1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
{- Url downloading.
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.Url (
exists,
download,
get
) where
import Control.Applicative
import qualified Network.Browser as Browser
import Network.HTTP
import Network.URI
import Utility.SafeCommand
import Utility.Path
type URLString = String
{- Checks that an url exists and could be successfully downloaded. -}
exists :: URLString -> IO Bool
exists url =
case parseURI url of
Nothing -> return False
Just u -> do
r <- request u HEAD
case rspCode r of
(2,_,_) -> return True
_ -> return False
{- Used to download large files, such as the contents of keys.
-
- Uses wget or curl program for its progress bar. (Wget has a better one,
- so is preferred.) Which program to use is determined at run time; it
- would not be appropriate to test at configure time and build support
- for only one in.
-}
download :: URLString -> FilePath -> IO Bool
download url file = do
e <- inPath "wget"
if e
then
boolSystem "wget"
[Params "-c -O", File file, File url]
else
-- Uses the -# progress display, because the normal
-- one is very confusing when resuming, showing
-- the remainder to download as the whole file,
-- and not indicating how much percent was
-- downloaded before the resume.
boolSystem "curl"
[Params "-L -C - -# -o", File file, File url]
{- Downloads a small file. -}
get :: URLString -> IO String
get url =
case parseURI url of
Nothing -> error "url parse error"
Just u -> do
r <- request u GET
case rspCode r of
(2,_,_) -> return $ rspBody r
_ -> error $ rspReason r
{- Makes a http request of an url. For example, HEAD can be used to
- check if the url exists, or GET used to get the url content (best for
- small urls). -}
request :: URI -> RequestMethod -> IO (Response String)
request url requesttype = Browser.browse $ do
Browser.setErrHandler ignore
Browser.setOutHandler ignore
Browser.setAllowRedirects True
snd <$> Browser.request (mkRequest requesttype url :: Request_String)
where
ignore = const $ return ()
|