Merge pull request #42 from DataManagementLab/6_Export_Basic_pdf_export_for_own_coursebook

export: basic pdf export for own coursebook

Author: bhaettasch

content/templates/content/export/Image.tex

@@ -0,0 +1,10 @@
+{% load cc_export_tags %}
+{% autoescape off %}
+
+\textbf{Image}
+\Image{ {{content.description|tex_escape}} }{% templatetag openbrace %}{{content.imagecontent.image.path}}{% templatetag closebrace%}
+\newline
+ {{content.description|tex_escape}}
+\newline
+
+{% endautoescape %}

content/templates/content/export/YouTubeVideo.tex

@@ -0,0 +1,9 @@
+{% load cc_export_tags %}
+{% autoescape off %}
+\textbf{YouTube video}
+\newline
+\href{ {{ content.ytvideocontent.url }} }{ {{ content.ytvideocontent.url }} }
+\newline
+{{content.description|tex_escape}}
+\newline
+{% endautoescape %}

content/templates/content/export/base.tex

@@ -0,0 +1,34 @@
+{% load cc_export_tags %}
+{% autoescape off %}
+
+\documentclass[a4paper]{article}
+
+\usepackage[utf8]{inputenc}
+\usepackage[T1]{fontenc}
+\usepackage[ngerman]{babel}
+\usepackage{graphicx}
+\usepackage{float}
+\usepackage{grffile}
+\usepackage{hyperref}
+\usepackage[left=1cm, right=1cm, top=2cm, bottom=2cm]{geometry}
+
+%% Generate a latex graphic
+% 1: caption
+% 2: image path
+\newcommand{\Image}[2]{
+    \begin{figure}[H]
+    \centering
+    \includegraphics[width=\textwidth]{#2}
+    \caption{#1}
+    \end{figure}
+}
+
+\begin{document}
+
+    \title{ {{ course.title|tex_escape }} }
+    \author{ {{user|tex_escape}} }
+    \maketitle
+
+% \end{document} gets appended in code
+
+{% endautoescape %}

content/templates/content/export/invalid.tex

@@ -0,0 +1 @@
+\textit{This content type is not supported at the moment.}

export/helper_functions.py

@@ -0,0 +1,48 @@
+import os
+import shutil
+import tempfile
+from subprocess import Popen, PIPE
+
+from django.template.loader import get_template
+
+from export.templatetags.cc_export_tags import export_template
+
+
+class LaTeX:
+
+    encoding = 'utf-8'
+
+    @staticmethod
+    def render(context, template_name, assets, app='export', external_assets=None):
+        """
+        https://github.com/d120/pyophase/blob/master/ophasebase/helper.py
+        Retrieved 10.08.2020
+        """
+
+        template = get_template(template_name)
+        rendered_tpl = template.render(context).encode(LaTeX.encoding)
+        # prerender content templates
+        for content in context['contents']:
+            rendered_tpl += LaTeX.pre_render(content)
+        rendered_tpl += "\end{document}".encode(LaTeX.encoding)
+
+        with tempfile.TemporaryDirectory() as tempdir:
+            # for asset in assets:
+            #     shutil.copy(os.path.dirname(os.path.realpath(__file__)) + '/../' + app + '/assets/' + asset, tempdir)
+            # if external_assets is not None:
+            #     for asset in external_assets:
+            #         shutil.copy(asset, tempdir)
+            process = Popen(['pdflatex'], stdin=PIPE, stdout=PIPE, cwd=tempdir, )
+            pdflatex_output = process.communicate(rendered_tpl)
+            try:
+                with open(os.path.join(tempdir, 'texput.pdf'), 'rb') as f:
+                    pdf = f.read()
+            except FileNotFoundError:
+                pdf = None
+        return pdf, pdflatex_output, rendered_tpl
+
+    @staticmethod
+    def pre_render(content):
+        template = get_template(export_template(content.type))
+        context = {'content': content}
+        return template.render(context).encode(LaTeX.encoding)

export/templatetags/__init__.py

@@ -0,0 +1,43 @@
+import os
+import re
+
+from django import template
+from django.template.defaultfilters import stringfilter
+from content.models import CONTENT_TYPES
+import content
+
+register = template.Library()
+
+
+@register.filter
+def export_template(type):
+    base_path = os.path.dirname(content.__file__)
+    path = base_path + f"/templates/content/export"
+    if type in CONTENT_TYPES.keys():
+        return path + f"/{type}.tex"
+    return path + "/invalid.tex"
+
+
+@register.filter
+@stringfilter
+def tex_escape(value):
+    """Escape characters with special meaning in LaTeX.
+    https://github.com/d120/pyophase/blob/master/ophasebase/templatetags/tex_escape.py
+    retrieved: 10.08.2020
+    """
+    replacements = {
+        '&': r'\&',
+        '%': r'\%',
+        '$': r'\$',
+        '#': r'\#',
+        '_': r'\_',
+        '{': r'\{',
+        '}': r'\}',
+        '~': r'\textasciitilde{}',
+        '^': r'\^{}',
+        '\\': r'\textbackslash{}',
+        '<': r'\textless{}',
+        '>': r'\textgreater{}',
+    }
+    regex = re.compile('|'.join(re.escape(key) for key in replacements))
+    return regex.sub(lambda match: replacements[match.group()], value)

export/templatetags/cc_export_tags.py

@@ -1,3 +1,34 @@
+from django.http import HttpResponse
 from django.shortcuts import render
 
-# Create your views here.
+from base.models import Course, Favorite
+from export.helper_functions import LaTeX
+
+
+def generate_coursebook(request, pk, template="content/export/base.tex", context=None):
+    """ Generates a PDF file with nametags for students in the queryset"""
+    if context is None:
+        context = {}
+    user = request.user
+    course = Course.objects.get(pk=pk)
+    context['user'] = user
+    context['course'] = course
+    context['contents'] = [favorite.content for favorite in Favorite.objects.filter(user=user.profile, course=course)]
+    (pdf, pdflatex_output, tex_template) = LaTeX.render(context, template, [])
+    return pdf, pdflatex_output, tex_template
+
+
+def generate_coursebook_response(request, pk, filename='coursebook.pdf'):
+    """ Generates a PDF file with nametags for students in the queryset and sends it to the browser"""
+    (pdf, pdflatex_output, tex_template) = generate_coursebook(request, pk)
+
+    return write_response(request, pdf, pdflatex_output, tex_template, filename)
+
+
+def write_response(request, pdf, pdflatex_output, tex_template, filename, content_type='application/pdf'):
+    if not pdf:
+        return render(request, "frontend/coursebook/rendering-error.html", {"content": pdflatex_output[0].decode("utf-8"), "tex_template": tex_template.decode("utf-8")})
+    response = HttpResponse(content_type=content_type)
+    response['Content-Disposition'] = 'attachment; filename=' + filename
+    response.write(pdf)
+    return response

export/views.py

@@ -7,7 +7,7 @@
 <div class="mt-3">
     {% with user|get_coursebook:course as topic_contents %}
         {% if topic_contents|length > 0 %}
-            <a href="" class="btn btn-primary float-right text-right">{% trans 'Export' %}</a>
+            <a href="{% url 'frontend:coursebook-generate' course.id %}" target="_blank" class="btn btn-primary float-right text-right">{% trans 'Export' %}</a>
         {% endif %}
         <button class="btn btn-primary float-left mr-1" type="button" data-toggle="collapse" data-target="#collapseCoursebook"
                 aria-expanded="false" aria-controls="collapseCoursebook">

frontend/templates/frontend/course/coursebook.html

@@ -0,0 +1,15 @@
+{% extends 'frontend/base_logged_in.html' %}
+
+{# Load the tag library #}
+{% load bootstrap4 %}
+{% load i18n %}
+
+{% block title %}Error - Collab Coursebook{% endblock %}
+
+{% block content %}
+    <h1>Error</h1>
+    <p>An error occured while generating your coursebook. Please see the log file below.</p>
+    <p>{{ content|linebreaks}}</p>
+    <h3>Latex Template</h3>
+    <p>{{ tex_template|linebreaksbr }}</p>
+{% endblock %}