我正在测试Django和matplotlib的几个案例,例如
this question或
in french.
每次,它都可以在我的Mac上运行,但不在我的服务器上,我收到以下错误：
Internal Server Error: /mj/charts/mplimage.png
Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/django/core/handlers/exception.py",line 35,in inner
response = get_response(request)
File "/usr/local/lib/python3.6/dist-packages/django/core/handlers/base.py",line 128,in _get_response
response = self.process_exception_by_middleware(e,request)
File "/usr/local/lib/python3.6/dist-packages/django/core/handlers/base.py",line 126,in _get_response
response = wrapped_callback(request,*callback_args,**callback_kwargs)
File "/root/src/jm/majority_judgment/views.py",line 39,in mplimage
canvas.print_png(response)
File "/usr/local/lib/python3.6/dist-packages/matplotlib/backends/backend_agg.py",line 526,in print_png
with cbook.open_file_cm(filename_or_obj,"wb") as fh:
File "/usr/lib/python3.6/contextlib.py",line 81,in __enter__
return next(self.gen)
File "/usr/local/lib/python3.6/dist-packages/matplotlib/cbook/__init__.py",line 624,in open_file_cm
fh,opened = to_filehandle(path_or_file,mode,True,encoding)
File "/usr/local/lib/python3.6/dist-packages/matplotlib/cbook/__init__.py",line 615,in to_filehandle
raise ValueError('fname must be a PathLike or file handle')
ValueError: fname must be a PathLike or file handle
[28/Mar/2018 19:09:11] "GET /mj/charts/mplimage.png HTTP/1.1" 500 82804
这是一个最小的片段：
def mplimage(request):
f = matplotlib.figure.Figure()
canvas = FigureCanvasAgg(f)
response = HttpResponse(content_type='image/png')
canvas.print_png(response)
plt.close(f)
return response
我试图更新matplotlib,django等,但它没有做任何事……
解决方法
目前,matplotlib的编写函数
require the
seek ducktype在文件中使用响应.您可以写入缓冲区,如下所示：
import io
def mplimage(request):
f = matplotlib.figure.Figure()
# Code that sets up figure goes here; in the question,that's ...
FigureCanvasAgg(f)
buf = io.BytesIO()
plt.savefig(buf,format='png')
plt.close(f)
response = HttpResponse(buf.getvalue(),content_type='image/png')
return response