Safe Haskell	None
Language	Haskell2010

Tahoe.Download

Description

A high-level interface to downloading share data as bytes from storage servers.

Synopsis

type LookupServer m = StorageServerAnnouncement -> m (Either LookupError StorageServer)
data DownloadError
- = NoConfiguredServers
- | NoReachableServers [DiscoverError]
- | NotEnoughShares {
  - notEnoughSharesNeeded :: Int
  - notEnoughSharesFound :: Int
  }
- | NotEnoughDecodedShares {
  - notEnoughDecodedSharesNeeded :: Int
  - notEnoughDecodedSharesFound :: Int
  }
- | ShareDecodingFailed
- | NoServers
- | ShareDownloadError String
data DirectoryDownloadError
- = UnderlyingDownloadError DownloadError
- | DecodingError
data LookupError
data DiscoverError
discoverShares :: LookupServer IO -> StorageIndex -> (StorageServerID, StorageServerAnnouncement) -> IO (Either DiscoverError (StorageServer, Set ShareNum))
download :: (MonadIO m, Readable readCap, Verifiable v, Verifier readCap ~ v) => Map StorageServerID StorageServerAnnouncement -> readCap -> LookupServer IO -> m (Either DownloadError ByteString)
downloadDirectory :: (MonadIO m, Readable readCap, Verifiable v, Verifier readCap ~ v) => Map StorageServerID StorageServerAnnouncement -> DirectoryCapability readCap -> LookupServer IO -> m (Either DirectoryDownloadError Directory)
announcementToImmutableStorageServer :: MonadIO m => StorageServerAnnouncement -> m (Either LookupError StorageServer)
announcementToMutableStorageServer :: MonadIO m => StorageServerAnnouncement -> m (Either LookupError StorageServer)
getShareNumbers :: (Verifiable v, MonadIO m) => v -> StorageServer -> m (Set ShareNum)

Documentation

type LookupServer m = StorageServerAnnouncement -> m (Either LookupError StorageServer) Source #

The type of a function that can produce a concrete StorageServer from that server's announcement.

data DownloadError Source #

An unrecoverable problem arose while attempting to download and/or read some application data.

Constructors

NoConfiguredServers	The configuration included no candidate servers from which to download.
NoReachableServers [DiscoverError]	Across all of the configured servers, none were actually connectable.
NotEnoughShares	Across all of the configured servers, fewer than the required number of shares were found. XXX Could split this into the different cases - did not locate enough shares, did not download enough shares, did not verify enough shares
Fields notEnoughSharesNeeded :: Int notEnoughSharesFound :: Int
NotEnoughDecodedShares	Across all of the shares that we could download, fewer than the required number could actually be decoded.
Fields notEnoughDecodedSharesNeeded :: Int notEnoughDecodedSharesFound :: Int
ShareDecodingFailed	Enough syntactically valid shares were recovered but they could not be interpreted.
NoServers	An attempt was made to download a share but no servers were given for the download.
ShareDownloadError String	An error occurred during share download.

Instances

Instances details

Eq DownloadError Source #
Instance details Defined in Tahoe.Download.Internal.Client Methods (==) :: DownloadError -> DownloadError -> Bool # (/=) :: DownloadError -> DownloadError -> Bool #
Ord DownloadError Source #
Instance details Defined in Tahoe.Download.Internal.Client Methods compare :: DownloadError -> DownloadError -> Ordering # (<) :: DownloadError -> DownloadError -> Bool # (<=) :: DownloadError -> DownloadError -> Bool # (>) :: DownloadError -> DownloadError -> Bool # (>=) :: DownloadError -> DownloadError -> Bool # max :: DownloadError -> DownloadError -> DownloadError # min :: DownloadError -> DownloadError -> DownloadError #
Show DownloadError Source #
Instance details Defined in Tahoe.Download.Internal.Client Methods showsPrec :: Int -> DownloadError -> ShowS # show :: DownloadError -> String # showList :: [DownloadError] -> ShowS #

data DirectoryDownloadError Source #

Constructors

UnderlyingDownloadError DownloadError
DecodingError

Instances

Instances details

Eq DirectoryDownloadError Source #
Instance details Defined in Tahoe.Download Methods (==) :: DirectoryDownloadError -> DirectoryDownloadError -> Bool # (/=) :: DirectoryDownloadError -> DirectoryDownloadError -> Bool #
Ord DirectoryDownloadError Source #
Instance details Defined in Tahoe.Download Methods compare :: DirectoryDownloadError -> DirectoryDownloadError -> Ordering # (<) :: DirectoryDownloadError -> DirectoryDownloadError -> Bool # (<=) :: DirectoryDownloadError -> DirectoryDownloadError -> Bool # (>) :: DirectoryDownloadError -> DirectoryDownloadError -> Bool # (>=) :: DirectoryDownloadError -> DirectoryDownloadError -> Bool # max :: DirectoryDownloadError -> DirectoryDownloadError -> DirectoryDownloadError # min :: DirectoryDownloadError -> DirectoryDownloadError -> DirectoryDownloadError #
Show DirectoryDownloadError Source #
Instance details Defined in Tahoe.Download Methods showsPrec :: Int -> DirectoryDownloadError -> ShowS # show :: DirectoryDownloadError -> String # showList :: [DirectoryDownloadError] -> ShowS #

data LookupError Source #

There was a problem while trying to look up a server from its announcement.

Constructors

URIParseError StorageServerAnnouncement	The server's announced URI was unparseable.
PortParseError String	The port integer in the server's URI was unparseable.
AnnouncementStructureUnmatched	The structure of the server's URI was unparseable.

Instances

Instances details

Eq LookupError Source #
Instance details Defined in Tahoe.Download.Internal.Client Methods (==) :: LookupError -> LookupError -> Bool # (/=) :: LookupError -> LookupError -> Bool #
Ord LookupError Source #
Instance details Defined in Tahoe.Download.Internal.Client Methods compare :: LookupError -> LookupError -> Ordering # (<) :: LookupError -> LookupError -> Bool # (<=) :: LookupError -> LookupError -> Bool # (>) :: LookupError -> LookupError -> Bool # (>=) :: LookupError -> LookupError -> Bool # max :: LookupError -> LookupError -> LookupError # min :: LookupError -> LookupError -> LookupError #
Show LookupError Source #
Instance details Defined in Tahoe.Download.Internal.Client Methods showsPrec :: Int -> LookupError -> ShowS # show :: LookupError -> String # showList :: [LookupError] -> ShowS #

data DiscoverError Source #

A problem arose while attempting to discover the shares held on a particular server.

Constructors

StorageServerLocationUnknown	An announcement did not include a location for a connection attempt.
StorageServerLocationUnsupported	An announcement included a location we could not interpret.
StorageServerUnreachable LookupError
StorageServerCommunicationError String

Instances

Instances details

Eq DiscoverError Source #
Instance details Defined in Tahoe.Download.Internal.Client Methods (==) :: DiscoverError -> DiscoverError -> Bool # (/=) :: DiscoverError -> DiscoverError -> Bool #
Ord DiscoverError Source #
Instance details Defined in Tahoe.Download.Internal.Client Methods compare :: DiscoverError -> DiscoverError -> Ordering # (<) :: DiscoverError -> DiscoverError -> Bool # (<=) :: DiscoverError -> DiscoverError -> Bool # (>) :: DiscoverError -> DiscoverError -> Bool # (>=) :: DiscoverError -> DiscoverError -> Bool # max :: DiscoverError -> DiscoverError -> DiscoverError # min :: DiscoverError -> DiscoverError -> DiscoverError #
Show DiscoverError Source #
Instance details Defined in Tahoe.Download.Internal.Client Methods showsPrec :: Int -> DiscoverError -> ShowS # show :: DiscoverError -> String # showList :: [DiscoverError] -> ShowS #

discoverShares :: LookupServer IO -> StorageIndex -> (StorageServerID, StorageServerAnnouncement) -> IO (Either DiscoverError (StorageServer, Set ShareNum)) Source #

Ask one server which shares it has related to the storage index in question.

download Source #

Arguments

:: (MonadIO m, Readable readCap, Verifiable v, Verifier readCap ~ v)
=> Map StorageServerID StorageServerAnnouncement	Information about the servers from which to consider downloading shares representing the application data.
-> readCap	The read capability for the application data.
-> LookupServer IO	Get functions for interacting with a server given its URL.
-> m (Either DownloadError ByteString)	Either a description of how the recovery failed or the recovered application data.

Recover the application data associated with a given capability from the given servers, if possible.

downloadDirectory Source #

Arguments

:: (MonadIO m, Readable readCap, Verifiable v, Verifier readCap ~ v)
=> Map StorageServerID StorageServerAnnouncement	Information about the servers from which to consider downloading shares representing the application data.
-> DirectoryCapability readCap	The read capability for the application data.
-> LookupServer IO	Get functions for interacting with a server given its URL.
-> m (Either DirectoryDownloadError Directory)	Either a description of how the recovery failed or the recovered application data.

Download the data associated with a directory capability and interpret it as a collection of entries.

announcementToImmutableStorageServer :: MonadIO m => StorageServerAnnouncement -> m (Either LookupError StorageServer) Source #

Interpret the location in an announcement as a Tahoe-LAFS fURL pointed at a Great Black Swamp server and construct a StorageServer for interacting with immutable shares stored on it.

announcementToMutableStorageServer :: MonadIO m => StorageServerAnnouncement -> m (Either LookupError StorageServer) Source #

Interpret the location in an announcement as a Tahoe-LAFS fURL pointed at a Great Black Swamp server and construct a StorageServer for interacting with mutable shares stored on it.

getShareNumbers :: (Verifiable v, MonadIO m) => v -> StorageServer -> m (Set ShareNum) Source #

Ask a storage server which share numbers related to this capability it is holding. This is an unverified result and the storage server could present incorrect information. Even if it correctly reports that it holds a share, it could decline to give it out when asked.