Add initial last.fm client implementation

conf/configuration.go

@@ -41,6 +41,7 @@ type configOptions struct {
 	AuthWindowLength time.Duration
 
 	Scanner scannerOptions
+	LastFM  lastfmOptions
 
 	// DevFlags. These are used to enable/disable debugging and incomplete features
 	DevLogSourceLine           bool
@@ -51,6 +52,12 @@ type scannerOptions struct {
 	Extractor string
 }
 
+type lastfmOptions struct {
+	ApiKey   string
+	Secret   string
+	Language string
+}
+
 var Server = &configOptions{}
 
 func LoadFromFile(confFile string) {
@@ -107,6 +114,7 @@ func init() {
 	viper.SetDefault("authwindowlength", 20*time.Second)
 
 	viper.SetDefault("scanner.extractor", "taglib")
+	viper.SetDefault("lastfm.language", "en")
 
 	// DevFlags. These are used to enable/disable debugging and incomplete features
 	viper.SetDefault("devlogsourceline", false)

core/lastfm/client.go

@@ -0,0 +1,67 @@
+package lastfm
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+)
+
+const (
+	apiBaseUrl = "https://ws.audioscrobbler.com/2.0/"
+)
+
+type HttpClient interface {
+	Do(req *http.Request) (*http.Response, error)
+}
+
+func NewClient(apiKey string, lang string, hc HttpClient) *Client {
+	return &Client{apiKey, lang, hc}
+}
+
+type Client struct {
+	apiKey string
+	lang   string
+	hc     HttpClient
+}
+
+// TODO SimilarArtists()
+func (c *Client) ArtistGetInfo(name string) (*Artist, error) {
+	params := url.Values{}
+	params.Add("method", "artist.getInfo")
+	params.Add("format", "json")
+	params.Add("api_key", c.apiKey)
+	params.Add("artist", name)
+	params.Add("lang", c.lang)
+	req, _ := http.NewRequest("GET", apiBaseUrl, nil)
+	req.URL.RawQuery = params.Encode()
+
+	resp, err := c.hc.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	defer resp.Body.Close()
+	data, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != 200 {
+		return nil, c.parseError(data)
+	}
+
+	var response Response
+	err = json.Unmarshal(data, &response)
+	return &response.Artist, err
+}
+
+func (c *Client) parseError(data []byte) error {
+	var e Error
+	err := json.Unmarshal(data, &e)
+	if err != nil {
+		return err
+	}
+	return fmt.Errorf("last.fm error(%d): %s", e.Code, e.Message)
+}

core/lastfm/client_test.go

@@ -0,0 +1,76 @@
+package lastfm
+
+import (
+	"bytes"
+	"errors"
+	"io/ioutil"
+	"net/http"
+	"os"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Client", func() {
+	var httpClient *fakeHttpClient
+	var client *Client
+
+	BeforeEach(func() {
+		httpClient = &fakeHttpClient{}
+		client = NewClient("API_KEY", "pt", httpClient)
+	})
+
+	Describe("ArtistInfo", func() {
+		It("returns an artist for a successful response", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.json")
+			httpClient.res = http.Response{Body: f, StatusCode: 200}
+
+			artist, err := client.ArtistGetInfo("U2")
+			Expect(err).To(BeNil())
+			Expect(artist.Name).To(Equal("U2"))
+			Expect(httpClient.savedRequest.URL.String()).To(Equal(apiBaseUrl + "?api_key=API_KEY&artist=U2&format=json&lang=pt&method=artist.getInfo"))
+		})
+
+		It("fails if Last.FM returns an error", func() {
+			httpClient.res = http.Response{
+				Body:       ioutil.NopCloser(bytes.NewBufferString(`{"error":3,"message":"Invalid Method - No method with that name in this package"}`)),
+				StatusCode: 400,
+			}
+
+			_, err := client.ArtistGetInfo("U2")
+			Expect(err).To(MatchError("last.fm error(3): Invalid Method - No method with that name in this package"))
+		})
+
+		It("fails if HttpClient.Do() returns error", func() {
+			httpClient.err = errors.New("generic error")
+
+			_, err := client.ArtistGetInfo("U2")
+			Expect(err).To(MatchError("generic error"))
+		})
+
+		It("fails if returned body is not a valid JSON", func() {
+			httpClient.res = http.Response{
+				Body:       ioutil.NopCloser(bytes.NewBufferString(`<xml>NOT_VALID_JSON</xml>`)),
+				StatusCode: 200,
+			}
+
+			_, err := client.ArtistGetInfo("U2")
+			Expect(err).To(MatchError("invalid character '<' looking for beginning of value"))
+		})
+
+	})
+})
+
+type fakeHttpClient struct {
+	res          http.Response
+	err          error
+	savedRequest *http.Request
+}
+
+func (c *fakeHttpClient) Do(req *http.Request) (*http.Response, error) {
+	c.savedRequest = req
+	if c.err != nil {
+		return nil, c.err
+	}
+	return &c.res, nil
+}

core/lastfm/lastfm_suite_test.go

@@ -0,0 +1,17 @@
+package lastfm
+
+import (
+	"testing"
+
+	"github.com/deluan/navidrome/log"
+	"github.com/deluan/navidrome/tests"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestLastFM(t *testing.T) {
+	tests.Init(t, false)
+	log.SetLevel(log.LevelCritical)
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "LastFM Test Suite")
+}

core/lastfm/responses.go

@@ -0,0 +1,45 @@
+package lastfm
+
+type Response struct {
+	Artist Artist `json:"artist"`
+}
+
+type Artist struct {
+	Name       string        `json:"name"`
+	MBID       string        `json:"mbid"`
+	URL        string        `json:"url"`
+	Image      []ArtistImage `json:"image"`
+	Streamable string        `json:"streamable"`
+	Stats      struct {
+		Listeners string `json:"listeners"`
+		Plays     string `json:"plays"`
+	} `json:"stats"`
+	Similar struct {
+		Artists []Artist `json:"artist"`
+	} `json:"similar"`
+	Tags struct {
+		Tag []ArtistTag `json:"tag"`
+	} `json:"tags"`
+	Bio ArtistBio `json:"bio"`
+}
+
+type ArtistImage struct {
+	URL  string `json:"#text"`
+	Size string `json:"size"`
+}
+
+type ArtistTag struct {
+	Name string `json:"name"`
+	URL  string `json:"url"`
+}
+
+type ArtistBio struct {
+	Published string `json:"published"`
+	Summary   string `json:"summary"`
+	Content   string `json:"content"`
+}
+
+type Error struct {
+	Code    int    `json:"error"`
+	Message string `json:"message"`
+}

core/lastfm/responses_test.go

@@ -0,0 +1,42 @@
+package lastfm
+
+import (
+	"encoding/json"
+	"io/ioutil"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("LastFM responses", func() {
+	Describe("Artist", func() {
+		It("parses the response correctly", func() {
+			var resp Response
+			body, _ := ioutil.ReadFile("tests/fixtures/lastfm.artist.getinfo.json")
+			err := json.Unmarshal(body, &resp)
+			Expect(err).To(BeNil())
+
+			Expect(resp.Artist.Name).To(Equal("U2"))
+			Expect(resp.Artist.MBID).To(Equal("a3cb23fc-acd3-4ce0-8f36-1e5aa6a18432"))
+			Expect(resp.Artist.URL).To(Equal("https://www.last.fm/music/U2"))
+			Expect(resp.Artist.Bio.Summary).To(ContainSubstring("U2 é uma das mais importantes bandas de rock de todos os tempos"))
+
+			similarArtists := []string{"Passengers", "INXS", "R.E.M.", "Simple Minds", "Bono"}
+			for i, similar := range similarArtists {
+				Expect(resp.Artist.Similar.Artists[i].Name).To(Equal(similar))
+			}
+		})
+	})
+
+	Describe("Error", func() {
+		It("parses the error response correctly", func() {
+			var error Error
+			body := []byte(`{"error":3,"message":"Invalid Method - No method with that name in this package"}`)
+			err := json.Unmarshal(body, &error)
+			Expect(err).To(BeNil())
+
+			Expect(error.Code).To(Equal(3))
+			Expect(error.Message).To(Equal("Invalid Method - No method with that name in this package"))
+		})
+	})
+})