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Does anyone know how to serve an Angular single page application using Flask?
I'm having trouble serving the default route, '/', which should load index.html and the associated components. Here's my Flask function:
@app.route('/')
def hello_world():
return send_file('templates/dist/templates/index.html')
When I visit localhost:5000, I get an empty Chrome browser window:
and the following errors in Chrome's dev console:
This is what should appear in Chrome:
I expect the errors are because Flask doesn't know where to find the supporting files to render the Angular components. As instructed in Angular's quickstart tutorial, my index.html is mostly empty, with app-root as a placeholder for the HTML body element:
<body>
<app-root></app-root>
<script type="text/javascript" src="runtime.js"></script><script type="text/javascript" src="polyfills.js"></script><script type="text/javascript" src="styles.js"></script><script type="text/javascript" src="vendor.js"></script><script type="text/javascript" src="main.js"></script></body>
Does anyone know how to tell Flask to let Angular render a page?
225
To simplify the setup, consider using Angular CLI to place all of the files in a distribution directory during the build process, i.e., by specifying the outputPath in angular.json. You can use the angular.json assets section to move your Python files during the build.
"your-project": {
"root": "your-project-directory",
"sourceRoot": "your-project-directory/src",
"projectType": "application",
"architect": {
"build": {
"builder": "@angular-devkit/build-angular:browser",
"options": {
"outputPath": "dist",
"index": "your-project-directory/src/index.html",
"main": "your-project-directory/src/main.ts",
...
"assets": [
{
"glob": "**/*",
"input": "your-project-directory/src/assets/",
"output": "assets"
},
{
"glob": "**/*",
"input": "your-project-directory/src/python/",
"output": "."
}
In the top level of the dist directory, place your main.py with the basic Flask setup along with index.html. Note the static_proxy to ensure that supporting files are served.
from flask import Flask, send_from_directory
app = Flask(__name__)
@app.route('/<path:path>', methods=['GET'])
def static_proxy(path):
return send_from_directory('./', path)
@app.route('/')
def root():
return send_from_directory('./', 'index.html')
if __name__ == '__main__':
# This is used when running locally only. When deploying use a webserver process
# such as Gunicorn to serve the app.
app.run(host='127.0.0.1', port=8080, debug=True)
@app.errorhandler(500)
def server_error(e):
return 'An internal error occurred [main.py] %s' % e, 500
This is an old question but accepted answer did not work for me. So here is my solution that works with angular routing:
My folder structure:
/angular
/src
angular.json
... angular project files
/public
index.html
... angular build files
/venv
server.py
In my angular.json I changed outputPath to achive above structure:
"outputPath": "../public"
And in server.py:
import os.path
@app.route("/custom-endpoint")
def custom_endpoint_handler():
return jsonify(myKey="myValue")
# Serving static files
@app.route('/', defaults={'path': ''})
@app.route('/<string:path>')
@app.route('/<path:path>')
def static_proxy(path):
if os.path.isfile('public/' + path):
# If request is made for a file by angular for example main.js
# condition will be true, file will be served from the public directory
return send_from_directory('public', path)
else:
# Otherwise index.html will be served,
# angular router will handle the rest
return app.send_static_file("index.html")
Footnote: I am new to flask. So any improvements or fixes if there are any errors are welcomed.
23
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