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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
--------------------------------------------------------------------------------
-- | Internal module to parse metadata
module Hakyll.Core.Provider.Metadata
( loadMetadata
, metadata
, page
-- This parser can be reused in some places
, metadataKey
) where
--------------------------------------------------------------------------------
import Control.Applicative
import Control.Arrow (second)
import qualified Data.ByteString.Char8 as BC
import Data.List (intercalate)
import qualified Data.Map as M
import System.IO as IO
import Text.Parsec ((<?>))
import qualified Text.Parsec as P
import Text.Parsec.String (Parser)
--------------------------------------------------------------------------------
import Hakyll.Core.Identifier
import Hakyll.Core.Metadata
import Hakyll.Core.Provider.Internal
import Hakyll.Core.Util.Parser
import Hakyll.Core.Util.String
--------------------------------------------------------------------------------
loadMetadata :: Provider -> Identifier -> IO (Metadata, Maybe String)
loadMetadata p identifier = do
hasHeader <- probablyHasMetadataHeader fp
(md, body) <- if hasHeader
then second Just <$> loadMetadataHeader fp
else return (M.empty, Nothing)
emd <- case mi of
Nothing -> return M.empty
Just mi' -> loadMetadataFile $ resourceFilePath p mi'
return (M.union md emd, body)
where
fp = resourceFilePath p identifier
mi = M.lookup identifier (providerFiles p) >>= resourceInfoMetadata
--------------------------------------------------------------------------------
loadMetadataHeader :: FilePath -> IO (Metadata, String)
loadMetadataHeader fp = do
contents <- readFile fp
case P.parse page fp contents of
Left err -> error (show err)
Right (md, b) -> return (M.fromList md, b)
--------------------------------------------------------------------------------
loadMetadataFile :: FilePath -> IO Metadata
loadMetadataFile fp = do
contents <- readFile fp
case P.parse metadata fp contents of
Left err -> error (show err)
Right md -> return $ M.fromList md
--------------------------------------------------------------------------------
-- | Check if a file "probably" has a metadata header. The main goal of this is
-- to exclude binary files (which are unlikely to start with "---").
probablyHasMetadataHeader :: FilePath -> IO Bool
probablyHasMetadataHeader fp = do
handle <- IO.openFile fp IO.ReadMode
bs <- BC.hGet handle 1024
IO.hClose handle
return $ isMetadataHeader bs
where
isMetadataHeader bs =
let pre = BC.takeWhile (\x -> x /= '\n' && x /= '\r') bs
in BC.length pre >= 3 && BC.all (== '-') pre
--------------------------------------------------------------------------------
-- | Space or tab, no newline
inlineSpace :: Parser Char
inlineSpace = P.oneOf ['\t', ' '] <?> "space"
--------------------------------------------------------------------------------
-- | Parse Windows newlines as well (i.e. "\n" or "\r\n")
newline :: Parser String
newline = P.string "\n" <|> P.string "\r\n"
--------------------------------------------------------------------------------
-- | Parse a single metadata field
metadataField :: Parser (String, String)
metadataField = do
key <- metadataKey
_ <- P.char ':'
P.skipMany1 inlineSpace <?> "space followed by metadata for: " ++ key
value <- P.manyTill P.anyChar newline
trailing' <- P.many trailing
return (key, trim $ intercalate " " $ value : trailing')
where
trailing = P.many1 inlineSpace *> P.manyTill P.anyChar newline
--------------------------------------------------------------------------------
-- | Parse a metadata block
metadata :: Parser [(String, String)]
metadata = P.many metadataField
--------------------------------------------------------------------------------
-- | Parse a metadata block, including delimiters and trailing newlines
metadataBlock :: Parser [(String, String)]
metadataBlock = do
open <- P.many1 (P.char '-') <* P.many inlineSpace <* newline
metadata' <- metadata
_ <- P.choice $ map (P.string . replicate (length open)) ['-', '.']
P.skipMany inlineSpace
P.skipMany1 newline
return metadata'
--------------------------------------------------------------------------------
-- | Parse a page consisting of a metadata header and a body
page :: Parser ([(String, String)], String)
page = do
metadata' <- P.option [] metadataBlock
body <- P.many P.anyChar
return (metadata', body)
|
