troggle-unchained/core/views/drawings.py

import os, stat
import re
from pathlib import Path
from urllib.parse import urljoin, unquote as urlunquote

from django.conf import settings
from django.shortcuts import render
from django.http import HttpResponse

from troggle.core.models.survex import DrawingFile
from troggle.core.views.expo import getmimetype
#import parsers.surveys

'''Some of these views serve files as binary blobs, and simply set the mime type based on the file extension,
as does the urls.py dispatcher which sends them here. Here they should actually have the filetype checked 
by looking inside the file before being served.


'''

todo='''- Need to check if invalid query string is invalid, or produces multiple replies
and render a user-friendly error page.
'''


def dwgallfiles(request):
    '''Report on all the drawing files in the system. These were loaded by parsing the entire directory tree
    '''
    dwgfiles = DrawingFile.objects.all()
    return render(request, 'dwgfiles.html', { 'dwgfiles':dwgfiles, 'settings': settings })
    

def dwgfilesingle(request, path):
    '''sends a single binary file to the user, We should have a renderer that syntax-colours this Tunnel xml 
    but it might be a Therion file. And it could be an old PNG, PDF or SVG for that matter,
    so we should attempt to render it.
    
    The db records created on datbase reset import are not use when we look for an individual drawing, only 
    collections of them.
    
    Note the infelicity that this will deliver files that exist, but are hidden on the previous
    webpage /dwgupload/... if the user types the filename into the browser bar. Could be a problem?
    Should we validate using uploads.py dwgvaliddisp() here too?
    '''
    tfile = Path(settings.DRAWINGS_DATA, path)
    if not tfile.is_file():
        message = f'Drawing file not found in filesystem at \'{path}\' .'
        return render(request, 'errors/generic.html', {'message': message})   
    
    if Path(tfile).suffix in ['.xml', 'th2', '.th']:
        try: # for display not download
            return HttpResponse(content=open(tfile, errors='strict'), content_type="text/xhtml") 
        except UnicodeDecodeError:
            try:
                return HttpResponse(content=open(tfile,encoding='iso-8859-1'), content_type="text/xhtml") 
            except: 
                return HttpResponse(content=open(tfile,mode='rb'), content_type="text/xhtml") 
            else:
                return HttpResponse(content=open(tfile, errors='ignore'), content_type="text/xhtml") 
        else:
            return HttpResponse(content="Unable to understand the encoding for this file: not UTF-8 nor iso-8859-1, or some other read error happened.") 
    else:
        return HttpResponse(content=open(tfile,"rb"), content_type=getmimetype(tfile))