python - Django - 使用 xhtml2pdf 将生成的 PDF 保存在模型中

Question

我正在尝试使用 xhtml2pdf 应用程序保存生成的 PDF。我希望它将 pdf 保存到模型中。 pdf 已完美创建，浏览器会下载该文件，但我不想下载，而是将其保存到模型中，在我的 models.py 中，我告诉它保存到媒体文件夹中的文件夹中。

模型.py:

class purchase(models.Model):
    purchase_id = models.AutoField(primary_key=True)
    transaction_date = models.DateTimeField()
    method_payment = models.CharField(max_length = 20)
    cmr_name = models.CharField(max_length = 60)
    cmr_address = models.CharField(max_length = 90)
    cmr_postcode = models.CharField(max_length = 10)
    cmr_tel = models.CharField(max_length = 14)
    cmr_email = models.CharField(max_length = 40)
    cmr_pod = models.FileField(upload_to='customers_id')
    cmr_signature = JSignatureField()
    receipt = models.FileField(upload_to='receipts', null=True, blank=True)
    added_by = models.CharField(max_length = 30)
    item_brand = models.CharField(max_length = 50)
    product = models.CharField(max_length = 100)
    model = models.CharField(max_length = 100)
    serial = models.CharField(max_length = 50)
    item_brand2 = models.CharField(max_length = 50)
    product2 = models.CharField(max_length = 100)
    model2 = models.CharField(max_length = 100)
    serial2 = models.CharField(max_length = 50)
    item_brand3 = models.CharField(max_length = 50)
    product3 = models.CharField(max_length = 100)
    model3 = models.CharField(max_length = 100)
    serial3 = models.CharField(max_length = 50)
    def __str__(self):
        return '{}'.format(self.cmr_name)

Utils.py:

from io import BytesIO
from django.http import HttpResponse
from django.template.loader import get_template

from xhtml2pdf import pisa

def render_to_pdf(template_src, context_dict={}):
    template = get_template(template_src)
    html  = template.render(context_dict)
    result = BytesIO()
    pdf = pisa.pisaDocument(BytesIO(html.encode("ISO-8859-1")), result)
    if not pdf.err:
        return HttpResponse(result.getvalue(), content_type='application/pdf')
    return None

views.py:

@login_required(login_url='/accounts/login/')
def add_purchase(request):
    username = None
    if request.user.is_authenticated:
        username = request.user.username
    viewing_info = pwl.objects.get(pk='1')
    viewing_ot = opening_times.objects.get(pk='1')
    viewing_brands = watch_brands.objects.all()
    viewing_watches = watch.objects.values_list('watch_brand_name', flat=True).distinct()
    template = loader.get_template('pwl-access/add_purchase.html')
    if request.method == 'POST':
        form = add_purchase_form(request.POST, request.FILES)
        if form.is_valid():
            ## Form Data
            transaction_date = str(datetime.now().strftime('%Y-%m-%d %H:%M:%S'))
            added_by = request.user
            cmr_name = form.cleaned_data['cmr_name']
            cmr_address = form.cleaned_data['cmr_address']
            cmr_postcode = form.cleaned_data['cmr_postcode']
            cmr_tel = form.cleaned_data['cmr_tel']
            cmr_email = form.cleaned_data['cmr_email']
            purchase_price = form.cleaned_data['purchase_price']
            method_payment = form.cleaned_data['method_payment']
            item_brand = form.cleaned_data['item_brand']
            product = form.cleaned_data['product']
            model = form.cleaned_data['model']
            serial = form.cleaned_data['serial']
            price = form.cleaned_data['price']
            item_brand2 = form.cleaned_data['item_brand2']
            product2 = form.cleaned_data['product2']
            model2 = form.cleaned_data['model2']
            serial2 = form.cleaned_data['serial2']
            price2 = form.cleaned_data['price2']
            item_brand3 = form.cleaned_data['item_brand3']
            product3 = form.cleaned_data['product3']
            model3 = form.cleaned_data['model3']
            serial3 = form.cleaned_data['serial3']
            price3 = form.cleaned_data['price3']
            cmr_pod = request.FILES['cmr_pod'] if 'cmr_pod' in request.FILES else False
            cmr_signature = form.cleaned_data.get('cmr_signature')
            receipt = False
            if cmr_signature:
                signature_picture = draw_signature(cmr_signature, as_file=True)
            new_purchase = purchase(transaction_date=transaction_date,
                                    added_by=added_by,
                                    cmr_name=cmr_name,
                                    cmr_address=cmr_address,
                                    cmr_postcode=cmr_postcode,
                                    cmr_tel=cmr_tel,
                                    cmr_email=cmr_email,
                                    cmr_pod=cmr_pod,
                                    cmr_signature=signature_picture,
                                    receipt=receipt,
                                    method_payment=method_payment,
                                    item_brand=item_brand,
                                    product=product,
                                    model=model,
                                    serial=serial,
                                    item_brand2=item_brand2,
                                    product2=product2,
                                    model2=model2,
                                    serial2=serial2,
                                    item_brand3=item_brand3,
                                    product3=product3,
                                    model3=model3,
                                    serial3=serial3, )
            new_purchase.save()

            ##Receipt Creation
            cb_data = {
                'purchase_price': purchase_price,
                'price': price,
                'price2': price2,
                'price3': price3,
                'new_purchase': new_purchase,
                'cmr_pod': cmr_pod,
                'signature_picture': signature_picture,
            }
            template = get_template('pwl-access/email-templates/receipt_p_email.html')
            pdf = render_to_pdf('pwl-access/email-templates/receipt_p_pdf.html', cb_data)
            purch_id = new_purchase.pk
            if pdf:
                response = HttpResponse(pdf, content_type='application/pdf')
                filename = 'purchase_%s.pdf' % (purch_id)
                download = request.GET.get('download')
                content = "attachment; filename=%s " % (filename)
                response['Content-Disposition'] = content
                receipt_file = File(BytesIO(pdf.content))
                purchase.objects.filter(pk=purch_id).update(receipt=receipt_file)

            email_subject = 'Your Receipt from  - ' + transaction_date
            email_to = 'email'
            filled_email = template.render(cb_data)
            msg = EmailMultiAlternatives(email_subject, filled_email, '<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="89ece7f8fce0fbe0ecfac9a7eae6a7fce2" rel="noreferrer noopener nofollow">[email protected]</a>',
                                         [email_to], )
            msg.content_subtype = "html"

            if email_subject:
                try:
                    msg.send()
                except BadHeaderError:
                    return HttpResponse('Invalid header found.')
                messages.success(request, 'Success! Purchase added and email has been sent to the customer ')
                return response
    else:
        form = add_purchase_form()

    context = {
        'viewing_info': viewing_info,
        'viewing_ot': viewing_ot,
        'viewing_brands': viewing_brands,
        'viewing_watches': viewing_watches,
        'form': form,
    }
    return HttpResponse(template.render(context, request))

管理和数据库显示没有上传任何内容，我没有收到任何错误。在views.py文件中，这些代码行是我希望用pdf文件更新数据库的代码:

receipt_file = File(BytesIO(pdf.content))
purchase.objects.filter(pk=purch_id).update(receipt=receipt_file)

不幸的是，它没有做任何事情。有人可以帮忙吗？被困在这个有一段时间了。我已经尝试了在 stackoverflow 和其他网站上看到的其他几个答案..

谢谢，如有任何帮助，我们将不胜感激。

编辑1:我尝试调用 save() 而不是 update，但没有什么区别:

                receipt_file = File(BytesIO(pdf.content))
                purch = purchase.objects.get(pk=purch_id)
                purch.receipt = receipt_file
                purch.save()

Edit2:我也尝试了多个版本的内容和 IOString(content) 没有任何效果

Edit3:仍然没有答案，任何 Django 专家可能知道发生了什么事吗？看起来好像很简单的事情..

Answer 1

最后我设法使用以下代码来做到这一点:

                receipt_file = BytesIO(pdf.content)
                purch_upd = purchase.objects.get(pk=purch_id)
                purch_upd.receipt = File(receipt_file, filename)
                purch_upd.save()

如此简单，不敢相信我在这个问题上坚持了这么久。