document (%s)", response.ContentType)
}
page, err := response.NormalizeBodyEncoding()
if err != nil {
if err = response.EnsureUnicodeBody(); err != nil {
return "", err
}
@ -52,11 +51,11 @@ func Fetch(websiteURL, rules, userAgent string) (string, error) {
var content string
if rules != "" {
logger.Debug(`[Scraper] Using rules "%s" for "%s"`, rules, websiteURL)
content, err = scrapContent(page, rules)
logger.Debug(`[Scraper] Using rules %q for %q`, rules, websiteURL)
content, err = scrapContent(response.Body, rules)
} else {
logger.Debug(`[Scraper] Using readability for "%s"`, websiteURL)
content, err = readability.ExtractContent(page)
logger.Debug(`[Scraper] Using readability for "%q`, websiteURL)
content, err = readability.ExtractContent(response.Body)
}
if err != nil {

21
reader/subscription/finder.go
View file

@ -5,15 +5,15 @@
package subscription // import "miniflux.app/reader/subscription"
import (
"bytes"
"fmt"
"io"
"strings"
"time"
"miniflux.app/errors"
"miniflux.app/http/client"
"miniflux.app/logger"
"miniflux.app/reader/feed"
"miniflux.app/reader/parser"
"miniflux.app/timer"
"miniflux.app/url"
@ -56,20 +56,12 @@ func FindSubscriptions(websiteURL, userAgent, username, password string) (Subscr
return nil, errors.NewLocalizedError(errEmptyBody)
}
body, err := response.NormalizeBodyEncoding()
if err != nil {
if err := response.EnsureUnicodeBody(); err != nil {
return nil, err
}
var buffer bytes.Buffer
size, _ := io.Copy(&buffer, body)
if size == 0 {
return nil, errors.NewLocalizedError(errEmptyBody)
}
reader := bytes.NewReader(buffer.Bytes())
if format := feed.DetectFeedFormat(reader); format != feed.FormatUnknown {
body := response.String()
if format := parser.DetectFeedFormat(body); format != parser.FormatUnknown {
var subscriptions Subscriptions
subscriptions = append(subscriptions, &Subscription{
Title: response.EffectiveURL,
@ -80,8 +72,7 @@ func FindSubscriptions(websiteURL, userAgent, username, password string) (Subscr
return subscriptions, nil
}
reader.Seek(0, io.SeekStart)
return parseDocument(response.EffectiveURL, bytes.NewReader(buffer.Bytes()))
return parseDocument(response.EffectiveURL, strings.NewReader(body))
}
func parseDocument(websiteURL string, data io.Reader) (Subscriptions, error) {