Made Feed.CanUpdate() public. This returns true if all cache timeout values have expired and a fresh remote update can be performed. Fixed bug where repeated calls to feed.Fetch() creates duplicate Channels instead of generating a fresh list. Did some minor code householding to replace manual slice appends with the builtin append() function.

src/atom.go

@@ -29,16 +29,14 @@ func (this *Feed) readAtom(doc *xmlx.Document) (err os.Error) {
 			ch.SubTitle.Text = tn.Value
 		}
 
-		tn = node.SelectNode(ns, "generator")
+		if tn = node.SelectNode(ns, "generator"); tn != nil {
-		if tn != nil {
 			ch.Generator = Generator{}
 			ch.Generator.Uri = tn.GetAttr("", "uri")
 			ch.Generator.Version = tn.GetAttr("", "version")
 			ch.Generator.Text = tn.Value
 		}
 
-		tn = node.SelectNode(ns, "author")
+		if tn = node.SelectNode(ns, "author"); tn != nil {
-		if tn != nil {
 			ch.Author = Author{}
 			ch.Author.Name = tn.GetValue("", "name")
 			ch.Author.Uri = tn.GetValue("", "uri")
@@ -61,14 +59,14 @@ func (this *Feed) readAtom(doc *xmlx.Document) (err os.Error) {
 					enc := Enclosure{}
 					enc.Url = lv.GetAttr("", "href")
 					enc.Type = lv.GetAttr("", "type")
-					item.addEnclosure(enc)
+					item.Enclosures = append(item.Enclosures, enc)
 				} else {
 					lnk := Link{}
 					lnk.Href = lv.GetAttr("", "href")
 					lnk.Rel = lv.GetAttr("", "rel")
 					lnk.Type = lv.GetAttr("", "type")
 					lnk.HrefLang = lv.GetAttr("", "hreflang")
-					item.addLink(lnk)
+					item.Links = append(item.Links, lnk)
 				}
 			}
 
@@ -78,18 +76,17 @@ func (this *Feed) readAtom(doc *xmlx.Document) (err os.Error) {
 				item.Contributors[ci] = cv.GetValue("", "name")
 			}
 
-			tn = v.SelectNode(ns, "content")
+			if tn = v.SelectNode(ns, "content"); tn != nil {
-			if tn != nil {
 				item.Content = Content{}
 				item.Content.Type = tn.GetAttr("", "type")
 				item.Content.Lang = tn.GetValue("xml", "lang")
 				item.Content.Base = tn.GetValue("xml", "base")
 				item.Content.Text = tn.Value
 			}
-			ch.addItem(item)
+			ch.Items = append(ch.Items, item)
 		}
 
-		this.addChannel(ch)
+		this.Channels = append(this.Channels, ch)
 	}
 	return
 }

src/channel.go

@@ -28,17 +28,3 @@ type Channel struct {
 	Author   Author
 	SubTitle SubTitle
 }
-
-func (this *Channel) addItem(item Item) {
-	c := make([]Item, len(this.Items)+1)
-	copy(c, this.Items)
-	c[len(c)-1] = item
-	this.Items = c
-}
-
-func (this *Channel) addLink(l Link) {
-	c := make([]Link, len(this.Links)+1)
-	copy(c, this.Links)
-	c[len(c)-1] = l
-	this.Links = c
-}

src/feed.go

@@ -26,13 +26,11 @@
 package feeder
 
 import "os"
-import "http"
 import "time"
 import "xmlx"
 import "fmt"
 import "strconv"
 import "strings"
-import "io/ioutil"
 
 type Feed struct {
 	// Custom cache timeout in minutes.
@@ -60,46 +58,25 @@ type Feed struct {
 }
 
 func New(cachetimeout int, enforcecachelimit bool) *Feed {
-	return &Feed{
+	v := new(Feed)
-		CacheTimeout:      cachetimeout,
+	v.CacheTimeout = cachetimeout
-		EnforceCacheLimit: enforcecachelimit,
+	v.EnforceCacheLimit = enforcecachelimit
-		Type:              "none",
+	v.Type = "none"
-		Version:           [2]int{0, 0},
+	return v
-		Channels:          make([]Channel, 0),
-	}
-}
-
-func (this *Feed) addChannel(ch Channel) {
-	c := make([]Channel, len(this.Channels)+1)
-	copy(c, this.Channels)
-	c[len(c)-1] = ch
-	this.Channels = c
 }
 
 func (this *Feed) Fetch(uri string) (err os.Error) {
-	if !this.canUpdate() {
+	if !this.CanUpdate() {
-		return
-	}
-
-	// Fetch data from remote location.
-	r, _, err := http.Get(uri)
-	if err != nil {
-		return
-	}
-
-	defer r.Body.Close()
-
-	var b []byte
-	if b, err = ioutil.ReadAll(r.Body); err != nil {
 		return
 	}
 
 	this.Url = uri
+	this.Channels = nil
 
 	// Extract type and version of the feed so we can have the appropriate
 	// function parse it (rss 0.91, rss 0.92, rss 2, atom etc).
 	doc := xmlx.New()
-	if err = doc.LoadString(string(b)); err != nil {
+	if err = doc.LoadUri(uri); err != nil {
 		return
 	}
 	this.Type, this.Version = this.GetVersionInfo(doc)
@@ -120,7 +97,12 @@ func (this *Feed) Fetch(uri string) (err os.Error) {
 	return
 }
 
-func (this *Feed) canUpdate() bool {
+// This function returns true or false, depending on whether the CacheTimeout
+// value has expired or not. Additionally, it will ensure that we adhere to the
+// RSS spec's SkipDays and SkipHours values (if Feed.EnforceCacheLimit is set to
+// true). If this function returns true, you can be sure that a fresh feed
+// update will be performed.
+func (this *Feed) CanUpdate() bool {
 	// Make sure we are not within the specified cache-limit.
 	// This ensures we don't request data too often.
 	utc := time.UTC()

src/feed_test.go

@@ -1,6 +1,7 @@
 package feeder
 
 import "testing"
+import "os"
 
 func TestFeed(t *testing.T) {
 	urilist := []string{

src/item.go

@@ -19,17 +19,3 @@ type Item struct {
 	Contributors []string
 	Content      Content
 }
-
-func (this *Item) addEnclosure(e Enclosure) {
-	c := make([]Enclosure, len(this.Enclosures)+1)
-	copy(c, this.Enclosures)
-	c[len(c)-1] = e
-	this.Enclosures = c
-}
-
-func (this *Item) addLink(l Link) {
-	c := make([]Link, len(this.Links)+1)
-	copy(c, this.Links)
-	c[len(c)-1] = l
-	this.Links = c
-}

src/rss.go

@@ -52,8 +52,7 @@ func (this *Feed) readRss2(doc *xmlx.Document) (err os.Error) {
 			ch.SkipDays[i] = mapDay(v.Value)
 		}
 
-		n = node.SelectNode("", "image")
+		if n = node.SelectNode("", "image"); n != nil {
-		if n != nil {
 			ch.Image.Title = n.GetValue("", "title")
 			ch.Image.Url = n.GetValue("", "url")
 			ch.Image.Link = n.GetValue("", "link")
@@ -62,8 +61,7 @@ func (this *Feed) readRss2(doc *xmlx.Document) (err os.Error) {
 			ch.Image.Description = n.GetValue("", "description")
 		}
 
-		n = node.SelectNode("", "cloud")
+		if n = node.SelectNode("", "cloud"); n != nil {
-		if n != nil {
 			ch.Cloud = Cloud{}
 			ch.Cloud.Domain = n.GetAttr("", "domain")
 			ch.Cloud.Port = n.GetAttri("", "port")
@@ -72,8 +70,7 @@ func (this *Feed) readRss2(doc *xmlx.Document) (err os.Error) {
 			ch.Cloud.Protocol = n.GetAttr("", "protocol")
 		}
 
-		n = node.SelectNode("", "textInput")
+		if n = node.SelectNode("", "textInput"); n != nil {
-		if n != nil {
 			ch.TextInput = Input{}
 			ch.TextInput.Title = n.GetValue("", "title")
 			ch.TextInput.Description = n.GetValue("", "description")
@@ -92,11 +89,10 @@ func (this *Feed) readRss2(doc *xmlx.Document) (err os.Error) {
 			for _, v := range list {
 				lnk := Link{}
 				lnk.Href = v.Value
-				i.addLink(lnk)
+				i.Links = append(i.Links, lnk)
 			}
 
-			n = item.SelectNode("", "author")
+			if n = item.SelectNode("", "author"); n != nil {
-			if n != nil {
 				i.Author = Author{}
 				i.Author.Name = n.Value
 			}
@@ -127,10 +123,10 @@ func (this *Feed) readRss2(doc *xmlx.Document) (err os.Error) {
 				i.Source.Text = src.Value
 			}
 
-			ch.addItem(i)
+			ch.Items = append(ch.Items, i)
 		}
 
-		this.addChannel(ch)
+		this.Channels = append(this.Channels, ch)
 	}
 	return
 }