From 2e1fca586f7767673199e2dd739a949533e18d53 Mon Sep 17 00:00:00 2001
From: Dominik Moritz <domoritz@gmail.com>
Date: Fri, 26 Oct 2012 12:46:34 +0200
Subject: [PATCH] Resource proxy plugin started

---
 ckanext/jsonpreview/plugin.py       | 17 +++++++-----
 ckanext/resourceproxy/__init__.py   |  0
 ckanext/resourceproxy/controller.py | 27 +++++++++++++++++++
 ckanext/resourceproxy/plugin.py     | 41 +++++++++++++++++++++++++++++
 setup.py                            |  1 +
 5 files changed, 79 insertions(+), 7 deletions(-)
 create mode 100644 ckanext/resourceproxy/__init__.py
 create mode 100644 ckanext/resourceproxy/controller.py
 create mode 100644 ckanext/resourceproxy/plugin.py

diff --git a/ckanext/jsonpreview/plugin.py b/ckanext/jsonpreview/plugin.py
index 8b24d456adc..9e18b26adf9 100644
--- a/ckanext/jsonpreview/plugin.py
+++ b/ckanext/jsonpreview/plugin.py
@@ -2,6 +2,9 @@
 
 import ckan.plugins as p
 import ckan.plugins.toolkit as toolkit
+import ckan.lib.base as base
+
+import ckanext.resourceproxy.plugin as proxy
 
 log = getLogger(__name__)
 
@@ -17,6 +20,9 @@ class JsonPreview(p.SingletonPlugin):
     p.implements(p.IConfigurer, inherit=True)
     p.implements(p.IResourcePreview, inherit=True)
 
+    def __init__(self):
+        self.proxy_enabled = True
+
     def update_config(self, config):
         ''' Set up the resource library, public directory and
         template directory for the preview
@@ -25,15 +31,12 @@ def update_config(self, config):
         toolkit.add_template_directory(config, 'theme/templates')
         toolkit.add_resource('theme/public', 'ckanext-jsonpreview')
 
-    def requires_same_orign(self, resource):
-        ''' json resources have to be from the same origin. jsonp resources don't
-        '''
-        format_lower = resource['format'].lower()
-        return format_lower in ['json']
-
     def can_preview(self, resource):
         format_lower = resource['format'].lower()
-        return format_lower in ['jsonp', 'json']
+        return format_lower in ['jsonp'] or format_lower in ['json'] and self.proxy_enabled
+
+    def setup_template_variables(self, context, data_dict):
+        base.c.resource['url'] = proxy.get_proxyfied_resource_url(data_dict)
 
     def preview_template(self, context):
         return 'json.html'
diff --git a/ckanext/resourceproxy/__init__.py b/ckanext/resourceproxy/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/ckanext/resourceproxy/controller.py b/ckanext/resourceproxy/controller.py
new file mode 100644
index 00000000000..affa2dc1bd5
--- /dev/null
+++ b/ckanext/resourceproxy/controller.py
@@ -0,0 +1,27 @@
+import urllib2
+from logging import getLogger
+
+import ckan.logic as logic
+import ckan.lib.base as base
+
+log = getLogger(__name__)
+
+
+@logic.side_effect_free
+def proxy_resource(context, data_dict):
+        resource_id = data_dict['resource_id']
+        log.info('Proxify resource {id}'.format(id=resource_id))
+        resource = logic.get_action('resource_show')(context, {'id': resource_id})
+        url = resource['url']
+        req = urllib2.urlopen(url)
+        base.response.headers = req.headers
+
+        import shutil
+        shutil.copyfileobj(req, base.response)
+
+
+class ProxyController(base.BaseController):
+    def proxy_resource(self, data_dict):
+        context = {'model': base.model, 'session': base.model.Session,
+                   'user': base.c.user or base.c.author}
+        return proxy_resource(context, data_dict)
diff --git a/ckanext/resourceproxy/plugin.py b/ckanext/resourceproxy/plugin.py
new file mode 100644
index 00000000000..ced7fa3b5f1
--- /dev/null
+++ b/ckanext/resourceproxy/plugin.py
@@ -0,0 +1,41 @@
+from logging import getLogger
+
+import ckan.plugins as p
+import ckan.lib.base as base
+
+import controller
+
+log = getLogger(__name__)
+
+
+def get_proxyfied_resource_url(data_dict):
+    url = base.h.url_for(
+        action='proxy_resource',
+        id=data_dict['package']['name'],
+        resource_id=data_dict['resource']['id'])
+    log.info('Proxified url is {0}'.format(url))
+    return url
+
+
+class ResourceProxy(p.SingletonPlugin):
+    """A proxy for CKAN resources to get around the same
+    origin policy for previews
+
+    This extension implements two interfaces
+
+      - ``IConfigurer`` allows to modify the configuration
+      - ``IRoutes`` allows to add a route to the proxy action
+      - ``IActions`` allows to add an action for the proxy
+    """
+    p.implements(p.IConfigurer, inherit=True)
+    p.implements(p.IRoutes, inherit=True)
+    p.implements(p.IActions)
+
+    def before_map(self, m):
+        m.connect('/dataset/{id}/resource/{resource_id}/proxy',
+                    controller='ckanext.resourceproxy.controller:ProxyController',
+                    action='proxy_resource')
+        return m
+
+    def get_actions(self):
+        return {'proxy_resource': controller.proxy_resource}
diff --git a/setup.py b/setup.py
index 2724343e8f1..da9fd72e13d 100644
--- a/setup.py
+++ b/setup.py
@@ -122,6 +122,7 @@
     jsonpreview=ckanext.jsonpreview.plugin:JsonPreview
     pdfpreview=ckanext.pdfpreview.plugin:PdfPreview
     reclinepreview=ckanext.reclinepreview.plugin:ReclinePreview
+    resourceproxy=ckanext.resourceproxy.plugin:ResourceProxy
 
     [ckan.system_plugins]
     domain_object_mods = ckan.model.modification:DomainObjectModificationExtension