From 376aedb143a62bcd09b0b6eaf512bc2fa9ba9ed8 Mon Sep 17 00:00:00 2001
From: Florian Dold <florian.dold@gmail.com>
Date: Tue, 18 Aug 2020 21:05:06 +0530
Subject: simplified paywall logic according to current merchant API

---
 talermerchantdemos/blog/blog.py | 56 ++++++++++++-----------------------------
 1 file changed, 16 insertions(+), 40 deletions(-)

(limited to 'talermerchantdemos/blog/blog.py')

diff --git a/talermerchantdemos/blog/blog.py b/talermerchantdemos/blog/blog.py
index a6e6be0..6c4c3ec 100644
--- a/talermerchantdemos/blog/blog.py
+++ b/talermerchantdemos/blog/blog.py
@@ -27,7 +27,6 @@ import flask
 import lxml.etree
 import time
 from urllib.parse import urljoin, urlencode, urlparse
-from cachelib import UWSGICache, SimpleCache
 from taler.util.talerconfig import TalerConfig
 from ..blog.content import ARTICLES, get_article_file, get_image_file
 from talermerchantdemos.httpcommon import backend_get, backend_post
@@ -95,16 +94,6 @@ def index():
     )
 
 
-##
-# @brief Cache for paid articles (in the form <session_id>-<article_name>),
-#        so we don't always have to ask the backend / DB, and so we don't
-#        have to store variable-size cookies on the client.
-try:
-    paid_articles_cache = UWSGICache(0, "paid_articles")
-except ImportError:
-    paid_articles_cache = SimpleCache()
-
-
 @app.route("/confirm-refund/<order_id>", methods=["GET"])
 def confirm_refund(order_id):
     # Here we don't care about the session ID
@@ -148,7 +137,6 @@ def refund(order_id):
         order_id=order_id, reason="Demo reimbursement", refund=ARTICLE_AMOUNT
     )
     resp = backend_post(BACKEND_URL, "refund", refund_spec)
-    paid_articles_cache.delete(session_id + "-" + article_name)
     return flask.redirect(pay_status["order_status_url"])
 
 
@@ -212,22 +200,17 @@ def article(article_name, data=None):
     # bound to a browser.  This forces re-play and prevents sharing the article
     # by just sharing the URL.
     session_id = flask.session.get("session_id")
-    order_id = flask.request.args.get("order_id")
+    order_id = flask.request.cookies.get("order_id")
 
     if not session_id:
         session_id = flask.session["session_id"] = str(uuid.uuid4())
-
-    cached_order_id = paid_articles_cache.get(session_id + "-" + article_name)
-    if cached_order_id:
-        return render_article(article_name, data, cached_order_id)
-
     ##
     # First-timer; generate order first.
     if not order_id:
         order = dict(
             amount=ARTICLE_AMOUNT,
             extra=dict(article_name=article_name),
-            fulfillment_url=flask.request.base_url + "?order_id=${ORDER_ID}",
+            fulfillment_url=flask.request.base_url,
             summary="Essay: " + article_name.replace("_", " "),
             # 10 minutes time for a refund
             refund_deadline=dict(t_ms=1000 * int(time.time() + 10 * 30)),
@@ -235,6 +218,7 @@ def article(article_name, data=None):
         )
         order_resp = backend_post(BACKEND_URL, "private/orders", dict(order=order))
         order_id = order_resp["order_id"]
+        flask.request.set_cookie("order_id", path=f"/essay/{article_name}")
 
     # Ask the backend for the status of the payment
     pay_status = backend_get(
@@ -244,24 +228,16 @@ def article(article_name, data=None):
     order_status = pay_status.get("order_status")
 
     if order_status == "paid":
-        # Checks to do:
-        #
-        # - check that the paid article is actually the one
-        #   mentioned in the requested URI.
-        #
-        # - check if the article was refunded before, and act
-        #   accordingly.
-
-        # FLOW HERE == ARTICLE PAID AND CAN BE SHOWN.
-
-        # Put the article in the cache.
-        paid_articles_cache.set(session_id + "-" + article_name, order_id)
-
-        ##
-        # Finally return the article.
-        return render_article(article_name, data, order_id)
-
-    ##
-    # Redirect the browser to a page where the wallet can
-    # run the payment protocol.
-    return flask.redirect(pay_status["order_status_url"])
+        refunded = pay_status["refunded"]
+        if refunded:
+            return flask.render_template(
+                "templates/article_refunded.html",
+                article_name=article_name,
+                order_id=order_id,
+            )
+        else:
+            return render_article(article_name, data, order_id)
+    else:
+        # Redirect the browser to a page where the wallet can
+        # run the payment protocol.
+        return flask.redirect(pay_status["order_status_url"])
-- 
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