Merge pull request #51 from velour/rss

barebones rss headline skimmer

main.go

@@ -18,6 +18,7 @@ import (
 	"github.com/velour/catbase/plugins/fact"
 	"github.com/velour/catbase/plugins/leftpad"
 	"github.com/velour/catbase/plugins/reminder"
+	"github.com/velour/catbase/plugins/rss"
 	"github.com/velour/catbase/plugins/talker"
 	"github.com/velour/catbase/plugins/your"
 	"github.com/velour/catbase/plugins/zork"
@@ -57,6 +58,7 @@ func main() {
 	b.AddHandler("reminder", reminder.New(b))
 	b.AddHandler("babbler", babbler.New(b))
 	b.AddHandler("zork", zork.New(b))
+	b.AddHandler("rss", rss.New(b))
 	// catches anything left, will always return true
 	b.AddHandler("factoid", fact.New(b))
 

plugins/rss/rss.go

@@ -0,0 +1,119 @@
+package rss
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/velour/catbase/bot"
+	"github.com/velour/catbase/bot/msg"
+
+	"github.com/mmcdole/gofeed"
+)
+
+type RSSPlugin struct {
+	Bot       bot.Bot
+	cache     map[string]*cacheItem
+	shelfLife time.Duration
+	maxLines  int
+}
+
+type cacheItem struct {
+	key         string
+	data        []string
+	currentLine int
+	expiration  time.Time
+}
+
+func (c *cacheItem) getCurrentPage(maxLines int) string {
+	if len(c.data) <= maxLines {
+		return strings.Join(c.data, "\n")
+	}
+
+	start := c.currentLine
+	end := start + maxLines
+	if end > len(c.data) {
+		end = len(c.data)
+	}
+
+	page := strings.Join(c.data[start:end], "\n")
+
+	if end - start == maxLines {
+		c.currentLine = end
+	} else {
+		c.currentLine = maxLines-(end-start)
+		page += "\n"
+		page += strings.Join(c.data[0:c.currentLine], "\n")
+	}
+
+	return page
+}
+
+func New(bot bot.Bot) *RSSPlugin {
+	return &RSSPlugin{
+		Bot:       bot,
+		cache:     map[string]*cacheItem{},
+		shelfLife: time.Minute * 20,
+		maxLines:  5,
+	}
+}
+
+func (p *RSSPlugin) Message(message msg.Message) bool {
+	tokens := strings.Fields(message.Body)
+	numTokens := len(tokens)
+
+	if numTokens == 2 && strings.ToLower(tokens[0]) == "rss" {
+		if item, ok := p.cache[strings.ToLower(tokens[1])]; ok && time.Now().Before(item.expiration) {
+			p.Bot.SendMessage(message.Channel, item.getCurrentPage(p.maxLines))
+			return true
+		} else {
+			fp := gofeed.NewParser()
+			feed, err := fp.ParseURL(tokens[1])
+			if err != nil {
+				p.Bot.SendMessage(message.Channel, fmt.Sprintf("RSS error: %s", err.Error()))
+				return true
+			}
+			item := &cacheItem{
+				key:         strings.ToLower(tokens[1]),
+				data:        []string{feed.Title},
+				expiration:  time.Now().Add(p.shelfLife),
+				currentLine: 0,
+			}
+
+			for _, feedItem := range feed.Items {
+				item.data = append(item.data, feedItem.Title)
+			}
+
+			p.cache[strings.ToLower(tokens[1])] = item
+
+			p.Bot.SendMessage(message.Channel, item.getCurrentPage(p.maxLines))
+			return true
+		}
+	}
+
+	return false
+}
+
+func (p *RSSPlugin) LoadData() {
+	// This bot has no data to load
+}
+
+// Help responds to help requests. Every plugin must implement a help function.
+func (p *RSSPlugin) Help(channel string, parts []string) {
+	p.Bot.SendMessage(channel, "try '!rss http://rss.cnn.com/rss/edition.rss'")
+}
+
+// Empty event handler because this plugin does not do anything on event recv
+func (p *RSSPlugin) Event(kind string, message msg.Message) bool {
+	return false
+}
+
+// Handler for bot's own messages
+func (p *RSSPlugin) BotMessage(message msg.Message) bool {
+	return false
+}
+
+// Register any web URLs desired
+func (p *RSSPlugin) RegisterWeb() *string {
+	return nil
+}

plugins/rss/rss_test.go

@@ -0,0 +1,58 @@
+package rss
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/velour/catbase/bot"
+	"github.com/velour/catbase/bot/msg"
+	"github.com/velour/catbase/bot/user"
+)
+
+func makeMessage(payload string) msg.Message {
+	isCmd := strings.HasPrefix(payload, "!")
+	if isCmd {
+		payload = payload[1:]
+	}
+	return msg.Message{
+		User:    &user.User{Name: "tester"},
+		Channel: "test",
+		Body:    payload,
+		Command: isCmd,
+	}
+}
+
+func TestRSS(t *testing.T) {
+	mb := bot.NewMockBot()
+	c := New(mb)
+	assert.NotNil(t, c)
+	res := c.Message(makeMessage("!rss http://rss.cnn.com/rss/edition.rss"))
+	assert.Len(t, mb.Messages, 1)
+	assert.True(t, res)
+}
+
+func TestRSSPaging(t *testing.T) {
+	mb := bot.NewMockBot()
+	c := New(mb)
+	assert.NotNil(t, c)
+	for i := 0; i < 20; i++ {
+		res := c.Message(makeMessage("!rss http://rss.cnn.com/rss/edition.rss"))
+		assert.True(t, res)
+	}
+
+	assert.Len(t, mb.Messages, 20)
+
+	for i := 0; i < len(mb.Messages); i++ {
+		if i > 0 && strings.Contains(mb.Messages[i], "CNN.com - RSS Channel - Intl Homepage - News") {
+			fmt.Println("----------------")
+			fmt.Println(mb.Messages[i])
+			fmt.Println("----------------")
+			break
+		}
+		fmt.Println("----------------")
+		fmt.Println(mb.Messages[i])
+		fmt.Println("----------------")
+	}
+}