hackage-security-0.5.2.2: Hackage security library

Safe Haskell | None
Language | Haskell2010

Hackage.Security.Client.Repository

Contents

- Files
- Repository proper
  - Downloaded files
  - Helpers
- Paths
- Utility

Description

Abstract definition of a Repository

Most clients should only need to import this module if they wish to define their own Repository implementations.

Synopsis

- data Metadata
- data Binary
- data RemoteFile :: * -> * -> * where
  - RemoteTimestamp :: RemoteFile (FormatUn :- ()) Metadata
  - RemoteRoot :: Maybe (Trusted FileInfo) -> RemoteFile (FormatUn :- ()) Metadata
  - RemoteSnapshot :: Trusted FileInfo -> RemoteFile (FormatUn :- ()) Metadata
  - RemoteMirrors :: Trusted FileInfo -> RemoteFile (FormatUn :- ()) Metadata
  - RemoteIndex :: HasFormat fs FormatGz -> Formats fs (Trusted FileInfo) -> RemoteFile fs Binary
  - RemotePkgTarGz :: PackageIdentifier -> Trusted FileInfo -> RemoteFile (FormatGz :- ()) Binary
- data CachedFile
  - = CachedTimestamp
  - | CachedRoot
  - | CachedSnapshot
  - | CachedMirrors
- data IndexFile :: * -> * where
  - IndexPkgMetadata :: PackageIdentifier -> IndexFile (Signed Targets)
  - IndexPkgCabal :: PackageIdentifier -> IndexFile ()
  - IndexPkgPrefs :: PackageName -> IndexFile ()
- remoteFileDefaultFormat :: RemoteFile fs typ -> Some (HasFormat fs)
- remoteFileDefaultInfo :: RemoteFile fs typ -> Maybe (Trusted FileInfo)
- data Repository down = DownloadedFile down => Repository {
  - repGetRemote :: forall fs typ. Throws SomeRemoteError => AttemptNr -> RemoteFile fs typ -> Verify (Some (HasFormat fs), down typ)
  - repGetCached :: CachedFile -> IO (Maybe (Path Absolute))
  - repGetCachedRoot :: IO (Path Absolute)
  - repClearCache :: IO ()
  - repWithIndex :: forall a. (Handle -> IO a) -> IO a
  - repGetIndexIdx :: IO TarIndex
  - repLockCache :: IO () -> IO ()
  - repWithMirror :: forall a. Maybe [Mirror] -> IO a -> IO a
  - repLog :: LogMessage -> IO ()
  - repLayout :: RepoLayout
  - repIndexLayout :: IndexLayout
  - repDescription :: String
  }
- newtype AttemptNr = AttemptNr Int
- data LogMessage
  - = LogRootUpdated
  - | LogVerificationError VerificationError
  - | LogDownloading (RemoteFile fs typ)
  - | LogUpdating (RemoteFile fs Binary)
  - | LogSelectedMirror MirrorDescription
  - | LogCannotUpdate (RemoteFile fs Binary) UpdateFailure
  - | LogMirrorFailed MirrorDescription SomeException
- data UpdateFailure
  - = UpdateImpossibleUnsupported
  - | UpdateImpossibleNoLocalCopy
  - | UpdateFailedTwice
  - | UpdateFailed SomeException
- data SomeRemoteError :: * where
  - SomeRemoteError :: Exception e => e -> SomeRemoteError
- class DownloadedFile down where
- mirrorsUnsupported :: Maybe [Mirror] -> IO a -> IO a
- remoteRepoPath :: RepoLayout -> RemoteFile fs typ -> Formats fs RepoPath
- remoteRepoPath' :: RepoLayout -> RemoteFile fs typ -> HasFormat fs f -> RepoPath
- data IsCached :: * -> * where
  - CacheAs :: CachedFile -> IsCached Metadata
  - DontCache :: IsCached Binary
  - CacheIndex :: IsCached Binary
- mustCache :: RemoteFile fs typ -> IsCached typ

# Files

data Metadata #

data Binary #

data RemoteFile :: * -> * -> * where #

Abstract definition of files we might have to download

`RemoteFile` is parametrized by the type of the formats that we can accept from the remote repository, as well as with information on whether this file is metadata actual binary content.

NOTE: Haddock lacks GADT support so constructors have only regular comments.

Constructors

RemoteTimestamp :: RemoteFile (FormatUn :- ()) Metadata |
RemoteRoot :: Maybe (Trusted FileInfo) -> RemoteFile (FormatUn :- ()) Metadata |
RemoteSnapshot :: Trusted FileInfo -> RemoteFile (FormatUn :- ()) Metadata |
RemoteMirrors :: Trusted FileInfo -> RemoteFile (FormatUn :- ()) Metadata |
RemoteIndex :: HasFormat fs FormatGz -> Formats fs (Trusted FileInfo) -> RemoteFile fs Binary |
RemotePkgTarGz :: PackageIdentifier -> Trusted FileInfo -> RemoteFile (FormatGz :- ()) Binary |

Instances

Show (RemoteFile fs typ) # |
Methods showsPrec :: Int -> RemoteFile fs typ -> ShowS # show :: RemoteFile fs typ -> String # showList :: [RemoteFile fs typ] -> ShowS #
Pretty (RemoteFile fs typ) # |
Methods pretty :: RemoteFile fs typ -> String #

data CachedFile #

Files that we might request from the local cache

Constructors

CachedTimestamp | Timestamp metadata (`timestamp.json`)
CachedRoot | Root metadata (`root.json`)
CachedSnapshot | Snapshot metadata (`snapshot.json`)
CachedMirrors | Mirrors list (`mirrors.json`)

Instances

Eq CachedFile # |
Methods (==) :: CachedFile -> CachedFile -> Bool # (/=) :: CachedFile -> CachedFile -> Bool #
Ord CachedFile # |
Methods compare :: CachedFile -> CachedFile -> Ordering # (<) :: CachedFile -> CachedFile -> Bool # (<=) :: CachedFile -> CachedFile -> Bool # (>) :: CachedFile -> CachedFile -> Bool # (>=) :: CachedFile -> CachedFile -> Bool # max :: CachedFile -> CachedFile -> CachedFile # min :: CachedFile -> CachedFile -> CachedFile #
Show CachedFile # |
Methods showsPrec :: Int -> CachedFile -> ShowS # show :: CachedFile -> String # showList :: [CachedFile] -> ShowS #
Pretty CachedFile # |
Methods pretty :: CachedFile -> String #

data IndexFile :: * -> * where #

Files that we might request from the index

The type index tells us the type of the decoded file, if any. For files for which the library does not support decoding this will be `()`. NOTE: Clients should NOT rely on this type index being `()`, or they might break if we add support for parsing additional file formats in the future.

TODO: If we wanted to support legacy Hackage, we should also have a case for the global preferred-versions file. But supporting legacy Hackage will probably require more work anyway..

Constructors

IndexPkgMetadata :: PackageIdentifier -> IndexFile (Signed Targets) |
IndexPkgCabal :: PackageIdentifier -> IndexFile () |
IndexPkgPrefs :: PackageName -> IndexFile () |

Instances

SomePretty IndexFile # |
Methods somePretty :: DictPretty (IndexFile a) #
SomeShow IndexFile # |
Methods someShow :: DictShow (IndexFile a) #
Show (IndexFile dec) # |
Methods showsPrec :: Int -> IndexFile dec -> ShowS # show :: IndexFile dec -> String # showList :: [IndexFile dec] -> ShowS #
Pretty (IndexFile dec) # |
Methods pretty :: IndexFile dec -> String #

remoteFileDefaultFormat :: RemoteFile fs typ -> Some (HasFormat fs) #

Default format for each file type

For most file types we don't have a choice; for the index the repository is only required to offer the GZip-compressed format so that is the default.

remoteFileDefaultInfo :: RemoteFile fs typ -> Maybe (Trusted FileInfo) #

Default file info (see also `remoteFileDefaultFormat`)

# Repository proper

data Repository down #

Repository

This is an abstract representation of a repository. It simply provides a way to download metafiles and target files, without specifying how this is done. For instance, for a local repository this could just be doing a file read, whereas for remote repositories this could be using any kind of HTTP client.

Constructors

DownloadedFile down => Repository |
- Fields repGetRemote :: forall fs typ. Throws SomeRemoteError => AttemptNr -> RemoteFile fs typ -> Verify (Some (HasFormat fs), down typ) Get a file from the server Responsibilies of `repGetRemote`: Download the file from the repository and make it available at a temporary location Use the provided file length to protect against endless data attacks. (Repositories such as local repositories that are not suspectible to endless data attacks can safely ignore this argument.) Move the file from its temporary location to its permanent location if verification succeeds. NOTE: Calls to `repGetRemote` should _always_ be in the scope of `repWithMirror`. repGetCached :: CachedFile -> IO (Maybe (Path Absolute)) Get a cached file (if available) repGetCachedRoot :: IO (Path Absolute) Get the cached root This is a separate method only because clients must ALWAYS have root information available. repClearCache :: IO () Clear all cached data In particular, this should remove the snapshot and the timestamp. It would also be okay, but not required, to delete the index. repWithIndex :: forall a. (Handle -> IO a) -> IO a Open the tarball for reading This function has this shape so that: We can read multiple files from the tarball without having to open and close the handle each time We can close the handle immediately when done. repGetIndexIdx :: IO TarIndex Read the index index repLockCache :: IO () -> IO () Lock the cache (during updates) repWithMirror :: forall a. Maybe [Mirror] -> IO a -> IO a Mirror selection The purpose of `repWithMirror` is to scope mirror selection. The idea is that if we have
      repWithMirror mirrorList $
        someCallback
then the repository may pick a mirror before calling `someCallback`, catch exceptions thrown by `someCallback`, and potentially try the callback again with a different mirror. The list of mirrors may be `Nothing` if we haven't yet downloaded the list of mirrors from the repository, or when our cached list of mirrors is invalid. Of course, if we did download it, then the list of mirrors may still be empty. In this case the repository must fall back to its primary download mechanism. Mirrors as currently defined (in terms of a "base URL") are inherently a HTTP (or related) concept, so in repository implementations such as the local-repo `repWithMirrors` is probably just an identity operation (see `ignoreMirrors`). Conversely, HTTP implementations of repositories may have other, out-of-band information (for example, coming from a cabal config file) that they may use to influence mirror selection. repLog :: LogMessage -> IO () Logging repLayout :: RepoLayout Layout of this repository repIndexLayout :: IndexLayout Layout of the index Since the repository hosts the index, the layout of the index is not independent of the layout of the repository. repDescription :: String Description of the repository (used in the show instance)

Instances

Show (Repository down) # |
Methods showsPrec :: Int -> Repository down -> ShowS # show :: Repository down -> String # showList :: [Repository down] -> ShowS #

newtype AttemptNr #

Are we requesting this information because of a previous validation error?

Clients can take advantage of this to tell caches to revalidate files.

Constructors

AttemptNr Int |

Instances

Eq AttemptNr # |
Methods (==) :: AttemptNr -> AttemptNr -> Bool # (/=) :: AttemptNr -> AttemptNr -> Bool #
Num AttemptNr # |
Methods (+) :: AttemptNr -> AttemptNr -> AttemptNr # (-) :: AttemptNr -> AttemptNr -> AttemptNr # (*) :: AttemptNr -> AttemptNr -> AttemptNr # negate :: AttemptNr -> AttemptNr # abs :: AttemptNr -> AttemptNr # signum :: AttemptNr -> AttemptNr # fromInteger :: Integer -> AttemptNr #
Ord AttemptNr # |
Methods compare :: AttemptNr -> AttemptNr -> Ordering # (<) :: AttemptNr -> AttemptNr -> Bool # (<=) :: AttemptNr -> AttemptNr -> Bool # (>) :: AttemptNr -> AttemptNr -> Bool # (>=) :: AttemptNr -> AttemptNr -> Bool # max :: AttemptNr -> AttemptNr -> AttemptNr # min :: AttemptNr -> AttemptNr -> AttemptNr #

data LogMessage #

Log messages

We use a `RemoteFile` rather than a `RepoPath` here because we might not have a `RepoPath` for the file that we were trying to download (that is, for example if the server does not provide an uncompressed tarball, it doesn't make much sense to list the path to that non-existing uncompressed tarball).

Constructors

LogRootUpdated | Root information was updated This message is issued when the root information is updated as part of the normal check for updates procedure. If the root information is updated because of a verification error WarningVerificationError is issued instead.
LogVerificationError VerificationError | A verification error Verification errors can be temporary, and may be resolved later; hence these are just warnings. (Verification errors that cannot be resolved are thrown as exceptions.)
LogDownloading (RemoteFile fs typ) | Download a file from a repository
LogUpdating (RemoteFile fs Binary) | Incrementally updating a file from a repository
LogSelectedMirror MirrorDescription | Selected a particular mirror
LogCannotUpdate (RemoteFile fs Binary) UpdateFailure | Updating a file failed (we will instead download it whole)
LogMirrorFailed MirrorDescription SomeException | We got an exception with a particular mirror (we will try with a different mirror if any are available)

Instances

Pretty LogMessage # |
Methods pretty :: LogMessage -> String #

data UpdateFailure #

Records why we are downloading a file rather than updating it.

Constructors

UpdateImpossibleUnsupported | Server does not support incremental downloads
UpdateImpossibleNoLocalCopy | We don't have a local copy of the file to update
UpdateFailedTwice | Update failed twice If we attempt an incremental update the first time, and it fails, we let it go round the loop, update local security information, and try again. But if an incremental update then fails _again_, we instead attempt a regular download.
UpdateFailed SomeException | Update failed (for example: perhaps the local file got corrupted)

Instances

Pretty UpdateFailure # |
Methods pretty :: UpdateFailure -> String #

data SomeRemoteError :: * where #

Repository-specific exceptions

For instance, for repositories using HTTP this might correspond to a 404; for local repositories this might correspond to file-not-found, etc.

Constructors

SomeRemoteError :: Exception e => e -> SomeRemoteError |

Instances

Show SomeRemoteError # |
Methods showsPrec :: Int -> SomeRemoteError -> ShowS # show :: SomeRemoteError -> String # showList :: [SomeRemoteError] -> ShowS #
Exception SomeRemoteError # |
Methods toException :: SomeRemoteError -> SomeException # fromException :: SomeException -> Maybe SomeRemoteError # displayException :: SomeRemoteError -> String #
Pretty SomeRemoteError # |
Methods pretty :: SomeRemoteError -> String #

## Downloaded files

class DownloadedFile down where #

Minimal complete definition

downloadedVerify, downloadedRead, downloadedCopyTo

Methods

downloadedVerify :: down a -> Trusted FileInfo -> IO Bool #

Verify a download file

downloadedRead :: down Metadata -> IO ByteString #

Read the file we just downloaded into memory

We never read binary data, only metadata.

downloadedCopyTo :: down a -> Path Absolute -> IO () #

Copy a downloaded file to its destination

Instances

DownloadedFile LocalFile # |
Methods downloadedVerify :: LocalFile a -> Trusted FileInfo -> IO Bool # downloadedRead :: LocalFile Metadata -> IO ByteString # downloadedCopyTo :: LocalFile a -> Path Absolute -> IO () #
DownloadedFile RemoteTemp # |
Methods downloadedVerify :: RemoteTemp a -> Trusted FileInfo -> IO Bool # downloadedRead :: RemoteTemp Metadata -> IO ByteString # downloadedCopyTo :: RemoteTemp a -> Path Absolute -> IO () #

## Helpers

mirrorsUnsupported :: Maybe [Mirror] -> IO a -> IO a #

Helper function to implement `repWithMirrors`.

# Paths

remoteRepoPath :: RepoLayout -> RemoteFile fs typ -> Formats fs RepoPath #

remoteRepoPath' :: RepoLayout -> RemoteFile fs typ -> HasFormat fs f -> RepoPath #

# Utility

data IsCached :: * -> * where #

Is a particular remote file cached?

Constructors

CacheAs :: CachedFile -> IsCached Metadata |
DontCache :: IsCached Binary |
CacheIndex :: IsCached Binary |

Instances

Eq (IsCached typ) # |
Methods (==) :: IsCached typ -> IsCached typ -> Bool # (/=) :: IsCached typ -> IsCached typ -> Bool #
Show (IsCached typ) # |
Methods showsPrec :: Int -> IsCached typ -> ShowS # show :: IsCached typ -> String # showList :: [IsCached typ] -> ShowS #

mustCache :: RemoteFile fs typ -> IsCached typ #

Which remote files should we cache locally?