It works!

src/documents/admin.py

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+from django.conf import settings
+from django.contrib import admin
+
+from .models import Document
+
+
+class DocumentAdmin(admin.ModelAdmin):
+
+    search_fields = ("sender", "title", "content",)
+    list_display = ("created", "sender", "title", "thumbnail", "pdf")
+    list_filter = ("created", "sender")
+    save_on_top = True
+
+    def thumbnail(self, obj):
+        return '<img src="{}documents/img/{:07}.jpg" width="100" />'.format(
+            settings.MEDIA_URL, obj.pk)
+    thumbnail.allow_tags = True
+
+    def pdf(self, obj):
+        return '<a href="{}documents/pdf/{:07}.pdf">Download</a>'.format(
+            settings.MEDIA_URL, obj.pk)
+    pdf.allow_tags = True
+
+admin.site.register(Document, DocumentAdmin)

src/documents/apps.py

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+from django.apps import AppConfig
+
+
+class DocumentsConfig(AppConfig):
+    name = 'documents'

src/documents/management/commands/consume.py

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+import glob
+import os
+import random
+import re
+import shutil
+import subprocess
+
+import pyocr
+
+from PIL import Image
+
+from django.conf import settings
+from django.core.management.base import BaseCommand
+
+from documents.models import Document
+
+
+class Command(BaseCommand):
+    """
+    Loop over every file found in CONSUMPTION_DIR and:
+      1. Convert it to a greyscale tif
+      2. Convert it to a full-colour jpg
+      3. Use tesseract on the tif
+      4. Store the OCR'd text in the database along with the paths to the jpg
+         and original pdf
+      5. Delete the pdf and images
+    """
+
+    CONVERT = settings.CONVERT_BINARY
+    SCRATCH = settings.SCRATCH_DIR
+    CONSUME = settings.CONSUMPTION_DIR
+
+    OCR = pyocr.get_available_tools()[0]
+
+    MEDIA_IMG = os.path.join(settings.MEDIA_ROOT, "documents", "img")
+    MEDIA_PDF = os.path.join(settings.MEDIA_ROOT, "documents", "pdf")
+
+    def __init__(self, *args, **kwargs):
+        self.verbosity = 0
+        BaseCommand.__init__(self, *args, **kwargs)
+
+    def handle(self, *args, **options):
+
+        self.verbosity = options["verbosity"]
+
+        self._setup()
+
+        for pdf in os.listdir(self.CONSUME):
+
+            if not os.path.isfile(os.path.join(self.CONSUME, pdf)):
+                continue
+
+            if not pdf.endswith(".pdf"):
+                continue
+
+            if self.verbosity > 1:
+                print("Consuming {}".format(pdf))
+
+            pdf = os.path.join(self.CONSUME, pdf)
+            pngs = self._get_greyscale(pdf)
+            jpgs = self._get_colour(pdf)
+            text = self._get_ocr(pngs)
+
+            self._store(text, jpgs, pdf)
+            self._cleanup(pngs, jpgs)
+
+    def _setup(self):
+        for d in (self.SCRATCH, self.MEDIA_IMG, self.MEDIA_PDF):
+            try:
+                os.makedirs(d)
+            except FileExistsError:
+                pass
+
+    def _get_greyscale(self, pdf):
+
+        i = random.randint(1000000, 4999999)
+        png = os.path.join(self.SCRATCH, "{}.png".format(i))
+
+        subprocess.Popen((
+            self.CONVERT, "-density", "300", "-depth", "8",
+            "-type", "grayscale", pdf, png
+        )).wait()
+
+        return sorted(glob.glob(os.path.join(self.SCRATCH, "{}*".format(i))))
+
+    def _get_colour(self, pdf):
+
+        i = random.randint(5000000, 9999999)
+        jpg = os.path.join(self.SCRATCH, "{}.jpg".format(i))
+
+        subprocess.Popen((self.CONVERT, pdf, jpg)).wait()
+
+        return sorted(glob.glob(os.path.join(self.SCRATCH, "{}*".format(i))))
+
+    def _get_ocr(self, pngs):
+
+        r = ""
+        for png in pngs:
+            with Image.open(os.path.join(self.SCRATCH, png)) as f:
+                r += self.OCR.image_to_string(f)
+                r += "\n\n\n\n\n\n\n\n"
+
+        return r
+
+    def _store(self, text, jpgs, pdf):
+
+        doc = Document.objects.create(content=text)
+
+        shutil.move(jpgs[0], os.path.join(
+            self.MEDIA_IMG, "{:07}.jpg".format(doc.pk)))
+        shutil.move(pdf, os.path.join(
+            self.MEDIA_PDF, "{:07}.pdf".format(doc.pk)))
+
+    def _cleanup(self, pngs, jpgs):
+
+        jpg_glob = os.path.join(
+            self.SCRATCH, re.sub(r"^.*/(\d+)-\d+.jpg$", "\\1*", jpgs[0]))
+        png_glob = os.path.join(
+            self.SCRATCH, re.sub(r"^.*/(\d+)-\d+.png$", "\\1*", pngs[0]))
+
+        for f in list(glob.glob(jpg_glob)) + list(glob.glob(png_glob)):
+            os.unlink(f)

src/documents/migrations/0001_initial.py

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+# -*- coding: utf-8 -*-
+# Generated by Django 1.9 on 2015-12-20 19:10
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Document',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('sender', models.CharField(blank=True, db_index=True, max_length=128)),
+                ('title', models.CharField(blank=True, db_index=True, max_length=128)),
+                ('content', models.TextField(db_index=True)),
+                ('created', models.DateTimeField(auto_now_add=True)),
+                ('modified', models.DateTimeField(auto_now=True)),
+            ],
+        ),
+    ]

src/documents/models.py

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+from django.db import models
+
+
+class Document(models.Model):
+
+    sender = models.CharField(max_length=128, blank=True, db_index=True)
+    title = models.CharField(max_length=128, blank=True, db_index=True)
+    content = models.TextField(db_index=True)
+    created = models.DateTimeField(auto_now_add=True)
+    modified = models.DateTimeField(auto_now=True)

src/documents/tests.py

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+from django.test import TestCase
+
+# Create your tests here.

src/documents/views.py

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+from django.shortcuts import render
+
+# Create your views here.