Add HTTP API

panodata · Jun 7, 2020 · bf9d801 · bf9d801
1 parent 4d610de
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diff --git a/CHANGES.rst b/CHANGES.rst
@@ -7,6 +7,11 @@ in progress
 ===========
 
 
+2020-06-08 0.2.0
+================
+- Add HTTP API
+
+
 2020-06-06 0.1.1
 ================
 - Update slogan

diff --git a/README.rst b/README.rst
@@ -50,9 +50,9 @@ With service API::
 Features
 ********
 - Colorspace conversion: monochrome, grayscale
-- Cropping with negative right/bottom padding
+- Cropping with negative right/bottom offsets
 - Resizing while keeping aspect ratio
-- Output format: Any image formats or bytes
+- Output format: Any image formats from Pillow or raw bytes
 - HTTP API
 
 
@@ -85,3 +85,20 @@ Start the Imagecast service as daemon::
 Example::
 
     /?uri=https%3A%2F%2Funsplash.com%2Fphotos%2FWvdKljW55rM%2Fdownload%3Fforce%3Dtrue&monochrome=80&crop=850,1925,-950,-900&width=640
+
+.. note::
+
+    You should not run the service without restricting the
+    list of allowed remote hosts on the public internet.
+
+    To do that, invoke the service like::
+
+        imagecast service --allowed-hosts=unsplash.com,media.example.org
+
+
+**************
+Other projects
+**************
+- https://github.com/DictGet/ecce-homo
+- https://github.com/agschwender/pilbox
+- https://github.com/francescortiz/image
diff --git a/imagecast/api.py b/imagecast/api.py
@@ -0,0 +1,101 @@
+# -*- coding: utf-8 -*-
+# (c) 2020 Andreas Motl <andreas@terkin.org>
+# License: GNU Affero General Public License, Version 3
+import io
+import logging
+from dataclasses import dataclass
+from typing import List
+
+from PIL import Image
+from fastapi import FastAPI, Query, Depends, HTTPException
+from fastapi.responses import HTMLResponse, PlainTextResponse
+from httptools.parser.parser import parse_url
+from pydantic import BaseSettings
+from starlette.responses import StreamingResponse
+from starlette.status import HTTP_403_FORBIDDEN
+
+from imagecast import __appname__, __version__
+from imagecast.core import process
+
+
+# https://fastapi.tiangolo.com/advanced/settings/
+class Settings(BaseSettings):
+    allowed_hosts: List[str] = []
+
+
+settings = Settings()
+app = FastAPI()
+
+log = logging.getLogger(__name__)
+
+
+# Using pydantic models for GET request query params.
+# https://github.com/tiangolo/fastapi/issues/318#issuecomment-584020926
+@dataclass
+class QueryOptions:
+    uri: str = Query(default=None)
+    monochrome: int = Query(default=None)
+    grayscale: bool = Query(default=False)
+    crop: str = Query(default=None)
+    width: int = Query(default=None)
+    height: int = Query(default=None)
+    dpi: int = Query(default=72)
+    format: str = Query(default=None)
+
+
+@app.get("/")
+def index(options: QueryOptions = Depends(QueryOptions)):
+    appname = f'{__appname__} {__version__}'
+    about = 'Imagecast is like ImageMagick but for Pythonistas. Optionally provides its features via HTTP API.'
+
+    if options.uri:
+
+        # Protect the service from accessing arbitrary remote URIs.
+        uri_parsed = parse_url(options.uri.encode('utf-8'))
+        remote_host = uri_parsed.host.decode()
+        if '*' not in settings.allowed_hosts and remote_host not in settings.allowed_hosts:
+            raise HTTPException(status_code=HTTP_403_FORBIDDEN)
+
+        ie = process(options)
+
+        options.format = options.format or ie.image.format
+
+        if options.format == 'bytes':
+            buffer = ie.to_bytes()
+        else:
+            buffer = ie.to_buffer(options.format, options.dpi)
+
+        mime_type = Image.MIME.get(options.format)
+
+        return StreamingResponse(io.BytesIO(buffer), media_type=mime_type)
+    else:
+        return HTMLResponse(f"""
+        <html>
+            <head>
+                <title>{appname}</title>
+            </head>
+            <body>
+                <h3>About</h3>
+                {about}
+                <h3>Examples</h3>
+                <ul>
+                <li><a href="?uri=https%3A%2F%2Funsplash.com%2Fphotos%2FWvdKljW55rM%2Fdownload%3Fforce%3Dtrue&monochrome=80&crop=850,1925,-950,-900&width=640&format=png">Unsplash example</a></li>
+                </ul>
+            </body>
+        </html>
+        """)
+
+
+@app.get("/robots.txt", response_class=PlainTextResponse)
+def robots():
+    return f"""
+User-agent: *
+Disallow: /
+    """.strip()
+
+
+def start_service(listen_address):
+    host, port = listen_address.split(':')
+    port = int(port)
+    from uvicorn.main import run
+    run(app='imagecast.api:app', host=host, port=port, reload=True)
diff --git a/imagecast/cli.py b/imagecast/cli.py
@@ -1,14 +1,15 @@
 # -*- coding: utf-8 -*-
 # (c) 2020 Andreas Motl <andreas@hiveeyes.org>
 # License: GNU Affero General Public License, Version 3
+import os
 import sys
 import json
 import logging
 
 from docopt import docopt, DocoptExit
 
 from imagecast import __appname__, __version__
-from imagecast.core import ImageEngine
+from imagecast.core import process
 from imagecast.util import normalize_options, setup_logging
 
 log = logging.getLogger(__name__)
@@ -20,7 +21,7 @@ def run():
 
     Usage:
       imagecast --uri=<uri> [--monochrome=<threshold>] [--grayscale] [--width=<width>] [--height=<height>] [--crop=<cropbox>] [--display] [--format=<format>] [--dpi=<dpi>] [--save=<save>]
-      imagecast service [--listen=<listen>]
+      imagecast service [--listen=<listen>] [--allowed-hosts=<allowed-hosts>]
       imagecast --version
       imagecast (-h | --help)
 
@@ -36,6 +37,7 @@ def run():
       --dpi=<dpi>                       Output DPI. [Default: 72]
       --save=<save>                     Path to output file
       --listen=<listen>                 HTTP server listen address. [Default: localhost:9999]
+      --allowed-hosts=<allowed-hosts>   Allowed hosts to request images from. [Default: *]
       --version                         Show version information
       --debug                           Enable debug messages
       -h --help                         Show this screen
@@ -61,6 +63,9 @@ def run():
 
     # Run service.
     if options.service:
+
+        os.environ['ALLOWED_HOSTS'] = json.dumps(options.allowed_hosts.split(','))
+
         listen_address = options.listen
         log.info(f'Starting {name}')
         log.info(f'Starting web service on {listen_address}')
@@ -73,25 +78,7 @@ def run():
     if not (options.display or options.save or options.format):
         raise KeyError('Please specify one of "--display", "--save" or "--format"')
 
-    ie = ImageEngine()
-    ie.download(options.uri)
-    ie.read()
-
-    if options.monochrome:
-        ie.monochrome(int(options.monochrome))
-
-    if options.grayscale:
-        ie.grayscale()
-
-    # (left, top, right, bottom)
-    if options.crop:
-        cropbox = map(int, options.crop.split(','))
-        ie.crop(cropbox)
-
-    if options.width:
-        ie.resize_width(int(options.width))
-    if options.height:
-        ie.resize_height(int(options.height))
+    ie = process(options)
 
     dpi = int(options.dpi)
 

diff --git a/imagecast/core.py b/imagecast/core.py
@@ -3,18 +3,24 @@
 # License: GNU Affero General Public License, Version 3
 import io
 import requests
+import ttl_cache
 from PIL import Image
 
 
+@ttl_cache(15)
+def fetch_cached(uri):
+    response = requests.get(uri)
+    return response.content
+
+
 class ImageEngine:
 
     def __init__(self):
         self.data = None
         self.image = None
 
-    def download(self, url):
-        response = requests.get(url)
-        self.data = response.content
+    def download(self, uri):
+        self.data = fetch_cached(uri)
 
     def read(self):
         self.image = Image.open(io.BytesIO(self.data))
@@ -62,3 +68,27 @@ def to_buffer(self, format, dpi):
         buffer = io.BytesIO()
         self.image.save(buffer, format=format, dpi=(dpi, dpi))
         return buffer.getvalue()
+
+
+def process(options):
+    ie = ImageEngine()
+    ie.download(options.uri)
+    ie.read()
+
+    if options.monochrome:
+        ie.monochrome(int(options.monochrome))
+
+    if options.grayscale:
+        ie.grayscale()
+
+    # (left, top, right, bottom)
+    if options.crop:
+        cropbox = map(int, options.crop.split(','))
+        ie.crop(cropbox)
+
+    if options.width:
+        ie.resize_width(int(options.width))
+    if options.height:
+        ie.resize_height(int(options.height))
+
+    return ie
diff --git a/setup.py b/setup.py
@@ -3,11 +3,11 @@
 from setuptools import setup, find_packages
 
 here = os.path.abspath(os.path.dirname(__file__))
-README = open(os.path.join(here, 'README.rst')).read()
+README = open(os.path.join(here, "README.rst")).read()
 
-setup(name='imagecast',
-      version='0.1.1',
-      description='Imagecast is like ImageMagick but for Pythonistas. Optionally provides its features via HTTP API.',
+setup(name="imagecast",
+      version="0.1.1",
+      description="Imagecast is like ImageMagick but for Pythonistas. Optionally provides its features via HTTP API.",
       long_description=README,
       license="AGPL 3, EUPL 1.2",
       classifiers=[
@@ -38,30 +38,31 @@
         "Operating System :: Unix",
         "Operating System :: MacOS"
         ],
-      author='Andreas Motl',
-      author_email='andreas.motl@panodata.org',
-      url='https://github.com/panodata/imagecast',
-      keywords='image conversion http api proxy',
+      author="Andreas Motl",
+      author_email="andreas.motl@panodata.org",
+      url="https://github.com/panodata/imagecast",
+      keywords="image conversion http api proxy",
       packages=find_packages(),
       include_package_data=True,
       package_data={
       },
       zip_safe=False,
       install_requires=[
-          'docopt==0.6.2',
-          'munch==2.3.2',
-          'Pillow==7.1.2',
-          'requests==2.23.0',
+          "docopt==0.6.2",
+          "munch==2.3.2",
+          "Pillow==7.1.2",
+          "requests==2.23.0",
+          "ttl-cache==1.6",
       ],
       extras_require={
-          'service': [
-              'fastapi==0.55.1',
-              'uvicorn==0.11.5',
+          "service": [
+              "fastapi==0.55.1",
+              "uvicorn==0.11.5",
           ],
       },
       entry_points={
-          'console_scripts': [
-              'imagecast = imagecast.cli:run',
+          "console_scripts": [
+              "imagecast = imagecast.cli:run",
           ],
       },
 )