adds ProxyFix for Cloud9

setup.py

@@ -16,5 +16,5 @@
     package_dir={"": "src"},
     packages=["cs50"],
     url="https://github.com/cs50/python-cs50",
-    version="2.4.5"
+    version="2.5.0"
 )

src/cs50/flask.py

@@ -1,4 +1,5 @@
 from distutils.version import StrictVersion
+from os import getenv
 from pkg_resources import get_distribution
 
 from .cs50 import formatException
@@ -9,12 +10,29 @@
     # Only patch >= 1.0
     version = StrictVersion(get_distribution("flask").version)
     assert version >= StrictVersion("1.0")
-    import flask.logging
 
     # Reformat logger's exceptions
     # http://flask.pocoo.org/docs/1.0/logging/
     # https://docs.python.org/3/library/logging.html#logging.Formatter.formatException
-    flask.logging.default_handler.formatter.formatException = lambda exc_info: formatException(*exc_info)
+    try:
+        import flask.logging
+        flask.logging.default_handler.formatter.formatException = lambda exc_info: formatException(*exc_info)
+    except:
+        pass
+
+    # Add support for Cloud9 proxy so that flask.redirect doesn't redirect from HTTPS to HTTP
+    # http://stackoverflow.com/a/23504684/5156190
+    if getenv("C9_PROJECT") == "ide50" and not getenv("IDE_OFFLINE"):
+        try:
+            import flask
+            from werkzeug.contrib.fixers import ProxyFix
+            before = flask.Flask.__init__
+            def after(self, *args, **kwargs):
+                before(self, *args, **kwargs)
+                self.wsgi_app = ProxyFix(self.wsgi_app)
+            flask.Flask.__init__ = after
+        except:
+            pass
 
 except:
     pass

tests/redirect/application.py

@@ -0,0 +1,12 @@
+import cs50
+from flask import Flask, redirect, render_template
+
+app = Flask(__name__)
+
+@app.route("/")
+def index():
+    return redirect("/foo")
+
+@app.route("/foo")
+def foo():
+    return render_template("foo.html")

tests/redirect/templates/foo.html

@@ -0,0 +1 @@
+foo