[PATCH 1/2] RecipePath: Add exists and resolve methods

[Jan Tluka]

These two new methods, exists() and resolve() are needed for proper handling
of python tasks if a recipe is specified as URL.

The exists() method returns True if a file or URL exists, False
otherwise.

The resolve() method returns the filename containing the data. In case
of ordinary file nothing special needs to be done. In case of URL, the
file is downloaded and saved in temporary file.

Signed-off-by: Jan Tluka <jtluka(a)redhat.com&gt;
---
 lnst/Common/RecipePath.py | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/lnst/Common/RecipePath.py b/lnst/Common/RecipePath.py
index 84c6acc..b976238 100644
--- a/lnst/Common/RecipePath.py
+++ b/lnst/Common/RecipePath.py
@@ -13,6 +13,7 @@ jtluka(a)redhat.com (Jan Tluka)
 import os
 from urlparse import urljoin
 from urllib2 import urlopen
+from tempfile import NamedTemporaryFile
 
 def get_recipepath_class(root, path):
     if root == None:
@@ -44,6 +45,12 @@ class RecipePath:
     def to_str(self):
         return self._recipepath_class.to_str()
 
+    def exists(self):
+        return self._recipepath_class.exists()
+
+    def resolve(self):
+        return self._recipepath_class.resolve()
+
 class RecipePathGeneric:
     def __init__(self, root, path):
         self._root = root
@@ -59,6 +66,12 @@ class RecipePathGeneric:
     def to_str(self):
         pass
 
+    def exists(self):
+        pass
+
+    def resolve(self):
+        pass
+
 class FileRecipePath(RecipePathGeneric):
     def _load_file(self):
         f = open(self.abs_path(),'r')
@@ -85,7 +98,14 @@ class FileRecipePath(RecipePathGeneric):
     def get_root(self):
         return os.path.dirname(self.abs_path())
 
+    def exists(self):
+        return os.path.isfile(self.abs_path())
+
+    def resolve(self):
+        return self.abs_path()
+
 class HttpRecipePath(RecipePathGeneric):
+    _file = None
     def _get_url(self):
         url = self.abs_path()
 
@@ -113,3 +133,23 @@ class HttpRecipePath(RecipePathGeneric):
     def get_root(self):
         url = self.abs_path()
         return url.rpartition('/')[0]
+
+    def exists(self):
+        url = self.abs_path()
+        try:
+            f = urlopen(url)
+        except HTTPError:
+            return False
+
+        f.close()
+        return True
+
+    def resolve(self):
+        if self._file:
+            return self._file.name
+
+        self._file = NamedTemporaryFile(suffix='.py',delete=True)
+        self._file.write(self.to_str())
+        self._file.flush()
+
+        return self._file.name
-- 
1.8.3.1