自动化PDF生成
2 个回答
5
最近,我需要为一个Django应用程序创建PDF报告。虽然有ReportLab的许可证,但我最后选择了LaTeX。这种方法的好处是,我们可以使用Django模板来生成LaTeX源代码,这样就不用为我们需要创建的多个报告写很多代码了。而且,LaTeX的语法相对简洁(虽然它也有很多独特之处,并不适合所有用途)。
这个代码片段提供了这种方法的一般概述。我发现有必要做一些修改,具体内容我在这个问题的最后提供了。主要的新增功能是检测Rerun LaTeX
消息,这表示需要进行额外的处理。使用起来非常简单:
def my_view(request):
pdf_stream = process_latex(
'latex_template.tex',
context=RequestContext(request, {'context_obj': context_obj})
)
return HttpResponse(pdf_stream, content_type='application/pdf')
在用LaTeX生成的PDF中嵌入视频是可能的,不过我没有这方面的经验。这里有一个很好的Google搜索结果。
这个解决方案确实需要启动一个新进程(pdflatex
),所以如果你想要一个纯Python的解决方案,那就继续寻找吧。
import os
from subprocess import Popen, PIPE
from tempfile import NamedTemporaryFile
from django.template import loader, Context
class LaTeXException(Exception):
pass
def process_latex(template, context={}, type='pdf', outfile=None):
"""
Processes a template as a LaTeX source file.
Output is either being returned or stored in outfile.
At the moment only pdf output is supported.
"""
t = loader.get_template(template)
c = Context(context)
r = t.render(c)
tex = NamedTemporaryFile()
tex.write(r)
tex.flush()
base = tex.name
names = dict((x, '%s.%s' % (base, x)) for x in (
'log', 'aux', 'pdf', 'dvi', 'png'))
output = names[type]
stdout = None
if type == 'pdf' or type == 'dvi':
stdout = pdflatex(base, type)
elif type == 'png':
stdout = pdflatex(base, 'dvi')
out, err = Popen(
['dvipng', '-bg', '-transparent', names['dvi'], '-o', names['png']],
cwd=os.path.dirname(base), stdout=PIPE, stderr=PIPE
).communicate()
os.remove(names['log'])
os.remove(names['aux'])
# pdflatex appears to ALWAYS return 1, never returning 0 on success, at
# least on the version installed from the Ubuntu apt repository.
# so instead of relying on the return code to determine if it failed,
# check if it successfully created the pdf on disk.
if not os.path.exists(output):
details = '*** pdflatex output: ***\n%s\n*** LaTeX source: ***\n%s' % (
stdout, r)
raise LaTeXException(details)
if not outfile:
o = file(output).read()
os.remove(output)
return o
else:
os.rename(output, outfile)
def pdflatex(file, type='pdf'):
out, err = Popen(
['pdflatex', '-interaction=nonstopmode', '-output-format', type, file],
cwd=os.path.dirname(file), stdout=PIPE, stderr=PIPE
).communicate()
# If the output tells us to rerun, do it by recursing over ourself.
if 'Rerun LaTeX.' in out:
return pdflatex(file, type)
else:
return out