Some Improvements

discogs.go

@@ -11,10 +11,18 @@ const (
 	discogsAPI = "https://api.discogs.com/"
 )
 
+type Options struct {
+	Currency  string
+	UserAgent string
+}
+
 // Client is a Discogs client for making Discogs API requests.
 type Client struct {
 	api      *apirequest.API
 	currency string
+
+	// services
+	Release *ReleaseService
 	Master  *MasterService
 	Artist  *ArtistService
 	Label   *LabelService
@@ -22,17 +30,26 @@ type Client struct {
 }
 
 // NewClient returns a new Client.
-func NewClient() *Client {
+func NewClient(o *Options) (*Client, error) {
 	base := apirequest.New().Client(&http.Client{}).Base(discogsAPI)
+	if o.UserAgent != "" {
+		base.Set("User-Agent", o.UserAgent)
+	}
+
+	cur, err := currency(o.Currency)
+	if err != nil {
+		return nil, err
+	}
+
 	return &Client{
 		api: base,
-		currency: "USD",
 
+		Release: newReleaseService(base.New(), cur),
 		Artist:  newArtistService(base.New()),
 		Label:   newLabelService(base.New()),
 		Master:  newMasterService(base.New()),
 		Search:  newSearchService(base.New()),
-	}
+	}, nil
 }
 
 // Token sets tokens, it's required for some queries like search
@@ -41,23 +58,15 @@ func (c *Client) Token(token string) *Client {
 	return c
 }
 
-// UserAgent sets specified user agent
-// Discogs requires it
-func (c *Client) UserAgent(useragent string) *Client {
-	c.api.Set("User-Agent", useragent)
-	return c
-}
-
-// SetCurrency determines currency for marketplace data.
+// currency validates currency for marketplace data.
 // Defaults to the authenticated users currency. Must be one of the following:
 // USD GBP EUR CAD AUD JPY CHF MXN BRL NZD SEK ZAR
-func (c *Client) Currency(currency string) error {
-	switch currency {
+func currency(c string) (string, error) {
+	switch c {
 	case "USD", "GBP", "EUR", "CAD", "AUD", "JPY", "CHF", "MXN", "BRL", "NZD", "SEK", "ZAR":
-		c.currency = currency
+		return c, nil
 	default:
-		return fmt.Errorf("%v\n", "Invalid currency abbreviation.")
+		return "", fmt.Errorf("%v\n", "Invalid currency abbreviation.")
 	}
-
-	return nil
+	return "USD", nil
 }

examples/discogs_example.go

@@ -7,13 +7,16 @@ import (
 )
 
 func main() {
-	d := discogs.NewClient().UserAgent("TestDiscogsClient/0.0.1 +http://example.com")
-	if err := d.Currency("EUR"); err != nil {
+	d, err := discogs.NewClient(&discogs.Options{
+		UserAgent: "TestDiscogsClient/0.0.1 +http://example.com",
+		Currency:  "EUR",
+	})
+	if err != nil {
 		fmt.Println(err)
 		return
 	}
 
-	release, err := d.Release(9893847)
+	release, err := d.Release.Release(9893847)
 	if err != nil {
 		fmt.Println(err)
 		return

releases.go

@@ -2,6 +2,8 @@ package discogs
 
 import (
 	"strconv"
+
+	apirequest "github.com/irlndts/go-apirequest"
 )
 
 // Release serves relesase response from discogs
@@ -45,12 +47,25 @@ type ReqRelease struct {
 	CurrAbbr string
 }
 
+// ReleaseService ...
+type ReleaseService struct {
+	api      *apirequest.API
+	currency string
+}
+
+func newReleaseService(api *apirequest.API, currency string) *ReleaseService {
+	return &ReleaseService{
+		api:      api.Path("releases/"),
+		currency: currency,
+	}
+}
+
 // Release returns release by release's ID
-func (c *Client) Release(releaseID int) (*Release, error) {
+func (s *ReleaseService) Release(releaseID int) (*Release, error) {
 	release := new(Release)
 	apiError := new(APIError)
 
-	req := &ReqRelease{CurrAbbr: c.currency}
-	_, err := c.api.New().Get("releases/"+strconv.Itoa(releaseID)).QueryStruct(req).Receive(release, apiError)
+	req := &ReqRelease{CurrAbbr: s.currency}
+	_, err := s.api.New().Get(strconv.Itoa(releaseID)).QueryStruct(req).Receive(release, apiError)
 	return release, relevantError(err, *apiError)
 }