Network.HTTP.Download

Documentation

data DownloadRequest

A request together with some checks to perform.

Construct using the downloadRequest smart constructor and associated setters. The constructor itself is not exposed to avoid breaking changes with additional fields.

Since: 0.2.0.0

mkDownloadRequest :: Request -> DownloadRequest

Construct a new DownloadRequest from the given Request. Use associated setters to modify the value further.

Since: 0.2.0.0

modifyRequest :: (Request -> Request) -> DownloadRequest -> DownloadRequest

Modify the Request inside a DownloadRequest. Especially intended for modifying the User-Agent request header.

Since: 0.2.0.0

setHashChecks :: [HashCheck] -> DownloadRequest -> DownloadRequest

Set the hash checks to be run when verifying.

Since: 0.2.0.0

setLengthCheck :: Maybe LengthCheck -> DownloadRequest -> DownloadRequest

Set the length check to be run when verifying.

Since: 0.2.0.0

setRetryPolicy :: RetryPolicy -> DownloadRequest -> DownloadRequest

Set the retry policy to be used when downloading.

Since: 0.2.0.0

setForceDownload :: Bool -> DownloadRequest -> DownloadRequest

If True, force download even if the file already exists. Useful for download a resource which may change over time.

drRetryPolicyDefault :: RetryPolicy

Default to retrying seven times with exponential backoff starting from one hundred milliseconds.

This means the tries will occur after these delays if necessary:

• 0.1s
• 0.2s
• 0.4s
• 0.8s
• 1.6s
• 3.2s
• 6.4s

data HashCheck

Constructors

forall a.(Show a, HashAlgorithm a) => HashCheck

Fields

• hashCheckAlgorithm :: a
• hashCheckHexDigest :: CheckHexDigest

Instances

Show HashCheck

Defined in Network.HTTP.Download.Verified

Methods

showsPrec :: Int -> HashCheck -> ShowS

show :: HashCheck -> String

showList :: [HashCheck] -> ShowS

data DownloadException

Constructors

RedownloadInvalidResponse Request (Path Abs File) (Response ())

RedownloadHttpError HttpException

Instances

Exception DownloadException

Defined in Network.HTTP.Download

Methods

toException :: DownloadException -> SomeException

fromException :: SomeException -> Maybe DownloadException

displayException :: DownloadException -> String

Show DownloadException

Defined in Network.HTTP.Download

Methods

showsPrec :: Int -> DownloadException -> ShowS

show :: DownloadException -> String

showList :: [DownloadException] -> ShowS

data CheckHexDigest

Constructors

CheckHexDigestString String

CheckHexDigestByteString ByteString

CheckHexDigestHeader ByteString

Instances

IsString CheckHexDigest

Defined in Network.HTTP.Download.Verified

Methods

fromString :: String -> CheckHexDigest

Show CheckHexDigest

Defined in Network.HTTP.Download.Verified

Methods

showsPrec :: Int -> CheckHexDigest -> ShowS

show :: CheckHexDigest -> String

showList :: [CheckHexDigest] -> ShowS

type LengthCheck = Int

data VerifiedDownloadException

An exception regarding verification of a download.

Constructors

WrongContentLength Request Int ByteString

WrongStreamLength Request Int Int

WrongDigest Request String CheckHexDigest String

DownloadHttpError HttpException

Instances

Exception VerifiedDownloadException

Defined in Network.HTTP.Download.Verified

Methods

toException :: VerifiedDownloadException -> SomeException

fromException :: SomeException -> Maybe VerifiedDownloadException

displayException :: VerifiedDownloadException -> String

Show VerifiedDownloadException

Defined in Network.HTTP.Download.Verified

Methods

showsPrec :: Int -> VerifiedDownloadException -> ShowS

show :: VerifiedDownloadException -> String

showList :: [VerifiedDownloadException] -> ShowS

download

Arguments

:: HasTerm env

=> Request

-> Path Abs File

destination

-> RIO env Bool

Was a downloaded performed (True) or did the file already exist (False)?

Download the given URL to the given location. If the file already exists, no download is performed. Otherwise, creates the parent directory, downloads to a temporary file, and on file download completion moves to the appropriate destination.

Throws an exception if things go wrong

redownload

Arguments

:: HasTerm env

=> Request

-> Path Abs File

destination

-> RIO env Bool

Same as download, but will download a file a second time if it is already present.

Returns True if the file was downloaded, False otherwise

verifiedDownload

Arguments

:: HasTerm env

=> DownloadRequest

-> Path Abs File

destination

-> (Maybe Integer -> ConduitM ByteString Void (RIO env) ())

custom hook to observe progress

-> RIO env Bool

Whether a download was performed

Copied and extended version of Network.HTTP.Download.download.

Has the following additional features: * Verifies that response content-length header (if present) matches expected length * Limits the download to (close to) the expected # of bytes * Verifies that the expected # bytes were downloaded (not too few) * Verifies md5 if response includes content-md5 header * Verifies the expected hashes

Throws VerifiedDownloadException. Throws IOExceptions related to file system operations. Throws HttpException.