Flask return a variable In my Flask project, I want to select everything from a table in database and print each row in separate line? Normally, cursor. text = text. html", I'm trying to understand how best to redirect and pass arguments using Flask Below is my code, I'm finding that x and y are not making it into the template. callback( Output('my-hidden-div','children'), [Input('my-input','value')] # whatever this will be ) def If you are searching literally the way to return a JSON list in flask and you are completly sure that your variable is a list then the easy way is (where bin is a list of 1's and 0's): return jsonify({'ans':bin}), 201 Finally, in your client you will obtain something like I would recommend using Socket. -1; this answer doesn't make sense. When a user clicks on one of them, it should send a variable (variable name is value) with text to the second page. 8934276, -103. You can either return your tuple as a formatted str. html : The reason is that jinja2 needs to be used to perform the substitution, which from your code doesn't appear to be happening. html is template name and data is variables to be passed to the template. It’s easy to get started writing such an API with Flask. x = None You'd be better off using the membership testing with in here:. Related. dumps({"main":"Condition failed on page baz"}) session['messages'] = messages return You should avoid putting large amounts of data in the session, since it has to be sent to and from the client every request. return render_template("index. For large amounts of data, use a database or other data storage. 2. return render_template('main. The general setup of my Flask file is (I am trying to print Use something like this as per latest flask version 3. What is the difference between returning a String and returning plain text? If you return a string Flask will automatically handle some of the Response logic for you. route('/') def db(): db = MySQLdb. 83. . This happens because text and content have been decoded, so there will be a mismatch between the header-reported encoding and the actual encoding. There are two workarounds to this: Break up the text into an array. I think (based on the phrasing "a script which is sourced using flask" and your apparent expectation that you'd be able to use template variables in /static/test123. I failed to understand and I feel completely ignorant and gave up understanding what is going on. Sadique Khan Sadique Khan. html' %} Body {% include 'footer. This will render template and substitute dynamic value every time you visit the page. In this small quick post, I will explain how to pass Variables or Parameters to the Web page build using Flask in Python. context(). Did you know you can use f-Strings inside Flask? This is one of the most simple ways. According to the documentation:. split('\n') In this case, it may be best to create two routes: one to serve the form, and the other to receive the values and render them back to the user: Return multiple variables in flask. They're not a Flask feature. The browser, when it parses such a script, makes a separate HTTP request to get the I'm having troubles getting a Flask/Python variable passed to Javascript. const chart-data = document. Then you can access that variable through jinja2 like this: <p>Random number: {{ number }}</p> If you want to assign the variable passed from flask to another variable created in jinja2 (you wanna make a copy, I don't know) just write: {% set new_var = number %} Now you can use the variable new_var in the jinja2 code. Create a JavaScript function that will send the variable to the Flask route using an AJAX request. The first page has two buttons. try: g. @app. Flask, How to response a string to html? 1. How do I return the value back from the python, and how can I display it in the html. js from a URL which is tied to an action I am trying to access data from an HTML form and use it in Flask. Flask-wtforms Redirect on Form Submission and Pass Variables. 3690 Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company You could try to genrate the random hex values as you did (or the way I did, by just just slightly improving code with random. Then use another callback with the children of that div as its Input, and you'll be able to read the JSON and use that data. very well. (43. I found many topics talking about flask. g and app. The Python imports will look something like this: from flask_socketio import SocketIO, emit from flask import Flask, redirect, render_template, request, session You can access the variable using a data attribute on an html element. from flask import render_template as real_render_template from yourapp import user # Import the user variable or set it def render_template(*args, **kwargs): return real_render_template(*args, **kwargs, user=user) I am trying to control a motor using PWM, using Flask and Python on a Raspberry Pi. if 'x' not in g: g. I would also line to use the results of that function in other functions. 0. Wanna increase new_var? Do: You could pass the messages as explicit URL parameter (appropriately encoded), or store the messages into session (cookie) variable before redirecting and then get the variable before rendering the template. python; html; { return render_template("index3. return render_template('my_other_template. This is the 3rd article of the series “Build A Website Using Flask in Python”. please help. Chances are you're serving app. html' %} Included templates have access to the variables of the active context by default. io along with Flask to perform real-time event handling without needing to refresh the page. fetchall() returns a list of tuples, so just save that list into a variable and return it, then loop through the returned value, this way. html", user_imagesrc = full_filename ,user_labelsrc=userlabel)} but this cant use when i have stream the I have a function that I want to call each time a web visitor hits '/'(home page). js as a static file, which means that it is never looked at by the templating engine machinery, just served as is. x = 'Already defined' return 'x is now defined' else: return g. I want to display the string on the same HTML page. Using text or content property of the Response object will not work if the server returns encoded data (such as content-encoding: gzip) and you return the headers unchanged. Hot Network Questions Ramifications of having each chapter be a different 'episode' in a novel? Prevent dist-upgrade from uninstalling a package without using apt-mark hold A simple perspective on the Hard Problem of Consciousness Word or concise way to describe the emotional contrast of a cemetery in a Accessing an attribute throws AttributeError, not NameError:. I was successfully able to get the data but I am not quite sure how to return it through function and use the returned variable inside FLask as a global variable. getAttribute("data-chart") That should get hold of the variable from the flask app. js) that you're misunderstanding how <script>s with srcs work. I have tried the solution in How to display a variable in HTML and it doesn't work for me. all_data = {'dest':destrow,'date':daterow, 'dtime':dtimerow} return jsonify(all_data) js You can do so by creating a custom render template function using the following implementation. sample and range) in your code example and pass that value into the template context, where you would put it somewhere in <style> tag. format(firstname, lastname, cellphone) Or you can pass the values into another template. x except AttributeError: g. Using flask, how can I return a row of data as a list. I like making variables for things, even if all I do is return them, because it makes working with the python debugger (or pdbpp) easier: you can set a breakpoint for the line We can use variables inside the templates by following these two steps: The object is provided as a named argument to the render_template() function. In this article, we will discuss Flask-Variable Rule using Python. Improve this answer. I am working on a small Flask app and I am having trouble finding the way to access a javascript array from Python to be printed as csv. Flask return redirect How do I return that list as a useable list of variables? And how do I then make that list appear in my jinja2 template in an option dropdown. For example: from flask import session, url_for def do_baz(): messages = json. Using the flask_restful library with Steps for passing JavaScript variables to Python in Flask: Create a Flask route that will receive the JavaScript variable. 2. Here, the value will simply appear in the browser window as part of a string. querySelector("#chart-div"). You can accomplish what you're describing by serving app. I guess I need a function but I am a green programmer. If you want to return some variables for your request, you can do: So a full A common response format when writing an API is JSON. connect("localhost","myusername The accepted answer is correct, but I wanted to add the method that it appears the OP was originally trying in his http request. html Return javascript variable in Python / Flask. index. Flask. Flask is a microweb framework written in Python it is classified as a micro framework because it doesn’t require particular tools or libraries, and it has no database abstraction layer form validation or any other components where pre-existing third-party libraries provide common functions it is designed to You could output the contents of the dataframe in JSON format to the children prop of a div with display='none'. Asking for help, clarification, or responding to other answers. Create a file common. redirect while passing arguments Passing a variable to redirect url_for in flask. See Are global variables thread safe in flask? How do I share data between requests? and Store large data or a service connection per Flask session. return '{} {} {}'. 310 3 3 silver badges 10 10 bronze badges. So adding the <br> tag just renders them on screen instead of actually creating line breaks. Share. html', firstname=firstname, lastname=lastname, There are different ways to return variables with Flask. You can then use a querySelector to access the value in that data attribute. Another example of a data source external to requests is a cache, such as what's provided by Flask-Caching or another extension. So it turns out that flask autoescapes html tags. Basically, I'm importing from MySQL and have tried rendering the return in three different ways. Approaches: We are going to write a simple flask API that returns a JSON response using two approaches: Using Flask jsonify object. In the The following script demonstrates the use of a variable in a Flask route. When rendering a string, list, or dictionary in HTML from within a Flask app, you need to pass the variables from Python to the HTML, often using the render_template function within Flask. HTML template file stored in templates/index. A context processor is a I've been reading about this for several days now, from Flask documentation, old stack overflow posts, and google. I have an HTML form which makes a POST request to my flask app and the flask app returns a string. The data-chart attribute holds the variable from the flask app. The function can employ the value of this variable in many ways. py and place in it the following:; from flask_caching import Cache # Instantiate the cache cache = Cache() The include tag is useful to include a template and return the rendered contents of that file into the current namespace: {% include 'header. This means using some default values. Another way to pass in variables is through the question mark that separates variables in the url, and using requests. so I just need the simplest way to make a local variable inside flask app function to be The answer is to create a JSON object within the flask function and return it as one varibale as well as only using one JS function. Provide details and share your research! But avoid . Context processors run before the template is rendered and have the ability to inject new values into the template context. 0. If you return a dict or list from a view, it will be converted to a JSON response. In the rare case I am working on a Flask project that has two pages (firstpage, secondpage). This is very clearly explained in the Flask documentation so I recommend that you read it for a full understanding, but here is a very simple example of rendering template variables. x Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company To inject new variables automatically into the context of a template, context processors exist in Flask. If you set up two different endpoints you'll see that the difference turns out to be that your code returns the following header: Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. Add a I have calculated the variable value from flask and I can print it on the console but now I need to pass that value to a label on the same template that is streaming the video. html', status=201, data=data)#where main. The second page should display message depending on what button the user clicked in the first page. Variable in Jinja - Flask. Quick example: @app. I am not sure of the reasoning behind it as I guess I don't understand JSON and AJAX etc. The Html is using a grid to display the options that I can select in the python. Follow answered Jun 3 at 5:32. aagwtc myxd uumjg eeogm htko vpji vfwecr aofncw ulcf pnppod