|safe outputs unicode (using for data visualization: Plotly/Bokeh)

Using Django Deployment
1

To embed an interactive chart with tools like Plotly or Bokeh in a Django project, procedure:

  • in views.py Plotly: fig=fig.to_html(), Bokeh: script1, div1 = components(p)
  • in template Plotly: {{ fig|safe }}, Bokeh: {{ script1|safe } {{ div1|safe }}

What works:

  • Using both libraries the charts display fine, locally in dev.

What doesn’t work:

  • Non-Latin data (title, labels) are displayed as unicode. In plotly also <br> tag displayed as unicode (which means the issue is not necessarily about the language).
  • MemoryError when deploying to a server (tested Plotly), pointing at the line with fig=fig.to_html(). (I am not using much data, it is a simple chart.)

The fact that the issue (unicode characters) repeats for both libraries probably means that the cause lies with Django.

Question:
How to embed interactive charts directly in Django minding international users with non-Latin data?

Any clues on MemoryError are also welcomed.

2

displayed as unicode

What does that mean? Do you mean escaped unicode or something?

3

Means in chart it would display something like “\u031f\u0435…” for a German word “für”. And something like “\u003cbr\u003e” for <br>, i.e. where there should be a new line in hover labels. Then labels appear on the same line with “\u003cbr\u003e” in between.

4

What does the HTML look like? Does it look correct?

5

The html, looks like:

  • with fig=fig.to_html() and {{ fig|safe }}
<text class="legendtext" text-anchor="start" style="font-family: ..." 
x="40" y="7.8" data-unformatted="\u0410\...u040b" 
data-math="N">\u0410\...\u040b</text>
  • with fig=fig.to_html() and {{ fig }}
"hovertemplate":"%{label}: %{value}","labels":["\u0442\u043..","\u043c\u0443\...\u0430",...]

Looks like {{ fig|safe }} already receives data in this format “\u..”

By the way, I also generated a static version of the chart with Plotly and it looks fine (non-Latin text appears correct). When generating a static chart what gets omitted in code is fig=fig.to_html() and {{ fig|safe }}.