PLT-3105 Files table migration (#4068)

* Implemented initial changes for files table

* Removed *_benchmark_test.go files

* Re-implemented GetPublicFile and added support for old path

* Localization for files table

* Moved file system code into utils package

* Finished server-side changes and added initial upgrade script

* Added getPostFiles api

* Re-add Extension and HasPreviewImage fields to FileInfo

* Removed unused translation

* Fixed merge conflicts left over after permissions changes

* Forced FileInfo.extension to be lower case

* Changed FileUploadResponse to contain the FileInfos instead of FileIds

* Fixed permissions on getFile* calls

* Fixed notifications for file uploads

* Added initial version of client code for files changes

* Permanently added FileIds field to Post object and removed Post.HasFiles

* Updated PostStore.Update to be usable in more circumstances

* Re-added Filenames field and switched file migration to be entirely lazy-loaded

* Increased max listener count for FileStore

* Removed unused fileInfoCache

* Moved file system code back into api

* Removed duplicate test case

* Fixed unit test running on ports other than 8065

* Renamed HasPermissionToPostContext to HasPermissionToChannelByPostContext

* Refactored handleImages to make it more easily understandable

* Renamed getPostFiles to getFileInfosForPost

* Re-added pre-FileIds posts to analytics

* Changed files to be saved as their ids as opposed to id/filename.ext

* Renamed FileInfo.UserId to FileInfo.CreatorId

* Fixed detection of language in CodePreview

* Fixed switching between threads in the RHS not loading new files

* Add serverside protection against a rare bug where the client sends the same file twice for a single post

* Refactored the important parts of uploadFile api call into a function that can be called without a web context

store/sql_channel_store.go

@@ -596,6 +596,36 @@ func (s SqlChannelStore) GetMember(channelId string, userId string) StoreChannel
 	return storeChannel
 }
 
+func (s SqlChannelStore) GetMemberForPost(postId string, userId string) StoreChannel {
+	storeChannel := make(StoreChannel, 1)
+
+	go func() {
+		result := StoreResult{}
+
+		member := &model.ChannelMember{}
+		if err := s.GetReplica().SelectOne(
+			member,
+			`SELECT
+				ChannelMembers.*
+			FROM
+				ChannelMembers,
+				Posts
+			WHERE
+				ChannelMembers.ChannelId = Posts.ChannelId
+				AND ChannelMembers.UserId = :UserId
+				AND Posts.Id = :PostId`, map[string]interface{}{"UserId": userId, "PostId": postId}); err != nil {
+			result.Err = model.NewLocAppError("SqlChannelStore.GetMemberForPost", "store.sql_channel.get_member_for_post.app_error", nil, "postId="+postId+", err="+err.Error())
+		} else {
+			result.Data = member
+		}
+
+		storeChannel <- result
+		close(storeChannel)
+	}()
+
+	return storeChannel
+}
+
 func (s SqlChannelStore) GetMemberCount(channelId string) StoreChannel {
 	storeChannel := make(StoreChannel, 1)
 
@@ -878,6 +908,35 @@ func (s SqlChannelStore) GetAll(teamId string) StoreChannel {
 	return storeChannel
 }
 
+func (s SqlChannelStore) GetForPost(postId string) StoreChannel {
+	storeChannel := make(StoreChannel, 1)
+
+	go func() {
+		result := StoreResult{}
+
+		channel := &model.Channel{}
+		if err := s.GetReplica().SelectOne(
+			channel,
+			`SELECT
+				Channels.*
+			FROM
+				Channels,
+				Posts
+			WHERE
+				Channels.Id = Posts.ChannelId
+				AND Posts.Id = :PostId`, map[string]interface{}{"PostId": postId}); err != nil {
+			result.Err = model.NewLocAppError("SqlChannelStore.GetForPost", "store.sql_channel.get_for_post.app_error", nil, "postId="+postId+", err="+err.Error())
+		} else {
+			result.Data = channel
+		}
+
+		storeChannel <- result
+		close(storeChannel)
+	}()
+
+	return storeChannel
+}
+
 func (s SqlChannelStore) AnalyticsTypeCount(teamId string, channelType string) StoreChannel {
 	storeChannel := make(StoreChannel, 1)