3 files changed, 34 insertions, 0 deletions
diff --git a/model/channel.go b/model/channel.go
index caf1bfd80..ac54a7e44 100644
--- a/model/channel.go
+++ b/model/channel.go
@@ -25,6 +25,7 @@ type Channel struct {
 	DisplayName   string `json:"display_name"`
 	Name          string `json:"name"`
 	Header        string `json:"header"`
+	Purpose       string `json:"purpose"`
 	LastPostAt    int64  `json:"last_post_at"`
 	TotalMsgCount int64  `json:"total_msg_count"`
 	ExtraUpdateAt int64  `json:"extra_update_at"`
@@ -93,6 +94,10 @@ func (o *Channel) IsValid() *AppError {
 		return NewAppError("Channel.IsValid", "Invalid header", "id="+o.Id)
 	}
 
+	if len(o.Purpose) > 128 {
+		return NewAppError("Channel.IsValid", "Invalid purpose", "id="+o.Id)
+	}
+
 	if len(o.CreatorId) > 26 {
 		return NewAppError("Channel.IsValid", "Invalid creator id", "")
 	}
diff --git a/model/channel_test.go b/model/channel_test.go
index e5dfa3734..590417cfe 100644
--- a/model/channel_test.go
+++ b/model/channel_test.go
@@ -67,6 +67,26 @@ func TestChannelIsValid(t *testing.T) {
 	if err := o.IsValid(); err != nil {
 		t.Fatal(err)
 	}
+
+	o.Header = strings.Repeat("01234567890", 100)
+	if err := o.IsValid(); err == nil {
+		t.Fatal("should be invalid")
+	}
+
+	o.Header = "1234"
+	if err := o.IsValid(); err != nil {
+		t.Fatal(err)
+	}
+
+	o.Purpose = strings.Repeat("01234567890", 20)
+	if err := o.IsValid(); err == nil {
+		t.Fatal("should be invalid")
+	}
+
+	o.Purpose = "1234"
+	if err := o.IsValid(); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestChannelPreSave(t *testing.T) {
diff --git a/model/client.go b/model/client.go
index c788ead67..8ca5c3bfb 100644
--- a/model/client.go
+++ b/model/client.go
@@ -452,6 +452,15 @@ func (c *Client) UpdateChannelHeader(data map[string]string) (*Result, *AppError
 	}
 }
 
+func (c *Client) UpdateChannelPurpose(data map[string]string) (*Result, *AppError) {
+	if r, err := c.DoApiPost("/channels/update_purpose", MapToJson(data)); err != nil {
+		return nil, err
+	} else {
+		return &Result{r.Header.Get(HEADER_REQUEST_ID),
+			r.Header.Get(HEADER_ETAG_SERVER), ChannelFromJson(r.Body)}, nil
+	}
+}
+
 func (c *Client) UpdateNotifyProps(data map[string]string) (*Result, *AppError) {
 	if r, err := c.DoApiPost("/channels/update_notify_props", MapToJson(data)); err != nil {
 		return nil, err