Merge pull request #30 from benoitbryon/29-httpdownloadview

Introducing HTTPDownloadView

CHANGELOG

@@ -6,6 +6,10 @@ Changelog
 
 **Backward incompatible changes.**
 
+- Added HTTPDownloadView to proxy to arbitrary URL.
+
+- Added VirtualDownloadView to support files living in memory.
+
 - Using StreamingHttpResponse introduced with Django 1.5. Makes Django 1.5 a
   requirement!
 

demo/demoproject/download/tests.py

@@ -87,3 +87,12 @@ class GeneratedDownloadViewTestCase(DownloadTestCase):
         download_url = reverse('generated_hello_world')
         response = self.client.get(download_url)
         self.assertDownloadHelloWorld(response)
+
+
+class ProxiedDownloadViewTestCase(DownloadTestCase):
+    """Test "http_hello_world" view."""
+    def test_download_readme(self):
+        """http_hello_world view proxies file from URL."""
+        download_url = reverse('http_hello_world')
+        response = self.client.get(download_url)
+        self.assertDownloadHelloWorld(response)

demo/demoproject/download/urls.py

@@ -20,6 +20,10 @@ urlpatterns = patterns(
     url(r'^path/(?P<path>[a-zA-Z0-9_-]+\.[a-zA-Z0-9]{1,4})$',
         'download_fixture_from_path',
         name='fixture_from_path'),
+    # URL-based downloads.
+    url(r'^http/readme\.txt$',
+        'download_http_hello_world',
+        name='http_hello_world'),
     # Generated downloads.
     url(r'^generated/hello-world\.txt$',
         'download_generated_hello_world',

demo/demoproject/download/views.py

@@ -6,11 +6,7 @@ from os.path import abspath, dirname, join
 from django.core.files.storage import FileSystemStorage
 
 from django_downloadview.files import VirtualFile
-from django_downloadview.views import (ObjectDownloadView,
-                                       PathDownloadView,
-                                       StorageDownloadView,
-                                       VirtualDownloadView)
-
+from django_downloadview import views
 from demoproject.download.models import Document
 
 
@@ -32,21 +28,21 @@ fixtures_storage = FileSystemStorage(location=fixtures_dir)
 # Here are the views.
 
 #: Pre-configured download view for :py:class:`Document` model.
-download_document = ObjectDownloadView.as_view(model=Document)
+download_document = views.ObjectDownloadView.as_view(model=Document)
 
 
 #: Pre-configured view using a storage.
-download_fixture_from_storage = StorageDownloadView.as_view(
+download_fixture_from_storage = views.StorageDownloadView.as_view(
     storage=fixtures_storage)
 
 
 #: Direct download of one file, based on an absolute path.
 #:
 #: You could use this example as a shortcut, inside other views.
-download_hello_world = PathDownloadView.as_view(path=hello_world_path)
+download_hello_world = views.PathDownloadView.as_view(path=hello_world_path)
 
 
-class CustomPathDownloadView(PathDownloadView):
+class CustomPathDownloadView(views.PathDownloadView):
     """Example of customized PathDownloadView."""
     def get_path(self):
         """Convert relative path (provided in URL) into absolute path.
@@ -67,12 +63,17 @@ class CustomPathDownloadView(PathDownloadView):
 download_fixture_from_path = CustomPathDownloadView.as_view()
 
 
-class StringIODownloadView(VirtualDownloadView):
+class StringIODownloadView(views.VirtualDownloadView):
     """Sample download view using StringIO object."""
     def get_file(self):
         """Return wrapper on StringIO object."""
-        file_obj = StringIO(u"Hello world!\n")
+        file_obj = StringIO(u"Hello world!\n".encode('utf-8'))
         return VirtualFile(file_obj, name='hello-world.txt')
 
 #: Pre-configured view that serves "Hello world!" via a StringIO.
 download_generated_hello_world = StringIODownloadView.as_view()
+
+
+download_http_hello_world = views.HTTPDownloadView.as_view(
+    url=u'https://raw.github.com/benoitbryon/django-downloadview/master/demo/demoproject/download/fixtures/hello-world.txt',
+    name=u'hello-world.txt')

demo/demoproject/nginx/urls.py

@@ -1,5 +1,5 @@
 """URL mapping."""
-from django.conf.urls import patterns, include, url
+from django.conf.urls import patterns, url
 
 
 urlpatterns = patterns('demoproject.nginx.views',

demo/demoproject/nginx/views.py

@@ -1,9 +1,10 @@
 """Views."""
 from django_downloadview.nginx import x_accel_redirect
 
-from demoproject.download.views import download_document
+from demoproject.download import views
 
 
-download_document_nginx = x_accel_redirect(download_document,
-                                           media_root='/var/www/files',
-                                           media_url='/download-optimized')
+download_document_nginx = x_accel_redirect(
+    views.download_document,
+    source_dir='/var/www/files',
+    destination_url='/download-optimized')

demo/demoproject/templates/home.html

@@ -5,23 +5,35 @@
 	</head>
 	<body>
         <h1>Welcome to django-downloadview demo!</h1>
-		<p>Here are some demo links. Browse the code to see how they are implemented</p>
+        <p>Here are some demo links. Browse the code to see how they are implemented</p>
+
+        <h2>Serving files with Django</h2>
+        <p>In the following views, Django streams the files, no optimization
+           has been setup.</p>
 		<ul>
-            <li><a href="{% url 'hello_world' %}">
-                Direct download to one file using PathDownloadView.
-            </a></li>
+            <li><a href="{% url 'hello_world' %}">PathDownloadView</a></li>
             <li><a href="{% url 'fixture_from_path' 'hello-world.txt' %}">
-                Download files using PathDownloadView and relative path in URL.
+                PathDownloadView + argument in URL
             </a></li>
             <li><a href="{% url 'fixture_from_storage' 'hello-world.txt' %}">
-                Download files using StorageDownloadView and path in URL.
+                StorageDownloadView + path in URL
             </a></li>
             <li><a href="{% url 'document' 'hello-world' %}">
                 ObjectDownloadView
             </a></li>
+            <li><a href="{% url 'http_hello_world' %}">
+                HTTPDownloadView</a>, a simple HTTP proxy</li>
+        </ul>
+
+        <h2>Optimized downloads</h2>
+        <p>In the following views, Django delegates actual streaming to another
+           server, for improved performances.</p>
+        <p>Since nginx and other servers aren't installed on the demo, you
+           will get raw "X-Sendfile" responses. Look at the headers!</p>
+        <ul>
             <li><a href="{% url 'download_document_nginx' 'hello-world' %}">
-                ObjectDownloadView decorated with nginx X-Accel-Redirect
-            </a> to be served behind Nginx</li>
+                ObjectDownloadView (nginx)
+            </a></li>
         </ul>
     </body>
 </html>

django_downloadview/files.py

@@ -1,6 +1,8 @@
 """File wrappers for use as exchange data between views and responses."""
 from django.core.files import File
 
+import requests
+
 
 class StorageFile(File):
     """A file in a Django storage.
@@ -134,11 +136,12 @@ class StorageFile(File):
 
 
 class VirtualFile(File):
+    """Wrapper for files that live in memory."""
     def __init__(self, file=None, name=u'', url='', size=None):
         """Constructor.
 
         file:
-          File object. Typically a StringIO.
+          File object. Typically an io.StringIO.
 
         name:
           File basename.
@@ -166,3 +169,44 @@ class VirtualFile(File):
         return super(VirtualFile, self)._set_size(value)
 
     size = property(_get_size, _set_size)
+
+
+class HTTPFile(File):
+    """Wrapper for files that live on remote HTTP servers.
+
+    Acts as a proxy.
+
+    Uses https://pypi.python.org/pypi/requests.
+
+    Always sets "stream=True" in requests kwargs.
+
+    """
+    def __init__(self, request_factory=requests.get, url='', name=u'',
+                 **kwargs):
+        self.request_factory = request_factory
+        self.url = url
+        self.name = name
+        kwargs['stream'] = True
+        self.request_kwargs = kwargs
+
+    @property
+    def request(self):
+        try:
+            return self._request
+        except AttributeError:
+            self._request = self.request_factory(self.url,
+                                                 **self.request_kwargs)
+            return self._request
+
+    @property
+    def file(self):
+        return self.request.raw
+
+    @property
+    def size(self):
+        """Return the total size, in bytes, of the file.
+
+        Reads response's "content-length" header.
+
+        """
+        return self.request.headers['Content-Length']

django_downloadview/views.py

@@ -6,7 +6,7 @@ from django.views.generic.base import View
 from django.views.generic.detail import BaseDetailView
 from django.views.static import was_modified_since
 
-from django_downloadview.files import StorageFile
+from django_downloadview import files
 from django_downloadview.response import DownloadResponse
 
 
@@ -116,7 +116,7 @@ class StorageDownloadView(PathDownloadView):
 
     def get_file(self):
         """Use path and storage to return wrapper around file to serve."""
-        return StorageFile(self.storage, self.get_path())
+        return files.StorageFile(self.storage, self.get_path())
 
 
 class VirtualDownloadView(BaseDownloadView):
@@ -132,6 +132,22 @@ class VirtualDownloadView(BaseDownloadView):
         raise NotImplementedError()
 
 
+class HTTPDownloadView(BaseDownloadView):
+    """Proxy files that live on remote servers."""
+    url = u''
+    request_kwargs = {}
+    name = u''
+
+    def get_url(self):
+        return self.url
+
+    def get_file(self):
+        """Return wrapper which has an ``url`` attribute."""
+        url = self.get_url()
+        request_kwargs = self.request_kwargs
+        return files.HTTPFile(name=self.name, url=url, **request_kwargs)
+
+
 class ObjectDownloadView(DownloadMixin, BaseDetailView):
     """Download view for models which contain a FileField.
 

docs/views.txt

@@ -48,6 +48,24 @@ Two main use cases:
   override :py:meth:`django_downloadview.views.PathDownloadView:get_path`.
 
 
+****************
+HTTPDownloadView
+****************
+
+The :py:class:`django_downloadview.views.HTTPDownloadView` class-based view
+allows you to **serve files given an URL**. That URL is supposed to be
+downloadable from the Django server.
+
+Use it when you want to setup a proxy to remote files:
+
+* the Django view filters input and computes target URL.
+* if you setup optimizations, Django itself doesn't proxies the file,
+* but, as a fallback, Django uses `requests`_ to proxy the file.
+
+Extend :py:class:`django_downloadview.views.HTTPDownloadView` then
+override :py:meth:`django_downloadview.views.HTTPDownloadView:get_url`.
+
+
 *******************
 VirtualDownloadView
 *******************
@@ -57,3 +75,10 @@ allows you to **serve files that don't live on disk**.
 
 Use it when you want to stream a file which content is dynamically generated
 or which lives in memory.
+
+
+.. rubric:: References
+
+.. target-notes::
+
+.. _`requests`: https://pypi.python.org/pypi/requests

setup.py

@@ -15,7 +15,7 @@ NAME = 'django-downloadview'
 README = read_relative_file('README')
 VERSION = read_relative_file('VERSION')
 PACKAGES = ['django_downloadview']
-REQUIRES = ['setuptools', 'django>=1.5']
+REQUIRES = ['setuptools', 'django>=1.5', 'requests']
 
 
 if __name__ == '__main__':  # Don't run setup() when we import this module.