#545 Fallback download process, wget, urllib, pip --trusted-host, to maximise possilities of success.

wx/tools/wxget.py

@@ -30,6 +30,9 @@ from __future__ import (division, absolute_import, print_function, unicode_liter
 import sys
 import os
 import wx
+import subprocess
+import ssl
+import pip
 
 if sys.version_info >= (3,):
     from urllib.error import (HTTPError, URLError)
@@ -87,31 +90,28 @@ def get_save_path(url, dest_dir, force=False):
 
     return (url, filename)
 
-def download_file(url, dest=None, force=False):
-    """
-    Download and save a file specified by url to dest directory, with force will
-    operate silently and overwrite any existing file.
-    """
-    url, filename = get_save_path(url, dest, force)
-    if url is None:
-        return 'Aborted!'
-
-    if url:
-        print("Download from:", url)
-        try:
-            url_res = urllib2.urlopen(url)
-            keep_going = True
-        except (HTTPError, URLError) as err:
-            msg = '\n'.join([
-            "\n\nERROR in Web Access! - you may be behind a firewall",
-            "You may be able to bybass this by using a browser to download:",
-            "\n\t%s\n\nand copying to:\n\n\t%s" % (url, filename),
-            ])
-            print(msg, '\n')
-            wx.MessageBox(msg, caption='WDOWNLOAD ERROR!',
-                          style=wx.OK|wx.CENTRE|wx.ICON_ERROR)
-            return "Error: %s" % err
+def download_wget(url, filename):
+    """ Try to donwload via wget."""
+    result = False
+    try:
+        cmd = ["wget", url, '-O', filename]
+        print("Trying:\n  ", ' '.join(cmd))
+        result = subprocess.check_call(cmd)
+        # note some users may need to add "--no-check-certificate" on some sites
+        result = result == 0
+    except Exception:
+        print("wget did not work or not installed - trying urllib")
+    return result
 
+def download_urllib(url, filename):
+    """ Try to donwload via urllib."""
+    print("Trying to Download via urllib from:\n  ", url)
+    keep_going = True
+    try:
+        url_res = urllib2.urlopen(url)
+    except (HTTPError, URLError, ssl.CertificateError) as err:
+        print("Error: %s" % err)
+        return False
     with open(filename, 'wb') as outfile:
         block_sz = 8192
         meta = url_res.info()
@@ -147,11 +147,71 @@ def download_file(url, dest=None, force=False):
             wx.Sleep(0.08)  # Give the GUI some update time
         progress.Destroy()
 
+def download_pip(url, filename, force=False, trusted=False):
+    """ Try to donwload via pip."""
+    download_dir = os.path.split(filename)[0]
+    if len(download_dir) == 0:
+        download_dir = '.'
+    print("Trying to use pip to download From:\n  ", url, 'To:\n  ', filename)
+    cmds = ['download', url, '--dest', download_dir, "--no-deps",
+            '--exists-action', 'i']
+    if force:
+        cmds.append('--no-cache-dir')
+    if trusted:
+        host = '/'.join(url.split('/')[:3])  # take up to http://something/ as host
+        cmds.extend(['--trusted-host', host])
+    if force and os.path.exists(filename):
+        print("Delete Existing", filename)
+        os.unlink(filename)
+    print("Running pip",  ' '.join(cmds))
+    try:
+        print("\nAbusing pip so expect an error in the next few lines.")
+        result = pip.main(cmds)
+        print(result)
+    except FileNotFoundError:
+        result = 0
+    return os.path.exists(filename)
+
+def download_file(url, dest=None, force=False, trusted=False):
+    """
+    Download and save a file specified by url to dest directory, with force will
+    operate silently and overwrite any existing file.
+    """
+    url, filename = get_save_path(url, dest, force)
+    keep_going = True
+    success = False
+    if url is None:
+        return 'Aborted!'
+
+    if url:
+        success = download_wget(url, filename)  # Try wget
+        if not success:
+            success = download_urllib(url, filename)  # Try urllib
+        if not success:
+            success = download_pip(url, filename, force, trusted)  # Try urllib
+        if not success:
+            msg = '\n'.join([
+                "\n\nERROR in Web Access! - you may be behind a firewall",
+                "You may be able to bybass this by using a browser to download:",
+                "\n\t%s\n\nand copying to:\n\n\t%s" % (url, filename),
+                ])
+            print(msg, '\n')
+            wx.MessageBox(msg, caption='WDOWNLOAD ERROR!',
+                          style=wx.OK|wx.CENTRE|wx.ICON_ERROR)
+            return "FAILURE or Abort!"
+
     return filename
 
 def main(args=sys.argv):
     """ Entry point for wxget."""
     APP = wx.App()
+    dest_dir = '.'
+    force_flag = '--force'
+    trusted_flag = '--trusted'
+
+    if force_flag in args:
+        force = True
+        args.remove(force_flag)
 
     if len(args) > 2:
         dest_dir = args[2]
@@ -169,7 +229,7 @@ def main(args=sys.argv):
         else:
             url = None
     if url:
-        FILENAME = download_file(url)
+        FILENAME = download_file(url, dest_dir, force)
         print(FILENAME)
 
 if __name__ == "__main__":  # Only run if this file is called directly

wx/tools/wxget_docs_demo.py

@@ -109,7 +109,7 @@ def get_item(final, url, cache, name, ext, forced=False):
                  "(Select No on charged or slow connections)"]),
             "Download Prompt", wx.YES_NO|wx.CENTER|wx.ICON_INFORMATION)
         if yes_no == wx.YES:
-            cached = wxget.download_file(url, cache, True)
+            cached = wxget.download_file(url, cache, force=forced, trusted=True)
         else:
             report_error("Download Cancelled!")