Move the TSN namespace (Xml.hs and FeedHosts.hs) into the top level.

[dead/htsn.git] / src / Xml.hs

diff --git a/src/Xml.hs b/src/Xml.hs
new file mode 100644 (file)
index 0000000..7f82a7d
--- /dev/null
+++ b/src/Xml.hs
@@ -0,0 +1,88 @@
+-- | Minimal XML functionality needed to parse each document's
+--   XML_File_ID.
+--
+module Xml (
+  parse_xmlfid,
+  xml_tests )
+where
+
+import Data.Either.Utils ( maybeToEither )
+import Test.Tasty ( TestTree, testGroup )
+import Test.Tasty.HUnit ( (@?=), Assertion, testCase )
+import Text.Read ( readMaybe )
+import Text.XML.HXT.Core (
+  (>>>),
+  (/>),
+  getChildren,
+  getText,
+  hasName,
+  runLA,
+  xreadDoc )
+
+
+-- | A tiny parser written in HXT to extract the "XML_File_ID" element
+--   from a document. If we fail to parse an XML_File_ID, we return
+--   the reason wrapped in a 'Left' constructor. The reason should be
+--   one of two things:
+--
+--     1. No XML_File_ID elements were found.
+--
+--     2. An XML_File_ID element was found, but it could not be read
+--        into an Integer.
+--
+--   We use an Either rather than a Maybe because we do expect some
+--   non-integer XML_File_IDs. In the examples, you will see
+--   NHL_DepthChart_XML.XML with an XML_File_ID of "49618.61" and
+--   CFL_Boxscore_XML1.xml with an XML_File_ID of "R28916". According
+--   to Brijesh Patel of TSN, these are special category files and not
+--   part of the usual feed.
+--
+--   We want to report them differently, "just in case."
+--
+parse_xmlfid :: String -- ^ The XML Document
+             -> Either String Integer
+parse_xmlfid doc =
+  case parse_results of
+    []    -> Left "No XML_File_ID elements found."
+    (x:_) -> x
+  where
+    parse :: String -> [String]
+    parse =
+      runLA (xreadDoc
+               >>> hasName "message"
+               />  hasName "XML_File_ID"
+               >>> getChildren
+               >>> getText)
+
+    read_either_integer :: String -> Either String Integer
+    read_either_integer s =
+      let msg = "Could not parse XML_File_ID " ++ s ++ " as an integer."
+      in
+        maybeToEither msg (readMaybe s)
+
+    elements = parse doc
+    parse_results = map read_either_integer elements
+
+
+-- * Tasty Tests
+xml_tests :: TestTree
+xml_tests =
+  testGroup
+    "XML tests"
+    [ xml_file_id_tests ]
+
+
+xml_file_id_tests :: TestTree
+xml_file_id_tests =
+  testCase "XML_File_ID is parsed correctly" $ do
+    let xmlfids = ["19908216", "19908216", "19908245", "19908246", "19908247"]
+    mapM_ check xmlfids
+  where
+    check :: String -> Assertion
+    check xmlfid = do
+      xml <- readFile ("test/xml/" ++ xmlfid ++ ".xml")
+      let actual = parse_xmlfid xml
+      -- The maybeToEither should always succeed here, so the error
+      -- message goes unused.
+      let expected = maybeToEither "derp" (readMaybe xmlfid)
+      actual @?= expected