在GAE上生成PDF不起作用

Question

我正在尝试为数据存储中存在的所有报告生成整个pdf。所以我创建了一个处理程序

class PDFPage(webapp2.RequestHandler):
    def get(self, vehicle_no):
        self.response.headers['Content-Type'] = 'application/pdf'
        self.response.headers['Content-Disposition'] = 'attachement; filename={}.pdf'.format(vehicle_no)

        report = Report.get_report_by_vehicle_no(vehicle_no)

        if not report:
            self.response.write('Vehicle Number does not exists')

        PDFHelper.generate_pdf(self.response, report)

    def generate_whole_report(self, reports):
        PDFHelper.generate_whole_pdf(self.response, reports)

    def post(self, *args):
        self.response.headers['Content-Type'] = 'application/pdf'
        self.response.headers['Content-Disposition'] = 'attachement; filename=whole_report.pdf'

        vehicle_nos = eval(self.request.body).get('vehicle_nos', None)
        reports = []
        for vehicle_no in vehicle_nos:
            reports.append(Report.get_report_by_vehicle_no(vehicle_no))

        self.generate_whole_report(reports)

你看，通过get方法为单个报表生成pdf是可行的，但它无法通过post方法为所有报表生成整个pdf。。我尝试从post方法本身调用PDFHelper.generate_pdf，但也失败了。所以问题主要是请求方法，而不是代码。。你知道吗

我不知道如何将pdf文件写入self.reponse方法内的post对象。你知道吗

我的PDFHelper类看起来像

class PDFHelper:
    def __init__(self):
        pass

    @classmethod
    def generate_pdf(cls, filename, report):
        doc = SimpleDocTemplate(filename, pagesize=A4, rightMargin=30, leftMargin=30, topMargin=30,
                                bottomMargin=18)
        doc.title = 'Self Regulation Report'

        doc.pagesize = landscape(A4)
        elements = []

        data = [
            ["Name", report.name],
            ["Vehicle Number", report.vehicle_no],
            ["Measured Temperature", str(report.measured_temperature)],
            ["Cleaning", convert_boolean_to_text(report.cleaning)],
            ["Hygienic Workflow", convert_boolean_to_text(report.hygienic_workflow)],
            ["Cabin Cleaning", convert_boolean_to_text(report.cabin_cleaning)],
            ["Problem", report.problem or ''],
            ["Solution", report.solution or ''],
            ["Created Date", str(report.date_created).split('.')[0]]
        ]

        # TODO: Get this line right instead of just copying it from the docs
        style = TableStyle([('ALIGN', (1, 1), (-2, -2), 'RIGHT'),
                            ('TEXTCOLOR', (1, 1), (-2, -2), colors.red),
                            ('VALIGN', (0, 0), (0, -1), 'TOP'),
                            ('TEXTCOLOR', (0, 0), (0, -1), colors.blue),
                            ('ALIGN', (0, -1), (-1, -1), 'CENTER'),
                            ('VALIGN', (0, -1), (-1, -1), 'MIDDLE'),
                            ('TEXTCOLOR', (0, -1), (-1, -1), colors.green),
                            ('INNERGRID', (0, 0), (-1, -1), 0.25, colors.black),
                            ('BOX', (0, 0), (-1, -1), 0.25, colors.black),
                            ])

        # Configure style and word wrap
        heading_style = getSampleStyleSheet()
        style_h = heading_style['Title']
        p = Paragraph("Report for Vehicle Number " + report.vehicle_no, style_h)
        elements.append(p)

        s = getSampleStyleSheet()
        s = s["BodyText"]
        s.wordWrap = 'CJK'
        data2 = [[Paragraph(cell, s) for cell in row] for row in data]
        t = Table(data2)
        t.setStyle(style)

        # Send the data and build the file
        elements.append(t)
        doc.build(elements)

    @classmethod
    def generate_sample_pdf(cls, filename, reports):
        doc = SimpleDocTemplate(filename, pagesize=A4, rightMargin=30, leftMargin=30, topMargin=30,
                                bottomMargin=18)
        doc.title = 'Self Regulation Sample Report'

        doc.pagesize = landscape(A4)
        doc.build([])

    @classmethod
    def generate_whole_pdf(cls, filename, reports):
        doc = SimpleDocTemplate(filename, pagesize=A4, rightMargin=30, leftMargin=30, topMargin=30,
                                bottomMargin=18)
        doc.title = 'Self Regulation Whole Report'

        doc.pagesize = landscape(A4)
        elements = []
        for report in reports:

            data = [
                ["Name", report.name],
                ["Vehicle Number", report.vehicle_no],
                ["Measured Temperature", str(report.measured_temperature)],
                ["Cleaning", convert_boolean_to_text(report.cleaning)],
                ["Hygienic Workflow", convert_boolean_to_text(report.hygienic_workflow)],
                ["Cabin Cleaning", convert_boolean_to_text(report.cabin_cleaning)],
                ["Problem", report.problem or ''],
                ["Solution", report.solution or ''],
                ["Created Date", str(report.date_created).split('.')[0]]
            ]

            # TODO: Get this line right instead of just copying it from the docs
            style = TableStyle([('ALIGN', (1, 1), (-2, -2), 'RIGHT'),
                                ('TEXTCOLOR', (1, 1), (-2, -2), colors.red),
                                ('VALIGN', (0, 0), (0, -1), 'TOP'),
                                ('TEXTCOLOR', (0, 0), (0, -1), colors.blue),
                                ('ALIGN', (0, -1), (-1, -1), 'CENTER'),
                                ('VALIGN', (0, -1), (-1, -1), 'MIDDLE'),
                                ('TEXTCOLOR', (0, -1), (-1, -1), colors.green),
                                ('INNERGRID', (0, 0), (-1, -1), 0.25, colors.black),
                                ('BOX', (0, 0), (-1, -1), 0.25, colors.black),
                                ])

            # Configure style and word wrap
            heading_style = getSampleStyleSheet()
            style_h = heading_style['Title']
            p = Paragraph("Report for Vehicle Number " + report.vehicle_no, style_h)
            elements.append(p)

            s = getSampleStyleSheet()
            s = s["BodyText"]
            s.wordWrap = 'CJK'
            data2 = [[Paragraph(cell, s) for cell in row] for row in data]
            t = Table(data2)
            t.setStyle(style)

            # Send the data and build the file
            elements.append(t)

        doc.build(elements)

在打印创建的pdf元素时，会显示

[Paragraph(
'encoding': 'utf8'
'text': u'Report for Vehicle Number dxc'
'frags': [ParaFrag(__tag__='para', bold=1, fontName='Helvetica-Bold', fontSize=18, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Report for Vehicle Number dxc', textColor=Color(0,0,0,1), underline=0)]
'bulletText': None
'debug': 0
'style': <ParagraphStyle 'Title'>
'caseSensitive': 1
) #Paragraph, Table(
 rowHeights=[None, None, None, None, None, None, None, None, None],
 colWidths=[None, None],
[[Paragraph(
  'encoding': 'utf8'
  'text': u'Name'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Name', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'Avinash'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Avinash', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Vehicle Number'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Vehicle Number', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'dxc'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'dxc', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Measured Temperature'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Measured Temperature', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'-25'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'-25', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Cleaning'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Cleaning', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'Ok'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Ok', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Hygienic Workflow'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Hygienic Workflow', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'Not Ok'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Not Ok', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Cabin Cleaning'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Cabin Cleaning', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'Not Ok'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Not Ok', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Problem'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Problem', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': ''
  'frags': []
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Solution'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Solution', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': ''
  'frags': []
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Created Date'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Created Date', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'2016-08-22 05:03:35'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'2016-08-22 05:03:35', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph]]
) # end table, Paragraph(
'encoding': 'utf8'
'text': u'Report for Vehicle Number dxc'
'frags': [ParaFrag(__tag__='para', bold=1, fontName='Helvetica-Bold', fontSize=18, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Report for Vehicle Number dxc', textColor=Color(0,0,0,1), underline=0)]
'bulletText': None
'debug': 0
'style': <ParagraphStyle 'Title'>
'caseSensitive': 1
) #Paragraph, Table(
 rowHeights=[None, None, None, None, None, None, None, None, None],
 colWidths=[None, None],
[[Paragraph(
  'encoding': 'utf8'
  'text': u'Name'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Name', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'Avinash'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Avinash', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Vehicle Number'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Vehicle Number', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'dxc'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'dxc', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Measured Temperature'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Measured Temperature', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'-25'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'-25', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Cleaning'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Cleaning', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'Ok'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Ok', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Hygienic Workflow'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Hygienic Workflow', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'Not Ok'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Not Ok', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Cabin Cleaning'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Cabin Cleaning', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'Not Ok'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Not Ok', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Problem'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Problem', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': ''
  'frags': []
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Solution'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Solution', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': ''
  'frags': []
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph],
   [Paragraph(
  'encoding': 'utf8'
  'text': u'Created Date'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'Created Date', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph,
    Paragraph(
  'encoding': 'utf8'
  'text': u'2016-08-22 05:03:35'
  'frags': [ParaFrag(__tag__='para', bold=0, fontName='Helvetica', fontSize=10, greek=0, italic=0, link=None, rise=0, strike=0, sub=0, sup=0, text=u'2016-08-22 05:03:35', textColor=Color(0,0,0,1), underline=0)]
  'bulletText': None
  'debug': 0
  'style': <ParagraphStyle 'BodyText'>
  'caseSensitive': 1
  ) #Paragraph]]
) # end table]