first stab at text consumer

src/paperless/settings.py

@@ -67,6 +67,7 @@ INSTALLED_APPS = [
     "documents.apps.DocumentsConfig",
     "reminders.apps.RemindersConfig",
     "paperless_tesseract.apps.PaperlessTesseractConfig",
+    "paperless_text.apps.PaperlessTextConfig",
 
     "flat_responsive",  # TODO: Remove as of Django 2.x
     "django.contrib.admin",

src/paperless_text/apps.py

@@ -0,0 +1,16 @@
+from django.apps import AppConfig
+
+
+class PaperlessTextConfig(AppConfig):
+
+    name = "paperless_text"
+
+    def ready(self):
+
+        from documents.signals import document_consumer_declaration
+
+        from .signals import ConsumerDeclaration
+
+        document_consumer_declaration.connect(ConsumerDeclaration.handle)
+
+        AppConfig.ready(self)

src/paperless_text/parsers.py

@@ -0,0 +1,113 @@
+import os
+import re
+import subprocess
+
+import dateparser
+from django.conf import settings
+
+from documents.parsers import DocumentParser, ParseError
+
+
+class TextDocumentParser(DocumentParser):
+    """
+    This parser directly parses a text document (.txt or .md)
+    """
+
+
+    CONVERT = settings.CONVERT_BINARY
+    THREADS = int(settings.OCR_THREADS) if settings.OCR_THREADS else None
+    UNPAPER = settings.UNPAPER_BINARY
+    DATE_ORDER = settings.DATE_ORDER
+    DEFAULT_OCR_LANGUAGE = settings.OCR_LANGUAGE
+    OCR_ALWAYS = settings.OCR_ALWAYS
+
+    def __init__(self, path):
+        super().__init__(path)
+        self._text = None
+
+    def get_thumbnail(self):
+        """
+        The thumbnail of a txt is just a 500px wide image of the text
+        rendered onto a letter-sized page.
+        """
+
+        run_convert(
+            self.CONVERT,
+            "-size", "500x647",
+            "xc:white",
+            "-pointsize", "12",
+            "-fill", "black",
+            "-draw", "\"text 0,12 \'$(cat {})\'\"".format(self.document_path),
+            os.path.join(self.tempdir, "convert-txt.png")
+        )
+
+        return os.path.join(self.tempdir, "convert-txt.png")
+
+    def get_text(self):
+
+        if self._text is not None:
+            return self._text
+
+        with open(self.document_path, 'r') as f:
+            self._text = f.read()
+
+        return self._text
+
+    def get_date(self):
+        date = None
+        datestring = None
+
+        try:
+            text = self.get_text()
+        except ParseError as e:
+            return None
+
+        # This regular expression will try to find dates in the document at
+        # hand and will match the following formats:
+        # - XX.YY.ZZZZ with XX + YY being 1 or 2 and ZZZZ being 2 or 4 digits
+        # - XX/YY/ZZZZ with XX + YY being 1 or 2 and ZZZZ being 2 or 4 digits
+        # - XX-YY-ZZZZ with XX + YY being 1 or 2 and ZZZZ being 2 or 4 digits
+        # - XX. MONTH ZZZZ with XX being 1 or 2 and ZZZZ being 2 or 4 digits
+        # - MONTH ZZZZ, with ZZZZ being 4 digits
+        # - MONTH XX, ZZZZ with XX being 1 or 2 and ZZZZ being 4 digits
+        pattern = re.compile(
+            r'\b([0-9]{1,2})[\.\/-]([0-9]{1,2})[\.\/-]([0-9]{4}|[0-9]{2})\b|' +
+            r'\b([0-9]{1,2}[\. ]+[^ ]{3,9} ([0-9]{4}|[0-9]{2}))\b|' +
+            r'\b([^\W\d_]{3,9} [0-9]{1,2}, ([0-9]{4}))\b|' +
+            r'\b([^\W\d_]{3,9} [0-9]{4})\b')
+
+        # Iterate through all regex matches and try to parse the date
+        for m in re.finditer(pattern, text):
+            datestring = m.group(0)
+
+            try:
+                date = dateparser.parse(
+                           datestring,
+                           settings={'DATE_ORDER': self.DATE_ORDER,
+                                     'PREFER_DAY_OF_MONTH': 'first',
+                                     'RETURN_AS_TIMEZONE_AWARE': True})
+            except TypeError:
+                # Skip all matches that do not parse to a proper date
+                continue
+
+            if date is not None:
+                break
+
+        if date is not None:
+            self.log("info", "Detected document date " + date.isoformat() +
+                             " based on string " + datestring)
+        else:
+            self.log("info", "Unable to detect date for document")
+
+        return date
+
+
+def run_convert(*args):
+    environment = os.environ.copy()
+    if settings.CONVERT_MEMORY_LIMIT:
+        environment["MAGICK_MEMORY_LIMIT"] = settings.CONVERT_MEMORY_LIMIT
+    if settings.CONVERT_TMPDIR:
+        environment["MAGICK_TMPDIR"] = settings.CONVERT_TMPDIR
+
+    if not subprocess.Popen(args, env=environment).wait() == 0:
+        raise ParseError("Convert failed at {}".format(args))

src/paperless_text/signals.py

@@ -0,0 +1,23 @@
+import re
+
+from .parsers import TextDocumentParser
+
+
+class ConsumerDeclaration:
+
+    MATCHING_FILES = re.compile("^.*\.(txt|md)$")
+
+    @classmethod
+    def handle(cls, sender, **kwargs):
+        return cls.test
+
+    @classmethod
+    def test(cls, doc):
+
+        if cls.MATCHING_FILES.match(doc.lower()):
+            return {
+                "parser": TextDocumentParser,
+                "weight": 10
+            }
+
+        return None