example: add flask server example

README.md

@@ -117,6 +117,11 @@ params = {
 
 ![Web server is working](doc/example2.png)
 
+### Using Flask server
+
+See [flask_server.py](examples/flask_server.py)
+
+
 ## Full Parameter Reference
 ``` JavaScript
 {

examples/flask_server.py

@@ -0,0 +1,67 @@
+import os
+import sys
+from flask import Flask, request, send_from_directory
+
+sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+from cloudflare_error_page import get_resources_folder, render as render_cf_error_page
+
+app = Flask(__name__)
+
+# You can use resources from Cloudflare CDN. But in case of changing, you can set use_cdn = False to use bundled resources.
+use_cdn = True
+
+if use_cdn:
+    res_folder = get_resources_folder()
+
+    # This handler is used to provide stylesheet and icon resources for the error page. If you pass use_cdn=True to render_cf_error_page
+    # or if your site is under proxy of Cloudflare (the cdn-cgi folder is already provided by Cloudflare), this handler can be removed.
+    @app.route("/cdn-cgi/<path:path>")
+    def cdn_cgi(path):
+        return send_from_directory(res_folder, path)
+
+
+@app.route("/")
+def index():
+    # Get real Ray ID from Cloudflare header
+    ray_id = request.headers.get('Http-Cf-Ray', '')
+
+    # Get real client ip from Cloudflare header or request.remote_addr
+    client_ip = request.headers.get('Http-X-Forwarded-For')
+    if not client_ip:
+        client_ip = request.remote_addr
+
+    # Render the error page
+    return render_cf_error_page({
+        'html_title': '500: Internal server error',
+        'title': 'Internal server error',
+        'error_code': 500,
+        'more_information': {
+            "hidden": False,
+            "text": "cloudflare.com",
+            "link": "https://youtube.com/watch?v=dQw4w9WgXcQ",
+        },
+        '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>',
+        'ray_id': ray_id,
+        'client_ip': client_ip,
+        'perf_sec_by': {
+            "text": "Cloudflare",
+            "link": "https://youtube.com/watch?v=dQw4w9WgXcQ",
+        },
+    }, use_cdn=use_cdn), 500
+
+
+if __name__ == "__main__":
+    app.run(debug=True)