Add initial prototype

internal/config.go

@@ -0,0 +1,85 @@
+package internal
+
+import (
+	"errors"
+	"io/ioutil"
+	"log"
+	"os"
+	"runtime"
+
+	"gopkg.in/yaml.v2"
+)
+
+// Configuration stores the global config
+type Configuration struct {
+	Feeds          []string `yaml:"feeds"`
+	ExternalViewer string   `yaml:"externalViewer,omitempty"`
+}
+
+// DefaultConfiguration can be used if a config is missing
+var DefaultConfiguration = Configuration{
+	Feeds: []string{
+		"https://news.ycombinator.com/rss",
+		"https://www.reddit.com/r/golang/.rss",
+		"https://www.zdnet.com/topic/security/rss.xml",
+	},
+}
+
+// Determines the default viewer
+func DetermineExternalViewer() (string, error) {
+	switch os := runtime.GOOS; os {
+	case "linux":
+		return "xdg-open", nil
+	case "darwin":
+		return "open", nil
+	}
+
+	return "", errors.New("Unable to determine a default external viewer")
+}
+
+// LoadConfiguration takes a filename (configuration) and loads it.
+func LoadConfiguration(file string) Configuration {
+	var config Configuration
+
+	// If the configuration file does not exist,
+	// write a default config
+	_, err := os.Stat(file)
+	if os.IsNotExist(err) {
+		WriteConfig(DefaultConfiguration, file)
+	}
+
+	data, err := ioutil.ReadFile(file)
+
+	if err != nil {
+		log.Println(err)
+		os.Exit(1)
+	}
+
+	if config.ExternalViewer == "" {
+		config.ExternalViewer, err = DetermineExternalViewer()
+		if err != nil {
+			log.Println(err)
+			os.Exit(1)
+		}
+	}
+
+	err = yaml.Unmarshal(data, &config)
+	if err != nil {
+		log.Panicln(err)
+	}
+	return config
+}
+
+// WriteConfig writes a config to disk
+func WriteConfig(config Configuration, file string) error {
+	c, err := yaml.Marshal(&config)
+	if err != nil {
+		log.Fatalf("Unable to marshal default config: %v", err)
+	}
+
+	err = ioutil.WriteFile(file, c, 0644)
+	if err != nil {
+		log.Fatalf("Unable to write default config: %v", err)
+	}
+	return nil
+}

internal/config_test.go

@@ -0,0 +1,36 @@
+package internal
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TestLoadConfiguration tests loading the example config
+func TestLoadConfiguration(t *testing.T) {
+	exampleConfig := LoadConfiguration("../config-example.yaml")
+
+	expectedFeeds := []string{
+		"https://news.ycombinator.com/rss",
+		"https://www.reddit.com/r/golang/.rss",
+		"https://www.reddit.com/r/linux/.rss",
+		"https://www.zdnet.com/topic/security/rss.xml",
+		"https://aws.amazon.com/blogs/security/feed/",
+		"https://www.archlinux.org/feeds/news/",
+	}
+
+	assert.Equal(
+		t,
+		expectedFeeds,
+		exampleConfig.Feeds,
+		"Expected configuration does not match.",
+	)
+
+	// ExternalViewer should default to either 'xdg-open' on Linux,
+	// or 'open' on macOS
+	assert.Contains(
+		t,
+		[]string{"xdg-open", "open"},
+		exampleConfig.ExternalViewer,
+	)
+}

internal/controller.go

@@ -0,0 +1,18 @@
+package internal
+
+import "time"
+
+// Controller keeps everything together
+type Controller struct {
+	Config     Configuration
+	lastUpdate time.Time
+	Rss        *RSS
+}
+
+// Init initiates the controller with config
+func (c *Controller) Init(config string) {
+	c.Config = LoadConfiguration(config)
+	c.Rss = &RSS{}
+	c.Rss.New(c)
+	c.Rss.Update()
+}

internal/rss.go

@@ -0,0 +1,79 @@
+package internal
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"sync"
+
+	browser "github.com/EDDYCJY/fake-useragent"
+	"github.com/mmcdole/gofeed"
+)
+
+type RSS struct {
+	Feeds []*gofeed.Feed
+	c     *Controller
+}
+
+func (r *RSS) New(c *Controller) {
+	r.c = c
+}
+
+// Update fetches all articles for all feeds
+func (r *RSS) Update() {
+	fp := gofeed.NewParser()
+	var wg sync.WaitGroup
+	var mux sync.Mutex
+	r.Feeds = []*gofeed.Feed{}
+	for _, f := range r.c.Config.Feeds {
+		f := f
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			feed, err := r.FetchURL(fp, f)
+			if err != nil {
+				log.Printf("error fetching url: %s, err: %v", f, err)
+			}
+			mux.Lock()
+			if feed != nil {
+				r.Feeds = append(r.Feeds, feed)
+			}
+			mux.Unlock()
+		}()
+	}
+	wg.Wait()
+}
+
+// FetchURL fetches the feed URL and parses it
+func (r *RSS) FetchURL(fp *gofeed.Parser, url string) (feed *gofeed.Feed, err error) {
+	client := &http.Client{}
+
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	userAgent := browser.Firefox()
+
+	req.Header.Set("User-Agent", userAgent)
+	resp, err := client.Do(req)
+
+	if err != nil {
+		return nil, err
+	}
+
+	if resp != nil {
+		defer func() {
+			ce := resp.Body.Close()
+			if ce != nil {
+				err = ce
+			}
+		}()
+	}
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return nil, fmt.Errorf("Failed to get url %v, %v", resp.StatusCode, resp.Status)
+	}
+
+	return fp.Parse(resp.Body)
+}