From c23b286540b6fcc8508cdcf60bffcdf45517f70a Mon Sep 17 00:00:00 2001
From: Kevin Froman <beardog@mailbox.org>
Date: Sat, 17 Oct 2020 07:51:28 +0000
Subject: [PATCH] added file reader offset

---
 .../private/register_private_blueprints.py    |  2 ++
 src/httpapi/fileoffsetreader/__init__.py      | 30 +++++++++++++++++++
 src/utils/readoffset.py                       | 17 +++++++++++
 src/utils/readstatic.py                       |  4 +--
 tests/test_read_offset.py                     | 29 ++++++++++++++++++
 5 files changed, 80 insertions(+), 2 deletions(-)
 create mode 100644 src/httpapi/fileoffsetreader/__init__.py
 create mode 100644 src/utils/readoffset.py
 create mode 100644 tests/test_read_offset.py

diff --git a/src/apiservers/private/register_private_blueprints.py b/src/apiservers/private/register_private_blueprints.py
index 8b6857b6..28d222ff 100644
--- a/src/apiservers/private/register_private_blueprints.py
+++ b/src/apiservers/private/register_private_blueprints.py
@@ -9,6 +9,7 @@ from httpapi import security, friendsapi, profilesapi, configapi, insertblock
 from httpapi import miscclientapi, onionrsitesapi, apiutils
 from httpapi import directconnections
 from httpapi import themeapi
+from httpapi import fileoffsetreader
 from httpapi.sse.private import private_sse_blueprint
 
 """
@@ -46,6 +47,7 @@ def register_private_blueprints(private_api, app):
         private_api).direct_conn_management_bp)
     app.register_blueprint(themeapi.theme_blueprint)
     app.register_blueprint(private_sse_blueprint)
+    app.register_blueprint(fileoffsetreader.offset_reader_api)
 
     def _add_events_bp():
         while True:
diff --git a/src/httpapi/fileoffsetreader/__init__.py b/src/httpapi/fileoffsetreader/__init__.py
new file mode 100644
index 00000000..ab427d36
--- /dev/null
+++ b/src/httpapi/fileoffsetreader/__init__.py
@@ -0,0 +1,30 @@
+from os.path import exists, dirname
+
+import ujson
+from flask import Blueprint, Response, request
+
+from utils.identifyhome import identify_home
+from utils.readoffset import read_from_offset
+
+offset_reader_api = Blueprint('offsetreaderapi', __name__)
+
+
+@offset_reader_api.route('/readfileoffset/<name>')
+def offset_reader_endpoint(name):
+    if not name[:-4].isalnum():
+        return Response(400, "Path must be alphanumeric except for file ext")
+
+    path = identify_home() + name
+
+    if not exists(path):
+        return Response(404, "Path not found in Onionr data directory")
+
+    offset = request.args.get('offset')
+
+    if not offset:
+        offset = 0
+    else:
+        offset = int(offset)
+    result = read_from_offset(path, offset)._asdict()
+
+    return ujson.dumps(result, reject_bytes=False)
diff --git a/src/utils/readoffset.py b/src/utils/readoffset.py
new file mode 100644
index 00000000..ecfcba4f
--- /dev/null
+++ b/src/utils/readoffset.py
@@ -0,0 +1,17 @@
+"""Onionr - Private P2P Communication.
+
+read from a file from an offset (efficiently)
+"""
+from collections import namedtuple
+
+OffsetReadResult = namedtuple('OffsetReadResult', ['data', 'new_offset'])
+
+
+def read_from_offset(file_path, offset=0):
+    with open(file_path, 'rb') as f:
+        if offset:
+            f.seek(offset)
+        data = f.read()
+        offset = f.tell()
+
+    return OffsetReadResult(data, offset)
diff --git a/src/utils/readstatic.py b/src/utils/readstatic.py
index 59b331c0..4d0f579c 100644
--- a/src/utils/readstatic.py
+++ b/src/utils/readstatic.py
@@ -20,11 +20,11 @@ import os
 """
 
 
-def get_static_dir()->str:
+def get_static_dir() -> str:
     return os.path.dirname(os.path.realpath(__file__)) + '/../../static-data/'
 
 
-def read_static(file:str, ret_bin:bool=False)->Union[str, bytes]:
+def read_static(file: str, ret_bin: bool = False) -> Union[str, bytes]:
     static_file = get_static_dir() + file
 
     if ret_bin:
diff --git a/tests/test_read_offset.py b/tests/test_read_offset.py
new file mode 100644
index 00000000..b7832667
--- /dev/null
+++ b/tests/test_read_offset.py
@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+import sys, os
+from time import sleep
+import tempfile
+sys.path.append(".")
+sys.path.append("src/")
+import uuid
+TEST_DIR = 'testdata/%s-%s' % (uuid.uuid4(), os.path.basename(__file__)) + '/'
+print("Test directory:", TEST_DIR)
+os.environ["ONIONR_HOME"] = TEST_DIR
+import unittest, json
+
+from utils import identifyhome, createdirs, readoffset
+from onionrsetup import setup_config
+createdirs.create_dirs()
+setup_config()
+
+class TestReadOffset(unittest.TestCase):
+    def test_read_whole(self):
+        temp = tempfile.mkstemp()[1]
+        f = open(temp, 'wb')
+        data = b"test1\ntest2\ntest3\test4"
+        f.write(data)
+        f.close()
+        self.assertEqual(readoffset.read_from_offset(temp).data, data)
+        os.remove(temp)
+
+
+unittest.main()