Failed to load image at data:image/svg+xml, incorrect padding

[sfdye]

I have an issue to render base64 svg to pdf that ends with something like:

"z48L2c+PC9zdmc+/"
(not ending in "=")

(The error message goes like: Incorrect padding)

I notice when I install/uninstall lxml, sometimes the problem goes away, but it's nondeterministic for different cases.

I am using pygal with weasyprint in Django and my code is like:

year_chart = pygal.HorizontalBar()
year_chart.add('2016', 4)
print(year_chart.render_data_uri())

The print will give different result based on whether lxml is installed or not.

I also saw #75, not sure if this is related.

[liZe]

That's really strange. render_data_uri uses the standard base64.b64encode to generate the base64 string. Could you provide a full example of base64 string that raises the "Incorrect padding" error?

[sfdye]

PFA
error.log

[liZe]

You have an extra / at the end of the data URL, it's probably not related to Pygal or WeasyPrint 😉.

[sfdye]

Interesting, but I didn't add the / myself. It's all rendered by the render_data_uri method.

My template goes like,

<embed type="image/svg+xml" src={{ year_chart|safe }}/>

Do you spot any error?

[liZe]

Yes! You have to add quotes after src=, or the slash used to close the tag is included in the src attribute!

<embed type="image/svg+xml" src="{{ year_chart|safe }}" />

[sfdye]

Oops, thanks for pointing out my silly mistake.