Implement GET channels endpoints for APIv4 (#5363)

* implement get channels endpoints and updated drivers and unittests

* removed channel deletion on tear down, removed manage permission on get channels endpoints, and updated utils to add constant channel length

* added constants for user, team and channel length, updated context to use the model functions

* make sure team name length should be less than the minimum length and revert underscore to team name validity

* changed post test condition from notfound to unauthorized

8 files changed, 213 insertions, 33 deletions

diff --git a/api4/api.go b/api4/api.go
index 6348714b2..b05c1a7db 100644
--- a/api4/api.go
+++ b/api4/api.go
@@ -32,13 +32,14 @@ type Routes struct {
 	TeamMembers  *mux.Router // 'api/v4/teams/{team_id:[A-Za-z0-9_-]+}/members'
 	TeamMember   *mux.Router // 'api/v4/teams/{team_id:[A-Za-z0-9_-]+}/members/{user_id:[A-Za-z0-9_-]+}'
 
-	Channels              *mux.Router // 'api/v4/channels'
-	Channel               *mux.Router // 'api/v4/channels/{channel_id:[A-Za-z0-9]+}'
-	ChannelByName         *mux.Router // 'api/v4/teams/{team_id:[A-Za-z0-9]+}/channels/name/{channel_name:[A-Za-z0-9_-]+}'
-	ChannelsForTeam       *mux.Router // 'api/v4/teams/{team_id:[A-Za-z0-9]+}/channels'
-	ChannelMembers        *mux.Router // 'api/v4/channels/{channel_id:[A-Za-z0-9]+}/members'
-	ChannelMember         *mux.Router // 'api/v4/channels/{channel_id:[A-Za-z0-9]+}/members/{user_id:[A-Za-z0-9]+}'
-	ChannelMembersForUser *mux.Router // 'api/v4/users/{user_id:[A-Za-z0-9]+}/teams/{team_id:[A-Za-z0-9]+}/channels/members'
+	Channels                 *mux.Router // 'api/v4/channels'
+	Channel                  *mux.Router // 'api/v4/channels/{channel_id:[A-Za-z0-9]+}'
+	ChannelByName            *mux.Router // 'api/v4/teams/{team_id:[A-Za-z0-9]+}/channels/name/{channel_name:[A-Za-z0-9_-]+}'
+	ChannelByNameForTeamName *mux.Router // 'api/v4/teams/name/{team_name:[A-Za-z0-9_-]+}/channels/name/{channel_name:[A-Za-z0-9_-]+}'
+	ChannelsForTeam          *mux.Router // 'api/v4/teams/{team_id:[A-Za-z0-9]+}/channels'
+	ChannelMembers           *mux.Router // 'api/v4/channels/{channel_id:[A-Za-z0-9]+}/members'
+	ChannelMember            *mux.Router // 'api/v4/channels/{channel_id:[A-Za-z0-9]+}/members/{user_id:[A-Za-z0-9]+}'
+	ChannelMembersForUser    *mux.Router // 'api/v4/users/{user_id:[A-Za-z0-9]+}/teams/{team_id:[A-Za-z0-9]+}/channels/members'
 
 	Posts           *mux.Router // 'api/v4/posts'
 	Post            *mux.Router // 'api/v4/posts/{post_id:[A-Za-z0-9]+}'
@@ -102,7 +103,8 @@ func InitApi(full bool) {
 
 	BaseRoutes.Channels = BaseRoutes.ApiRoot.PathPrefix("/channels").Subrouter()
 	BaseRoutes.Channel = BaseRoutes.Channels.PathPrefix("/{channel_id:[A-Za-z0-9]+}").Subrouter()
-	BaseRoutes.ChannelByName = BaseRoutes.Team.PathPrefix("/name/{channel_name:[A-Za-z0-9_-]+}").Subrouter()
+	BaseRoutes.ChannelByName = BaseRoutes.Team.PathPrefix("/channels/name/{channel_name:[A-Za-z0-9_-]+}").Subrouter()
+	BaseRoutes.ChannelByNameForTeamName = BaseRoutes.TeamByName.PathPrefix("/channels/name/{channel_name:[A-Za-z0-9_-]+}").Subrouter()
 	BaseRoutes.ChannelsForTeam = BaseRoutes.Team.PathPrefix("/channels").Subrouter()
 	BaseRoutes.ChannelMembers = BaseRoutes.Channel.PathPrefix("/members").Subrouter()
 	BaseRoutes.ChannelMember = BaseRoutes.ChannelMembers.PathPrefix("/{user_id:[A-Za-z0-9]+}").Subrouter()
diff --git a/api4/apitestlib.go b/api4/apitestlib.go
index 0761a8b15..08ca338c5 100644
--- a/api4/apitestlib.go
+++ b/api4/apitestlib.go
@@ -278,11 +278,11 @@ func GenerateTestUsername() string {
 }
 
 func GenerateTestTeamName() string {
-	return "faketeam" + model.NewId()
+	return "faketeam" + model.NewRandomString(6)
 }
 
 func GenerateTestChannelName() string {
-	return "fakechannel" + model.NewId()
+	return "fakechannel" + model.NewRandomString(10)
 }
 
 func VerifyUserEmail(userId string) {
diff --git a/api4/channel.go b/api4/channel.go
index 09ed4b571..938511c14 100644
--- a/api4/channel.go
+++ b/api4/channel.go
@@ -18,6 +18,10 @@ func InitChannel() {
 	BaseRoutes.Channels.Handle("", ApiSessionRequired(createChannel)).Methods("POST")
 	BaseRoutes.Channels.Handle("/direct", ApiSessionRequired(createDirectChannel)).Methods("POST")
 
+	BaseRoutes.Channel.Handle("", ApiSessionRequired(getChannel)).Methods("GET")
+	BaseRoutes.ChannelByName.Handle("", ApiSessionRequired(getChannelByName)).Methods("GET")
+	BaseRoutes.ChannelByNameForTeamName.Handle("", ApiSessionRequired(getChannelByNameForTeamName)).Methods("GET")
+
 	BaseRoutes.ChannelMembers.Handle("", ApiSessionRequired(getChannelMembers)).Methods("GET")
 	BaseRoutes.ChannelMembersForUser.Handle("", ApiSessionRequired(getChannelMembersForUser)).Methods("GET")
 	BaseRoutes.ChannelMember.Handle("", ApiSessionRequired(getChannelMember)).Methods("GET")
@@ -88,6 +92,72 @@ func createDirectChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func getChannel(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireChannelId()
+	if c.Err != nil {
+		return
+	}
+
+	if !app.SessionHasPermissionToChannel(c.Session, c.Params.ChannelId, model.PERMISSION_READ_CHANNEL) {
+		c.SetPermissionError(model.PERMISSION_READ_CHANNEL)
+		return
+	} 
+
+	if channel, err := app.GetChannel(c.Params.ChannelId); err != nil {
+		c.Err = err
+		return
+	} else {
+		w.Write([]byte(channel.ToJson()))
+		return
+	}
+}
+
+func getChannelByName(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireTeamId().RequireChannelName()
+	if c.Err != nil {
+		return
+	}
+
+	var channel *model.Channel
+	var err *model.AppError
+
+	if channel, err = app.GetChannelByName(c.Params.ChannelName, c.Params.TeamId); err != nil {
+		c.Err = err
+		return
+	} 
+
+	if !app.SessionHasPermissionToChannel(c.Session, channel.Id, model.PERMISSION_READ_CHANNEL) {
+		c.SetPermissionError(model.PERMISSION_READ_CHANNEL)
+		return
+	}
+	
+	w.Write([]byte(channel.ToJson()))
+	return
+}
+
+func getChannelByNameForTeamName(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireTeamName().RequireChannelName()
+	if c.Err != nil {
+		return
+	}
+
+	var channel *model.Channel
+	var err *model.AppError
+
+	if channel, err = app.GetChannelByNameForTeamName(c.Params.ChannelName, c.Params.TeamName); err != nil {
+		c.Err = err
+		return
+	}
+
+	if !app.SessionHasPermissionToChannel(c.Session, channel.Id, model.PERMISSION_READ_CHANNEL) {
+		c.SetPermissionError(model.PERMISSION_READ_CHANNEL)
+		return
+	} 
+
+	w.Write([]byte(channel.ToJson()))
+	return
+}
+
 func getChannelMembers(c *Context, w http.ResponseWriter, r *http.Request) {
 	c.RequireChannelId()
 	if c.Err != nil {
diff --git a/api4/channel_test.go b/api4/channel_test.go
index 91d055bff..7e59f60e8 100644
--- a/api4/channel_test.go
+++ b/api4/channel_test.go
@@ -221,6 +221,84 @@ func TestCreateDirectChannel(t *testing.T) {
 	CheckNoError(t, resp)
 }
 
+func TestGetChannel(t *testing.T) {
+	th := Setup().InitBasic().InitSystemAdmin()
+	defer TearDown()
+	Client := th.Client
+
+	_, resp := Client.GetChannel(th.BasicChannel.Id, "")
+	CheckNoError(t, resp)
+
+	_, resp = Client.GetChannel(model.NewId(), "")
+	CheckForbiddenStatus(t, resp)
+
+	Client.Logout()
+	_, resp = Client.GetChannel(th.BasicChannel.Id, "")
+	CheckUnauthorizedStatus(t, resp)
+
+	user := th.CreateUser()
+	Client.Login(user.Email, user.Password)
+	_, resp = Client.GetChannel(th.BasicChannel.Id, "")
+	CheckForbiddenStatus(t, resp)
+
+	_, resp = th.SystemAdminClient.GetChannel(th.BasicChannel.Id, "")
+	CheckNoError(t, resp)
+
+	_, resp = th.SystemAdminClient.GetChannel(th.BasicUser.Id, "")
+	CheckNotFoundStatus(t, resp)
+}
+
+func TestGetChannelByName(t *testing.T) {
+	th := Setup().InitBasic().InitSystemAdmin()
+	defer TearDown()
+	Client := th.Client
+
+	_, resp := Client.GetChannelByName(th.BasicChannel.Name, th.BasicTeam.Id, "")
+	CheckNoError(t, resp)
+
+	_, resp = Client.GetChannelByName(GenerateTestChannelName(), th.BasicTeam.Id, "")
+	CheckNotFoundStatus(t, resp)
+
+	Client.Logout()
+	_, resp = Client.GetChannelByName(th.BasicChannel.Name, th.BasicTeam.Id, "")
+	CheckUnauthorizedStatus(t, resp)
+
+	user := th.CreateUser()
+	Client.Login(user.Email, user.Password)
+	_, resp = Client.GetChannelByName(th.BasicChannel.Name, th.BasicTeam.Id, "")
+	CheckForbiddenStatus(t, resp)
+
+	_, resp = th.SystemAdminClient.GetChannelByName(th.BasicChannel.Name, th.BasicTeam.Id, "")
+	CheckNoError(t, resp)
+}
+
+func TestGetChannelByNameForTeamName(t *testing.T) {
+	th := Setup().InitBasic().InitSystemAdmin()
+	defer TearDown()
+	Client := th.Client
+
+	_, resp := th.SystemAdminClient.GetChannelByNameForTeamName(th.BasicChannel.Name, th.BasicTeam.Name, "")
+	CheckNoError(t, resp)
+
+	_, resp = Client.GetChannelByNameForTeamName(th.BasicChannel.Name, th.BasicTeam.Name, "")
+	CheckNoError(t, resp)
+
+	_, resp = Client.GetChannelByNameForTeamName(th.BasicChannel.Name, model.NewRandomString(15), "")
+	CheckNotFoundStatus(t, resp)
+
+	_, resp = Client.GetChannelByNameForTeamName(GenerateTestChannelName(), th.BasicTeam.Name, "")
+	CheckNotFoundStatus(t, resp)
+
+	Client.Logout()
+	_, resp = Client.GetChannelByNameForTeamName(th.BasicChannel.Name, th.BasicTeam.Name, "")
+	CheckUnauthorizedStatus(t, resp)
+
+	user := th.CreateUser()
+	Client.Login(user.Email, user.Password)
+	_, resp = Client.GetChannelByNameForTeamName(th.BasicChannel.Name, th.BasicTeam.Name, "")
+	CheckForbiddenStatus(t, resp)
+}
+
 func TestGetChannelMembers(t *testing.T) {
 	th := Setup().InitBasic().InitSystemAdmin()
 	defer TearDown()
@@ -255,7 +333,7 @@ func TestGetChannelMembers(t *testing.T) {
 	}
 
 	_, resp = Client.GetChannelMembers("", 0, 60, "")
-	CheckNotFoundStatus(t, resp)
+	CheckUnauthorizedStatus(t, resp)
 
 	_, resp = Client.GetChannelMembers("junk", 0, 60, "")
 	CheckBadRequestStatus(t, resp)
diff --git a/api4/context.go b/api4/context.go
index 06523152f..6a844795f 100644
--- a/api4/context.go
+++ b/api4/context.go
@@ -364,12 +364,8 @@ func (c *Context) RequireUsername() *Context {
 		return c
 	}
 
-	if len(c.Params.Username) < 3 {
-		c.SetInvalidUrlParam("username")
-	} 
-
-	if len(c.Params.Username) > 22 {
-		c.SetInvalidUrlParam("username")
+	if !model.IsValidUsername(c.Params.Username) {
+		c.SetInvalidParam("username")
 	}
 
 	return c
@@ -386,16 +382,40 @@ func (c *Context) RequirePostId() *Context {
 	return c
 }
 
+func (c *Context) RequireTeamName() *Context {
+	if c.Err != nil {
+		return c
+	}
+
+	if !model.IsValidTeamName(c.Params.TeamName){
+		c.SetInvalidUrlParam("team_name")
+	}
+
+	return c
+}
+
+func (c *Context) RequireChannelName() *Context {
+	if c.Err != nil {
+		return c
+	}
+
+	if !model.IsValidChannelIdentifier(c.Params.ChannelName) {
+		c.SetInvalidUrlParam("channel_name")
+	} 
+
+	return c
+}
+
 func (c *Context) RequireEmail() *Context {
 	if c.Err != nil {
 		return c
 	}
 
-	pos := strings.Index(c.Params.Email, "@")
-	if pos < 0 {
+	if !model.IsValidEmail(c.Params.Email) {
 		c.SetInvalidUrlParam("email")
 	}
 
 	return c
 }
 
+
diff --git a/api4/params.go b/api4/params.go
index 4de1da401..9b371e71a 100644
--- a/api4/params.go
+++ b/api4/params.go
@@ -17,18 +17,20 @@ const (
 )
 
 type ApiParams struct {
-	UserId    string
-	TeamId    string
-	ChannelId string
-	PostId    string
-	FileId    string
-	CommandId string
-	HookId    string
-	EmojiId   string
-	Email     string
-	Username  string
-	Page      int
-	PerPage   int
+	UserId      string
+	TeamId      string
+	ChannelId   string
+	PostId      string
+	FileId      string
+	CommandId   string
+	HookId      string
+	EmojiId     string
+	Email       string
+	Username    string
+	TeamName    string
+	ChannelName string
+	Page        int
+	PerPage     int
 }
 
 func ApiParamsFromRequest(r *http.Request) *ApiParams {
@@ -76,6 +78,14 @@ func ApiParamsFromRequest(r *http.Request) *ApiParams {
 		params.Username = val
 	}
 
+	if val, ok := props["team_name"]; ok {
+		params.TeamName = val
+	}
+
+	if val, ok := props["channel_name"]; ok {
+		params.ChannelName = val
+	}
+
 	if val, err := strconv.Atoi(r.URL.Query().Get("page")); err != nil {
 		params.Page = PAGE_DEFAULT
 	} else {
diff --git a/api4/post_test.go b/api4/post_test.go
index 32f259d3d..604920b96 100644
--- a/api4/post_test.go
+++ b/api4/post_test.go
@@ -159,7 +159,7 @@ func TestGetPostsForChannel(t *testing.T) {
 	}
 
 	_, resp = Client.GetPostsForChannel("", 0, 60, "")
-	CheckNotFoundStatus(t, resp)
+	CheckUnauthorizedStatus(t, resp)
 
 	_, resp = Client.GetPostsForChannel("junk", 0, 60, "")
 	CheckBadRequestStatus(t, resp)
diff --git a/api4/user_test.go b/api4/user_test.go
index 82c7f921d..79589bdad 100644
--- a/api4/user_test.go
+++ b/api4/user_test.go
@@ -154,7 +154,7 @@ func TestGetUserByUsername(t *testing.T) {
 	_, resp = Client.GetUserByUsername(GenerateTestUsername(), "")
 	CheckNotFoundStatus(t, resp)
 
-	_, resp = Client.GetUserByUsername(model.NewRandomString(25), "")
+	_, resp = Client.GetUserByUsername(model.NewRandomString(1), "")
 	CheckBadRequestStatus(t, resp)
 
 	// Check against privacy config settings