add simple error page generator

.gitignore

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+.vscode/
+
+build/
+*.egg-info/
+__pycache__/
+dist/
+
+.venv/
+venv/
+ttt/

LICENSE.txt

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+MIT License
+
+Copyright (c) 2025 Anthony Donlon
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

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+# Customizable Cloudflare error page generator
+
+## QuickStart Guide (Python)
+
+``` Bash
+pip install git+https://github.com/donlon/cloudflare-error-page.git
+```
+
+``` Python
+import webbrowser
+from cloudflare_error_page import render as render_cf_error_page
+
+error_page = render_cf_error_page({
+    'browser_status': {
+        "status": 'ok',
+    },
+    'cloudflare_status': {
+        "status": 'error',
+        "status_text": 'Not Working',
+    },
+    'host_status': {
+        "status": 'ok',
+        "location": 'example.com',
+    },
+    'error_source': 'cloudflare',  # 'browser', 'cloudflare', or 'host'
+
+    'what_happened': '<p>There is an internal server error on Cloudflare\'s network.</p>',
+    'what_can_i_do': '<p>Please try again in a few minutes.</p>',
+})
+
+with open('error.html', 'w') as f:
+    f.write(error_page)
+
+webbrowser.open('error.html')
+```
+
+## Examples
+
+``` Python
+params =  {
+    'title': 'Catastrophic infrastructure failure',
+    'more_information': {
+        "text": "cloudflare.com",
+        "link": "https://youtube.com/watch?v=dQw4w9WgXcQ",
+    },
+    'browser_status': {
+        'status': 'error',
+        'status_text': 'Out of Memory',
+    },
+    'cloudflare_status': {
+        'status': 'error',
+        'location': 'Everywhere',
+        'status_text': 'Not Working',
+    },
+    'host_status': {
+        'status': 'error',
+        'location': 'example.com',
+        'status_text': 'On Fire',
+    },
+    'error_source': 'cloudflare',
+    'what_happened': '<p>There is a catastrophic failure.</p>',
+    'what_can_i_do': '<p>Please try again in a few years.</p>',
+    'perf_sec_by': {
+        "text": "Cloudflare",
+        "link": "https://youtube.com/watch?v=dQw4w9WgXcQ",
+    },
+}
+```
+
+![Catastrophic infrastructure failure](doc/example.png)
+
+## Full Parameter Reference
+``` JavaScript
+{
+    "html_title": "cloudflare.com | 500: Internal server error",
+    "title": "Internal server error",
+    "error_code": 999,
+    "time": "2025-11-18 12:34:56 UTC",  // if not set, current UTC time is shown
+
+    // Configuration for "Visit ... for more information" line
+    "more_information": {
+        "hidden": false,
+        "text": "cloudflare.com", 
+        "link": "https://youtube.com/watch?v=dQw4w9WgXcQ",
+    },
+
+    // Configuration for the Browser/Cloudflare/Host status
+    "browser_status": {
+        "status": "ok", // "ok" or "error"
+        "location": "You",
+        "name": "Browser",
+        "status_text": "Working",
+        "status_text_color": "#9bca3e",
+    },
+    "cloudflare_status": {
+        "status": "error",
+        "location": "Cloud",
+        "name": "Cloudflare",
+        "status_text": "Not Working",
+        "status_text_color": "#bd2426",
+    },
+    "host_status": {
+        "status": "ok",
+        "location": "The Site",
+        "name": "Host",
+        "status_text": "Working",
+        "status_text_color": "#9bca3e",
+    },
+    "error_source": "host", // Position of the error indicator, can be "browser", "cloudflare", or "host"
+
+    "what_happened": "<p>There is an internal server error on Cloudflare's network.</p>",
+    "what_can_i_do": "<p>Please try again in a few minutes.</p>",
+
+    "ray_id": '0123456789abcdef',  // if not set, random hex string is shown
+    "client_ip": '1.1.1.1',
+
+    // Configuration for 'Performance & security by ...' in the footer
+    "perf_sec_by": {
+        "text": "Cloudflare",
+        "link": "https://youtube.com/watch?v=dQw4w9WgXcQ",
+    },
+}
+```

cloudflare_error_page/__init__.py

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+import os
+import secrets
+from datetime import datetime, timezone
+
+from jinja2 import Environment, PackageLoader, select_autoescape
+
+env = Environment(
+    loader=PackageLoader("cloudflare_error_page"),
+    autoescape=select_autoescape()
+)
+
+
+def get_resources_folder() -> str:
+    """
+    Get resources folder that contains stylesheet and icons for the error page.
+    If you pass resources_use_cdn=True to render(), local resources are not used.
+    """
+    return os.path.join(os.path.dirname(os.path.abspath(__file__)), 'resources')
+
+
+def render(params: dict, use_cdn: bool=True) -> str:
+    """
+    Render a customized Cloudflare error page.
+    """
+    params = {**params}
+    if not params.get('time'):
+        utc_now = datetime.now(timezone.utc)
+        params['time'] = utc_now.strftime("%Y-%m-%d %H:%M:%S UTC")
+    if not params.get('ray_id'):
+        params['ray_id'] = secrets.token_hex(8)
+
+    template = env.get_template("error.html")
+    return template.render(params=params, resources_use_cdn=use_cdn)

cloudflare_error_page/templates/error.html

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+{% set resources_cdn = 'https://cloudflare.com' if resources_use_cdn else '' %}
+
+<!DOCTYPE html>
+<!--[if lt IE 7]> <html class="no-js ie6 oldie" lang="en-US"> <![endif]-->
+<!--[if IE 7]>    <html class="no-js ie7 oldie" lang="en-US"> <![endif]-->
+<!--[if IE 8]>    <html class="no-js ie8 oldie" lang="en-US"> <![endif]-->
+<!--[if gt IE 8]><!--> <html class="no-js" lang="en-US"> <!--<![endif]-->
+<head>
+{% set error_code = params.error_code or 500 %}
+{% set title = params.title or 'Internal server error' %}
+<title>{{ params.html_title or ((error_code | string) + ': ' + title) }}</title>
+<meta charset="UTF-8" />
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+<meta http-equiv="X-UA-Compatible" content="IE=Edge" />
+<meta name="robots" content="noindex, nofollow" />
+<meta name="viewport" content="width=device-width,initial-scale=1" />
+<link rel="stylesheet" id="cf_styles-css" href="{{resources_cdn}}/cdn-cgi/styles/main.css" />
+</head>
+<body>
+<div id="cf-wrapper">
+    <div id="cf-error-details" class="p-0">
+        <header class="mx-auto pt-10 lg:pt-6 lg:px-8 w-240 lg:w-full mb-8">
+            <h1 class="inline-block sm:block sm:mb-2 font-light text-60 lg:text-4xl text-black-dark leading-tight mr-2">
+                <span class="inline-block">{{ title }}</span>
+                <span class="code-label">Error code {{ error_code }}</span>
+            </h1>
+            {% set more_info = params.more_information or {} %}
+            {% if not more_info.hidden or false %}
+            <div>
+                Visit <a href="{{more_info.link or 'https://www.cloudflare.com/'}}" target="_blank" rel="noopener noreferrer">{{more_info.text or 'cloudflare.com'}}</a> for more information.
+            </div>
+            {% endif %}
+            <div class="mt-3">{{ params.time }}</div>
+        </header>
+        <div class="my-8 bg-gradient-gray">
+          <div class="w-240 lg:w-full mx-auto">
+                <div class="clearfix md:px-8">
+                {% for item_id in ['browser', 'cloudflare', 'host'] %}
+                    {% if item_id == 'browser' %}
+                        {% set icon = 'browser' -%}
+                        {% set default_location = 'You' -%}
+                        {% set default_name = 'Browser' -%}
+                    {% elif item_id == 'cloudflare' %}
+                        {% set icon = 'cloud' -%}
+                        {% set default_location = 'San Francisco' -%}
+                        {% set default_name = 'Cloudflare' -%}
+                    {% else %}
+                        {% set icon = 'server' -%}
+                        {% set default_location = 'example.com' -%}
+                        {% set default_name = 'Host' -%}
+                    {% endif %}
+                    {% set item = params.get(item_id + '_status', {}) -%}
+                    {% set status = item.get('status', 'ok') -%}
+                    {% if item.status_text_color %}
+                        {% set text_color = item.status_text_color -%}
+                    {% elif status == 'ok' %}
+                        {% set text_color = '#9bca3e' -%} {# text-green-success #}
+                    {% elif status == 'error' %}
+                        {% set text_color = '#bd2426' -%} {# text-red-error #}
+                    {% endif %}
+                    {% set status_text = item.get('status_text', 'Working' if status == 'ok' else 'Not Working') -%}
+                    <div id="cf-{{item_id}}-status" class="{{'cf-error-source' if params.error_source == item_id else ''}} relative w-1/3 md:w-full py-15 md:p-0 md:py-8 md:text-left md:border-solid md:border-0 md:border-b md:border-gray-400 overflow-hidden float-left md:float-none text-center">
+                        <div class="relative mb-10 md:m-0">
+                            <span class="cf-icon-{{icon}} block md:hidden h-20 bg-center bg-no-repeat"></span>
+                            <span class="cf-icon-{{status}} w-12 h-12 absolute left-1/2 md:left-auto md:right-0 md:top-0 -ml-6 -bottom-4"></span>
+                        </div>
+                        <span class="md:block w-full truncate">{{item.location or default_location}}</span>
+                        <h3 class="md:inline-block mt-3 md:mt-0 text-2xl text-gray-600 font-light leading-1.3">{{item.name or default_name}}</h3>
+                        <span class="leading-1.3 text-2xl" style="color: {{text_color}}">{{status_text}}</span>
+                    </div>
+                {% endfor %}
+                </div>
+            </div>
+        </div>
+
+        <div class="w-240 lg:w-full mx-auto mb-8 lg:px-8">
+            <div class="clearfix">
+                <div class="w-1/2 md:w-full float-left pr-6 md:pb-10 md:pr-0 leading-relaxed">
+                    <h2 class="text-3xl font-normal leading-1.3 mb-4">What happened?</h2>
+                    {{ (params.what_happened or '<p>There is an internal server error on Cloudflare\'s network.</p>') | safe }}
+                </div>
+                <div class="w-1/2 md:w-full float-left leading-relaxed">
+                    <h2 class="text-3xl font-normal leading-1.3 mb-4">What can I do?</h2>
+                    {{ (params.what_can_i_do or '<p>Please try again in a few minutes.</p>') | safe }}
+                </div>
+            </div>
+        </div>
+
+        <div class="cf-error-footer cf-wrapper w-240 lg:w-full py-10 sm:py-4 sm:px-8 mx-auto text-center sm:text-left border-solid border-0 border-t border-gray-300">
+            <p class="text-13">
+                <span class="cf-footer-item sm:block sm:mb-1">Cloudflare Ray ID: <strong class="font-semibold">{{ params.ray_id }}</strong></span>
+                <span class="cf-footer-separator sm:hidden">&bull;</span>
+                <span id="cf-footer-item-ip" class="cf-footer-item hidden sm:block sm:mb-1">
+                    Your IP:
+                    <button type="button" id="cf-footer-ip-reveal" class="cf-footer-ip-reveal-btn">Click to reveal</button>
+                    <span class="hidden" id="cf-footer-ip">{{ params.client_ip or '1.1.1.1' }}</span>
+                    <span class="cf-footer-separator sm:hidden">&bull;</span>
+                </span>
+                {% set perf_sec_by = params.get('perf_sec_by', {}) %}
+                <span class="cf-footer-item sm:block sm:mb-1"><span>Performance &amp; security by</span> <a rel="noopener noreferrer" href="{{perf_sec_by.link or 'https://www.cloudflare.com/'}}" id="brand_link" target="_blank">{{perf_sec_by.get('text', 'Cloudflare')}}</a></span>
+            </p>
+        </div><!-- /.error-footer -->
+    </div>
+</div>
+<script>(function(){function d(){var b=a.getElementById("cf-footer-item-ip"),c=a.getElementById("cf-footer-ip-reveal");b&&"classList"in b&&(b.classList.remove("hidden"),c.addEventListener("click",function(){c.classList.add("hidden");a.getElementById("cf-footer-ip").classList.remove("hidden")}))}var a=document;document.addEventListener&&a.addEventListener("DOMContentLoaded",d)})();</script>
+</body>
+</html>

examples/example.py

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+import os
+import sys
+import webbrowser
+
+sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+from cloudflare_error_page import render as render_cf_error_page
+
+error_page = render_cf_error_page({
+    'browser_status': {
+        "status": 'ok',
+    },
+    'cloudflare_status': {
+        "status": 'error',
+        "status_text": 'Not Working',
+    },
+    'host_status': {
+        "status": 'ok',
+        "location": 'example.com',
+    },
+    'error_source': 'cloudflare',  # 'browser', 'cloudflare', or 'host'
+
+    'what_happened': '<p>There is an internal server error on Cloudflare\'s network.</p>',
+    'what_can_i_do': '<p>Please try again in a few minutes.</p>',
+})
+
+with open('error.html', 'w') as f:
+    f.write(error_page)
+
+webbrowser.open('error.html')

pyproject.toml

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+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "cloudflare-error-page"
+version = "0.0.1"
+description = "A customizable Cloudflare error page generator"
+authors = [{ name = "Anthony Donlon" }]
+license = { text = "MIT" }
+readme = "README.md"
+requires-python = ">=3.8"
+dependencies = [
+    "jinja2>=3.0"
+]
+
+[project.urls]
+Homepage = "https://github.com/donlon/cloudflare-error-page"
+
+[tool.hatch.build]
+include = [
+    "cloudflare_error_page/*.py",
+    "cloudflare_error_page/resources/*",
+    "cloudflare_error_page/templates/*",
+]