So I am attempting to use bottle.py and twitter bootstrap together to make a small website. I need to be able to insert a reasonable amount of data at various points in the HTML using Python but I am not really sure I understand how the HTML and python are communicating.
Here is an example of twitter and bottle working together.
He mentions linking a couple of .js files in the html and I can see where he does that but I am not really sure how that affects how the python interacts with the html. Is there a callback from the Javascript that the python catches using request.GET.get().strip():?
Also one of the last lines is:
return template('templates/gpio.tpl', colour1=colour1, colour2=colour2, colour3=colour3)
I am not sure how the templates/gpio.tpl is connected to the html he mentions below. I understand that the colour# variables are referenced in the html (I assume this happens with the {{}} syntax) but I am not sure how the html gets called at all.
From what I understand (which so far isnt a whole lot) this is how it goes:
User enters "server:port/gpio" into a webbrowser
The python decorator gets called by bottle and the function is run returning the template at the bottom.
This is where I get confused.
A) How does the python script know to call the html?
B) How does the gpio.tpl template code get sent to the html?
C) Is it safe to assume that the python arguements sent to the template function can be referenced using the {{}} syntax or is there more to it?
D) How does the html call back to the python to update the buttons he shows at the bottom?
D.1) does the JS linked at the top have something to do with this?
Lastly: If anyone has a another/better example of linking bootstrap and bottle I would be very happy to see it.
This is quite a loaded post. Thank you for your patience. :D
You'd really need to first learn how the HTTP protocol works... But let's try to quickly answer your main question:
how the HTML and python are communicating
Quite simply: they don't. What happens is:
your client (usually your browser) send an HTTP request to your site
the front web server (Apache, Nginx, whatever) sends this request to the bottle.py application
the bottle.py app dispatch the request to the right controller function matching the url's path portion and request's method against the defined routes)
the controller function does what it has to do and returns an HTTP response to the front web server
the front web server send this response to your client
Usually - but not necessarily - the HTTP response contains HTML content, generated by the controller using a template. IOW : bottle.py uses the template to generate html that is sent back to the client.
Once the response is sent, there's no more "communication" until the client sends another request.
So if I wanted to make an html button that changed something on the page how would I send that response back to bottle.py regenerate the page with the change?
It depends on what you want to change...
For example, pushing the button could trigger a new HTTP request, you should then define a new feature in your code.
Let's take the previous example, and imagine you want to add a switchOff button.
You have to add the following button somewhere in the gpio.tpl :
<input type="submit" class="btn" name="LedsOff" value="Turn off the leds!">
Then, modify the function gpio() to add a new condition with the following :
elif request.GET.get('LedsOff','').strip():
from quick2wire.gpio import Pin, exported
with exported(Pin(12, Pin.Out)) as out1, exported(Pin(13, Pin.Out)) as out2:
out1.value = 0
out2.value = 0
Related
This question already has answers here:
Sending data from HTML form to a Python script in Flask
(2 answers)
Closed 3 months ago.
I have a very simple python code that retrieves the share price of some stocks. I have managed to include that in Django/Flask so I can see this in a html page. I would like to create an html button that when I click on it it runs the python script and the share prices refresh (and remain on the same html page e.g. index.html) however I can't make it work. Can you please help with the html code for the button and the piece of code that I need to add to the app to make it work?
If you have written a class, or a method, then you can just call it an store the returned value in a variable and pass it to the html file using jinja2.
would be something like:
return render_template("index.html", parameter1 = returned_value)
and in your html file:
<p>{{ parameter1 }}</p>
Take a look:
https://hackersandslackers.com/flask-jinja-templates/
The only way to do what you want is by a remote call to the server. But by no mean you can refresh your list entirely client-side, especially with Python only.
What you must do if you really want not to reload the page is to :
client-side : make a request to the server from a Javascript function then fetch the response and refresh your share prices the incoming data
server-side : create a new view that will not render a template then return an html response, but serialize your data and return a JSON response.
That's all I can say to you. Do not expect the Stackoverflow community to give you a ready-to-use answer before you have brought a proof that you tried by yourself.
I am developing a location based web app/website. The website involves an HTML webpage, which has a button which when clicked by the user should:
Extract the user location coordinates
Run a python Program whose input will be the extracted user location, perform some manipulation.
Finally display real-time results back to the html webpage/ i.e. user computer screen.
The python Program is currently accepting the user location by using geocoder function. The program is successfully running on my system/PC.
I have an AWS EC2 Ubuntu server, to which the location of the vehicle GPS device is being sent.
Finally once everything is set up, I will be hosting/deploying the website so that individual users can test it on their system. I am aware of the hosting part.
Can someone please tell me how do I get along with the task of running the python program on an HTML button click and sending back real time results (which is the output of the python program) back to the html webpage?
To run python code on a buttonClick, you can set a href attribute to a link, which you catch in your flask backend. For example <a href="http://myapp/runthiscode"/> in the HTML and app.rout("/runthiscode") in flask. After that, the manipulation, you can give the updated variables to the page, by redirecting with redirect("/", args=args). args are the updated variables, which you can use in the HTML. For example like this: <a> {{ args }} </a>
The simplest way I can think of doing this is creating a basic API endpoint to do this data processing and return it to your frontend.
The process will look like:
User clicks button
Grab the user's longitutde and latitude (most likely using this, though from the sounds you might be able to do this already)
Submit a POST request to your Flask backend
Render the response in the frontend
Jonas answer gives you a rough sense of what this would look like; the only thing I would add is a tutorial. This one from FreeCodeCamp looks great.
I was not able to come up with a better title for this post, so if anybody does not find it appropriate , please go ahead and edit it.
I am using flask as my python framework, and normally I render templates doing somnething like the below:-
#app.route('/home')
def userhome():
data=go get user details from the database
return render_template("home.html",userdata=data)
Now I have a template name home.html in which I iterate over the values of "userdata" like userdata.name, userdata.age etc and these values take their appropriate spaces in the template.
However I am working on an application in which navigation is via ajax and no fall back if javascript is not available(basically the app does not work for ppl without javascript).
The navigation menu has say few tabs on the left ,(home,youroffers,yourlastreads). The right column is supposed to dynamically change based on what the user clicks.
I am unable to understand how I handle templating here. Based on what the user clicks I can send him the required data from the db via a json through an xhrGET or xhrPOST.Does the entire templating have to be handled at the server end and then transfer the entire template via an ajax call. I actually dont like that idea much. Would be great if someone could point me in the right direction here.
Now in the page that is loaded via ajax , there are some scripts which are present. Will these scripts work, if loaded via ajax.
You have two options: template on the server, or template in the browser.
To template in the server, you create an endpoint much like you already have, except the template only creates a portion of the page. Then you hit the URL with an Ajax call, and insert the returned HTML somewhere into your page.
To template in the browser, your endpoint creates a JSON response. Then a Javascript templating library can take that JSON, create HTML from it, and insert it into the page. There are lots of jQuery templating solutions, for example.
I would choose server side templating, because unless you find a JS library that handles the same templating language your code isn't going go be DRY.
In the home.html template, I'd do something like
<%extends base.html%>
<%include _user_details.html%>
... <% footer and other stuff%>
And keep the actual markup in _user_details.html. This way, for an AJAX request you just render the _user_details.html partial only.
I would like to know if it is possible to submit a flash form from python and, if it is, how?
I have done form submitting from python before, but the forms were HTML not flash. I really have no idea on how to do this. In my research about this I kept getting 'Ming'. However, Ming is only to create .swf files and that's not what I intend to do.
Any help on this is greatly appreciated.
You can set the url attribute (I think it's url, please correct me if I'm wrong) on a Flash form control to a Python script - then it will pass it through HTTP POST like any normal HTML form.
You've got nothing to be afraid of, it uses the same protocol to communicate, it's just a different submission process.
For your flash app, there's no difference if the backend is python, php or anything, so you can follow a normal "php + flash contact form" guide and then build the backend using django or any other python web framework, receive the information from the http request (GET or POST, probably the last one) and do whatever you wanted to do with them.
Notice the response from python to flash works the same as with php, it's just http content, so you can use XML or even better, JSON.
I have a python script that, once executed from command line, performs the needed operations and exit. If, during the execution, the program is not able to perform a choice, he prompts the user and asks them to take a decision!
Now I have to implement a web interface, and here comes the problems ... I created an htm file with a simple form that, once the user "submits" he passes the parameters to a cgi script that contains just one line and runs my python program ! And it seems to work.
My question is: if it happens that the program needs to ask the user for a choice, how can I return this value to my python script? To prompt the user for a choice I need to create a webpage with the possible choices ... Does anybody know how can I open a webpage with python ?
The second and most important question is: how can I return a value from a web page to my "original" python module? In python I would simply make a
return choice
but with a web page I have no idea how to do it.
Recap:
Starting from a web page, I run a cgi script ! Done
This CGI script runs my python program... Done
If the program is not able to take a decision,
3a create a web page with the possible choices I can do it
3b display the created web page ????????
3c return the response to the original python module ????????
"Does anybody know how can I open a webpage with python ? The second and most important question is: how can I return a value from a web page to my "original" python module ??"
This is all very simple.
However, you need to read about what the web really is. You need to read up on web servers, browsers and the HTTP protocol.
Here's the golden rule: A web server responds to HTTP requests with a web page.
The second part of that rules is: A Request is a URL and a method (GET or POST). There's more to a request, but that's the important part.
That's all that ever happens. So, you have to recast your use case into the above form.
Person clicks a bookmark; browser makes an empty request (to a URL of "/") and gets a form.
Person fills in the form, clicks the button; browser POST's the request (to the URL in the form) and gets one of two things.
If your script worked, they get their page that says it all worked.
If your script needed information, they get another form.
Person fills in the form, clicks the button; browser POST's the request (to the URL in the form) and gets the final page that says it all worked.
You can do all of this from a "CGI" script. Use mod_wsgi and plug your stuff into the Apache web server.
Or, you can get a web framework. Django, TurboGears, web.py, etc. You'll be happier with a framework even though you think your operation is simple.
I think you could modify the Python script to return an error if it needs a choice and accept choices as arguments. If you do that, you can check the return value from your cgi script and use that to call the python script appropriately and return the information to the user.
Is there a reason why you can't call the python script directly? I suspect you'd end up with a neater implementation if you were to avoid the intermediate CGI.
What webserver are you using? What cgi language? Perl maybe?
Web pages don't return values, and they aren't programs - a web page is just a static collection of HTML or something similar which a browser can display. Your CGI script can't wait for the user to send a response - it must send the web page to the user and terminate.
However, if the browser performs a second query to your CGI program (or a different CGI program) based on the data in that page, then you can collect the information that way and continue from that point.
Probably easier if you write your cgi in python then call your python script from the cgi script.
Update your script to separate the UI from the logic.
Then it should be relatively easy to interface your script with the (python) cgi script.
For python cgi reference:
Five minutes to a Python CGI
http://docs.python.org/library/cgihttpserver.html
I think first off you need to separate your code from your interface. When you run a script, it spits out a page. You can pass arguments to it using url parameters. Ideally you want to do your logic, and then pass the results into a template that python prints to the cgi.