For use cases see: Bulk File/Table Download via Web Client
File sizes
One of the implied requirements from Ljubomir's design is the availability of the total size of all files in both view query results and folder navigation.
View Query Results
Since the user will only have the option to add all of the files from a give view result, and not just the currently shown page, the file size results will need to include the size of all files for a given query. This is similar to the query count already available to in table query results. The proposal is to add a new mask to the existing QueryBundleRequest.partMask call 'fileSizes' with a value of 0x20. When the 'fileSize' mask is include the resulting QueryResultBundle will include a numeric value called 'sizeOfAllFilesMB'.
Folder Navigation
Unlike View query results, users will have the option to add one file at a time from the folder navigation. This implies that we will need to show the size of each individual file in the folder navigation. We should be able to use the existing POST/fileHandle/batch to get the file handles for a single page of files shown in the folder navigation.
To support adding all of the files in a folder (non-recursive) (use case 1a) we will need to return the total number of files in a folder and the total size of all files in the folder from POST/entity/children. The proposal is to add a 'partMask' (similar to QueryBundleRequest) with 0x01=count and 0x02=totalFileSizeMB.