Say that I have a Python Flask server running which has a backend script that produces a number and a string.
How can I pass the number and string from the backend to a script that runs of client-side so that the user can run it rather than the server?
Example:
backend script data_producer.py produces "asdaslkdjasdlksja" and 18 from its functions
I want to pass "asdaslkdjasdlksja" and 18 to a Brython or JavaScript HTML embed ( tag) so that it can be processed in the browser and the results be sent back to my server.
Edit: I realized that I can just use Jinja2's "{{ }}" when rendering a template so that I can use data in an HTML script embed
The question you asked is too broad. It's almost equivalent to asking, how you can connect two computers. Since you haven't even specified any data type, the first thing that comes to my mind is using sockets which is as low level as you can get.
A more high level and appropriate approach would be to use an HTTP REST server (with flask-RESTful), since you already have a flask server running.
However, there's another million ways to transfer data between two Python scripts, from WebSockets, WebRTCs, sshing, the new IPFS to even emails. Now most of them would probably be overkill, so I would suggest you to make a simple REST server and make the client send GET or POST requests to it.
After looking at the new edit, I still think a REST api is the best option. Since you can easily make a GET or POST request using the fetch api in Javascript. In Brython you can use ajax to do the same thing.
Related
maybe it is simple but I didn't find a satisfactory answer yet.
I have a python application that collects data over CAN bus (temperature, weight, ...) and I want to visualize them over Angular.
On the one side, I wrote the Python application that cyclic read the CAN-bus data and writes them to the console and on the other hand I wrote a small Angular application that contains the first step a simple table.
Now I want to fill in the table every 10 seconds with data from the Python application instead of printing them to the console.
How can I connect these both?
My first thought was a simple file where I save the values from Python and read them with Angular.
The second solution is a database, but I think this is too much for only a few values
So is there a direct way to access the Python data from Angular?
Basic idea is to create an api in python and let angular consume that
then there is the question of weather you want to have backup data in python,
if so then save it a db or file and use that as response for angular
if you want to do some fancy real time stuff may be look into long polling or http event stream
There are several ways you can access Python data from an Angular application:
One way is to use a REST API. You can create a REST API in Python
using a web framework like Flask or Django, and then use Angular's
HTTP client to make requests to the API and retrieve the data.
Another option is to use WebSockets. You can use a Python library
like asyncio or websockets to set up a WebSocket server, and then
use Angular's WebSocket client to connect to the server and receive
updates in real-time.
You can also use a message queue like RabbitMQ or ZeroMQ to allow
your Python and Angular applications to communicate with each other
asynchronously.
Overall, the best approach will depend on your specific requirements and how you want to structure your application. A REST API is a good choice if you need to retrieve data from the Python application on demand, while WebSockets or a message queue can be used for real-time communication and updates.
I have a running python application that needs to receive some data and process them. and I also have a PHP server that can get these data. I want to send JSON data from PHP to my python app.
anyway except running a python web server and send data to it, or insert into DB and get from DB with python?
thanks.
I tried using python cherryPy web server.
#Niklas D It would be easier to answer your question, if you can give some more context about the application or use case you want to solve.
Some further possibilities are:
Glue Code (I never did it with python and php only C++ with python, but you should be able to find examples on the internet e.g. https://wiki.python.org/moin/IntegratingPythonWithOtherLanguages#PHP )
Messaging Systems like RabbitMQ, ActiveMQ, ZeroMQ, etc.
Redis (I know you said except writing to a database, but Redis provides some features for publish subscribe https://redis.io/commands/pubsub which allows you to write to Redis from the one side and get data on the other side without polling the db all the time, which is the issue you have with using a database I guess) It's a bit easier to setup and use, than a messaging system.
TCP connection between the python and php application. https://medium.com/swlh/lets-write-a-chat-app-in-python-f6783a9ac170
If you want to send data to a python application using web protocols, i.e send POST, GET requests etc then you need to create a python web app to receive and handle those requests. Which in turn needs to be running off a webserver or you could build serverless functions to handle this, see https://serverless.com/
If you want to get data using a python application, i.e the python app sends POST and GET requests etc to your php app to ask for the JSON payload you can build an app using python's standard requests library https://docs.python.org/3/library/urllib.request.html or better still us the Requests package http://docs.python-requests.org/en/master/
Or you could do something and save the JSON file to disk and then open it with your python app. You'd need to set up scheduling or make your php app execute python code on the server... This last suggestion is a bad idea please don't unless your app is isolated and not publicly accessible or you know how to lock down your security.
I created a simple python script which takes a URL as input and once passed will do curl using multiple proxies and show the response code, now I want to create a webpage where others can use(my colleagues) as it will help them too, I want to create simple webpage which let them select set of proxy addresses, and input URL and upon submission, it will run the script on a machine(webserver) and populate the result to webpage using dynatable or datatable frameworks, but am not sure how or if it is possible as I didn't worked much in webserver thing, I want to know what tools I will need and how do I design it.
If python script can be called in terminal(as it needs to run curl) and show result on webpage based on output from script(which I will export to csv file), how can I do that? what to use xampp, wamp, lamp etc ?
You need a framework for this, something that will listen to your request coming from the front-end (webpage), there are tons out there as python framework, you can check bottle framework as a starting point.
So the flow would be something below.
1. from webpage, a request is sent to the backend
2. backend receive the request and run your logic (connecting to some server, computing logic, etc)
3. once backend process is done, backend then send the response to webpage
you can either use a REST approach or use templating functionality of the framework
You will need a request. You can do this in JavaScript with an ajax request there are frameworks to hook it up straight to your python which allow you not to code the JavaScript https://www.w3schools.com/xml/ajax_intro.asp there are many JavaScript frameworks that will make this easier/ shorter to code.
I've thoroughly searched for the answer for my question, but I don't think I know the correct terminology to make my searches effective. Anyway, I'm looking to set up my web server to route a request for a static page through a Python "PageBuilder" program which will dynamically implant content into templates.
In other words:
user requests mysite.com/index.html
server passes request to certain python script (my server is currently Apache2)
python script generates output, passes output to server
server serves content to user
Could someone please help me or at least give me the "proper terminology" with which to search?
This isn't really static content any more. You want to dynamically generate content using a script.
In Python, this is generally done using the WSGI interface (in olden days, the de facto standard was CGI), which defines a standard way for your Python code to get input (information about the HTTP request), and send back a response (HTTP headers, and the content you want to serve -- typically HTML).
To this end, there's the excellent mod_wsgi Apache module that sets up the plumbing between the server-stuff (receiving requests and sending back content) and your code, using this WSGI interface.
You may also want to check out some sort of templating engine to make generating dynamic HTML easier (my favourite is Jinja2).
This is called CGI.
http://en.wikipedia.org/wiki/Common_Gateway_Interface
Disclaimer: I'm not very familiar with any of the things mentioned in the question title.
Would it be possible to use a browser control (like Webkit) as a frontend for a WSGI app (using a framework like Flask) without starting a local WSGI server?
Basically the requests and responses are managed by a middle layer between the HTML UI and the WSGI backend. A certain URI could mean "Local", for instance "local://" or something similar, and will be routed to the embedded WSGI app with all the original headers etc.
You will lose any features that a normal WSGI server provides unless you implement it yourself or somehow embed a server that is also usable via an API instead of real HTTP requests.
Now that I think of it, this is the only real requirement: A WSGI server that is callable via an API and not just real HTTP requests.
I know the usefulness of this is questionable (and maybe doesn't even make sense). My question is whether this is at all possible?
EDIT: Here's another way of putting it:
I want a single codebase to be both a web app and a desktop app, using an HTML frontend and a Python backend. I don't want to run a server on any port for the desktop app. What's the easiest way to achieve this?
It is in theory possible to write your own WSGI container that implements a full API and adapts that to WSGI. flup might bring some inspiration.
Earlier today I saw exactly what you're asking for -- a way to call WSGI through an API without actually connecting over the network. However, it shouldn't be that hard.
On a side note, you might want to look at PySide, of particular interest to you may be the ability to bind python elements to DOM events, so if you're just looking to trigger python code that's an even shorter route.
If you give some more detail on what you're hoping to achieve we might be able to dial it in for you.
Reviving this, since we're facing the same problem and are about to scale things up from a single view/widget to the whole app.
What I did was to simply set the base URL to something where I serve static content, and from a QRC file that's easy:
html = jinjatemplate.render(...)
self._mainFrame.setHtml(html.decode('utf-8'), Qt.QUrl('qrc:///Orsync/html/'))
For the communication, our HTML uses AJAX over jQuery for most things. You could wrap that in a layer that either does $.post(...) or api.post(...) like this:
self._mainFrame.addToJavaScriptWindowObject('api', self._webapi)
You'd need to decode the URL and create a request object yourself, but maybe that's not too hard to do? We use very few URLs currently (who are mapped directly to python objects/functions) so it's easy to do the mapping ourselves.
Data that goes back is just sent using QMainFrame.evaluateJavaScript(...), either as a direct Qt call or as a bunch of code lines fetched using $.getScript(...) (which just evaluates the code received).
I'm currently rebuilding things a bit using CherryPy, and it maps urls -> Python objects straight off, so I'm hoping there's something to be gained by that.
Otherwise, I would wish one could run QWebKit over named pipes or something similarly localized and not a tcp-socket. :)