Better constant value management (#1335)

* Starts work on #929 
* Adds Enum classes that can be accessed from JS, Jinja, and Python code. This allows for the sharing of constant values between the three major codebases in CTFd.

CTFd/constants/__init__.py

@@ -0,0 +1,63 @@
+from enum import Enum
+from flask import current_app
+
+JS_ENUMS = {}
+
+
+class RawEnum(Enum):
+    """
+    This is a customized enum class which should be used with a mixin.
+    The mixin should define the types of each member.
+
+    For example:
+
+    class Colors(str, RawEnum):
+        RED = "red"
+        GREEN = "green"
+        BLUE = "blue"
+    """
+
+    def __str__(self):
+        return str(self._value_)
+
+    @classmethod
+    def keys(cls):
+        return list(cls.__members__.keys())
+
+    @classmethod
+    def values(cls):
+        return list(cls.__members__.values())
+
+    @classmethod
+    def test(cls, value):
+        try:
+            return bool(cls(value))
+        except ValueError:
+            return False
+
+
+def JSEnum(cls):
+    """
+    This is a decorator used to gather all Enums which should be shared with
+    the CTFd front end. The JS_Enums dictionary can be taken be a script and
+    compiled into a JavaScript file for use by frontend assets. JS_Enums
+    should not be passed directly into Jinja. A JinjaEnum is better for that.
+    """
+    if cls.__name__ not in JS_ENUMS:
+        JS_ENUMS[cls.__name__] = dict(cls.__members__)
+    else:
+        raise KeyError("{} was already defined as a JSEnum".format(cls.__name__))
+    return cls
+
+
+def JinjaEnum(cls):
+    """
+    This is a decorator used to inject the decorated Enum into Jinja globals
+    which allows you to access it from the front end. If you need to access
+    an Enum from JS, a better tool to use is the JSEnum decorator.
+    """
+    if cls.__name__ not in current_app.jinja_env.globals:
+        current_app.jinja_env.globals[cls.__name__] = cls
+    else:
+        raise KeyError("{} was already defined as a JinjaEnum".format(cls.__name__))
+    return cls

manage.py

@@ -12,6 +12,21 @@ manager = Manager(app)
 manager.add_command("db", MigrateCommand)
 
 
+def jsenums():
+    from CTFd.constants import JS_ENUMS
+    import json
+    import os
+
+    path = os.path.join(app.root_path, "themes/core/assets/js/constants.js")
+
+    with open(path, "w+") as f:
+        for k, v in JS_ENUMS.items():
+            f.write("const {} = Object.freeze({});".format(k, json.dumps(v)))
+
+
+BUILD_COMMANDS = {"jsenums": jsenums}
+
+
 @manager.command
 def get_config(key):
     with app.app_context():
@@ -24,5 +39,12 @@ def set_config(key, value):
         print(set_config_util(key, value).value)
 
 
+@manager.command
+def build(cmd):
+    with app.app_context():
+        cmd = BUILD_COMMANDS.get(cmd)
+        cmd()
+
+
 if __name__ == "__main__":
     manager.run()

tests/constants/test_constants.py

@@ -0,0 +1,52 @@
+from CTFd.constants import RawEnum, JSEnum, JinjaEnum
+from tests.helpers import create_ctfd, destroy_ctfd
+
+
+def test_RawEnum():
+    class Colors(str, RawEnum):
+        RED = "red"
+        GREEN = "green"
+        BLUE = "blue"
+
+    class Numbers(str, RawEnum):
+        ONE = 1
+        TWO = 2
+        THREE = 3
+
+    assert Colors.RED == "red"
+    assert Colors.GREEN == "green"
+    assert Colors.BLUE == "blue"
+    assert Colors.test("red") is True
+    assert Colors.test("purple") is False
+    assert str(Numbers.ONE) == "1"
+    assert sorted(Colors.keys()) == sorted(["RED", "GREEN", "BLUE"])
+    assert sorted(Colors.values()) == sorted(["red", "green", "blue"])
+
+
+def test_JSEnum():
+    from CTFd.constants import JS_ENUMS
+    import json
+
+    @JSEnum
+    class Colors(str, RawEnum):
+        RED = "red"
+        GREEN = "green"
+        BLUE = "blue"
+
+    assert JS_ENUMS["Colors"] == {"RED": "red", "GREEN": "green", "BLUE": "blue"}
+    assert json.dumps(JS_ENUMS)
+
+
+def test_JinjaEnum():
+    app = create_ctfd()
+    with app.app_context():
+
+        @JinjaEnum
+        class Colors(str, RawEnum):
+            RED = "red"
+            GREEN = "green"
+            BLUE = "blue"
+
+        assert app.jinja_env.globals["Colors"] is Colors
+        assert app.jinja_env.globals["Colors"].RED == "red"
+    destroy_ctfd(app)