Add the new paperless_tika parser

This parser will use an external Tika and Gotenberg server to parse
"Office" documents (.doc, .xls, .odt, etc.)

Signed-off-by: Jo Vandeginste <Jo.Vandeginste@kuleuven.be>

src/paperless_tika/parsers.py

@@ -0,0 +1,118 @@
+import os
+import subprocess
+import tika
+import requests
+import dateutil.parser
+
+from PIL import ImageDraw, ImageFont, Image
+from django.conf import settings
+
+from documents.parsers import DocumentParser, ParseError, run_convert
+from paperless_tesseract.parsers import RasterisedDocumentParser
+from tika import parser
+
+
+class TikaDocumentParser(DocumentParser):
+    """
+    This parser sends documents to a local tika server
+    """
+
+    def get_thumbnail(self, document_path, mime_type):
+        self.log("info", f"[TIKA_THUMB] Generating thumbnail for{document_path}")
+        archive_path = self.archive_path
+
+        out_path = os.path.join(self.tempdir, "convert.png")
+
+        # Run convert to get a decent thumbnail
+        try:
+            run_convert(
+                density=300,
+                scale="500x5000>",
+                alpha="remove",
+                strip=True,
+                trim=False,
+                input_file="{}[0]".format(archive_path),
+                output_file=out_path,
+                logging_group=self.logging_group,
+            )
+        except ParseError:
+            # if convert fails, fall back to extracting
+            # the first PDF page as a PNG using Ghostscript
+            self.log(
+                "warning",
+                "Thumbnail generation with ImageMagick failed, falling back "
+                "to ghostscript. Check your /etc/ImageMagick-x/policy.xml!",
+            )
+            gs_out_path = os.path.join(self.tempdir, "gs_out.png")
+            cmd = [
+                settings.GS_BINARY,
+                "-q",
+                "-sDEVICE=pngalpha",
+                "-o",
+                gs_out_path,
+                archive_path,
+            ]
+            if not subprocess.Popen(cmd).wait() == 0:
+                raise ParseError("Thumbnail (gs) failed at {}".format(cmd))
+            # then run convert on the output from gs
+            run_convert(
+                density=300,
+                scale="500x5000>",
+                alpha="remove",
+                strip=True,
+                trim=False,
+                input_file=gs_out_path,
+                output_file=out_path,
+                logging_group=self.logging_group,
+            )
+
+        return out_path
+
+    def parse(self, document_path, mime_type):
+        self.log("info", f"[TIKA_PARSE] Sending {document_path} to Tika server")
+
+        try:
+            parsed = parser.from_file(document_path)
+        except requests.exceptions.HTTPError as err:
+            raise ParseError(f"Could not parse {document_path} with tika server: {err}")
+
+        try:
+            content = parsed["content"].strip()
+        except:
+            content = ""
+
+        try:
+            creation_date = dateutil.parser.isoparse(
+                parsed["metadata"]["Creation-Date"]
+            )
+        except:
+            creation_date = None
+
+        archive_path = os.path.join(self.tempdir, "convert.pdf")
+        convert_to_pdf(self, document_path, archive_path)
+
+        self.archive_path = archive_path
+        self.date = creation_date
+        self.text = content
+
+
+def convert_to_pdf(self, document_path, pdf_path):
+    pdf_path = os.path.join(self.tempdir, "convert.pdf")
+    gotenberg_server = settings.GOTENBERG_SERVER_ENDPOINT
+    url = gotenberg_server + "/convert/office"
+
+    self.log("info", f"[TIKA] Converting {document_path} to PDF as {pdf_path}")
+    files = {"files": open(document_path, "rb")}
+    headers = {}
+
+    try:
+        response = requests.post(url, files=files, headers=headers)
+        response.raise_for_status()  # ensure we notice bad responses
+    except requests.exceptions.HTTPError as err:
+        raise ParseError(
+            f"Could not contact gotenberg server at {gotenberg_server}: {err}"
+        )
+
+    file = open(pdf_path, "wb")
+    file.write(response.content)
+    file.close()