Functional overview

• Only files & embedded documents are downloaded. Other doc types are ignored.
• Only the last version of the document is downloaded (the document history is not part of the archive).
• On download action, if the amount of files to d/l (uncompressed) is bigger than a given threshold (50MB?) there is a warning + confirm
• As content is streamed and zipped on the fly, the end users cannot have a progress bar to inform them the time it will take.
• Download works on root folder too
• Site administrators (site admin / Document) can set a max size:
  • as as warning threshold to warn that people are about to d/l something large. Default is set to 50MB
  • as a blocker to avoid download of big archives. Default is set to 2GB
• Embedded are downloaded without templating (body & raw content).
• When some files can't be added to the archive for some reason (file corrupted, not
  found, not readable, memory overflow), a file named TULEAP_ERRORS.txt will be created at the root of the archive. This file will list all the impacted files and their paths. Errors will be properly logged in codendi_syslog to ease the debugging.

Technical overview

• Zip is generated on the fly and streamed from the backend (with PHP) to avoid creation of fat archives on the backend.
• The lib to be used will be ZipStream
• Zip will only be used as a container but content won't be actually compressed inside in order to be as light as possible on the server CPU
  • This will also allow to compute the size of the data to download (as it's the sum of the recorded filesize)
• There are some limitations to take into account
  • Archive meant to be used on OSX cannot be bigger than 4GB or 64k files (known issue). If either condition is detected before download, a warning is raised to users (if such a big archive is allowed).

Implementation warnings

• Action menu on folders is not unique. It depends on context (creation & co). This needs to be reviewed carefully.
• Fetch of total file size is made in a dedicated REST route (/!\ permissions)