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LICENSE | ||
README.md | ||
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feed.go | ||
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parser.go | ||
translator.go |
README.md
gofeed
The gofeed
library is a robust feed parser that supports parsing both RSS and Atom feeds. The library provides a universal gofeed.Parser
that will parse and convert all feed types into a hybrid gofeed.Feed
model. You also have the option of utilizing the feed specific atom.Parser
or rss.Parser
parsers which generate atom.Feed
and rss.Feed
respectively.
Table of Contents
- Features
- Overview
- Basic Usage
- Advanced Usage
- Extensions
- Invalid Feeds
- Default Mappings
- Dependencies
- License
- Credits
Features
Supported feed types:
- RSS 0.90
- Netscape RSS 0.91
- Userland RSS 0.91
- RSS 0.92
- RSS 0.93
- RSS 0.94
- RSS 1.0
- RSS 2.0
- Atom 0.3
- Atom 1.0
Extension Support
The gofeed
library provides support for parsing several popular predefined extensions into ready-made structs, including Dublin Core and Apple’s iTunes.
It parses all other feed extensions in a generic way (see the Extensions section for more details).
Invalid Feeds
A best-effort attempt is made at parsing broken and invalid XML feeds. Currently, gofeed
can succesfully parse feeds with the following issues:
- Unescaped/Naked Markup in feed elements
- Undeclared namespace prefixes
- Missing closing tags on certain elements
- Illegal tags within feed elements without namespace prefixes
- Missing "required" elements as specified by the respective feed specs.
- Incorrect date formats
Overview
The gofeed
library is comprised of a universal feed parser and several feed specific parsers. Which one you choose depends entirely on your usecase. If you will be handling both rss and atom feeds then it makes sense to use the gofeed.Parser
. If you know ahead of time that you will only be parsing one feed type then it would make sense to use rss.Parser
or atom.Parser
.
Universal Feed Parser
The universal gofeed.Parser
works in 3 stages: detection, parsing and translation. It first detects the feed type that it is currently parsing. Then it uses a feed specific parser to parse the feed into its true representation which will be either a rss.Feed
or atom.Feed
. These models cover every field possible for their respective feed types. Finally, they are translated into a gofeed.Feed
model that is a hybrid of both feed types. Performing the universal feed parsing in these 3 stages allows for more flexibility and keeps the code base more maintainable by separating RSS and Atom parsing into seperate packages.
The translation step is done by anything which adheres to the gofeed.Translator
interface. The DefaultRSSTranslator
and DefaultAtomTranslator
are used behind the scenes when you use the gofeed.Parser
with its default settings. You can see how they translate fields from atom.Feed
or rss.Feed
to the universal gofeed.Feed
struct in the Default Mappings section. However, should you disagree with the way certain fields are translated you can easily supply your own gofeed.Translator
and override this behavior. See the Advanced Usage section for an example how to do this.
Feed Specific Parsers
The gofeed
library provides two feed specific parsers: atom.Parser
and rss.Parser
. If the hybrid gofeed.Feed
model that the universal gofeed.Parser
produces does not contain a field from the atom.Feed
or rss.Feed
model that you require, it might be beneficial to use the feed specific parsers. When using the atom.Parser
or rss.Parser
directly, you can access all of fields found in the atom.Feed
and rss.Feed
models. It is also marginally faster because you are able to skip the translation step.
Basic Usage
Universal Feed Parser
The most common usage scenario will be to use gofeed.Parser
to parse an arbitrary RSS or Atom feed into the hybrid gofeed.Feed
model. This hybrid model allows you to treat RSS and Atom feeds the same.
Parse a feed from an URL:
fp := gofeed.NewParser()
feed, _ := fp.ParseURL("http://feeds.twit.tv/twit.xml")
fmt.Println(feed.Title)
Parse a feed from a string:
feedData := `<rss version="2.0">
<channel>
<title>Sample Feed</title>
</channel>
</rss>`
fp := gofeed.NewParser()
feed, _ := fp.ParseString(feedData)
fmt.Println(feed.Title)
Parse a feed from an io.Reader:
file, _ := os.Open("/path/to/a/file.xml")
defer file.Close()
fp := gofeed.NewParser()
feed, _ := fp.Parse(file)
fmt.Println(feed.Title)
Parse a feed from an URL with a 60s timeout:
ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
defer cancel()
fp := gofeed.NewParser()
feed, _ := fp.ParseURLWithContext("http://feeds.twit.tv/twit.xml", ctx)
fmt.Println(feed.Title)
Feed Specific Parsers
You can easily use the rss.Parser
and atom.Parser
directly if you have a usage scenario that requires it:
Parse a RSS feed into a rss.Feed
feedData := `<rss version="2.0">
<channel>
<webMaster>example@site.com (Example Name)</webMaster>
</channel>
</rss>`
fp := rss.Parser{}
rssFeed, _ := fp.Parse(strings.NewReader(feedData))
fmt.Println(rssFeed.WebMaster)
Parse an Atom feed into a atom.Feed
feedData := `<feed xmlns="http://www.w3.org/2005/Atom">
<subtitle>Example Atom</subtitle>
</feed>`
fp := atom.Parser{}
atomFeed, _ := fp.Parse(strings.NewReader(feedData))
fmt.Println(atomFeed.Subtitle)
Advanced Usage
Parse a feed while using a custom translator
The mappings and precedence order that are outlined in the Default Mappings section are provided by the following two structs: DefaultRSSTranslator
and DefaultAtomTranslator
. If you have fields that you think should have a different precedence, or if you want to make a translator that is aware of an unsupported extension you can do this by specifying your own RSS or Atom translator when using the gofeed.Parser
.
Here is a simple example of creating a custom Translator
that makes the /rss/channel/itunes:author
field have a higher precedence than the /rss/channel/managingEditor
field in RSS feeds. We will wrap the existing DefaultRSSTranslator
since we only want to change the behavior for a single field.
First we must define a custom translator:
import (
"fmt"
"github.com/mmcdole/gofeed"
"github.com/mmcdole/gofeed/rss"
)
type MyCustomTranslator struct {
defaultTranslator *gofeed.DefaultRSSTranslator
}
func NewMyCustomTranslator() *MyCustomTranslator {
t := &MyCustomTranslator{}
// We create a DefaultRSSTranslator internally so we can wrap its Translate
// call since we only want to modify the precedence for a single field.
t.defaultTranslator = &gofeed.DefaultRSSTranslator{}
return t
}
func (ct* MyCustomTranslator) Translate(feed interface{}) (*gofeed.Feed, error) {
rss, found := feed.(*rss.Feed)
if !found {
return nil, fmt.Errorf("Feed did not match expected type of *rss.Feed")
}
f, err := ct.defaultTranslator.Translate(rss)
if err != nil {
return nil, err
}
if rss.ITunesExt != nil && rss.ITunesExt.Author != "" {
f.Author = rss.ITunesExt.Author
} else {
f.Author = rss.ManagingEditor
}
return f
}
Next you must configure your gofeed.Parser
to utilize the new gofeed.Translator
:
feedData := `<rss version="2.0">
<channel>
<managingEditor>Ender Wiggin</managingEditor>
<itunes:author>Valentine Wiggin</itunes:author>
</channel>
</rss>`
fp := gofeed.NewParser()
fp.RSSTranslator = NewMyCustomTranslator()
feed, _ := fp.ParseString(feedData)
fmt.Println(feed.Author) // Valentine Wiggin
Extensions
Every element which does not belong to the feed's default namespace is considered an extension by gofeed
. These are parsed and stored in a tree-like structure located at Feed.Extensions
and Item.Extensions
. These fields should allow you to access and read any custom extension elements.
In addition to the generic handling of extensions, gofeed
also has built in support for parsing certain popular extensions into their own structs for convenience. It currently supports the Dublin Core and Apple iTunes extensions which you can access at Feed.ItunesExt
, feed.DublinCoreExt
and Item.ITunesExt
and Item.DublinCoreExt
Default Mappings
The DefaultRSSTranslator
and the DefaultAtomTranslator
map the following rss.Feed
and atom.Feed
fields to their respective gofeed.Feed
fields. They are listed in order of precedence (highest to lowest):
gofeed.Feed |
RSS | Atom |
---|---|---|
Title | /rss/channel/title /rdf:RDF/channel/title /rss/channel/dc:title /rdf:RDF/channel/dc:title |
/feed/title |
Description | /rss/channel/description /rdf:RDF/channel/description /rss/channel/itunes:subtitle |
/feed/subtitle /feed/tagline |
Link | /rss/channel/link /rdf:RDF/channel/link |
/feed/link[@rel=”alternate”]/@href /feed/link[not(@rel)]/@href |
FeedLink | /rss/channel/atom:link[@rel="self"]/@href /rdf:RDF/channel/atom:link[@rel="self"]/@href |
/feed/link[@rel="self"]/@href |
Updated | /rss/channel/lastBuildDate /rss/channel/dc:date /rdf:RDF/channel/dc:date |
/feed/updated /feed/modified |
Published | /rss/channel/pubDate | |
Author | /rss/channel/managingEditor /rss/channel/webMaster /rss/channel/dc:author /rdf:RDF/channel/dc:author /rss/channel/dc:creator /rdf:RDF/channel/dc:creator /rss/channel/itunes:author |
/feed/author |
Language | /rss/channel/language /rss/channel/dc:language /rdf:RDF/channel/dc:language |
/feed/@xml:lang |
Image | /rss/channel/image /rdf:RDF/image /rss/channel/itunes:image |
/feed/logo |
Copyright | /rss/channel/copyright /rss/channel/dc:rights /rdf:RDF/channel/dc:rights |
/feed/rights /feed/copyright |
Generator | /rss/channel/generator | /feed/generator |
Categories | /rss/channel/category /rss/channel/itunes:category /rss/channel/itunes:keywords /rss/channel/dc:subject /rdf:RDF/channel/dc:subject |
/feed/category |
gofeed.Item |
RSS | Atom |
---|---|---|
Title | /rss/channel/item/title /rdf:RDF/item/title /rdf:RDF/item/dc:title /rss/channel/item/dc:title |
/feed/entry/title |
Description | /rss/channel/item/description /rdf:RDF/item/description /rss/channel/item/dc:description /rdf:RDF/item/dc:description |
/feed/entry/summary |
Content | /rss/channel/item/content:encoded | /feed/entry/content |
Link | /rss/channel/item/link /rdf:RDF/item/link |
/feed/entry/link[@rel=”alternate”]/@href /feed/entry/link[not(@rel)]/@href |
Updated | /rss/channel/item/dc:date /rdf:RDF/rdf:item/dc:date |
/feed/entry/modified /feed/entry/updated |
Published | /rss/channel/item/pubDate /rss/channel/item/dc:date |
/feed/entry/published /feed/entry/issued |
Author | /rss/channel/item/author /rss/channel/item/dc:author /rdf:RDF/item/dc:author /rss/channel/item/dc:creator /rdf:RDF/item/dc:creator /rss/channel/item/itunes:author |
/feed/entry/author |
GUID | /rss/channel/item/guid | /feed/entry/id |
Image | /rss/channel/item/itunes:image /rss/channel/item/media:image |
|
Categories | /rss/channel/item/category /rss/channel/item/dc:subject /rss/channel/item/itunes:keywords /rdf:RDF/channel/item/dc:subject |
/feed/entry/category |
Enclosures | /rss/channel/item/enclosure | /feed/entry/link[@rel=”enclosure”] |
Dependencies
License
This project is licensed under the MIT License
Credits
- cristoper for his work on implementing xml:base relative URI handling.
- Mark Pilgrim and Kurt McKee for their work on the excellent Universal Feed Parser Python library. This library was the inspiration for the
gofeed
library. - Dan MacTough for his work on node-feedparser. It provided inspiration for the set of fields that should be covered in the hybrid
gofeed.Feed
model. - Matt Jibson for his date parsing function in the goread project.
- Jim Teeuwen for his method of representing arbitrary feed extensions in the go-pkg-rss library.