Add support for the prune endpoint (#282)

* Add support for the prune endpoint

Adds functions to get the amount of members that could be pruned
and to prune members using the prune endpoint.
May close: bwmarrin/discordgo#147

* Deal with the go vet error

Removed the json tags from the unexported struct.
Should pass the tests now.

* Make the PR consistent with the rest of the file.

Removes url building in favour of string concatenation.

* Fix the previous commit

Adds back the result struct.
Converts the uint32 to string.

* Deal with golint comments

* Remove the failing test

Cleans up the uri concatenation.
Removes the failing test due to incorrect permissions.

ratelimit.go

@@ -7,7 +7,7 @@ import (
 	"time"
 )
 
-// Ratelimiter holds all ratelimit buckets
+// RateLimiter holds all ratelimit buckets
 type RateLimiter struct {
 	sync.Mutex
 	global          *Bucket
@@ -15,7 +15,7 @@ type RateLimiter struct {
 	globalRateLimit time.Duration
 }
 
-// New returns a new RateLimiter
+// NewRatelimiter returns a new RateLimiter
 func NewRatelimiter() *RateLimiter {
 
 	return &RateLimiter{

restapi.go

@@ -874,6 +874,71 @@ func (s *Session) GuildRoleDelete(guildID, roleID string) (err error) {
 	return
 }
 
+// GuildPruneCount Returns the number of members that would be removed in a prune operation.
+// Requires 'KICK_MEMBER' permission.
+// guildID	: The ID of a Guild.
+// days		: The number of days to count prune for (1 or more).
+func (s *Session) GuildPruneCount(guildID string, days uint32) (count uint32, err error) {
+	count = 0
+
+	if days <= 0 {
+		err = errors.New("The number of days should be more than or equal to 1.")
+		return
+	}
+
+	p := struct {
+		Pruned uint32 `json:"pruned"`
+	}{}
+
+	uri := EndpointGuildPrune(guildID) + fmt.Sprintf("?days=%d", days)
+	body, err := s.RequestWithBucketID("GET", uri, nil, EndpointGuildPrune(guildID))
+
+	err = unmarshal(body, &p)
+	if err != nil {
+		return
+	}
+
+	count = p.Pruned
+
+	return
+}
+
+// GuildPrune Begin as prune operation. Requires the 'KICK_MEMBERS' permission.
+// Returns an object with one 'pruned' key indicating the number of members that were removed in the prune operation.
+// guildID	: The ID of a Guild.
+// days		: The number of days to count prune for (1 or more).
+func (s *Session) GuildPrune(guildID string, days uint32) (count uint32, err error) {
+
+	count = 0
+
+	if days <= 0 {
+		err = errors.New("The number of days should be more than or equal to 1.")
+		return
+	}
+
+	data := struct {
+		days uint32
+	}{days}
+
+	p := struct {
+		Pruned uint32 `json:"pruned"`
+	}{}
+
+	body, err := s.RequestWithBucketID("POST", EndpointGuildPrune(guildID), data, EndpointGuildPrune(guildID))
+	if err != nil {
+		return
+	}
+
+	err = unmarshal(body, &p)
+	if err != nil {
+		return
+	}
+
+	count = p.Pruned
+
+	return
+}
+
 // GuildIntegrations returns an array of Integrations for a guild.
 // guildID   : The ID of a Guild.
 func (s *Session) GuildIntegrations(guildID string) (st []*GuildIntegration, err error) {

restapi_test.go

@@ -238,3 +238,39 @@ func TestChannelMessageSend2(t *testing.T) {
 		t.Errorf("ChannelMessageSend returned error: %+v", err)
 	}
 }
+
+// TestGuildPruneCount tests GuildPruneCount() function. This should not return an error.
+func TestGuildPruneCount(t *testing.T) {
+
+	if envGuild == "" {
+		t.Skip("Skipping, DG_GUILD not set.")
+	}
+
+	if dg == nil {
+		t.Skip("Skipping, dg not set.")
+	}
+
+	_, err := dg.GuildPruneCount(envGuild, 1)
+	if err != nil {
+		t.Errorf("GuildPruneCount returned error: %+v", err)
+	}
+}
+
+/*
+// TestGuildPrune tests GuildPrune() function. This should not return an error.
+func TestGuildPrune(t *testing.T) {
+
+	if envGuild == "" {
+		t.Skip("Skipping, DG_GUILD not set.")
+	}
+
+	if dg == nil {
+		t.Skip("Skipping, dg not set.")
+	}
+
+	_, err := dg.GuildPrune(envGuild, 1)
+	if err != nil {
+		t.Errorf("GuildPrune returned error: %+v", err)
+	}
+}
+*/