service: http: Command line option to redirect URLs

Add the ability to redirect one URL to another via a 307 Temporary
Redirect plus Location header response for a given HTTP method and path.

Fixes: intel#746

Signed-off-by: John Andersen <[email protected]>

CHANGELOG.md

@@ -61,6 +61,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Example showing usage of locks in dataflow.
 - `-skip` flag to `service dev install` command to let users not install certain
   core plugins
+- HTTP service got a `-redirect` flag which allows for URL redirection via a
+  HTTP 307 response
 ### Changed
 - Renamed `-seed` to `-inputs` in `dataflow create` command
 - Renamed configloader/png to configloader/image and added support for loading JPEG and TIFF file formats

service/http/dffml_service_http/cli.py

@@ -1,5 +1,6 @@
 import ssl
 import asyncio
+import inspect
 import argparse
 import subprocess
 from typing import List
@@ -170,6 +171,41 @@ class MultiCommCMD(CMD):
     CONFIG = MultiCommCMDConfig
 
 
+class RedirectFormatError(Exception):
+    """
+    Raises when -redirects was not divisible by 3
+    """
+
+
+class ParseRedirectsAction(argparse.Action):
+    def __call__(self, parser, namespace, values, option_string=None):
+        if not isinstance(values, list):
+            values = [values]
+        if len(values) % 3 != 0:
+            raise RedirectFormatError(
+                inspect.cleandoc(
+                    r"""
+                -redirect usage: METHOD SOURCE_PATH DESTINATION_PATH
+
+                Examples
+                --------
+
+                Redirect / to /index.html for GET requests
+
+                    -redirect GET / /index.html
+
+                Redirect / to /index.html for GET requests and /signup to
+                /mysignup for POST requests
+
+                    -redirect \
+                        GET / /index.html \
+                        POST /signup /mysignup
+                """
+                ).strip()
+            )
+        setattr(namespace, self.dest, values)
+
+
 @config
 class ServerConfig(TLSCMDConfig, MultiCommCMDConfig):
     port: int = field(
@@ -208,6 +244,11 @@ class ServerConfig(TLSCMDConfig, MultiCommCMDConfig):
         action=list_action(Sources),
         labeled=True,
     )
+    redirect: List[str] = field(
+        "list of METHOD SOURCE_PATH DESTINATION_PATH pairs, number of elements must be divisible by 3",
+        action=ParseRedirectsAction,
+        default_factory=lambda: [],
+    )
 
 
 class Server(TLSCMD, MultiCommCMD, Routes):

service/http/dffml_service_http/routes.py

@@ -760,6 +760,15 @@ async def api_js(self, request):
             headers={"Content-Type": "application/javascript"},
         )
 
+    def mkredirect(self, destination_path):
+        async def redirector(request):
+            return web.Response(
+                status=HTTPStatus.TEMPORARY_REDIRECT,
+                headers={"Location": destination_path},
+            )
+
+        return redirector
+
     async def on_shutdown(self, app):
         self.logger.debug("Shutting down service and exiting all contexts")
         await app["exit_stack"].__aexit__(None, None, None)
@@ -878,6 +887,11 @@ async def setup(self, **kwargs):
                 ),
             ]
         )
+        # Redirects
+        for method, src, dst in (
+            self.redirect[i : i + 3] for i in range(0, len(self.redirect), 3)
+        ):
+            self.routes.append((method.upper(), src, self.mkredirect(dst)))
         # Serve api.js
         if self.js:
             self.routes.append(("GET", "/api.js", self.api_js))

service/http/docs/cli.rst

@@ -53,3 +53,32 @@ for record retrieval or updating, use the ``-sources`` flag.
     $ dffml service http server \
         -sources mysource=csv \
         -source-mysource-filename training.csv
+
+Redirects
+---------
+
+You might want to have the HTTP service redirect one URL to another. You can do
+this using the ``-redirect`` flag. Syntax is as follows
+
+.. code-block::
+
+    -redirect \
+        METHOD_1 SOURCE_PATH_1 DESTINATION_PATH_1 \
+        METHOD_2 SOURCE_PATH_2 DESTINATION_PATH_2 \
+        METHOD_3 SOURCE_PATH_3 DESTINATION_PATH_3 \
+        ...
+
+Example of redirecting ``/`` to ``/index.html`` for GET requests
+
+.. code-block::
+
+    -redirect GET / /index.html
+
+Redirect ``/`` to ``/index.html`` for GET requests and ``/signup`` to
+``/mysignup`` for POST requests
+
+.. code-block::
+
+        -redirect \
+            GET / /index.html \
+            POST /signup /mysignup

service/http/tests/test_cli.py

@@ -13,7 +13,7 @@
 from dffml import Record, Features, Feature, save, train, accuracy
 from dffml.util.asynctestcase import AsyncTestCase
 
-from dffml_service_http.cli import HTTPService
+from dffml_service_http.cli import HTTPService, RedirectFormatError
 from dffml_service_http.util.testing import ServerRunner, ServerException
 
 from .test_routes import TestRoutesMultiComm
@@ -292,3 +292,44 @@ async def test_sources(self):
                     cli, "/source/mysource/record/myrecord"
                 ) as r:
                     self.assertEqual(await r.json(), myrecord.export())
+
+    async def test_redirect_format_error(self):
+        with self.assertRaises(RedirectFormatError):
+            async with ServerRunner.patch(HTTPService.server) as tserver:
+                await tserver.start(
+                    # Missing METHOD
+                    HTTPService.server.cli(
+                        "-insecure",
+                        "-port",
+                        "0",
+                        "-redirect",
+                        "/",
+                        "/index.html",
+                    )
+                )
+
+    async def test_redirect(self):
+        with tempfile.TemporaryDirectory() as tempdir:
+            pathlib.Path(tempdir, "index.html").write_text("Hello World")
+            pathlib.Path(tempdir, "mysignup").write_text("MySignUp")
+            async with ServerRunner.patch(HTTPService.server) as tserver:
+                cli = await tserver.start(
+                    HTTPService.server.cli(
+                        "-insecure",
+                        "-port",
+                        "0",
+                        "-static",
+                        tempdir,
+                        "-redirect",
+                        "GET",
+                        "/",
+                        "/index.html",
+                        "GET",
+                        "/signup",
+                        "/mysignup",
+                    )
+                )
+                async with self.get(cli, "/") as r:
+                    self.assertEqual(await r.text(), "Hello World")
+                async with self.get(cli, "/signup") as r:
+                    self.assertEqual(await r.text(), "MySignUp")