Django upload for processing - django

I'm looking for a way to upload file to django server. The thing is I'm not trying to save in I just to open it and get data for processing. I looked through some of the examples here, but I couldn't find anything that answers this. I'm probably just not looking for a correct thing please help.
I don't want to use models, just a simple website with a upload button.
Thanks!

Use a Form:
class UploadForm(forms.Form):
file = forms.FileField()
def process(self):
file = self.cleaned_data.get('file')
# do whatever you need here to process the file
# e.g. data = file.read()
In your view, call process() on your form after the user uploads the file and the form is successfully validated.
def my_view(request):
if request.method == 'POST':
form = UploadForm(files=request.FILES)
if form.is_valid():
form.process()
return ...
Depending on the size of the file and your Django settings for FILE_UPLOAD_HANDLERS, the file is discarded immediately after the view is done processing if MemoryFileUploadHandler is used. The operating system will also eventually discard the file if TemporaryFileUploadHandler is used.

Related

How to add file to django model form with onetonefield to User

Is there any reason why uploading image file does not work .I have posted this question several times .I will need help for some one to show me the best code practice to upload image file .
If you want the user to be the user who uploads the file, then you can do something like this in your view.
if form.is_valid():
new_file = form.save(commit=False)
new_file.user = request.user
new_file.save()

Django Drama: (Drag-n-Drop File Uploader in Multi-part Form) + (Bind File to Form / Model & Save to Postgres)

There are a few tiny related questions buried in here, but they really point to one big, hairy best practice question. This is kind of a tough feature to implement because it's supposed to do a couple tricky things at once...
drag-and-drop multi-file uploader (via Javascript)
multi-page form (page one: upload and associate files with an existing document model;
page two: update and save file/document objects and meta-data to database)
...and I haven't found a pre-existing code sample or implementation anywhere. (Depending on one's approach, it could sweep off the table or automagically answer all the related/embedded/follow-on questions.) Bottom-line, the purpose of this post is to answer this question: What's the most elegant approach which minimizes the intervening questions/problems?
I'm using this implementation of a drag-and-drop JQuery File Uploader in Django to upload files...
https://github.com/miki725/Django-jQuery-File-Uploader-Integration-demo
The solution I link to above saves files on the filesystem, of course, but in batches per upload session, via creating a directory for each batch of files, and then assigning a UUID to each of those directories. Each uniquely named directory on the filesystem contains files uploaded during that particular upload session. That means any sort of database storage method first has to tease apart and iterate over all the files in the filesystem directory created for each upload session by this solution.
Note: the JQuery solution linked to above doesn't use a form (in forms.py) inside the app directory. The form is hardcoded into the template, which is already a bit of a bummer...'cause now I also have to find a nice way to bind each of the above files in each batch to a form.
I think the simplest--albeit perhaps least performant solution--is to create two views, for two forms...to save each file to the database in the view on the first page, and then update the database on the second page. Here's the direction I'm presently rolling in:
IN THE TEMPLATE...
...uploader javascripts in header...
<form action="{% url my_upload_handler %}" method="POST" enctype="multipart/form-data">
<input type="file" name="files[]" multiple
</form>
IN VIEWS.PY...
def my_upload_handler_0r_form_part_one(request):
# POST (in the upload handler; request triggered by an upload action)
if request.method == 'POST':
if not ("f" in request.GET.keys()):
...validators and exception handling...
...response_data, which is a dict...
uid = request.POST[u"uid"]
file = request.FILES[u'files[]']
filename = os.path.join(temp_path, str(uuid.uuid4()) + file.name)
destination = open(filename, "wb+")
for chunk in file.chunks():
destination.write(chunk)
destination.close()
response_data = simplejson.dumps([response_data])
response_type = "application/json"
# return the data to the JQuery uploader plugin...
return HttpResponse(response_data, mimetype=response_type)
# GET (in the same upload handler)
else:
return render_to_response('my_first_page_template.html',
{ <---NO 'form':form HERE
'uid': uuid.uuid4(),
},
context_instance = RequestContext(request))
def form_part_two(request):
#here I need to retrieve and update stuff uploaded on first page
return render_to_response('my_second_page_template.html',
{},
context_instance = RequestContext(request))
This view for the first page leverages the JQuery uploader, which works great for multi-file uploads per session and does what it's supposed to do. However, as hinted above, the view, as an upload handler, is only the first page in what needs to be a two page form. On page two, the end user would subsequently need to retrieve each uploaded file, attach additional data to the files they just uploaded on page one, and re-save to the database.
I've tried to make this work as a two-part form via various solutions, including form wizards and/or generic class based views...following examples mainly enabling data persistence via the session. These solutions get rather thorny very quickly.
In summary, I need to...
upload multiple files in a uniquely identified batch (via drag and drop)
tease apart and iterate over each batch of uploaded files
bind each file in the batch to a form and associate it with an existing document model
submit / save all of these files at once to the database
retrieve each of those files on the following page/template of a potentially new form
update metadata for each file
resubmit / save all of those files at once to the database
So...you can see how all of the above compounds the complexity of a simple file upload, and increases the complexity of providing the feature, by involving related questions like:
forms.py: how best to bind each file to a form
models.py: how to associate each file with a pre-existing document model
views.py how to save each file in accordance with pre-existing document model in Postgres in the first page; update and save each document in the second page
...and, again, I'd like to do all of that without a form wizard, and without class-based views. (CBVs, especially, for this use case elude me a bit.) In other words: I'm looking for advice leading toward the most bulletproof and easy to read/understand solution possible. If it causes multiple hits to the database, that's fine by me. (If saving a file to the database seems anti best practice, please see this other post: Storing file content in DB
Might I be able to just create a separate view for two forms, and subclass a standard upload form, like so...
In forms.py...
class FileUploadForm(forms.Form):
files = forms.FileField(widget=forms.ClearableFileInput(attrs={'name':'files[]', 'multiple':'multiple'}))
#how to iterate over files in list or batch of files here...?
file = forms.FileField()
file = forms.FileField()
def clean_file(self):
data = self.cleaned_data["file"]
# read, parse, and create `data_dict` from file...
# subclass pre-existing UploadModelForm
**form = UploadModelForm(data_dict)**
if form.is_valid():
self.instance = form.save(commit=False)
else:
raise forms.ValidationError
return data
...and then refactor the earlier upload handler above with something like...
In views.py, substituting the following for present upload handler...
def view_for_form_one(request):
...
# the aforementioned upload handler logic, plus...
...
form = FileUploadForm(request.POST, request.FILES)
if form.is_valid():
form.save()
else:
# display errors
pass
...
def view_for_form_two(request):
# update and commit all data here
...?
In general, with this type of problem, I like to create single page with one <form> on it, but multiple sections which the user progresses through with javascript.
Breaking a form into a multi-part, wizard-style form series is much easier with javascript, especially if the data it produces is dynamic in nature.
If you absolutely must break it out into multiple pages, I would advise you to set up your app to be able to save the data into the database at the end of each step.
You can do that by making the metadata which the user adds at step 2 a nullable field, or even moving the metadata to a separate model.

Django file upload...why is this working?

This is the first time I've tried to upload a file with Django. I did something and it worked, though I realized later that it's not the correct way to do it. When I called save on the object, did it call a built-in handler for the FileField? I realize that I should create my own handler but I was just curious why this worked.
def upload_test(request):
user=User.objects.get(pk=user.id)
photoform=PhotoForm()
if request.method=='POST':
photoform=Post_PhotoForm(request.POST,request.FILES)
if photoform.is_valid():
photo=photoform.save(commit=False)
photo.user=user
photo.save()
return HttpResponse('success')
else:
return HttpResponse('%s' %photoform.errors)
return render_to_response("site/upload_test.html", {'photoform':photoform}, context_instance=RequestContext(request))
This is saving the object and uploading the file to the directory specified in the FileField.
If I create a handler which writes the file in chunks, how can I also save the photoform instance? Will it create duplicates?
Thanks for the insight.
I imagine PhotoForm is a ModelForm? Manual handling of uploaded files as described in the docs is only required for standard Forms. The chunk handling is performed in the background by the models.FileField and its storage object, etc.

Allow users to play mp3 files but don't expose them directly on the web

I want to store some mp3s in a folder which is not public, can't be directly accessed through the web and allow users to hear/download the songs with a browser only if they are logged in.
How can I do that?
I do my web development with Django, but if I know how it works is enough.
You first need to setup authentication. The django tutorials thoroughly explore this.
You don't' link the mp3's directly, You link to a django script that checks the auth, then reads the mp3 and serves it to the client with a mp3 content type header.
http://yourserver.com/listen?file=Fat+Boys+Greatest+Hits
I assume you use django. Then you can try something like this:
from django.conf import settings
from django.contrib.auth.decorators import login_required
from django.http import HttpResponse
#login_required
def listen(request, file_name):
# note that MP3_STORAGE should not be in MEDIA_ROOT
file = open("%smp3/%s" % (settings.MP3_STORAGE, file_name))
response = HttpResponse(file.read(), mimetype="audio/mpeg")
return response
Note that you will get dramatic speed decrease. Using generator to read file in blocks may help to save memory.
Lazy Method for Reading Big File in Python?
File outside of public access (not in
MEDIA_URL folders)
Check if user logged in
Serve files only via a view, with
unique links for every user
Pseudocode:
class Mp3(models.Model):
file = models.FileField(upload_to=path_outside_of_public_access)
hash = models.CharField(unique=True)
def generate_link_hash(request, file):
return hashlib.md5("%s_%i_%s_%s" % (request.session.session_key, file.id, str(file.date_added), file.hash)) # or however u like
def files_list(request)
""" view to show files list """
for file in files:
file.link_hash = generate_link_hash(request, file)
#login_required
def download_file(request, file_hash, link_hash):
""" view to download file """
file = Mp3.objects.get(hash=file_hash)
if link_hash == generate_link_hash(request, file):
file = open(file.file)
return HttpResponse(file.read(), mimetype="audio/mpeg")
else:
raise Http404
Should do the job enough, but remember - what is once accessed, you have no control where it goes from now on. And that every file download needs reading the file through the app (it's not given statically), which will affect the performance of your app.

Can django-piston module create upload image restful webservice

I trying to restful server that one can upload image, By use django-piston I can put,get,post information restfully but don't know how to upload image.
pretty much.
technically it's just a http post.
On the one hand, yes. If you have the image data, it's possible to send it via post to a handler that knows how to handle it; if you do it right, it should, theoretically, be available in request.FILES to your handler. Simple HTTP.
On the other hand, no. In order to do an AJAX upload like this, you would have to somehow get the image data without the user actually submitting a form. This is why "ajax upload forms" are so difficult to implement, and usually use tricks like hidden iframes to do their stuff.
To the best of my knowledge, only Firefox and its gecko kin allow this kind of access to a file field's binary content, via the File object's getAsBinary() method.
You can certainly do the POST. The file(s) will be available in the request.FILES (piston won't get in the way of this).
In order to do the PUT, we'll have to make some changes to piston to support the x-method-override header. That's what I do to allow PUT and DEL from flash. ( Don't forget to add the header when you do the POST to make it get interpreted as a PUT )
Here's some example middleware:
class x_http_methodoverride_middleware():
def process_request(self, request):
if 'HTTP_X_HTTP_METHODOVERRIDE' in request.META:
newMethod = request.META['HTTP_X_HTTP_METHODOVERRIDE']
if 'PUT' == newMethod.upper():
request.method = 'PUT'
request.META['REQUEST_METHOD'] = 'PUT'
request.PUT = request.POST
if 'DELETE' == newMethod.upper() or 'DEL' == newMethod.upper():
request.method = 'DELETE'
request.META['REQUEST_METHOD'] = 'DELETE'
request.DELETE = request.POST
( the code is from an open piston ticket here http://bitbucket.org/jespern/django-piston/issue/83/use-x-http-method-override-to-override-put )
You can find two answers here: http://groups.google.com/group/django-piston/browse_thread/thread/6f3f964b8b3ccf72/bd1658121bb1874c?show_docid=bd1658121bb1874c&pli=1
One way is to use request.FILES to get the filename, and then to save the image:
def create(self, request, nickname):
name = request.FILES["image"].name
image = PIL.Image.open(request.FILES["image"])
image.save(SOME_PATH+name)
return rc.ALL_OK
The second suggestion is to define an Image model and an ImageForm form, and use those:
def create(self, request, nickname):
form = ImageForm(request.POST, request.FILES)
if form.is_valid():
Image.objects.create(image=form.cleaned_data['image'])
return rc.ALL_OK
return rc.BAD_REQUEST
WARNING: I haven't tested either of these methods!