Develop Reference

jQuery/Django retrieving file

I have seen many answers to questions like this, but none has solved my problem...
I want to produce a pdf in the backend and then download it to the user.
So I have a basic blank page with a button. For that button there is a jQuery function:
$.post("{% url 'printReport' %}",
{
'params' : JSON.stringify({
'reportcode' : 'HelloWorld',
})
}, function(data, status) {
$("#testZone").text(data)
});
On the server side, I produce the pdf and save it locally in the server folder. This goes perfect.
Then, in the views file I have this:
def printRreport(request):
if request.method=="POST":
res = producePdf(request) #works fine! the PDF is birght an shiny, saved on the server
response = HttpResponse(res.data,content_type='application/pdf')
response['Content-Disposition'] = 'attachment; filename="report.pdf"' #setting response headers
return response
where res.data is actually open(pdf_path,'r').read()
this is 70% fine, because the browser actually receives the pdf data inside the request response (I can see it on the dev console). It's 30% wrong because this does not give me a download dialog and does not allow me to save a pdf file on the client side.
What is wrong here? In my case I opted by using a POST method, I know it's debatable, but I don't think that is the problem...
Edit: I found a solution for this, maybe not optimal, but it works.
I marked below the answer I ended up following. I kept the code above, but I decided to generate the pdf file on the first view (which receives the POST request), then redirect the user to another view where it would download it. And it works!
I'll still check this as suggested by Abdul though.
Thanks!

Instead of using HttpResponse try using FileResponse:
from django.http import FileResponse
def printRreport(request):
res = producePdf(request)
file_ptr = # something that would get you something like open(pdf_path,'rb')
return FileResponse(file_ptr)
Now in your javascript the problem is you are making the request as ajax and the content is with javascript, an easier thing would be to let your browser handle the url (It is a file download anyway no need for ajax):
var link = document.createElement("a");
link.download = "Report";
link.href = "{% url 'printReport' %}";
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
Note: If you don't need to run this dynamically consider just an anchor with the url. Instead of javascript.

Use Python to make HTTP Post Request for form

I am trying to make an HTTP Post request using Python. The specific form I want to submit is on the following page: http://143.137.111.105/Enlace/Resultados2010/Basica2010/R10Folio.aspx
Using Chrome Dev Tools it seems like pushing the button makes an HTTP Post request but I am trying to figure out the exact request that is made. I currently have the following in Python:
import requests
url = 'http://143.137.111.105/Enlace/Resultados2010/Basica2010/R10Folio.aspx'
values = {
'txtFolioAlumno': '210227489P10',
}
r = requests.post(url, values)
print r.content
However, when I run this it simply prints out the HTML of the old page instead of returning the data from the new page (I am interested in getting the number next to 'Matematicas', 422 in this case). I have achieved this task using Selenium which actually opens a test browser, but I want to query the server directly.

Sending GET query using Javascript to GAE to redirect to another page

On GAE (Python) I'm trying to send a GET request from local javascript and on receipt of the request redirect to another page. This is my code:
Local Javascript sending the POST:
$.get("/editor");
The Python on GAE
class Editor(webapp2.RequestHandler):
def get(self):
template = jinja_environment.get_template('index.html')
self.response.out.write(template.render())
app = webapp2.WSGIApplication([('/', StartScreen), ('/editor', Editor)],
debug=True)
I can type in the url /editor in the url bar and it does take me there. Why does my javascript GET request not activate the Editor handler and open /editor?

I am not sure if I understand the problem, but still give it a try:
The current way to use jQuery.get() should call the server but throw away the response, so you will see nothing of it in the browser.
You want at least to do:
$.get("/editor", function(response) {
document.location.href = 'another page';
});
where another page is where you want to redirect to. Then this still throws away what you content you get from the server. (response will be some HTML ... I am not sure how you want to get a location from that.) So I wonder if a simple HTML-link would just do what you want.

JSONP web service with python

I'm writing an AJAX function that requests data from my JSON Python webservice. My AJAX request looks like:
url = "http://localhost:8001/blah"
$.ajax({
url: url,
type: 'get',
dataType: 'jsonp',
success: function(data) {
console.log('hi')
}
});
For now, my python web service has a function that handles the request to '/blah' that has the following return statement:
return json.dumps({'a':1, 'b':2 })
My AJAX function is not successfully retrieving a response from my Python Webservice, but I don't get any errors in Firebug. What is my webservice or javascript doing wrong?

What happens when you use Jquery's JSONP datatype, is that a callback function name is sent as a GET param as part of your URL, so you're actually querying something like "http://localhost:8001/blah?callback=json125348274839".
Your response from your web server should look like this:
return "%s({'a':1, 'b':2 })" % _GET_PARAMS('callback')
so your web server will return somthing like "json125348274839({'a':1, 'b':2 })"
Hope that helps!

Zack got it. My javascript was correct. I changed my python return statement to the following:
callback = request.args.get('callback')
return '{0}({1})'.format(callback, {'a':1, 'b':2})

Turn on (or add) logging in your Python web service. Inspect your web server logs... are you receiving the request from your javascript client? Is your web server logging that it is returning a response?
Possibly it depends on the framework that you are using. Is it as simple as returning a string from the handler function? Perhaps the handler is supposed to return a list of strings and, because it is not getting a list, it is returning nothing to the client. Look in your web server logs for errors.

You forgot closing quote and semicolon in the first line =)
If it is not helps, check following:
List item
What are you using as python service? Django, flask, something else? Maybe you can provide provide python code?
Also, look at the 'Net' Firebug's tab and, after ensure that request to 'url' is actually handled (not returned 404 or 50x codes, but 200), check 'Response' sub-tab.
Hope this helps!

Posting JSON and python Flask - any techniques to use the Werkzeug debugger?

Alright, I'm working with a RESTful backend on my project, and submitting data via jquery.
I must say the werkzeug debugger is excellent for debugging specially when you're a terrible python programmer as me. You throw an exception on purpose where you want to investigate, and inspect the code and variables using the html the debugger rendered.
However when you send a post request instead of a get, if you throw an exception on the backend code, of course, the browser won't render the response text.
Is there any technique I can use to render the response text, considering it has javascript and everything?
I'm trying different things such as trying to inject the response text into a popup window, like:
$.postJSON = function(url, data, callback, error_callback) {
return jQuery.ajax({
'type': 'POST',
'url': url,
'contentType': 'application/json',
'data': JSON.stringify(data),
'dataType': 'json',
'success': callback,
'error': error_callback
});
};
$.postJSON('/the_uri', {'foo': 'bar'},
function(response) {
var a = 0;
},
function(response) {
var html = response.responseText;
var my_window = window.open('', 'mywindow1', 'width=350,height=150');
$(my_window.document).find('html').html(html);
});
});
But this won't take care of the javascript very well.
Does anyone have any suggestion?

Your approach was nearly correct. I am using the following code to open the response text in a new window (not specific to Werkzeug or Flask at all):
var w = window.open('', 'debug_stuff', 'width=540,height=150');
w.document.open();
w.document.write(response.responseText);
w.document.close();
The last line is the most important. Without it, the code would behave as yours -- it would not execute any JavaScript, because the browser doesn't know the DOM has been fully loaded.

Not javascript, but have you tried to use Firebug, you can use the option for viewing the response in a new tab (Open Response in New Tab).

If you're ready to make some changes on both the client and the server code, you can try this. In your error callback you would re-send the JSON data but as a synchonous form submission. You would create the form using jQuery, give it an input tag and put your JSON in that and submit the form. Something like:
$('<form method="post" style="display:none;">')
.attr('action', 'xxx')
.append(
$('<input>').val(JSON.stringify(data))
).appendTo('body')
.submit();
On the server-side, you would have to accept JSON the regular way when the request's content type is application/json and as form data, eg:
json_string = request.form.get('__json')
if json_string:
data = json.loads(json_string)
I have never tried this but I know the problem you're having and it can waste a lot of time. If you try it I'd like to know how it works out.

Markus' answer works perfectly. thanks so much! this saved me so much hassle.
also consider assigning your handlers to a jqxhr object
http://api.jquery.com/jQuery.post/#jqxhr-object
var jqxhr = $.post(...)
then you would write to your new window
w.document.write(jqxhr.responseText);