如何更正 TypeError：Unicode 对象必须在使用 ReportLab 散列之前进行编码

Question

最近，我一直在工作ReportLab。目前，我想使用ReportLab 在 PDF 中生成可点击的目录。

当我尝试查看它的工作原理时，我不断收到此错误：TypeError: Unicode-objects must be encoded before hashing

当我尝试使用 ReportLab 库在 Python 3.7.4 上执行此代码时：

class MyDocTemplate(BaseDocTemplate):
    def __init__(self, filename, **kw):
        self.allowSplitting = 0
        apply(BaseDocTemplate.__init__, (self, filename), kw)
        template = PageTemplate('normal', [Frame(2.5*cm, 2.5*cm, 15*cm, 25*cm, id='F1')])
        self.addPageTemplates(template)


    def afterFlowable(self, flowable):
        "Registers TOC entries."
        if flowable.__class__.__name__ == 'Paragraph':
            text = flowable.getPlainText()
            style = flowable.style.name
            if style == 'Heading1':
                level = 0
            elif style == 'Heading2':
                level = 1
            else:
                return
            E = [level, text, self.page]
            #if we have a bookmark name append that to our notify data
            bn = getattr(flowable,'_bookmarkName',None)
            if bn is not None: E.append(bn)
            self.notify('TOCEntry', tuple(E))

centered = PS(name = 'centered',
    fontSize = 30,
    leading = 16,
    alignment = 1,
    spaceAfter = 20)

h1 = PS(
    name = 'Heading1',
    fontSize = 14,
    leading = 16)


h2 = PS(name = 'Heading2',
    fontSize = 12,
    leading = 14)


# Build story.
story = []

toc = TableOfContents()
toc.levelStyles = [
    PS(fontName='Times-Bold', fontSize=20, name='TOCHeading1', leftIndent=20, firstLineIndent=-20, spaceBefore=10, leading=16),
    PS(fontSize=18, name='TOCHeading2', leftIndent=40, firstLineIndent=-20, spaceBefore=5, leading=12),
]
story.append(toc)

def doHeading(text,sty):
    from hashlib import sha1
    #create bookmarkname
    bn=sha1(text+sty.name).hexdigest()
    #modify paragraph text to include an anchor point with name bn
    h=Paragraph(text+'<a name="%s"/>' % bn,sty)
    #store the bookmark name on the flowable so afterFlowable can see this
    h._bookmarkName=bn
    story.append(h)

story.append(Paragraph('<b>Table of contents</b>', centered))
story.append(PageBreak())
doHeading('First heading', h1)
story.append(Paragraph('Text in first heading', PS('body')))
doHeading('First sub heading', h2)
story.append(Paragraph('Text in first sub heading', PS('body')))
story.append(PageBreak())
doHeading('Second sub heading', h2)
story.append(Paragraph('Text in second sub heading', PS('body')))
story.append(PageBreak())
doHeading('Last heading', h1)
story.append(Paragraph('Text in last heading', PS('body')))
doc = MyDocTemplate('mintoc.pdf')
doc.multiBuild(story)

我尝试解决此问题，但无法正确解决此问题。感谢您在这方面的帮助。

Answer 1

你应该传递字节，而不是字符串，所以问题就在这里：

bn=sha1(text+sty.name).hexdigest()

你可以做的就是改变它：

bn=sha1((text+sty.name).encode("utf8")).hexdigest()

另外，你真的应该把你的 sha1 导入到文件的顶部，不需要每次运行函数时都调用它