Obsolete:Media server/FileBackend

Needed operations are in the following table. In addition, we need three spaces: one which is publicly accessible, and another which is private (for deleted files), and a third which is private and temporary.

Operation	Existing function name
File existence	fileExists
File MD5 (for storeBatch)	no
Write from filesystem	store
Write from virtual URL	publish
Read into filesystem	getPath() (doesn't exactly have the right semantics)
Open stream	no
Get a file's properties	getFileProps (fallback is to read the file into the filesystem and fetch them that way)
List files	getThumbnailList (sorta)
Delete files	deleteBatch
Rename files	LocalFileMoveBatch (although copy && delete is a substitute)
Append to a file	append -- may be tricky with some object stores
Finish appending to the file	appendFinish

Appends

Chunked uploads, and perhaps some other things, require appending to an existing object.

We may need to devise workarounds (such as migrating from one obj to another in a temp space) for those.

• Swift: we know this is possible.
• Azure: we know it's possible from .net; Ben(MS) is checking if can be done from general code
• S3: ???

We (Tim, Bob, and Russ) decided that "Append", which is currently only used by ChunkedUploads, needs to be recast as "concatenate". So whatever kind of chunking happens, it stores a bunch of chunks in the store (probably to the temp zone), and then hands them to concatenate(), which puts them all in the order given into the file given.

FileRepo operations

• publish
  • Move dest -> archive
  • Copy source -> dest
  • Optionally delete source
• store
  • If dest exists, check overwrite mode
  • Copy source -> dest
  • Optionally delete source
• storeTemp
  • Generate name
  • Fail if dest exists
  • Copy source -> dest
• append/concatenate
• freeTemp
  • Delete a file if it exists
• fileExists
• delete
  • Either:
    • Move file to deletion archive, overwrite same
    • Delete file
• getFileProps
• enumFiles
• cleanupDeletedBatch
  • Delete file

FileBackend basic operations

src is mwrepo:// or a file:/// url dest is mwrepo://

• copy -- fails if the destination exists.
  • ignoreMissingSource
  • overwriteDest
  • overwriteSame - does not actually overwrite, just checks and passes if they are same
  • source
  • dest
• delete -- delete src (ignores zone and destination)
  • source
• move
  • ignoreMissingSource
  • overwriteDest
  • overwriteSame - does not actually overwrite, just checks and passes if they are same
  • source
  • dest
• concatenate
  • source array
  • dest
  • overwriteDest
• fileExists
  • source
• getFileProps
  • source
• enumFiles
• getLocalCopy
  • source
• streamFile
  • source

Copy can accept either a mwrepo:// or a relative local pathname Delete can accept either a mwrepo:// or a relative local pathname