@@ 52,15 52,13 @@ The new wiki contains a help page about 
 Structure of a local wiki
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
-A new wiki at ``/path/to/wiki`` consists of the following files and directories: 
+A new wiki at ``/path/to/wiki`` consists of the following files and directories:
 
 ``wiki.db``
   An `SQLite`_ database containing wiki pages.
 ``media/images``
-  Wiki image links refer to files located here (see in-wiki help for details). 
-``media/math``
-  Used to store rendered formula images (see in-wiki help for details).
-       
+  Wiki image links refer to files located here (see in-wiki help for details).
+
 The whole wiki s file based which makes it easy to share it across
 multiple computers, e.g. using services like `UbuntuOne`_ or `Dropbox`_.
 

          
@@ 89,13 87,10 @@ 3.  Set *Diggie* specific options  in th
 
     ``DIGGIE_WIKINAME = "Diggie"``
       Name of the wiki.
-    
-    ``DIGGIE_MEDIA = ""``
-      Path relative to ``MEDIA_ROOT`` (and ``MEDIA_URL``) to use for wiki
-      content files (e.g. images). Must use *slashes*! The server needs write
-      access to ``MEDIA_ROOT/DIGGIE_MEDIA/math`` for saving rendered math
-      images.
-    
+
+    ``DIGGIE_IMAGES = ""``
+      Path (relative to ``MEDIA_URL``) where wiki images are located.
+
     ``DIGGIE_MDX = []``
       List of additional or custom markdown extensions.
 

          
@@ 135,7 130,7 @@ browsers.
 Personally I use it in Google Chrome 6. If you find something not working in
 other browsers, feel free to fix this and share your patches by forking the
 source repository. I'll happily integrate improvements, except dirty hacks for
-old IE versions.  
+old IE versions.
 
 ===============================================================================
 Feature wish list

          
@@ 145,6 140,9 @@ Feature wish list
     match).
 -   Compress page history.
 -   Provide a *diff* view for page revisions.
+-   Support uploading of files and images. This is not needed when using
+    *Diggie* as a local wiki (where you use your file browser to put files into
+    a wiki) but when the *Diggie* app runs on a remote machine.
 
 ===============================================================================
 Changes

          

@@ 163,7 163,6 @@ def init(opts):
         _die("path already exists")
 
     os.makedirs(join(opts.path, "media", "images"))
-    os.makedirs(join(opts.path, "media", "math"))
 
     LOCALSITE['settings.py'] = LOCALSITE['settings.py'] % opts.name
     dizzie = join(opts.path, "dizzie")

          

@@ 1,38 0,0 @@ 
-import markdown
-
-from django.db.models import TextField
-
-from diggie.mdx import DiggieExtension
-from diggie.settings import MDX
-
-class MarkdownTextField (TextField):
-    """
-    A TextField that automatically implements DB-cached Markdown translation.
-
-    NOTE: The MarkdownTextField is not able to check whether the model
-    defines any other fields with the same name as the HTML field it
-    attempts to add - if there are other fields with this name, a
-    database duplicate column error will be raised.
-
-    Based on http://djangosnippets.org/snippets/882/
-
-    """
-    def contribute_to_class (self, cls, name):
-        TextField(editable=False).contribute_to_class(cls, "html")
-        TextField(editable=False).contribute_to_class(cls, "targets")
-        super(MarkdownTextField, self).contribute_to_class(cls, name)
-
-    def pre_save (self, model, add):
-        value = getattr(model, self.attname)
-
-        dx = DiggieExtension(None)
-        mx = ["abbr", "toc", "tables", "def_list", "footnotes", dx] + MDX
-        md = markdown.Markdown(extensions=mx, output_format="xhtml1")
-        html = md.convert(value)
-
-        setattr(model, "html", html)
-        setattr(model, "targets", ",".join(md.targets))
-        return value
-
-    def __unicode__ (self):
-        return self.attname

          

@@ 1,63 0,0 @@ 
-from subprocess import Popen, PIPE, STDOUT
-import tempfile
-from os.path import join
-import re
-from shutil import rmtree
-
-_LATEX = r"""
-\documentclass{article}
-\usepackage{color}
-\usepackage{amsmath}
-\usepackage{amsfonts}
-\usepackage[active,tightpage]{preview}
-\definecolor{bg}{rgb}{
-1,1,1
-}
-\definecolor{fg}{rgb}{
-0,0,0
-}
-\pagestyle{empty}
-\pagecolor{bg}
-\begin{document}
-\color{fg}
-\begin{preview}
-$
-%s
-$
-\end{preview}
-\end{document}
-"""
-
-class MathException(Exception):
-
-    def __init__(self, msg, output):
-        super(MathException, self).__init__(msg)
-        self.output = output
-
-def math_to_png(source, dpi, fname):
-
-    def run(cmd):
-        try:
-            p = Popen(cmd, stdout=PIPE, stderr=STDOUT, cwd=tdir)
-            out = p.communicate()[0]
-        except OSError, e:
-            rmtree(tdir)
-            raise MathException("failed to run *%s*" % cmd[0], e)
-        if p.returncode != 0:
-            rmtree(tdir)
-            raise MathException("*%s* had problems" % cmd[0], out)
-        return out
-
-    tdir = tempfile.mkdtemp()
-    with open(join(tdir, "math.latex"), 'w') as fp:
-        fp.write(_LATEX % source)
-    cmd = ["latex", "-interaction=nonstopmode", "math.latex"]
-    run(cmd)
-    cmd = ["dvipng", "-D", dpi, "-z", "9", "--depth*", "-o", fname,
-           "math.dvi"]
-    output = run(cmd)
-    rmtree(tdir)
-    depth = (re.findall(r'depth=([0-9]+)', output) + [0])[0]
-    valign = -int(depth)
-    return valign
-

          

@@ 1,16 1,16 @@ 
 from hashlib import md5
-from os.path import exists, join
-from os import mkdir
 import re
 
 from markdown import Extension, etree, AtomicString
 from markdown.inlinepatterns import Pattern
 
+from django.core.exceptions import ObjectDoesNotExist
+from django.core.urlresolvers import reverse
 from django.template.defaultfilters import slugify
 
 from diggie.urls import RE_PAGE_NAME
-from diggie.settings import MEDIA_DIR, MEDIA_URL
-from diggie.math import math_to_png, MathException
+from diggie.settings import IMAGES
+from diggie.util import math_to_png, MathException
 
 # =============================================================================
 # regular expressions

          
@@ 34,10 34,10 @@ RX_PAGE_LINK_CLASS = re.compile(r'^PAGEL
 
 class LinkPattern(Pattern):
 
-    def __init__(self, md):
+    def __init__(self, targets):
         Pattern.__init__(self, None)
 
-        self.md = md
+        self.targets = targets
 
     def getCompiledRegExp(self):
 

          
@@ 49,7 49,7 @@ class LinkPattern(Pattern):
         name, anchor, alt = [s is not None and s.strip() for s in m.groups()[1:4]]
         anchor = anchor and "#%s" % slugify(anchor) or ""
 
-        self.md.targets.add(name)
+        self.targets.add(name)
 
         el = etree.Element('a')
         el.set("href", "/page/%s%s" % (name, anchor))

          
@@ 93,7 93,7 @@ class ImagePattern(Pattern):
             style = ""
 
         el = etree.Element('img')
-        el.set("src", "%simages/%s" % (MEDIA_URL, fname))
+        el.set("src", IMAGES + fname)
         el.set("style", style)
         for key, value in [p.split("=", 1) for p in params if "=" in p]:
             el.set(key, value.strip("'\""))

          
@@ 108,7 108,7 @@ class ImagePattern(Pattern):
 
 # -----------------------------------------------------------------------------
 
-MATHERR = """The following math expression caused errors:
+MATH_ERROR = """The following math expression caused errors:
 -------------------------------------------------------------------------------
 %s
 -------------------------------------------------------------------------------

          
@@ 120,14 120,12 @@ MATHERR = """The following math expressi
 class MathPattern(Pattern):
 
     dpi = "120"
-    mathdir = join(MEDIA_DIR, "math")
-    mathurl = MEDIA_URL + "math/"
 
-    def __init__(self):
+    def __init__(self, math_all, math_rev):
         Pattern.__init__(self, None)
 
-        if not exists(self.mathdir):
-            mkdir(self.mathdir)
+        self.math_all = math_all
+        self.math_rev = math_rev
 
     def getCompiledRegExp(self):
 

          
@@ 138,27 136,26 @@ class MathPattern(Pattern):
 
         math, dpi = m.group(2), m.group(3) or self.dpi
         mhash = md5(math + dpi).hexdigest()
-        fpng = join(self.mathdir, "%s.png" % mhash)
-        fmeta = join(self.mathdir, "%s.meta" % mhash)
 
-        if exists(fpng):
-            with open(fmeta) as fp:
-                valign = int(fp.read().strip())
-        else:
+        try:
+            fml = self.math_all.get(key=mhash)
+        except ObjectDoesNotExist:
             try:
-                valign = math_to_png(math, dpi, fpng)
+                img, valign = math_to_png(math, dpi)
             except MathException, e:
                 el = etree.Element('pre')
                 el.set('class', 'matherror')
-                el.text = AtomicString(MATHERR % (math, e, e.output))
+                el.text = AtomicString(MATH_ERROR % (math, e, e.output))
                 return el
-            with open(fmeta, 'w') as fp:
-                fp.write(str(valign))
+            img = img.encode("base64")
+            fml = self.math_all.create(key=mhash, img=img, valign=valign)
+
+        self.math_rev.add(fml)
 
         el = etree.Element('img')
-        el.set('src', "%s%s.png" % (self.mathurl, mhash))
+        el.set('src', reverse('diggie.views.math', args=(mhash,)))
         el.set('class', "math")
-        el.set('style', "vertical-align: %dpx" % valign)
+        el.set('style', "vertical-align: %dpx" % fml.valign)
         return el
 
 # =============================================================================

          
@@ 166,18 163,36 @@ class MathPattern(Pattern):
 # =============================================================================
 
 class DiggieExtension(Extension):
+    """A markdown extension for Diggie specific patterns."""
+
+    def __init__(self, math_all):
+        """Create a new extension instance.
+
+        @param math_all:
+            A QuerySet for Math objects. Used to check for existing Math
+            objects and to create new ones.
+
+        After markdown has been run, the attributes ``targets`` and
+        ``math_rev`` of this extension instance provide Diggie specific
+        processing results. ``targets`` is a set of page names linked to by the
+        processed revision. ``math_rev`` is a set of Math objects used in the
+        processed revision.
+
+        """
+        Extension.__init__(self, None)
+
+        self.targets = set()       # names of linked pages
+        self.math_all = math_all   # all existing Math objects
+        self.math_rev = set()      # Math objects in current revision
 
     def extendMarkdown(self, md, md_globals):
 
-        md.targets = set()
-        md.equations = set()
-
-        lpatt = LinkPattern(md)
+        lpatt = LinkPattern(self.targets)
         md.inlinePatterns.add('diggie_link', lpatt, "<reference")
 
         ipatt = ImagePattern()
         md.inlinePatterns.add('diggie_image', ipatt, "<reference")
 
-        mpatt = MathPattern()
+        mpatt = MathPattern(self.math_all, self.math_rev)
         md.inlinePatterns.insert(0, 'diggie_math', mpatt)
 

          

@@ 1,13 1,16 @@ 
 from datetime import datetime
 import re
 
+import markdown
+
+from django.core.cache import cache
 from django.db import models
 from django.db.models.aggregates import Count
-from django.core.cache import cache
+from django.db.models.fields import TextField
 
 from diggie.urls import RE_LABEL_NAME, RE_PAGE_NAME
-from diggie.mdx import RE_PAGE_LINK_RENAME
-from diggie.fields import MarkdownTextField
+from diggie.mdx import RE_PAGE_LINK_RENAME, DiggieExtension
+from diggie.settings import MDX
 
 class Label(models.Model):
 

          
@@ 19,7 22,8 @@ class Label(models.Model):
     @staticmethod
     def delete_unused():
 
-        for label in Label.objects.annotate(pcount=Count('page')).filter(pcount=0):
+        annotated = Label.objects.annotate(pcount=Count('page'))
+        for label in annotated.filter(pcount=0):
             label.delete()
 
     @staticmethod

          
@@ 61,6 65,19 @@ class Label(models.Model):
 
     page_set_nd = property(fget=__page_set_nd)
 
+class Math(models.Model):
+
+    key = models.CharField(max_length=32, primary_key=True)
+    img = models.TextField()
+    valign = models.IntegerField(default=0)
+
+    @staticmethod
+    def delete_unused():
+
+        annotated = Math.objects.annotate(rcount=Count('revision'))
+        for fml in annotated.filter(rcount=0):
+            fml.delete()
+
 class Revision(models.Model):
 
     page = models.ForeignKey('Page')

          
@@ 69,7 86,10 @@ class Revision(models.Model):
     name = models.CharField(max_length=200)
     summary = models.CharField(max_length=200)
     lnames = models.CharField(max_length=200)
-    source = MarkdownTextField()
+    source = TextField()
+    html = TextField()
+    targets = TextField()
+    math = models.ManyToManyField(Math)
     comment = models.CharField(max_length=200)
     mtime = models.DateTimeField(default=datetime.now)
 

          
@@ 98,6 118,24 @@ class Revision(models.Model):
         pages = pages.filter(tip__targets__regex=regex)
         return pages
 
+    def save(self, *args, **kwargs):
+
+        def nextid():
+            revs = Revision.objects.all()
+            return revs.order_by('-id')[0].id + 1 if revs.exists() else 0
+
+        dx = DiggieExtension(Math.objects)
+
+        mx = ["abbr", "toc", "tables", "def_list", "footnotes", dx] + MDX
+        md = markdown.Markdown(extensions=mx, output_format="xhtml1")
+
+        self.id = nextid() if self.id is None else self.id
+        self.html = md.convert(self.source)
+        self.targets = ",".join(dx.targets)
+        self.math = dx.math_rev
+
+        super(Revision, self).save(*args, **kwargs)
+
 class Page(models.Model):
 
     labels = models.ManyToManyField(Label)

          
@@ 165,6 203,8 @@ class Page(models.Model):
 
         if clnames:
             Label.delete_unused()
+        if csource:
+            Math.delete_unused()
 
         cache.clear()
 

          
@@ 207,6 247,6 @@ class Page(models.Model):
         super(Page, self).delete()
 
         Label.delete_unused()
+        Math.delete_unused()
 
         cache.clear()
-

          

@@ 1,17 1,9 @@ 
-from os.path import join
-
 from django.conf import settings
 
 WIKINAME = getattr(settings, 'DIGGIE_WIKINAME', "Diggie")
 
-# path for wiki media (relative to MEDIA_URL and MEDIA_ROOT, must use slashes)
-MEDIA = getattr(settings, 'DIGGIE_MEDIA', "").rstrip("/")
-
-# wiki media base URL
-MEDIA_URL = settings.MEDIA_URL + MEDIA + (MEDIA and "/" or "")
+# path (relative to MEDIA_URL) where wiki images are located
+IMAGES = settings.MEDIA_URL + getattr(settings, 'DIGGIE_IMAGES', "images/")
 
-# wiki media path
-MEDIA_DIR = join(settings.MEDIA_ROOT, *MEDIA.split("/"))
-
-# list of additional markdown extensions to use
+# list of markdown extensions to activate (additional to those used anyway)
 MDX = getattr(settings, 'DIGGIE_MDX', [])
  No newline at end of file

          

@@ 11,6 11,7 @@ urlpatterns = patterns('',
     (r'^pages/(?P<label>%s)/?$' % RE_LABEL_NAME, 'diggie.views.pages'),
     (r'^page/(?P<name>%s)/?$' % RE_PAGE_NAME, 'diggie.views.page'),
     (r'^page/(?P<name>%s)/(?P<revn>\d+)/?$' % RE_PAGE_NAME, 'diggie.views.page'),
+    (r'^math/(?P<key>[0-9a-fA-F]+)/?$', 'diggie.views.math'),
     (r'^edit/?$', 'diggie.views.edit'),
     (r'^edit/(?P<name>%s)/?$' % RE_PAGE_NAME, 'diggie.views.edit'),
     (r'^edit/(?P<name>%s)/(?P<revn>\d+)/?$' % RE_PAGE_NAME, 'diggie.views.edit'),

          

@@ 1,4 1,87 @@ 
+from os.path import join
 import re
+from shutil import rmtree
+from subprocess import Popen, PIPE, STDOUT
+import tempfile
+
+# =============================================================================
+# math rendering
+# =============================================================================
+
+_LATEX = r"""
+\documentclass{article}
+\usepackage{color}
+\usepackage{amsmath}
+\usepackage{amsfonts}
+\usepackage[active,tightpage]{preview}
+\definecolor{bg}{rgb}{
+1,1,1
+}
+\definecolor{fg}{rgb}{
+0,0,0
+}
+\pagestyle{empty}
+\pagecolor{bg}
+\begin{document}
+\color{fg}
+\begin{preview}
+$
+%s
+$
+\end{preview}
+\end{document}
+"""
+
+class MathException(Exception):
+    """Exception for math rendering errors."""
+
+    def __init__(self, msg, output):
+        super(MathException, self).__init__(msg)
+        self.output = output
+
+def math_to_png(source, dpi):
+    """Convert LaTeX math code to a PNG image.
+
+    @param source:
+        latex math code
+    @param dpi:
+        image DPI
+
+    @return:
+        the image as a data string and a CSS vertical alignment value for
+        baseline matching
+
+    """
+    def run(cmd):
+        try:
+            p = Popen(cmd, stdout=PIPE, stderr=STDOUT, cwd=tdir)
+            out = p.communicate()[0]
+        except OSError, e:
+            rmtree(tdir)
+            raise MathException("failed to run *%s*" % cmd[0], e)
+        if p.returncode != 0:
+            rmtree(tdir)
+            raise MathException("*%s* had problems" % cmd[0], out)
+        return out
+
+    tdir = tempfile.mkdtemp()
+    with open(join(tdir, "math.latex"), 'w') as fp:
+        fp.write(_LATEX % source)
+    cmd = ["latex", "-interaction=nonstopmode", "math.latex"]
+    run(cmd)
+    cmd = ["dvipng", "-D", dpi, "-z", "9", "--depth*", "-o", "math.png",
+           "math.dvi"]
+    output = run(cmd)
+    depth = (re.findall(r'depth=([0-9]+)', output) + [0])[0]
+    valign = -int(depth)
+    with open(join(tdir, "math.png")) as fp:
+        img = fp.read()
+    rmtree(tdir)
+    return img, valign
+
+# =============================================================================
+# parse pragmas at the beginning of a document
+# =============================================================================
 
 RX_PRAGMA = re.compile(r'^#([a-z]+)(?: +(.*?) *)?$', re.IGNORECASE)
 

          

@@ 2,19 2,21 @@ from datetime import datetime, timedelta
 import re
 
 from django.db.models import Q
-from django.http import HttpResponseRedirect
+from django.http import HttpResponseRedirect, HttpResponse, HttpResponseNotFound
 from django.shortcuts import render_to_response
 from django.core.exceptions import ObjectDoesNotExist
 from django.core.urlresolvers import reverse
 from django.views.decorators.cache import cache_page, never_cache
 from django.conf import settings
 
-from diggie.models import Page, Label, Revision
+from diggie.models import Page, Label, Revision, Math
 from diggie.util import xpragmas
 from diggie.urls import RE_LABEL_NAME
 from diggie.settings import WIKINAME
 
 A_VERY_LONG_TIME = 31536000 # one year
+A_WHILE = 300 # 5 minutes
+A_MOMENT = 60 # 1 minute
 HIT_COUNT_DELAY = timedelta(seconds=60)
 
 class count_hits(object):

          
@@ 73,8 75,8 @@ def _rq_param(pdict, key, choices):
         val = choices[0]
     return val
 
-@never_cache    # no upstream caching
-@cache_page(60) # server-side caching
+@never_cache          # no upstream caching
+@cache_page(A_MOMENT) # server-side caching
 def main(request):
     _dview("main", request)
 

          
@@ 115,8 117,8 @@ def labels(request):
 
     return render_to_response('diggie/labels.html', rqc)
 
-@never_cache    # no upstream caching
-@cache_page(60) # server-side caching
+@never_cache          # no upstream caching
+@cache_page(A_MOMENT) # server-side caching
 def pages(request, label=None):
     _dview("pages", request)
 

          
@@ 227,8 229,19 @@ def page(request, name, revn="-1"):
 
     return render_to_response('diggie/page.html', rqc)
 
-@never_cache    # no upstream caching
-@cache_page(60) # server-side caching
+@cache_page(A_WHILE) # server-side caching + upstream caching
+def math(request, key):
+    _dview("math", request)
+
+    try:
+        fml = Math.objects.get(key=key)
+    except ObjectDoesNotExist:
+        return HttpResponseNotFound()
+
+    return HttpResponse(fml.img.decode("base64"), mimetype="image/png")
+
+@never_cache          # no upstream caching
+@cache_page(A_MOMENT) # server-side caching
 def history(request, name=None):
     _dview("history", request)
 

          
@@ 267,16 280,16 @@ PAGE_TMPL = """#name %s
 %s
 """
 
-PAGE_EXAMPLE = """Section 1
+PAGE_EXAMPLE = """Section
 =========
 
-Section 1.2
------------
+Subsection
+----------
 
 Here comes a *nice* list:
 
- * item 1
- * item 2
+ - item `1`
+ - item **2**
 """
 
 def edit(request, name="", revn="-1"):