How to open a generated PDF file in browser? - django

I have written a Pdf merger which merges an original file with a watermark.
What I want to do now is to open 'document-output.pdf' file in the browser by a Django view. I already checked Django's related articles, but since my approach is relatively different, I don't directly create the PDF object, using the response object as its "file.", so I am kind of lost.
So, how can I do is in a Django view?
from pyPdf import PdfFileWriter, PdfFileReader
from reportlab.pdfgen.canvas import Canvas
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
output = PdfFileWriter()
input = PdfFileReader(file('file.pdf', 'rb'))
# get number of pages
num_pages = input.getNumPages()
# register new chinese font
pdfmetrics.registerFont(TTFont('chinese_font','/usr/share/fonts/truetype/mac/LiHeiPro.ttf'))
# generate watermark on the fly
pdf = Canvas("watermark.pdf")
pdf.setFont("chinese_font", 12)
pdf.setStrokeColorRGB(0.5, 1, 0)
pdf.drawString(10, 830, "你好")
pdf.save()
# put on watermark
watermark = PdfFileReader(file('watermark.pdf', 'rb'))
page1 = input.getPage(0)
page1.mergePage(watermark.getPage(0))
# add processed pdf page
output.addPage(page1)
# then, add rest of pages
for num in range(1, num_pages):
output.addPage(input.getPage(num))
outputStream = file("document-output.pdf", "wb")
output.write(outputStream)
outputStream.close()

I know its an older post but we can use the embed tag of html to implement this kind of functionality. For e.g.:
<embed height="100%" width="100%" name="plugin" src="filename.pdf" type="application/pdf">
So in your case, you can simply send the response using render to response as:
return render_to_response("abc.html",{"filename":filename})
and in the abc.html you can put this filename (with the path) in the embed tag, as mentioned above.
Hope this helps.

In addition to sending your PDF back to the browser, you can also save some cycles by storing your watermark in a string buffer.
from pyPdf import PdfFileWriter, PdfFileReader
from reportlab.pdfgen.canvas import Canvas
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
from django.http import HttpResponse
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
def some_view(request):
output = PdfFileWriter()
input = PdfFileReader(file('file.pdf', 'rb'))
#create response object
response = HttpResponse(mimetype='application/pdf')
response['Content-Disposition'] = 'attachment; filename=somefilename.pdf'
# get number of pages
num_pages = input.getNumPages()
#register the font
pdfmetrics.registerFont(TTFont('chinese_font','/usr/share/fonts/truetype/mac/LiHeiPro.ttf'))
# generate watermark on the fly
buffer = StringIO() # create string buffer for PDF
pdf = Canvas(buffer)
pdf.setFont("chinese_font", 12)
pdf.setStrokeColorRGB(0.5, 1, 0)
pdf.drawString(96, 26, "88888")
pdf.save()
# put on watermark from buffer
watermark = PdfFileReader(buffer)
page1 = input.getPage(0)
page1.mergePage(watermark.getPage(0))
# add processed pdf page
output.addPage(page1)
#stream to browser
outputStream = response
output.write(response)
outputStream.close()
return response

I am not sure I follow. If you want the PDF content to be sent to the browser you should use an HttpResponse instance. This line in your code
outputStream = file("document-output.pdf", "wb")
will not serve to write the PDF contents to the response. Instead it looks to me like it will write the contents to a local file, which is not the same.
Update
Based on comment:
How to send PDF content to a HttpResponse object as it will open in the browser, not as an attachment.
AFAIK (if anyone knows better, correct me) this is browser dependent.
If you leave out the Content-Disposition = "attachment; filename=foo.pdf from the response headers you can send the contents to the browser without a specific filename. This prompted my Firefox browser (3.6.10, Ubuntu Jaunty) to ask me if I wanted to open it using a program. On Chrome (6.0.472.62, Ubuntu Jaunty) the file got downloaded as download.pdf without any prompting.

remove 'attachment' from this line with Chris comment
response['Content-Disposition'] = 'attachment; filename=somefilename.pdf'

Related

Filling MS Word Template from Django

I found some python docs relating to docxtpl at this link:
https://docxtpl.readthedocs.io/en/latest/
I followed the instruction and entered the code found at this site into a view and created the associated URL. When I go to the URL I would like for a doc to be generated - but I get an error that no HTTP response is being returned. I understand I am not defining one, but I am a bit confused about what HTTP response I need to define (I am still very new to this). The MS word template that I have saved is titled 'template.docx'.
Any help would be greatly appreciated!
VIEWS.PY
def doc_test(request):
doc = DocxTemplate("template.docx")
context = { 'ultimate_consignee' : "World company" }
doc.render(context)
doc.save("generated_doc.docx")
I would like accessing this view to generate the doc, where the variables are filled with what is defined in the context above.
Gist: Read the contents of the file and return the data in an HTTP response.
First of all, you'll have to save the file in memory so that it's easier to read. Instead of saving to a file name like doc.save("generated_doc.docx"), you'll need to save it to a file-like object.
Then read the contents of this file-like object and return it in an HTTP response.
import io
from django.http import HttpResponse
def doc_test(request):
doc = DocxTemplate("template.docx")
# ... your other code ...
doc_io = io.BytesIO() # create a file-like object
doc.save(doc_io) # save data to file-like object
doc_io.seek(0) # go to the beginning of the file-like object
response = HttpResponse(doc_io.read())
# Content-Disposition header makes a file downloadable
response["Content-Disposition"] = "attachment; filename=generated_doc.docx"
# Set the appropriate Content-Type for docx file
response["Content-Type"] = "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
return response
Note: This code may or may not work because I haven't tested it. But the general principle remains the same i.e. read the contents of the file and return it in an HTTP response with appropriate headers.
So if this code doesn't work, maybe because the package you're using doesn't support writing to file-like objects or for some other reason, then it would be a good idea to ask the creator of the package or file an issue on their Github about how to read the contents of the file.
Here is a more concise solution:
import os
from io import BytesIO
from django.http import FileResponse
from docxtpl import DocxTemplate
def downloadWord(request, pk):
context = {'first_name' : 'xxx', 'sur_name': 'yyy'}
byte_io = BytesIO()
tpl = DocxTemplate(os.path.join(BASE_PATH, 'template.docx'))
tpl.render(context)
tpl.save(byte_io)
byte_io.seek(0)
return FileResponse(byte_io, as_attachment=True, filename=f'generated_{pk}.docx')

error serving pdf in django 1.8

In django 1.8 I have a couple of functions that read pdf files and return them, and that generate a pdf with reportlab and return it.
In some cases the file is served correctly, but sometimes the PDF is opened by the browser as if it were html and what is even more strange, pdf source is displayed in my django base template.
In this case, if reloading the page after the error, the pdf is served.
This is the code of a view:
fpdf = open (path, 'rb')
return HttpResponse (FileWrapper (fpdf), content_type = 'application/pdf')
and this is the code of the other:
pdf = pisa.CreatePDF (StringIO.StringIO (html.encode ("UTF-8")), result)
if not pdf.err:
response = HttpResponse (result.getvalue (), content_type = 'application / pdf')
response ['Content-Disposition'] = 'attachment; filename =% S.pdf '% (doc.name.replace ("", "_"))
return response
#Return HttpResponse (result.getvalue (), content_type = 'application/pdf')
Returning the PDF as an attachment is a test that I made to see if solved, because the desired behavior would be directly open the file.
Unfortunately, the error still occurs even so.
Change this line
response = HttpResponse (result.getvalue (), content_type = 'application / pdf')
To this line
response = HttpResponse (result.getvalue (), content_type = 'application/octet-stream')
This will make the file to be treated as a binary, and downloaded to the user instead of opening it in the browser.
If you view it inside the browser, follow Igor Pomaranskiy advice, and remove the space inside your content_type variable by doing the following
Change this
content_type = 'application / pdf'
to this
content_type = 'application/pdf'

Django - Getting PIL Image save method to work with Amazon s3boto Storage

In order to resize images upon upload (using PIL), I'm overriding the save method for my Article model like so:
def save(self):
super(Article, self).save()
if self.image:
size = (160, 160)
image = Image.open(self.image)
image.thumbnail(size, Image.ANTIALIAS)
image.save(self.image.path)
This works locally but in production I get an error:
NotImplementedError: This backend doesn't support absolute paths.
I tried replacing the image.save line with
image.save(self.image.url)
but then I get an IOError:
[Errno 2] No such file or directory: 'https://my_bucket_name.s3.amazonaws.com/article/article_images/2.jpg'
That is the correct location of the image though. If I put that address in the browser, the image is there. I tried a number of other things but so far, no luck.
You should try and avoid saving to absolute paths; there is a File Storage API which abstracts these types of operations for you.
Looking at the PIL Documentation, it appears that the save() function supports passing a file-like object instead of a path.
I'm not in an environment where I can test this code, but I believe you would need to do something like this instead of your last line:
from django.core.files.storage import default_storage as storage
fh = storage.open(self.image.name, "w")
format = 'png' # You need to set the correct image format here
image.save(fh, format)
fh.close()
For me default.storage.write() did not work, image.save() did not work, this one worked. See this code if anyone is still interested. I apologize for the indentation. My project was using Cloudinary and Django small project.
from io import BytesIO
from django.core.files.base import ContentFile
from django.core.files.storage import default_storage as storage
def save(self, *args, **kargs):
super(User, self).save(*args, **kargs)
# After save, read the file
image_read = storage.open(self.profile_image.name, "r")
image = Image.open(image_read)
if image.height > 200 or image.width > 200:
size = 200, 200
# Create a buffer to hold the bytes
imageBuffer = BytesIO()
# Resize
image.thumbnail(size, Image.ANTIALIAS)
# Save the image as jpeg to the buffer
image.save(imageBuffer, image.format)
# Check whether it is resized
image.show()
# Save the modified image
user = User.objects.get(pk=self.pk)
user.profile_image.save(self.profile_image.name, ContentFile(imageBuffer.getvalue()))
image_read = storage.open(user.profile_image.name, "r")
image = Image.open(image_read)
image.show()
image_read.close()
If you are working with cloud storages for files in Django
NotImplementedError: This backend doesn't support absolute paths
To fix it you need to replace file.path with file.name
For code in the the question: image.save(self.image.path) with image.save(self.image.name)
Here how it looks like in the console
>>> c = ContactImport.objects.last()
>>> c.json_file.name
'protected/json_files/data_SbLN1MpVGetUiN_uodPnd9yE2prgeTVTYKZ.json'
>>> c.json_file
<FieldFile: protected/json_files/data_SbLN1MpVGetUiN_uodPnd9yE2prgeTVTYKZ.json>
>>> c.json_file.url
'https://storage.googleapis.com/super-secret/media/api/protected/json_files/data_SbLN1MpVGetUiN_uodPnd9yE2prgeTVTYKZ.json?Expires=1631378947&GoogleAccessId=secret&Signature=ga7...'

How to create 2 pages from reportlab using one PageTemplate?

Hi all reportlab master,
I've search the web and also here in stackoverflow but can't find a similar situation on my problem I'm trying to solve during this Holiday vacation.
In django admin, I'm trying to create an action to view my database to a specific format. If I select one record I can view the report in one page pdf. Which is fine. In case the user try to more record that's where the problem start. For example I select multiple record, I can view the report but all content is still in one page pdf.
Is there a way to show a record per page in pdf? All reportlab master jedi, Please help me how to do this the right way.
Here's my code on what I did.
from django.contrib import admin
from models import LatestRsl
from io import BytesIO
from reportlab.pdfgen import canvas
from django.http import HttpResponse
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
from reportlab.lib.units import inch
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.platypus import BaseDocTemplate, PageTemplate, Paragraph, Frame
from reportlab.lib.pagesizes import letter
def go(modeladmin, request, queryset):
response = HttpResponse(mimetype='application/pdf')
response['Content-Disposition'] = 'filename = testframe.pdf'
buffer = StringIO()
c = canvas.Canvas(buffer)
doc = BaseDocTemplate(buffer, showBoundary=1, leftMargin= 0.1*inch, rightMargin= 0.1*inch,
topMargin= 0.1*inch, bottomMargin= 0.1*inch)
signfr = Frame(5.1*inch, 1.2*inch, 2.8*inch, 0.44*inch, showBoundary=1)
modelfr = Frame(3.6*inch, 4.6*inch, 2.8*inch, 0.44*inch, showBoundary=1)
doc.addPageTemplates([PageTemplate(id= 'rsl_frame', frames=[signfr, modelfr]),
PageTemplate(id= 'rsl_frame2', frames=[signfr, modelfr])])
story = []
styles=getSampleStyleSheet()
styles.add(ParagraphStyle(name='Verdana9', fontName= 'Verdana', fontSize= 9))
styles.add(ParagraphStyle(name='VerdanaB10', fontName= 'VerdanaB', fontSize= 10))
for obj in queryset:
#1st frame
model = Paragraph(obj.make,styles["Verdana9"])
story.append(model)
modelfr.addFromList(story,c)
#2nd frame
signatory = Paragraph(obj.signatory,styles["VerdanaB10"])
story.append(signatory)
signfr.addFromList(story,c)
doc.build(story)
c.showPage()
c.save()
pdf = buffer.getvalue()
buffer.close()
response.write(pdf)
return response
Assuming your queryset variable contains all the records you need, you could insert a PageBreak object. Just add from reportlab.platypus import PageBreak to the top of your file, then append a PageBreak object to your document's elements.
If you want to change the template for each page, you can also append a NextPageTemplate and pass the id of your PageTemplate. You'll need to add from reportlab.platypus import NextPageTemplate to the top of your file as well.
for obj in queryset:
#1st frame
model = Paragraph(obj.make,styles["Verdana9"])
story.append(model)
modelfr.addFromList(story,c)
#2nd frame
signatory = Paragraph(obj.signatory,styles["VerdanaB10"])
story.append(signatory)
signfr.addFromList(story,c)
# Force the report to use a different PageTemplate on the next page
story.append(NextPageTemplate('rsl_frame2'))
# Start a new page for the next object in the query
story.append(PageBreak())
You could move the PageBreak wherever you need it, but it's a simple "function" flowable. NextPageTemplate can take the id of any valid PageTemplate object that you've added via addPageTemplates.

how to unit test file upload in django

In my django app, I have a view which accomplishes file upload.The core snippet is like this
...
if (request.method == 'POST'):
if request.FILES.has_key('file'):
file = request.FILES['file']
with open(settings.destfolder+'/%s' % file.name, 'wb+') as dest:
for chunk in file.chunks():
dest.write(chunk)
I would like to unit test the view.I am planning to test the happy path as well as the fail path..ie,the case where the request.FILES has no key 'file' , case where request.FILES['file'] has None..
How do I set up the post data for the happy path?Can somebody tell me?
I used to do the same with open('some_file.txt') as fp: but then I needed images, videos and other real files in the repo and also I was testing a part of a Django core component that is well tested, so currently this is what I have been doing:
from django.core.files.uploadedfile import SimpleUploadedFile
def test_upload_video(self):
video = SimpleUploadedFile("file.mp4", "file_content", content_type="video/mp4")
self.client.post(reverse('app:some_view'), {'video': video})
# some important assertions ...
In Python 3.5+ you need to use bytes object instead of str. Change "file_content" to b"file_content"
It's been working fine, SimpleUploadedFile creates an InMemoryFile that behaves like a regular upload and you can pick the name, content and content type.
From Django docs on Client.post:
Submitting files is a special case. To POST a file, you need only
provide the file field name as a key, and a file handle to the file
you wish to upload as a value. For example:
c = Client()
with open('wishlist.doc') as fp:
c.post('/customers/wishes/', {'name': 'fred', 'attachment': fp})
I recommend you to take a look at Django RequestFactory. It's the best way to mock data provided in the request.
Said that, I found several flaws in your code.
"unit" testing means to test just one "unit" of functionality. So,
if you want to test that view you'd be testing the view, and the file
system, ergo, not really unit test. To make this point more clear. If
you run that test, and the view works fine, but you don't have
permissions to save that file, your test would fail because of that.
Other important thing is test speed. If you're doing something like
TDD the speed of execution of your tests is really important.
Accessing any I/O is not a good idea.
So, I recommend you to refactor your view to use a function like:
def upload_file_to_location(request, location=None): # Can use the default configured
And do some mocking on that. You can use Python Mock.
PS: You could also use Django Test Client But that would mean that you're adding another thing more to test, because that client make use of Sessions, middlewares, etc. Nothing similar to Unit Testing.
I do something like this for my own event related application but you should have more than enough code to get on with your own use case
import tempfile, csv, os
class UploadPaperTest(TestCase):
def generate_file(self):
try:
myfile = open('test.csv', 'wb')
wr = csv.writer(myfile)
wr.writerow(('Paper ID','Paper Title', 'Authors'))
wr.writerow(('1','Title1', 'Author1'))
wr.writerow(('2','Title2', 'Author2'))
wr.writerow(('3','Title3', 'Author3'))
finally:
myfile.close()
return myfile
def setUp(self):
self.user = create_fuser()
self.profile = ProfileFactory(user=self.user)
self.event = EventFactory()
self.client = Client()
self.module = ModuleFactory()
self.event_module = EventModule.objects.get_or_create(event=self.event,
module=self.module)[0]
add_to_admin(self.event, self.user)
def test_paper_upload(self):
response = self.client.login(username=self.user.email, password='foz')
self.assertTrue(response)
myfile = self.generate_file()
file_path = myfile.name
f = open(file_path, "r")
url = reverse('registration_upload_papers', args=[self.event.slug])
# post wrong data type
post_data = {'uploaded_file': i}
response = self.client.post(url, post_data)
self.assertContains(response, 'File type is not supported.')
post_data['uploaded_file'] = f
response = self.client.post(url, post_data)
import_file = SubmissionImportFile.objects.all()[0]
self.assertEqual(SubmissionImportFile.objects.all().count(), 1)
#self.assertEqual(import_file.uploaded_file.name, 'files/registration/{0}'.format(file_path))
os.remove(myfile.name)
file_path = import_file.uploaded_file.path
os.remove(file_path)
I did something like that :
from django.core.files.uploadedfile import SimpleUploadedFile
from django.test import TestCase
from django.core.urlresolvers import reverse
from django.core.files import File
from django.utils.six import BytesIO
from .forms import UploadImageForm
from PIL import Image
from io import StringIO
def create_image(storage, filename, size=(100, 100), image_mode='RGB', image_format='PNG'):
"""
Generate a test image, returning the filename that it was saved as.
If ``storage`` is ``None``, the BytesIO containing the image data
will be passed instead.
"""
data = BytesIO()
Image.new(image_mode, size).save(data, image_format)
data.seek(0)
if not storage:
return data
image_file = ContentFile(data.read())
return storage.save(filename, image_file)
class UploadImageTests(TestCase):
def setUp(self):
super(UploadImageTests, self).setUp()
def test_valid_form(self):
'''
valid post data should redirect
The expected behavior is to show the image
'''
url = reverse('image')
avatar = create_image(None, 'avatar.png')
avatar_file = SimpleUploadedFile('front.png', avatar.getvalue())
data = {'image': avatar_file}
response = self.client.post(url, data, follow=True)
image_src = response.context.get('image_src')
self.assertEquals(response.status_code, 200)
self.assertTrue(image_src)
self.assertTemplateUsed('content_upload/result_image.html')
create_image function will create image so you don't need to give static path of image.
Note : You can update code as per you code.
This code for Python 3.6.
from rest_framework.test import force_authenticate
from rest_framework.test import APIRequestFactory
factory = APIRequestFactory()
user = User.objects.get(username='#####')
view = <your_view_name>.as_view()
with open('<file_name>.pdf', 'rb') as fp:
request=factory.post('<url_path>',{'file_name':fp})
force_authenticate(request, user)
response = view(request)
As mentioned in Django's official documentation:
Submitting files is a special case. To POST a file, you need only provide the file field name as a key, and a file handle to the file you wish to upload as a value. For example:
c = Client()
with open('wishlist.doc') as fp:
c.post('/customers/wishes/', {'name': 'fred', 'attachment': fp})
More Information: How to check if the file is passed as an argument to some function?
While testing, sometimes we want to make sure that the file is passed as an argument to some function.
e.g.
...
class AnyView(CreateView):
...
def post(self, request, *args, **kwargs):
attachment = request.FILES['attachment']
# pass the file as an argument
my_function(attachment)
...
In tests, use Python's mock something like this:
# Mock 'my_function' and then check the following:
response = do_a_post_request()
self.assertEqual(mock_my_function.call_count, 1)
self.assertEqual(
mock_my_function.call_args,
call(response.wsgi_request.FILES['attachment']),
)
if you want to add other data with file upload then follow the below method
file = open('path/to/file.txt', 'r', encoding='utf-8')
data = {
'file_name_to_receive_on_backend': file,
'param1': 1,
'param2': 2,
.
.
}
response = self.client.post("/url/to/view", data, format='multipart')`
The only file_name_to_receive_on_backend will be received as a file other params received normally as post paramas.
In Django 1.7 there's an issue with the TestCase wich can be resolved by using open(filepath, 'rb') but when using the test client we have no control over it. I think it's probably best to ensure file.read() returns always bytes.
source: https://code.djangoproject.com/ticket/23912, by KevinEtienne
Without rb option, a TypeError is raised:
TypeError: sequence item 4: expected bytes, bytearray, or an object with the buffer interface, str found
from django.test import Client
from requests import Response
client = Client()
with open(template_path, 'rb') as f:
file = SimpleUploadedFile('Name of the django file', f.read())
response: Response = client.post(url, format='multipart', data={'file': file})
Hope this helps.
Very handy solution with mock
from django.test import TestCase, override_settings
#use your own client request factory
from my_framework.test import APIClient
from django.core.files import File
import tempfile
from pathlib import Path
import mock
image_mock = mock.MagicMock(spec=File)
image_mock.name = 'image.png' # or smt else
class MyTest(TestCase):
# I assume we want to put this file in storage
# so to avoid putting garbage in our MEDIA_ROOT
# we're using temporary storage for test purposes
#override_settings(MEDIA_ROOT=Path(tempfile.gettempdir()))
def test_send_file(self):
client = APIClient()
client.post(
'/endpoint/'
{'file':image_mock},
format="multipart"
)
I am using Python==3.8.2 , Django==3.0.4, djangorestframework==3.11.0
I tried self.client.post but got a Resolver404 exception.
Following worked for me:
import requests
upload_url='www.some.com/oaisjdoasjd' # your url to upload
with open('/home/xyz/video1.webm', 'rb') as video_file:
# if it was a text file we would perhaps do
# file = video_file.read()
response_upload = requests.put(
upload_url,
data=video_file,
headers={'content-type': 'video/webm'}
)
I am using django rest framework and I had to test the upload of multiple files.
I finally get it by using format="multipart" in my APIClient.post request.
from rest_framework.test import APIClient
...
self.client = APIClient()
with open('./photo.jpg', 'rb') as fp:
resp = self.client.post('/upload/',
{'images': [fp]},
format="multipart")
I am using GraphQL, upload for test:
with open('test.jpg', 'rb') as fp:
response = self.client.execute(query, variables, data={'image': [fp]})
code in class mutation
#classmethod
def mutate(cls, root, info, **kwargs):
if image := info.context.FILES.get("image", None):
kwargs["image"] = image
TestingMainModel.objects.get_or_create(
id=kwargs["id"],
defaults=kwargs
)