Flask beginner here, bear with me please !
In this little piece of code I simplified for the question, I have for a defined route / with 2 forms : I'd like the add form to add things to the db and the delete form to delete things, simple.
However my issue is that in this code I can't differentiate which input button from the form is pressed as formadd.validate() and formdel.validate() both always return true.
How can I differentiate which submit button is pressed in order to manipulate the database accordingly ?
At first I wrote what is currently commented below, but obviously it doesn't work since the validate method returns true....
from flask import Flask, render_template, request
from flask.ext.sqlalchemy import SQLAlchemy
from wtforms import Form, StringField
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///botdb.db'
db = SQLAlchemy(app)
class BotFormAdd(Form):
botname = StringField('bot name')
botdescription = StringField('bot description')
class BotFormDelete(Form):
botid = StringField('bot id')
#app.route('/', methods=['GET', 'POST'])
def index():
formadd = BotFormAdd(request.form)
formdel = BotFormDelete(request.form)
if request.method == 'POST':
print(formadd.validate(), formdel.validate())
# if request.method == 'POST' and formadd.validate():
# print('in formadd')
# bot = Bot(name=formadd.botname.data, description=formadd.botdescription.data)
# db.session.add(bot)
# db.session.commit()
# return redirect(url_for('index'))
# if request.method == 'POST' and formdel.validate():
# print('in formdel')
# db.session.delete(formdel.botid.data)
# db.session.commit()
# return redirect(url_for('index'))
return render_template('index.html', title='Home', formadd=formadd, formdel=formdel)
if __name__ == '__main__':
app.run(debug=True)
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title>this is a test</title>
</head>
<body>
<form method=post action="/">
<dl>
{{ formadd.botname }}
{{ formadd.botdescription }}
</dl>
<p><input type=submit name='add' value='add this'>
</form>
<form method=post action="/">
<dl>
{{ formdel.botid }}
</dl>
<p><input type=submit name='delete' value='delete this'>
</form>
</body>
</html>
There's lots of ways of doing this, but it breaks down into two categories-- either you indicate it via the route, or via an element on a form.
Most people would just add separate routes:
#app.route('/delete-bot/', methods=['post'])
def delete_bot():
form = BotFormDelete()
if form.validate():
delete_bot(id=form.botid.data)
flash('Bot is GONE')
return redirect(url_for('index'))
So your delete form would submit to that route, get processed and sent back to index.
<form method='post' action='url_for('delete_bot')>
And you'd have a different route for adding a bot.
Alternatively you could check what type of form it was from it's contents. E.g.
if request.form.get('botid'):
# it has a botid field, it must be a deletion request
form = BotFormDelete()
form.validate()
delete_bot(form.botid.data)
else:
form = BotFormAdd()
....
But that way seems like it would get messy quickly.
Related
This question already has answers here:
Passing HTML to template using Flask/Jinja2
(7 answers)
Closed 4 months ago.
I have this code that compute the similarity between 2 strings:
import spacy
from spacy.lang.pt.examples import sentences
X ="some string 1"
Y ="some string 2"
nlp = spacy.load('pt_core_news_sm')
X_nlp = nlp(X)
Y_nlp = nlp(Y)
token_x = [token.text for token in X_nlp]
token_y = [token.text for token in Y_nlp]
print("Similarity:", X_nlp.similarity(Y_nlp))
Now I want to transform this code in an API with flask, I tried to follow a tutorial:
from flask import Flask,render_template,url_for,request
import re
import spacy
from spacy.lang.pt.examples import sentences
nlp = spacy.load('pt_core_news_sm')
app = Flask(__name__)
#app.route('/',methods=["POST"])
def process():
X_nlp = nlp(input())
Y_nlp = nlp(input())
print("Similarity:", X_nlp.similarity(Y_nlp))
if __name__ == '__main__':
app.run(debug=True)
the code above returns: "GET / HTTP/1.1" 405 -
You are trying to reach the URL "/". However, within your code there is no route defined for this path. Thus, the error 404 is returned.
You need a route that accepts both a GET and a POST request to both display a form and receive data from a submitted form sent via POST.
Otherwise, a 405 error is returned because the request method is not allowed.
#app.route('/', method=['GET', 'POST'])
def index():
if request.method == 'POST':
# Handle a POST request and the data sent here.
# ...
Within Flask it is not possible to request input with input().
As mentioned above, you need a form within an HTML page. Within this form you can define input fields that must be provided with a name attribute in order to query them on the server side.
<form method="POST">
<input type="text" name="x" />
<input type="text" name="y" />
<input type="submit">
</form>
If the submit button is now pressed, the data of the form, as defined in the method attribute, is sent to the server via POST and can be queried here. The input fields are queried using the name attribute.
Finally, the endpoint must have a return value. In your case, this is the template that displays the page with the form and outputs the possible result.
#app.route('/', methods=['GET', 'POST'])
def index():
if request.method == 'POST':
x = request.form.get('x', '')
y = reutest.form.get('y', '')
# ...
return render_template('index.html')
So the entire code of your application should look something like this.
Flask (app.py)
from flask import (
Flask,
render_template,
request
)
import spacy
nlp = spacy.load('pt_core_news_sm')
app = Flask(__name__)
#app.route('/', methods=['GET', 'POST'])
def index():
if request.method == 'POST':
# Handle a POST request and the data sent here.
x_nlp = nlp(request.form.get('x', ''))
y_nlp = nlp(request.form.get('y', ''))
resultado = x_nlp.similarity(y_nlp)
# Return a rendered template and pass defined variables to the template.
return render_template('index.html', **locals())
HTML (templates/index.html)
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Index</title>
</head>
<body>
<form method="POST">
<input type="text" name="x" />
<input type="text" name="y" />
<input type="submit">
</form>
{% if resultado -%}
<p>Similaridade: {{ resultado }}</p>
{% endif -%}
</body>
</html>
This question already has answers here:
Get the data received in a Flask request
(23 answers)
Closed 2 years ago.
I'm new to flask and web programming in general. I'm trying a simple example. I have a HTML base template that shows a text box and a picture of an animal. The template is rendered by flask. The idea is that a user can type the name of a new animal in the text box and the picture changes to the new animal.
I tested the code. There is a problem - that the input text given in the html textbox doesn't seem to go to the proper app.route. Or at least I can't figure out (as I'm running on pythonanywhere and the print statements in the server don't show up on console).
Here is the code and the template. Please let me know what I'm doing wrong. Thanks!
Here is the flask_app.py:
from flask import render_template
from flask import request, redirect
from flask import Flask
app = Flask(__name__)
#app.route('/')
def index():
imgname = "tiger2.png"
return render_template('untitled1.html', title='TIGER', fname=imgname)
#app.route('/', methods=['POST', 'GET'])
def imgshow(animal):
#assert request.method == 'POST'
#print("New request!")
animal = request.form['animal']
if animal.lower() == 'tiger':
imgname = 'tiger2.png'
elif animal.lower() == 'lion':
imgname = 'lion1.png'
elif animal.lower() == 'panther':
imgname = 'panther.png'
else:
imgname = 'lion1.png'
return render_template('untitled1.html', title=animal.upper(), fname=imgname)
And here is the template untitled1.html
<!DOCTYPE html>
<html>
<head>
<title>{{ title }}</title>
</head>
<body>
<!-- Serving an Image -->
<h1>Hello, World!</h1>
<form action="">
<label for="animal">Animal: </label>
<input type="text" id="animal" name="animal"><br><br>
</form>
<img src="{{ url_for('static', filename=fname ) }}" alt="Tiger">
</body>
</html>
Try this:
from flask import render_template
from flask import request, redirect
from flask import Flask
app = Flask(__name__)
#app.route('/', methods=['GET', 'POST'])
def index():
if request.method == 'GET':
imgname = "tiger2.png"
title='TIGER'
else:
variants = {
'tiger': 'tiger2.png',
'lion': 'lion1.png',
'panther': 'panther.png'
}
animal = request.form.get('animal').lower()
imgname = variants.get(animal)
title = animal.upper()
return render_template('untitled1.html', title='TIGER', fname=imgname)
For me, the best approach is to use only the GET method:
from flask import Flask, render_template, request, redirect
app = Flask(__name__)
animals = {'tiger': 'tiger2.png', \
'lion': 'lion1.png', \
'panther': 'panther.png'}
#app.route('/')
def index():
animal = request.args.get('animal', 'tiger')
image = animals.get(animal, 'lion')
return render_template('untitled1.html', title=animal.upper(), fname=image)
The POST method is best when you need to do some processing (write data from the database) and then redirect to another GET route.
app.route registers that under the given web address (in your case \), the function listed just below be implemented. The problem is that you have two functions registered under the same route which means that the first registration is erased.
You don't need the first app.route. It basically should say that the default value of an animal is a tiger. The second function should be modified as below:
display_map = {
'tiger': 'tiger2.png',
'lion': 'lion1.png',
'panther': 'panther.png'
}
#app.route('/', methods=['POST', 'GET'])
def imgshow(animal):
if request.method == 'POST':
animal = request.form.get('animal', 'lion').lower()
imgname = display_map.get(animal, 'lion1.png')
return render_template('untitled1.html', title=animal.upper(), fname=imgname)
else:
return render_template('untitled1.html', title='TIGER', fname='tiger.png')
And you also need to actually submit results to the server.
<html>
<head>
<title>{{ title }}</title>
</head>
<body>
<!-- Serving an Image -->
<h1>Hello, World!</h1>
<form method="POST">
<label for="animal">Animal: </label>
<input type="text" id="animal" name="animal"><br><be>
<input type="submit" name="submit" value="submit">
</form>
<img src="{{ url_for('static', filename=fname ) }}" alt="Tiger">
</body>
</html>
I'm trying to implement a simple dashboard with Flask that will:
Accept a user text input, with a "submit" button. POST this user input to flask.
Flask accepts this input, does some stuff to it, then makes a GET request to another API.
This GET request returns data and shows it somehow (can just be console.log for now)
As an example, with the star wars API:
User inputs name of a Star Wars character (assume no spelling errors)
Flask reads this input name, and maps it to an ID number, because the Star Wars API accepts id numbers. Form a GET request to the Star Wars API, to get full character information.
For now, we can just console.log character information (e.g. "height", "mass", etc.)
What I have now:
app.py
from flask import Flask, jsonify, request, render_template
import random
import json
app = Flask(__name__)
#app.route("/")
def index():
return render_template('index.html')
#app.route("/form_example", methods=["GET", "POST"])
def form_example():
if request.method == "POST":
language = request.form("character_name")
starwars_dictionary = {"Luke Skywalker":"1", "C-3PO":"2", "R2-D2": "3"}
# starwars_dictionary is a dictionary with character_name:character_number key-value pairs.
# GET URL is of the form https://swapi.co/api/people/<character_number>
return render_template("index.html")
if __name__ == "__main__":
app.run(debug=True)
index.html
<!DOCTYPE html>
<html>
<head>
<title>py-to-JS</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
</head>
<body>
<h3>Sample Inputs</h3>
<ul>
<li>Luke Skywalker</li>
<li>C-3PO</li>
<li>R2-D2</li>
</ul>
<form method="POST">
Enter Name: <input type="text" name="character_name"><br>
<input type="submit" value="Submit"><br>
</form>
</body>
</html>
In this current form, when I run the app, it returns "Method not allowed; this method is not allowed for the requested URL".
I'm not sure what I'm missing; it's probably just not wired together properly but I'm not sure what the proper syntax is.
Working version after implementing the accepted answer:
app.py
from flask import Flask, jsonify, request, render_template
import requests
import random
import json
app = Flask(__name__)
#app.route("/index", methods=["GET", "POST"])
def index():
#character_height = "" # init a default value of empty string...seems unwieldy
if request.method == "POST":
character_name = request.form.get("character_name")
# Map user input to a numbers
starwars_dictionary = {"Luke Skywalker":"1", "C-3PO":"2", "R2-D2": "3"}
char_id = starwars_dictionary[character_name]
url = "https://swapi.co/api/people/"+char_id
response = requests.get(url)
response_dict = json.loads(response.text)
character_height = response_dict["height"]
return render_template("index.html", character_height=character_height)
return render_template("index.html")
##app.route("/form_example", methods=["GET", "POST"])
#def form_example():
if __name__ == "__main__":
app.run(debug=True)
index.html
<!DOCTYPE html>
<html>
<head>
<title>py-to-JS</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
</head>
<body>
<h3>Sample Inputs</h3>
<ul>
<li>Luke Skywalker</li>
<li>C-3PO</li>
<li>R2-D2</li>
</ul>
<form method="POST" action="/index">
Enter Name: <input type="text" name="character_name"><br>
<input type="submit" value="Submit"><br>
</form>
{{ character_height }}
</body>
</html>
Probably the form is posting to the / endpoint, because you didn't declare a form action.
Needs to be more like:
<form method="POST" action="/form_example">
Or if you want to get snazzy and use Jinja's url_for function:
<form method="POST" action="{{ url_for('form_example') }}">
EDIT: That said, you could handle this with a single route function:
#app.route("/", methods=["GET", "POST"])
def index():
if request.method == "POST":
language = request.form("character_name")
starwars_dictionary = {"Luke Skywalker":"1", "C-3PO":"2", "R2-D2": "3"}
# Logic to query remote API ges here.
else: # Assume method is GET
return render_template("index.html")
Then make the form action {{ url_for('index') }}
I am closely following the very brief tutorial from Flask-wtf here. I have an issue where after I submit my name in my submit page form, it gives a "405 Method Not Allowed" message instead of directing me to the success page.
from flask import Flask, render_template, redirect
from forms import MyForm
app = Flask(__name__)
app.secret_key = 'mysecretKey'
#app.route('/submit', methods=('GET', 'POST'))
def submit():
form = MyForm()
if form.validate_on_submit():
return redirect('/success')
return render_template('submit.html', form=form)
#app.route('/success')
def success():
return "Well done for entering your name!"
if __name__ == '__main__':
app.run(debug=True)
My form is here:
from flask_wtf import FlaskForm
from wtforms import StringField
from wtforms.validators import DataRequired
class MyForm(FlaskForm):
name = StringField('name', validators=[DataRequired()])
My submit.html code is shown below (just like in the tutorial):
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Password page</title>
</head>
<body>
<form method="POST" action="/">
{{ form.hidden_tag() }}
{{ form.name.label }} {{ form.name(size=20) }}
<input type="submit" value="Go">
</form>
</body>
</html>
EDIT: The if form.validate_on_submit() condition does not return True so the contents of the loop do not execute. I added a simple print statement in it which didn't execute.
I'd be lying if I pretended to know exactly how all relative paths are resolved. However, you can fix this by changing:
<form method="POST" action="/">
to:
<form method="POST" action="{{ url_for('submit') }}">
It's one of those things that it really does make sense to pass the issue off to the library to figure out. Use url_for which also works in Jinja2 when rendering the template.
The problem is you are not mentioning that the method success should handle POST requests.
from flask import Flask, render_template, redirect
from forms import MyForm
app = Flask(__name__)
app.secret_key = 'mysecretKey'
#app.route('/submit', methods=('GET', 'POST'))
def submit():
form = MyForm()
if form.validate_on_submit():
return redirect('/success')
return render_template('submit.html', form=form)
#app.route('/success')
def success():
return "Well done for entering your name!"
if __name__ == '__main__':
app.run(debug=True)
with
from flask import Flask, render_template, redirect
from forms import MyForm
app = Flask(__name__)
app.secret_key = 'mysecretKey'
#app.route('/submit', methods=['GET', 'POST'])
def submit():
form = MyForm()
if form.validate_on_submit():
return redirect('/success')
return render_template('submit.html', form=form)
# This is the change I made.
#app.route('/success', methods=['POST'])
def success():
return "Well done for entering your name!"
if __name__ == '__main__':
app.run(debug=True)
I am new to flask and web development, I follow a tutorial and I get Internal Server Error. i get the error when trying to access #app.route('question/<title>') by entering the Url "/question/title"
code:
from flask import flash, url_for, request, render_template
from app import app
import redis
#connect to redis data store
r = redis.StrictRedis(host='localhost', port=6379, db=0, charset='utf-8', decode_responses= True)
#alternate ways to connect to redis, each command is equivalent
#r = redis.StrictRedis()
#r = redis.StrictRedis('localhost', 6379, 0)
# server/
#app.route('/')
def hello():
#ceating a link to the second page
create_page = url_for('create')
return 'Creat Question'
# server/create
#app.route('/create', methods =['GET', 'POST'])
def create():
if request.method == 'GET':
# send to user the form
return render_template('CreateQuestion.html')
elif request.method == 'POST':
#read the data and save it
title = request.form['title']
answer = request.form['answer']
question = request.form['question']
#store data in data store
r.set(title + ':question', question)
r.set(title + ':answer', answer)
return render_template('CreatedQuestion.html', question = question)
else:
return "<h2>Invalid request</h2>"
#app.route('/question/<title>', methods = ['GET', 'POST'])
def question(title):
if request.method == 'GET':
# send the user the form
question = r.get(title + ':question')
return render_template('AnswerQuestion.html', question = question)
elif requset.method == 'POST':
# user has attempt answer. cheak if they're correct
submittedAnswer = request.form['submittedAnswer']
answer = r.get(title + ':answer')
if submittedAnswer == answer:
return render_template('Correct.html')
else:
return render_template('Incorrect.html', submittedAnswer = submittedAnswer, answer = answer)
else:
return '<h2>Invalid request</h2>'
I get the title from here:
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title>Create a new question</title>
</head>
<body>
<h2>Please create a new question</h2>
<form method="post">
<div>
<label for="title">Title</label>
<input type="text" name="title" />
</div>
<div>
<label for="question">Question</label>
<input type="text" name="question" />
</div>
<div>
<label for="answer">Answer</label>
<input type="text" name="answer" />
</div>
<button type="submit">Submit question</button>
</form>
</body>
</html>
The app is simply a question and answer app, I have four HTML files in Jinja templates folder, it's supposed to take the title from the user input and replace it with the function argument, so if I enter "python" as a title the Url must become "/question/python", that what I trying to do.
So can anyone tell me what I missed?
I thought what you want is redirect():
from flask import Flask, redirect, url_for, render_template
...
#app.route('/create', methods =['GET', 'POST'])
def create():
if request.method == 'POST'
...
return redirect(url_for('question', title=title)) # this line
...
#app.route('/question/<title>', methods = ['GET', 'POST'])
def question(title):
...