I have a function to create a simple PDF. But when working on special characters, it returns something like that. How do I correctly save characters such as śćźż in my pdf file?
I tried to change the font type using setFont (Helvetica, TimesRoman) according this doc but I was not able to get the expected results.
Views.py (oficial doc)
def some_view_aa(request):
# Create a file-like buffer to receive PDF data.
buffer = io.BytesIO()
# Create the PDF object, using the buffer as its "file."
p = canvas.Canvas(buffer)
# Draw things on the PDF. Here's where the PDF generation happens.
# See the ReportLab documentation for the full list of functionality.
p.drawString(100, 100, "Hello AZX AĄĄŻĄ world.")
# Close the PDF object cleanly, and we're done.
p.showPage()
p.save()
# FileResponse sets the Content-Disposition header so that browsers
# present the option to save the file.
buffer.seek(0)
return FileResponse(buffer, as_attachment=True, filename='hello.pdf')
Related
I have a Django app where users can upload images and can have a processed version of the images if they want. and the processing function returns the path, so my approach was
model2.processed_image = processingfunction( model1.uploaded_image.path)
and as the processing function returns path here's how it looks in my admin view
not like the normally uploaded images
In my machine it worked correctly and I always get a 404 error for the processed ones while the normally uploaded is shown correctly when I try to change the url of the processed from
myurl.com/media/home/ubuntu/Eyelizer/media/path/to/the/image
to
myurl.com/media/path/to/the/image
so how can I fix this ? is there a better approach to saving the images manually to the database ?
I have the same function but returns a Pil.image.image object and I've tried many methods to save it in a model but I didn't know how so I've made the function return a file path.
I think the problem is from nginx where I define the media path.
should/can I override the url attribute of the processedimage?
making something like
model.processed_image.url = media/somefolder/filename
Instead of using the PIL Image directly, create a django.core.files.File.
Example:
from io import BytesIO
from django.core.files import File
img_io = BytesIO() # create a BytesIO object to temporarily save the file in memory
img = processingfunction( model1.uploaded_image.path)
img.save(img_io, 'PNG') # save the PIL image to the BytesIO object
img_file = File(thumb_io, name='some-name.png') # create the File object
# you can use the `name` from `model1.uploaded_image` and use
# that above
# finally, pass the image file to your model field
model2.processed_image = img_file
To avoid repetition of this code, it would be a good idea to keep this code in processingfunction and return the File object directly from there.
My approach is a bit different from #Xyres's, I thought xyres's would make a duplicate of the existing image and create a new one and when I tried overriding the URL attribute it returned an error of
can't set the attribute
but when I saw this question and this ticket I tried making this and it worked
model2.processed_image = processingfunction(model1.uploaded_image.path)
full_path = model2.processed_image.path
model2.processed_image.name = full_path.split('media')[1]
so that explicitly making the URL media/path/to/image and cut out all of the unneeded parts like home/ubuntu and stuff
I would like some help about my code. My goal is to send at the same time string variables as a ini plain text and a bmp file in an httpResponse.
For the moment I insert the decoded bytes of the bmp file in an ini parameter, take into account that I communicate with an interphone which is only client but not server so I can only make httpresponses but no requests.
If I base64 encode my image, I'll need to change the software of our interphone to decode it, for the moment I can't, can you tell me if base64 encode bytes is mandatory in my case ?
I made some researches on the web and I saw that people base64 encode their images or they make multipart response.
Could you help me to implement a multipart response please, even hand made, that would interest me ?
I show you how I do for the moment, I put the image in the "string" ini parameter:
def send_bmp():
outputConfig = io.StringIO()
outputConfig.write('[RETURN_INFO]\r\n')
outputConfig.write('config_id=255\r\n')
outputConfig.write('config_type=2\r\n')
outputConfig.write('action=3\r\n')
outputConfig.write('[DATABASE]\r\n')
file = open(django_settings.TMP_DIR+'/qrcode.bmp', 'rb').read()
outputConfig.write('size_all='+str(len(file))+'\r\n')
outputConfig.write('string='+file.decode('iso-8859-1')+'\r\n')
outputConfig.write('csum='+str(sum(file))+'\r\n')
body = outputConfig.getvalue()
httpR = HttpResponse(body, content_type='text/plain;charset=iso-8859-1')
httpR['Content-Length'] = len(body)
return httpR
Here is the response I get :
https://gist.github.com/Ezekiah/e6fd50f13c05f338f27a
If you need to mix the image file content with the rest of the response I think you have to use Base64 encoding. If it is possible to return the ini parameters in one request and the file in another Django provides a FileResponse class(subclass of StreamingHttpResponse) that you can use to return the bmp file in chunks, like this:
from django.http import FileResponse
def send_bmp(request):
file = open(django_settings.TMP_DIR+'/qrcode.bmp', 'rb')
return FileResponse(file)
I'm writing a Django function that takes some user input, and generates a pdf for the user. However, the process for generating the pdf is quite intensive, and I'll get a lot of repeated requests so I'd like to store the generated pdfs on the server and check if they already exist before generating them.
The problem is that django-wkhtmltopdf (which I'm using for generation) is meant to return to the user directly, and I'm not sure how to store it on the file.
I have the following, which works for returning a pdf at /pdf:
urls.py
urlpatterns = [
url(r'^pdf$', views.createPDF.as_view(template_name='site/pdftemplate.html', filename='my_pdf.pdf'))
]
views.py
class createPDF(PDFTemplateView):
filename = 'my_pdf.pdf'
template_name = 'site/pdftemplate.html'
So that works fine to create a pdf. What I'd like is to call that view from another view and save the result. Here's what I've got so far:
#Create pdf
pdf = createPDF.as_view(template_name='site/pdftemplate.html', filename='my_pdf.pdf')
pdf = pdf(request).render()
pdfPath = os.path.join(settings.TEMP_DIR,'temp.pdf')
with open(pdfPath, 'w') as f:
f.write(pdf.content)
This creates temp.pdf and is about the size I'd expect but the file isn't valid (it renders as a single completely blank page).
Any suggestions?
Elaborating on the previous answer given: to generate a pdf file and save to disk do this anywhere in your view:
...
context = {...} # build your context
# generate response
response = PDFTemplateResponse(
request=self.request,
template=self.template_name,
filename='file.pdf',
context=context,
cmd_options={'load-error-handling': 'ignore'})
# write the rendered content to a file
with open("file.pdf", "wb") as f:
f.write(response.rendered_content)
...
I have used this code in a TemplateView class so request and template fields were set like that, you may have to set it to whatever is appropriate in your particular case.
Well, you need to take a look to the code of wkhtmltopdf, first you need to use the class PDFTemplateResponse in wkhtmltopdf.views to get access to the rendered_content property, this property get us access to the pdf file:
response = PDFTemplateResponse(
request=<your_view_request>,
template=<your_template_to_render>,
filename=<pdf_filename.pdf>,
context=<a_dcitionary_to_render>,
cmd_options={'load-error-handling': 'ignore'})
Now you could use the rendered_content property to get access to the pdf file:
mail.attach('pdf_filename.pdf', response.rendered_content, 'application/pdf')
In my case I'm using this pdf to attach to an email, you could store it.
I'm trying to write a script that will save a pdf created by xhtml2pdf directly to the server, without doing the usual route of prompting the user to download it to their computer. Documents() is the Model I am trying to save to, and the new_project and output_filename variables are set elsewhere.
html = render_to_string(template, RequestContext(request, context)).encode('utf8')
result = open(output_filename, "wb")
pdf = CreatePDF(src=html, dest=results, path = "", encoding = 'UTF-8', link_callback=link_callback) #link callback was originally set to link_callback, defined below
result.close()
if not pdf.err:
new_doc=Documents()
new_doc.project=new_project
new_doc.posted_by=old_mess[0].from_user_fk.username
new_doc.documents = result
new_doc.save()
With this configuration when it reaches new_doc.save() I get the error: 'file' object has no attribute '_committed'
Does anyone know how I can fix this? Thanks!
After playing around with it I found a working solution. The issue was I was not creating the new Document while result (the pdf) was still open.
"+" needed to be added to open() so that the pdf file was available for reading and writing, and not just writing.
Note that this does save the pdf in a different folder first (Files). If that is not the desired outcome for your application you will need to delete it.
html = render_to_string(template, RequestContext(request, context)).encode('utf8')
results = StringIO()
result = open("Files/"+output_filename, "w+b")
pdf = CreatePDF(src=html, dest=results, path = "", encoding = 'UTF-8', link_callback=link_callback) #link callback was originally set to link_callback, defined below
if not pdf.err:
result.write(results.getvalue())
new_doc=Documents()
new_doc.project=new_project
new_doc.documents.save(output_filename, File(result))
new_doc.posted_by=old_mess[0].from_user_fk.username
new_doc.save()
result.close()
I have a lot of user uploaded content and I want to validate that uploaded image files are not, in fact, malicious scripts. In the Django documentation, it states that ImageField:
"Inherits all attributes and methods from FileField, but also validates that the uploaded object is a valid image."
Is that totally accurate? I've read that compressing or otherwise manipulating an image file is a good validation test. I'm assuming that PIL does something like this....
Will ImageField go a long way toward covering my image upload security?
Django validates the image uploaded via form using PIL.
See https://code.djangoproject.com/browser/django/trunk/django/forms/fields.py#L519
try:
# load() is the only method that can spot a truncated JPEG,
# but it cannot be called sanely after verify()
trial_image = Image.open(file)
trial_image.load()
# Since we're about to use the file again we have to reset the
# file object if possible.
if hasattr(file, 'reset'):
file.reset()
# verify() is the only method that can spot a corrupt PNG,
# but it must be called immediately after the constructor
trial_image = Image.open(file)
trial_image.verify()
...
except Exception: # Python Imaging Library doesn't recognize it as an image
raise ValidationError(self.error_messages['invalid_image'])
PIL documentation states the following about verify():
Attempts to determine if the file is broken, without actually decoding
the image data. If this method finds any problems, it raises suitable
exceptions. This method only works on a newly opened image; if the
image has already been loaded, the result is undefined. Also, if you
need to load the image after using this method, you must reopen the
image file.
You should also note that ImageField is only validated when uploaded using form. If you save the model your self (e.g. using some kind of download script), the validation is not performed.
Another test is with the file command. It checks for the presence of "magic numbers" in the file to determine its type. On my system, the file package includes libmagic as well as a ctypes-based wrapper /usr/lib64/python2.7/site-packages/magic.py. It looks like you use it like:
import magic
ms = magic.open(magic.MAGIC_NONE)
ms.load()
type = ms.file("/path/to/some/file")
print type
f = file("/path/to/some/file", "r")
buffer = f.read(4096)
f.close()
type = ms.buffer(buffer)
print type
ms.close()
(Code from here.)
As to your original question: "Read the Source, Luke."
django/core/files/images.py:
"""
Utility functions for handling images.
Requires PIL, as you might imagine.
"""
from django.core.files import File
class ImageFile(File):
"""
A mixin for use alongside django.core.files.base.File, which provides
additional features for dealing with images.
"""
def _get_width(self):
return self._get_image_dimensions()[0]
width = property(_get_width)
def _get_height(self):
return self._get_image_dimensions()[1]
height = property(_get_height)
def _get_image_dimensions(self):
if not hasattr(self, '_dimensions_cache'):
close = self.closed
self.open()
self._dimensions_cache = get_image_dimensions(self, close=close)
return self._dimensions_cache
def get_image_dimensions(file_or_path, close=False):
"""
Returns the (width, height) of an image, given an open file or a path. Set
'close' to True to close the file at the end if it is initially in an open
state.
"""
# Try to import PIL in either of the two ways it can end up installed.
try:
from PIL import ImageFile as PILImageFile
except ImportError:
import ImageFile as PILImageFile
p = PILImageFile.Parser()
if hasattr(file_or_path, 'read'):
file = file_or_path
file_pos = file.tell()
file.seek(0)
else:
file = open(file_or_path, 'rb')
close = True
try:
while 1:
data = file.read(1024)
if not data:
break
p.feed(data)
if p.image:
return p.image.size
return None
finally:
if close:
file.close()
else:
file.seek(file_pos)
So it looks like it just reads the file 1024 bytes at a time until PIL says it's an image, then stops. This obviously does not integrity-check the entire file, so it really depends on what you mean by "covering my image upload security": illicit data could be appended to an image and passed through your site. Someone could DOS your site by uploading a lot of junk or a really big file. You could be vulnerable to an injection attack if you don't check any uploaded captions or make assumptions about the image's uploaded filename. And so on.