add download to request

pydu/request.py

@@ -1,10 +1,14 @@
 import os
+import shutil
+import tempfile
 from pydu.compat import PY2, string_types
 from pydu.string import safeunicode
 
 if PY2:
+    import urllib as ulib
     import urlparse
 else:
+    import urllib.request as ulib
     import urllib.parse as urlparse
 
 
@@ -24,27 +28,81 @@ class FileName(object):
     def from_headers(headers):
         """
         Detect filename from Content-Disposition headers if present.
-        headers as dict, list or string
-        filename from content-disposition header or None
+
+        headers: as dict, list or string
+        filename: from content-disposition header or None
         """
+        if not headers:
+            return None
+
         if isinstance(headers, string_types):
             headers = [line.split(':', 1) for line in headers.splitlines()]
         if isinstance(headers, list):
             headers = dict(headers)
+
         cdisp = headers.get("Content-Disposition")
         if not cdisp:
             return None
+
         cdtype = cdisp.split(';')
         if len(cdtype) == 1:
             return None
         if cdtype[0].strip().lower() not in ('inline', 'attachment'):
             return None
+
         # several filename params is illegal, but just in case
         fnames = [x for x in cdtype[1:] if x.strip().startswith('filename=')]
         if len(fnames) > 1:
             return None
+
         name = fnames[0].split('=')[1].strip(' \t"')
         name = os.path.basename(name)
         if not name:
             return None
         return name
+
+    @classmethod
+    def from_any(cls, dst=None, headers=None, url=None):
+        return dst or cls.from_headers(headers) or cls.from_url(url)
+
+
+def download(url, dst=None):
+    """
+    High level function, which downloads URL into tmp file in current
+    directory and then renames it to filename autodetected from either URL
+    or HTTP headers.
+
+    bar: function to track download progress (visualize etc.)
+    out: output filename or directory
+    filename: where URL is downloaded to
+    """
+    # detect of dst is a directory
+    dst_ = None
+    if dst and os.path.isdir(dst):
+        dst_ = dst
+        dst = None
+
+    # get filename for temp file in current directory
+    prefix = FileName.from_any(dst=dst, url=url)
+    fd, tmpfile = tempfile.mkstemp(".tmp", prefix=prefix, dir=".")
+    os.close(fd)
+    os.unlink(tmpfile)
+
+    if PY2:
+        binurl = url
+    else:
+        # Python 3 can not quote URL as needed
+        binurl = list(urlparse.urlsplit(url))
+        binurl[2] = urlparse.quote(binurl[2])
+        binurl = urlparse.urlunsplit(binurl)
+    tmpfile, headers = ulib.urlretrieve(binurl, tmpfile)
+    filename = FileName.from_any(dst=dst, headers=headers, url=url)
+    if dst_:
+        filename = os.path.join(dst_, filename)
+
+    # add numeric ' (x)' suffix if filename already exists
+    if os.path.exists(filename):
+        os.unlink(filename)
+    shutil.move(tmpfile, filename)
+
+    return filename