将Base64字符串另存为.PNG不起作用

Question

I have a base64 string that I got from using Google Charts. The project is being written in Python/Django/Javascript if that helps.

chartStr = chart.getImageURI()

I want to save this string as a .png on my server.

I've tried

with open('foo.png',"wb") as f:
    f.write(chartStr.decode('base64'))

but I get an incorrect padding error. I fix this by adding a '=' at the end of the string chartStr. WHen I do that, the foo.png image is created but when I try to open it I get an error that says

Any advice? Thanks!

Answer 1

When you added the = to the string the returned string from .decode("base64") was the same as the input string minus the appended = .

To write the .png to a file you need to do the following:

head, data = chartStr.split(",", 1)
with open('foo.png',"wb") as f:
     f.write(data.decode('base64'))

This removes the data:image/png;base64, stuff and leaves you with some base64 encoded data.