From: Guillaume Pellerin <guillaume.pellerin@ircam.fr>
Date: Fri, 13 Nov 2015 14:35:47 +0000 (+0100)
Subject: begin CSV streaming
X-Git-Tag: 1.6b~7^2~46^2~3
X-Git-Url: https://git.parisson.com/?a=commitdiff_plain;h=6e75823b7f496408b05be7b9896b06b32a2c09bc;p=telemeta.git

begin CSV streaming
---

diff --git a/telemeta/util/unicode.py b/telemeta/util/unicode.py
index 152a9fad..a21005e7 100644
--- a/telemeta/util/unicode.py
+++ b/telemeta/util/unicode.py
@@ -50,46 +50,58 @@ def _stringify_list(l, encoding):
     return [_stringify(s, encoding) for s in l]
 
 
-class UnicodeWriter(object):
+class UnicodeCSVWriter(object):
     def __init__(self, f, dialect=csv.excel, encoding="utf-8", **kwds):
-        self.writer = csv.writer(f)
         self.dialect = dialect
         self.encoding = encoding
         self.writer = csv.writer(f, dialect=dialect, **kwds)
+        self.line = 0
+        self.tags = []
+
+    def write_tags(self, element):
+        element_dict = element.to_dict_with_more()
+
+        for key in element_dict.keys():
+            if not key in self.tags:
+                self.tags.append(key)
+
+        # code and title on the two first column
+        self.tags.remove('code')
+        self.tags.remove('title')
+        self.tags.sort()
+        self.tags.insert(0, 'title')
+        self.tags.insert(0, 'code')
+        self.writer.writerow(self.tags)
+        self.line += 1
+        print self.tags
+
+    def write_element(self, element):
+        if self.line == 0:
+            self.write_tags(element)
+        row = []
+        element_dict = element.to_dict_with_more()
+
+        for tag in self.tags:
+            if tag in element_dict.keys():
+                row.append(element_dict[tag])
+            else:
+                row.append('')
+        self.writerow(row)
+        print row
 
     def writerow(self, row):
         self.writer.writerow(_stringify_list(row, self.encoding))
+        self.line += 1
 
     def writerows(self, rows):
         for row in rows:
           self.writerow(row)
 
 
-class CSVExport(object):
-
-    def __init__(self, writer):
-        self.writer = writer
-
-    def write(self, elements):
-        tags = []
-        element_dicts = [e.to_dict_with_more() for e in elements]
-        for e in element_dicts:
-            for key in e.keys():
-                if not key in tags:
-                    tags.append(key)
-        # code and title on the two first column
-        tags.remove('code')
-        tags.remove('title')
-        tags.sort()
-        tags.insert(0, 'title')
-        tags.insert(0, 'code')
-        self.writer.writerow(tags)
-
-        for element in element_dicts:
-            data = []
-            for tag in tags:
-                if tag in element.keys():
-                    data.append(element[tag])
-                else:
-                    data.append('')
-            self.writer.writerow(data)
+class Echo(object):
+    """An object that implements just the write method of the file-like
+    interface.
+    """
+    def write(self, value):
+        """Write the value by returning it, instead of storing in a buffer."""
+        return value
diff --git a/telemeta/views/core.py b/telemeta/views/core.py
index 0ac49103..badd0585 100644
--- a/telemeta/views/core.py
+++ b/telemeta/views/core.py
@@ -85,7 +85,7 @@ from telemeta.interop.oaidatasource import TelemetaOAIDataSource
 from telemeta.util.unaccent import unaccent
 from telemeta.util.unaccent import unaccent_icmp
 from telemeta.util.logger import Logger
-from telemeta.util.unicode import UnicodeWriter, CSVExport
+from telemeta.util.unicode import UnicodeCSVWriter, Echo
 from telemeta.cache import TelemetaCache
 import pages
 from telemeta.forms import *
diff --git a/telemeta/views/playlist.py b/telemeta/views/playlist.py
index 8ee10ef6..f7aca7a0 100644
--- a/telemeta/views/playlist.py
+++ b/telemeta/views/playlist.py
@@ -85,15 +85,13 @@ class PlaylistView(object):
         m = PlaylistResource.objects.get(public_id=public_id)
         m.delete()
 
-
     def playlist_csv_export(self, request, public_id, resource_type):
         playlist = Playlist.objects.get(public_id=public_id, author=request.user)
         resources = PlaylistResource.objects.filter(playlist=playlist)
-        response = HttpResponse(content_type='text/csv')
-        response['Content-Disposition'] = 'attachment; filename='+playlist.title+'_'+resource_type+'.csv'
-        writer = UnicodeWriter(response)
-
+        pseudo_buffer = Echo()
+        writer = UnicodeCSVWriter(pseudo_buffer)
         elements = []
+
         for resource in resources:
             if resource_type == 'items':
                 if resource.resource_type == 'collection':
@@ -114,8 +112,6 @@ class PlaylistView(object):
                     collection = MediaCollection.objects.get(id=resource.resource_id)
                     elements.append(collection)
 
-        if elements:
-            csv = CSVExport(writer)
-            csv.write(elements)
-
+        response = StreamingHttpResponse((writer.write_element(element) for element in elements), content_type='text/csv')
+        response['Content-Disposition'] = 'attachment; filename='+playlist.title+'_'+resource_type+'.csv'
         return response