Django ReportLab 错误 - 'str' 对象没有属性 'getKeepWithNext

Question

我在用ReportLab生成PDF的时候，想加一张图片，却遇到了一个错误 - 'str'对象没有'getKeepWithNext'这个属性。

我使用的是Django 1.6。

以下是我的文件：

printing.py

import os.path
from reportlab.lib.pagesizes import letter, A4
from reportlab.platypus import SimpleDocTemplate, Paragraph, Image
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.pdfgen import canvas
from reportlab.lib.units import mm
from reportlab.lib.units import inch
from reportlab.lib.enums import TA_CENTER
from reportlab.lib.enums import TA_RIGHT
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
from django.conf import settings

from catalog.models import Product

class MyPrint:
    def __init__(self, buffer, pagesize):
        self.buffer = buffer
        if pagesize == 'A4':
            self.pagesize = A4
        elif pagesize == 'Letter':
            self.pagesize = letter
        self.width, self.height = self.pagesize

    @staticmethod
    def _header_footer(canvas, doc):
        # Save the state of our canvas so we can draw on it
        canvas.saveState()
        styles = getSampleStyleSheet()

        # Header
        header = Paragraph('This is a multi-line header.  It goes on every page.   ' * 5, styles['Normal'])
        w, h = header.wrap(doc.width, doc.topMargin)
        header.drawOn(canvas, doc.leftMargin, doc.height + doc.topMargin - h)

        # Footer
        footer = Paragraph('This is a multi-line footer.  It goes on every page.   ' * 5, styles['Normal'])
        w, h = footer.wrap(doc.width, doc.bottomMargin)
        footer.drawOn(canvas, doc.leftMargin, h)

        # Release the canvas
        canvas.restoreState()


    def print_products(self):
        buffer = self.buffer
        doc = SimpleDocTemplate(buffer,
                                rightMargin=inch/4,
                                leftMargin=inch/4,
                                topMargin=inch/2,
                                bottomMargin=inch/4,
                                pagesize=self.pagesize)

        # Our container for 'Flowable' objects
        elements = []

        # A large collection of style sheets pre-made for us
        styles = getSampleStyleSheet()
        styles.add(ParagraphStyle(name='centered', alignment=TA_CENTER))
        styles.add(ParagraphStyle(name='RightAlign', fontName='Arial', align=TA_RIGHT))

        # Draw things on the PDF. Here's where the PDF generation happens.
        # See the ReportLab documentation for the full list of functionality.
        products = Product.objects.all()
        elements.append(Paragraph('My Products', styles['Heading1']))

        elements.append('<img src="el45.jpg" height="5">')


        for i, product in enumerate(products):
            elements.append(Paragraph(product.info(), styles['Normal']))

        doc.build(elements, onFirstPage=self._header_footer, onLaterPages=self._header_footer, canvasmaker=NumberedCanvas)

        # Get the value of the BytesIO buffer and write it to the response.
        pdf = buffer.getvalue()
        buffer.close()
        return pdf

class NumberedCanvas(canvas.Canvas):
    def __init__(self, *args, **kwargs):
        canvas.Canvas.__init__(self, *args, **kwargs)
        self._saved_page_states = []

    def showPage(self):
        self._saved_page_states.append(dict(self.__dict__))
        self._startPage()

    def save(self):
        """add page info to each page (page x of y)"""
        num_pages = len(self._saved_page_states)
        for state in self._saved_page_states:
            self.__dict__.update(state)
            self.draw_page_number(num_pages)
            canvas.Canvas.showPage(self)
        canvas.Canvas.save(self)

    def draw_page_number(self, page_count):
        # Change the position of this to wherever you want the page number to be
        self.drawRightString(211 * mm, 15 * mm + (0.2 * inch),
                             "Page %d of %d" % (self._pageNumber, page_count))

views.py

def print_products(request):
    # Create the HttpResponse object with the appropriate PDF headers.
    response = HttpResponse(content_type='application/pdf')
    response['Content-Disposition'] = 'filename="Product.pdf"'

    buffer = BytesIO()

    report = MyPrint(buffer, 'Letter')
    pdf = report.print_products()

    response.write(pdf)
    return response

我的图片文件和这两个文件在同一个文件夹里。

django 错误处理 reportlab web开发 pdf生成图片插入

Django ReportLab 错误 - 'str' 对象没有属性 'getKeepWithNext

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