qrcode support

1 files changed, 25 insertions, 4 deletions

diff --git a/talerblog/blog/blog.py b/talerblog/blog/blog.py
index 6f09852..e35dd0e 100644
--- a/talerblog/blog/blog.py
+++ b/talerblog/blog/blog.py
@@ -17,14 +17,17 @@
 # @author Marcello Stanisci
 # @brief Implementation of a Taler-compatible blog.
 
-from urllib.parse import urljoin, quote
+from urllib.parse import urljoin, quote, urlencode
 import logging
 import os
 import traceback
 import uuid
+import qrcode
+import qrcode.image.svg
 import base64
 import requests
 import flask
+import lxml.etree
 from cachelib import UWSGICache, SimpleCache
 from talerblog.talerconfig import TalerConfig
 from ..blog.content import ARTICLES, get_article_file, get_image_file
@@ -224,6 +227,10 @@ def render_article(article_name, data, order_id):
                                  article_name=article_name,
                                  order_id=order_id)
 
+def get_qrcode_svg(data):
+    factory = qrcode.image.svg.SvgImage
+    img = qrcode.make(data, image_factory=factory)
+    return lxml.etree.tostring(img.get_image())
 
 ##
 # Trigger a article purchase.  The logic follows the main steps:
@@ -281,10 +288,16 @@ def article(article_name, data=None):
         order_id = order_resp["order_id"]
 
     ##
+    # The resource URL uniquely identifies the Web resource that
+    # the customer is paying for, and is used to detect that an
+    # article has already been puchased when the cookie was lost.
+    resource_url = flask.request.base_url
+
+    ##
     # Prepare data for the upcoming payment check.
     pay_params = dict(instance=INSTANCE,
                       order_id=order_id,
-                      resource_url=flask.request.base_url,
+                      resource_url=resource_url,
                       session_id=session_id,
                       session_sig=session_sig)
 
@@ -316,9 +329,17 @@ def article(article_name, data=None):
         # Redirect the browser to a page where the wallet can
         # run the payment protocol.
         contract_url = pay_status["contract_url"]
-        headers = {"X-Taler-Contract-Url": contract_url}
+        headers = {
+                "X-Taler-Contract-Url": contract_url,
+                "X-Taler-Session-Url": session_id,
+                "X-Taler-Resource-Url": resource_url,
+        }
+
+        qrcode_data = "talerpay:" + urlencode(contract_url) + ";" + session_id
+        qrcode_svg = get_qrcode_svg(qrcode_data)
         content = flask.render_template("templates/request_payment.html",
-                                         article_name=article_name)
+                                         article_name=article_name,
+                                         qrcode_svg=qrcode_svg)
         resp = flask.Response(content, status=402, headers=headers)
         return resp