Add marketplace APIs (#43)

* Add marketplace APIs

README.md

@@ -22,6 +22,9 @@ The lib is under MIT but be sure you are familiar with [Discogs API Terms of Use
     * Folder
     * Collection Items by Folder
     * Collection Items by Release
+ * [Marketplace](#marketplace)
+    * Price Suggestions
+    * Release Statistics
  
 Install
 --------
@@ -84,7 +87,6 @@ type SearchRequest struct {
 }
 ```
 
-Example
 ```go
   request := discogs.SearchRequest{Artist: "reggaenauts", ReleaseTitle: "river rock", Page: 0, PerPage: 1}
   search, _ := client.Search(request)
@@ -99,22 +101,38 @@ Example
 Query a users [collection](https://www.discogs.com/developers#page:user-collection).
 
 ##### Collection Folders
-Example
 ```go
   collection, err := client.CollectionFolders("my_user")
 ```
 ##### Folder
-Example
 ```go
   folder, err := client.Folder("my_user", 0)
 ```
 ##### Collection Items by Folder
-Example
 ```go
   items, err := client.CollectionItemsByFolder("my_user", 0, &Pagination{Sort: "artist", SortOrder: "desc", PerPage: 2})
 ```
 ##### Collection Items by Release
-Example
 ```go
   items, err := client.CollectionItemsByRelease("my_user", 12934893)
 ```
+
+#### Marketplace
+
+Query a user's [marketplace](https://www.discogs.com/developers/#page:marketplace)
+
+##### Price Suggestions
+
+Retrieve price suggestions for the provided Release ID
+
+```go
+  suggestions, err := client.PriceSuggestions(12345)
+```
+
+##### Release Statistics
+
+Retrieve marketplace statistics for the provided Release ID
+
+```go
+  stats, err := client.ReleaseStatisctics(12345)
+```

discogs.go

@@ -28,6 +28,7 @@ type Options struct {
 type Discogs interface {
 	CollectionService
 	DatabaseService
+	MarketPlaceService
 	SearchService
 }
 
@@ -35,6 +36,7 @@ type discogs struct {
 	CollectionService
 	DatabaseService
 	SearchService
+	MarketPlaceService
 }
 
 var header *http.Header
@@ -67,6 +69,7 @@ func New(o *Options) (Discogs, error) {
 		newCollectionService(o.URL + "/users"),
 		newDatabaseService(o.URL, cur),
 		newSearchService(o.URL + "/database/search"),
+		newMarketPlaceService(o.URL+"/marketplace", cur),
 	}, nil
 }
 

marketplace.go

@@ -0,0 +1,72 @@
+package discogs
+
+import (
+	"net/url"
+	"strconv"
+)
+
+const (
+	priceSuggestionsURI = "/price_suggestions/"
+	releaseStatsURI     = "/stats/"
+)
+
+type marketPlaceService struct {
+	url      string
+	currency string
+}
+
+type MarketPlaceService interface {
+	// The best price suggestions according to grading
+	// Authentication is required.
+	PriceSuggestions(releaseID int) (*PriceListing, error)
+	// Short summary of marketplace listings
+	// Authentication is optional.
+	ReleaseStatistics(releaseID int) (*Stats, error)
+}
+
+func newMarketPlaceService(url string, currency string) MarketPlaceService {
+	return &marketPlaceService{
+		url:      url,
+		currency: currency,
+	}
+}
+
+// Listing is a marketplace listing with the user's currency and a price value
+type Listing struct {
+	Currency string  `json:"currency"`
+	Value    float64 `json:"value"`
+}
+
+// PriceListings are Listings per grading quality
+type PriceListing struct {
+	VeryGood     *Listing `json:"Very Good (VG),omitempty"`
+	GoodPlus     *Listing `json:"Good Plus (G+),omitempty"`
+	NearMint     *Listing `json:"Near Mint (NM or M-)"`
+	Good         *Listing `json:"Good (G),omitempty"`
+	VeryGoodPlus *Listing `json:"Very Good Plus (VG+),omitempty"`
+	Mint         *Listing `json:"Mint (M),omitempty"`
+	Fair         *Listing `json:"Fair (F),omitempty"`
+	Poor         *Listing `json:"Poor (P),omitempty"`
+}
+
+// Stats returns the marketplace stats summary for a release containing
+type Stats struct {
+	LowestPrice *Listing `json:"lowest_price"`
+	ForSale     int      `json:"num_for_sale"`
+	Blocked     bool     `json:"blocked_from_sale"`
+}
+
+func (s *marketPlaceService) ReleaseStatistics(releaseID int) (*Stats, error) {
+	params := url.Values{}
+	params.Set("curr_abbr", s.currency)
+
+	var stats *Stats
+	err := request(s.url+releaseStatsURI+strconv.Itoa(releaseID), params, &stats)
+	return stats, err
+}
+
+func (s *marketPlaceService) PriceSuggestions(releaseID int) (*PriceListing, error) {
+	var listings *PriceListing
+	err := request(s.url+priceSuggestionsURI+strconv.Itoa(releaseID), nil, &listings)
+	return listings, err
+}

marketplace_test.go

@@ -0,0 +1,76 @@
+package discogs
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+	"testing"
+)
+
+const testReleaseID = 9893847
+
+func MarketplaceServer(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "GET" {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		return
+	}
+
+	switch r.URL.Path {
+	case "/marketplace" + priceSuggestionsURI + strconv.Itoa(testReleaseID):
+		w.WriteHeader(http.StatusOK)
+		if _, err := io.WriteString(w, priceSuggestionJson); err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+	case "/marketplace" + releaseStatsURI + strconv.Itoa(testReleaseID):
+		w.WriteHeader(http.StatusOK)
+		if _, err := io.WriteString(w, releaseStatsJson); err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+	default:
+		w.WriteHeader(http.StatusMethodNotAllowed)
+	}
+}
+
+func TestMarketplacePriceSuggestions(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(MarketplaceServer))
+	defer ts.Close()
+
+	d := initDiscogsClient(t, &Options{URL: ts.URL})
+
+	suggestion, err := d.PriceSuggestions(testReleaseID)
+	if err != nil {
+		t.Fatalf("failed to get price suggestion: %s", err)
+	}
+
+	json, err := json.Marshal(suggestion)
+	if err != nil {
+		t.Fatalf("failed to marshal folder: %s", err)
+	}
+
+	compareJson(t, string(json), priceSuggestionJson)
+}
+
+func TestMarketplaceReleaseStatistics(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(MarketplaceServer))
+	defer ts.Close()
+
+	d := initDiscogsClient(t, &Options{URL: ts.URL})
+
+	stats, err := d.ReleaseStatistics(testReleaseID)
+	if err != nil {
+		t.Fatalf("failed to get price suggestion: %s", err)
+	}
+
+	json, err := json.Marshal(stats)
+	if err != nil {
+		t.Fatalf("failed to marshal folder: %s", err)
+	}
+
+	compareJson(t, string(json), releaseStatsJson)
+}

testing_data.go

@@ -15,3 +15,7 @@ const collectionJson = `{"folders": [{"id": 0, "name": "All", "count": 95, "reso
 const collectionItemsByFolderJson = `{"pagination": {"page": 1, "pages": 48, "per_page": 2, "items": 95, "urls": {"last": "https://api.discogs.com/users/test_user/collection/folders/0/releases?sort=artist&sort_order=desc&per_page=2&page=48", "next": "https://api.discogs.com/users/test_user/collection/folders/0/releases?sort=artist&sort_order=desc&per_page=2&page=2"}}, "releases": [{"id": 12934893, "instance_id": 431009995, "date_added": "2020-01-19T14:19:11-08:00", "rating": 0, "basic_information": {"id": 12934893, "master_id": 0, "master_url": null, "resource_url": "https://api.discogs.com/releases/12934893", "thumb": "", "cover_image": "", "title": "Zonk", "year": 2018, "formats": [{"name": "Vinyl", "qty": "1", "text": "Purple", "descriptions": ["LP", "Album"]}], "labels": [{"name": "Permanent Record", "catno": "PR014", "entity_type": "1", "entity_type_name": "Label", "id": 833694, "resource_url": "https://api.discogs.com/labels/833694"}], "artists": [{"name": "Zoo Lake", "anv": "", "join": "", "role": "", "tracks": "", "id": 6868154, "resource_url": "https://api.discogs.com/artists/6868154"}], "genres": ["Rock"], "styles": ["Post-Punk", "Shoegaze", "Psychedelic Rock", "Noise", "Garage Rock", "Lo-Fi"]}}, {"id": 4825435, "instance_id": 146424864, "date_added": "2015-11-08T14:42:02-08:00", "rating": 0, "basic_information": {"id": 4825435, "master_id": 17200, "master_url": "https://api.discogs.com/masters/17200", "resource_url": "https://api.discogs.com/releases/4825435", "thumb": "", "cover_image": "", "title": "You And Me Both", "year": 1983, "formats": [{"name": "Vinyl", "qty": "1", "descriptions": ["LP", "Album"]}], "labels": [{"name": "Mute", "catno": "STUMM 12", "entity_type": "1", "entity_type_name": "Label", "id": 26391, "resource_url": "https://api.discogs.com/labels/26391"}, {"name": "CBS", "catno": "DNW 2885", "entity_type": "1", "entity_type_name": "Label", "id": 3072, "resource_url": "https://api.discogs.com/labels/3072"}], "artists": [{"name": "Yazoo", "anv": "", "join": "", "role": "", "tracks": "", "id": 2713, "resource_url": "https://api.discogs.com/artists/2713"}], "genres": ["Electronic"], "styles": ["Synth-pop"]}}]}`
 
 const collectionItemsByRelease = `{"pagination": {"page": 1, "pages": 1, "per_page": 50, "items": 1, "urls": {}}, "releases": [{"id": 12934893, "instance_id": 431009995, "date_added": "2020-01-19T14:19:11-08:00", "rating": 0, "basic_information": {"id": 12934893, "master_id": 0, "master_url": null, "resource_url": "https://api.discogs.com/releases/12934893", "thumb": "", "cover_image": "", "title": "Zonk", "year": 2018, "formats": [{"name": "Vinyl", "qty": "1", "text": "Purple", "descriptions": ["LP", "Album"]}], "labels": [{"name": "Permanent Record", "catno": "PR014", "entity_type": "1", "entity_type_name": "Label", "id": 833694, "resource_url": "https://api.discogs.com/labels/833694"}], "artists": [{"name": "Zoo Lake", "anv": "", "join": "", "role": "", "tracks": "", "id": 6868154, "resource_url": "https://api.discogs.com/artists/6868154"}], "genres": ["Rock"], "styles": ["Post-Punk", "Shoegaze", "Psychedelic Rock", "Noise", "Garage Rock", "Lo-Fi"]}}]}`
+
+const priceSuggestionJson = `{"Mint (M)": {"currency": "EUR", "value": 16.625}, "Near Mint (NM or M-)": {"currency": "EUR", "value": 14.875000000000002}, "Very Good Plus (VG+)": {"currency": "EUR", "value": 11.375000000000002}, "Very Good (VG)": {"currency": "EUR", "value": 7.875000000000001}, "Good Plus (G+)": {"currency": "EUR", "value": 4.375}, "Good (G)": {"currency": "EUR", "value": 2.625}, "Fair (F)": {"currency": "EUR", "value": 1.7500000000000002}, "Poor (P)": {"currency": "EUR", "value": 0.8750000000000001}}`
+
+const releaseStatsJson = `{"num_for_sale": 4, "lowest_price": {"value": 18.07, "currency": "USD"}, "blocked_from_sale": false}`