From bec124bf8be1bee61c11b802c864a069d27a4b2b Mon Sep 17 00:00:00 2001
From: syn <isaqtm@gmail.com>
Date: Wed, 18 Mar 2020 20:24:53 +0300
Subject: More exceptions

---
 app/templates/404.html.j2 |  6 ++++++
 app/util.py               | 36 ++++++++++++++++++++++++--------
 app/views.py              | 52 +++++++++++++++++++++++++++++++++++++----------
 3 files changed, 74 insertions(+), 20 deletions(-)
 create mode 100644 app/templates/404.html.j2

diff --git a/app/templates/404.html.j2 b/app/templates/404.html.j2
new file mode 100644
index 0000000..dd04c11
--- /dev/null
+++ b/app/templates/404.html.j2
@@ -0,0 +1,6 @@
+{% extends "base.html.j2" %}
+{% block content %}
+<center>
+  <p style="font-size: 4.04em;">404</p>
+</center>
+{% endblock %}
\ No newline at end of file
diff --git a/app/util.py b/app/util.py
index 69b3ea7..69593ac 100644
--- a/app/util.py
+++ b/app/util.py
@@ -1,10 +1,15 @@
 from base64 import b32encode, b32decode
 import logging
-from hashlib import blake2b  # because it is fast as fuck
+from hashlib import blake2b
+from binascii import Error as Base32DecodeError
 
 log = logging.getLogger('blure')
 
 
+class URLDecodeError(ValueError):
+    pass
+
+
 class URLCoder:
     '''
     URLCoder shuffles sequential ids into non-sequential strings,
@@ -16,17 +21,21 @@ class URLCoder:
     _endian = 'big'
 
     @classmethod
-    def _humanify(self, data: bytes):
+    def _humanify(cls, data: bytes):
         b32 = b32encode(data).decode('ascii')
-        if self._pad > 0:
-            return b32[:-self._pad]
+        if cls._pad > 0:
+            return b32[:-cls._pad]
         else:
             return b32
 
     @classmethod
-    def _dehumanify(self, data: str):
-        binary = b32decode(data + '=' * self._pad)
-        assert len(binary) == self._bs * 2
+    def _dehumanify(cls, data: str):
+        binary = b32decode(data + '=' * cls._pad)
+        if len(binary) != cls._bs * 2:
+            raise URLDecodeError(
+                f'Padded url len must be exactly {cls._bs * 2} bytes'
+                f'(binary="{binary}", len = {len(binary)})'
+            )
         return binary
 
     def __init__(self, secret: bytes):
@@ -39,13 +48,22 @@ class URLCoder:
         self.reverse_keys = self.keys[::-1]
 
     def to_url(self, id: int) -> str:
-        assert 0 <= id and id <= self._bound
+        if 0 > id or id >= self._bound:
+            raise URLDecodeError(
+                'id(={id}) is outside valid range [0, {self._bound})'
+            )
+
         as_bytes = int.to_bytes(id, self._bs * 2, self._endian)
         encoded = self._blake_enc(as_bytes, self.keys)
+
         return self._humanify(encoded)
 
     def to_id(self, url: str) -> int:
-        binary = self._dehumanify(url.upper())
+        try:
+            binary = self._dehumanify(url.upper())
+        except Base32DecodeError as e:
+            raise URLDecodeError(e)
+
         as_bytes = self._blake_enc(binary, self.reverse_keys)
         return int.from_bytes(as_bytes, self._endian)
 
diff --git a/app/views.py b/app/views.py
index 8ffb946..8cb0755 100644
--- a/app/views.py
+++ b/app/views.py
@@ -2,9 +2,21 @@ from io import BytesIO
 from .request_routine import db_route
 from sanic.response import text, redirect, json
 from jinja2_sanic import render_template
-from app import log
+from app import log, blure
 from requests import get as fetch_url
 from .imutil import NGXImage
+from .util import URLDecodeError
+from sanic.exceptions import NotFound
+
+
+async def is_image_exists(pg, id: int):
+    rec = await pg.fetchval('SELECT 1 FROM pics WHERE id=$1', id)
+    return rec is not None
+
+
+@blure.exception(NotFound)
+async def not_found(req, exc):
+    return render_template('404.html.j2', req, dict())
 
 
 @db_route('/')
@@ -16,12 +28,13 @@ async def index(ctx):
 
 @db_route('/i/<url>')
 async def raw_image(ctx, url):
-    id = ctx.app.url.to_id(url)
-    if id is None:
+    try:
+        id = ctx.app.url.to_id(url)
+    except URLDecodeError as err:
+        log.warn(f'URL not decoded: {err}')
         return NGXImage.not_found()
 
-    name = await ctx.pg.fetchval('SELECT 1 FROM pics WHERE id=$1', id)
-    if name is None:
+    if not await is_image_exists(ctx.pg, id):
         log.error('Image not in db')
         return NGXImage.not_found()
 
@@ -30,12 +43,12 @@ async def raw_image(ctx, url):
 
 @db_route('/t/<url>')
 async def thumb_image(ctx, url):
-    id = ctx.app.url.to_id(url)
-    if id is None:
+    try:
+        id = ctx.app.url.to_id(url)
+    except URLDecodeError:
         return NGXImage.not_found()
 
-    name = await ctx.pg.fetchval('SELECT 1 FROM pics WHERE id=$1', id)
-    if name is None:
+    if not await is_image_exists(ctx.pg, id):
         log.error('Image not in db')
         return NGXImage.not_found()
 
@@ -44,7 +57,18 @@ async def thumb_image(ctx, url):
 
 @db_route('/p/<url>')
 async def pic_profile(ctx, url):
-    return render_template('profile.html.j2', ctx.r, dict(url=url, tags=[]))
+    log.warn(url)
+    try:
+        id = ctx.app.url.to_id(url)
+        log.warn(id)
+        if await is_image_exists(ctx.pg, id):
+            return render_template('profile.html.j2',
+                                   ctx.r,
+                                   dict(url=url, tags=[]))
+        else:
+            raise NotFound('Url not found')
+    except URLDecodeError:
+        raise NotFound('Invalid url')
 
 
 @db_route('/c/push', methods=['POST'])
@@ -54,7 +78,13 @@ async def pic_push(ctx):
         image_stream = BytesIO(file.body)
         ext = file.name.split('.')[-1]
         id = await ctx.pg.fetchval(
-            'INSERT INTO pics(src_url, ext) VALUES ($1, $2) RETURNING id', '', ext
+            '''
+            INSERT INTO pics(src_url, ext)
+            VALUES ($1, $2)
+            RETURNING id
+            ''',
+            '',
+            ext
         )
 
         im = NGXImage(id)
-- 
cgit v1.2.1-18-gbd029