Replace Jinja2 with PyYAML

.gitlab-ci.yml

@@ -1,5 +1,5 @@
 ---
-image: s3lph/spaceapi-server-ci:20200620-01
+image: s3lph/spaceapi-server-ci:20210530-01
 
 stages:
   - test
@@ -57,7 +57,7 @@ build_debian:
       Section: web
       Priority: optional
       Architecture: all
-      Depends: python3 (>= 3.6), python3-jinja2, python3-bottle
+      Depends: python3 (>= 3.9), python3-yaml, python3-bottle
       Description: Lightweight SpaceAPI endpoint server
        Lightweight server for SpaceAPI endpoints. Includes support for pluggable
        templating, so dynamic content, like sensor values, can be added.
@@ -77,8 +77,8 @@ build_debian:
     - python3 setup.py egg_info install --root=package/debian/spaceapi-server/ --prefix=/usr --optimize=1
     - cd package/debian/spaceapi-server
     - mkdir -p usr/lib/python3/dist-packages/
-    - cp -r usr/lib/python3.8/site-packages/spaceapi_server* usr/lib/python3/dist-packages/
+    - cp -r usr/lib/python3.9/site-packages/spaceapi_server* usr/lib/python3/dist-packages/
-    - rm -rf usr/lib/python3.8/
+    - rm -rf usr/lib/python3.9/
     # Remove compiled Python files
     - find usr/lib/python3/dist-packages -name __pycache__ -exec rm -r {} \; 2>/dev/null || true
     - find usr/lib/python3/dist-packages -name '*.pyc' -exec rm {} \;
@@ -109,7 +109,7 @@ build_archlinux:
   script:
     - find package/archlinux -name .gitkeep -delete
     # Install dependencies
-    - pacman -Sy --noconfirm namcap python python-setuptools python-pip python-wheel python-jinja python-bottle base-devel
+    - pacman -Sy --noconfirm namcap python python-setuptools python-pip python-wheel python-yaml python-bottle base-devel
     - export SPACEAPI_SERVER_VERSION=$(python -c 'import spaceapi_server; print(spaceapi_server.__version__)')
     # Copy example plugin
     - install -m0644 examples/plugins/example.py package/archlinux/spaceapi-server/etc/spaceapi-server/plugins/example.py

CHANGELOG.md

@@ -1,5 +1,19 @@
 # SpaceAPI Server Changelog
 
+<!-- BEGIN RELEASE v0.4 -->
+## Version 0.4
+
+Replace Jinja2+JSON with PyYAML
+
+### Changes
+
+<!-- BEGIN CHANGES 0.4 -->
+- Switch config file format from JSON to YAML
+- Remove Jinja2, replaced with YAML custom tags for plugin calls
+<!-- END CHANGES 0.4 -->
+
+<!-- END RELEASE v0.4 -->
+
 <!-- BEGIN RELEASE v0.3.1 -->
 ## Version 0.3
 

README.md

@@ -11,7 +11,7 @@ values, can be added.
 
 - Python 3 (>=3.6)
 - [Bottle][pypi-bottle]
-- [Jinja2][pypi-jinja2]
+- [PyYAML][pypi-yaml]
 
 ## License
 
@@ -24,9 +24,9 @@ SpaceAPI endpoint server.  In its simplest configuration, it just
 serves a plain, static, boring JSON document.
 
 In order to provide dynamic content (e.g. whether your space is
-currently open), you can replace parts of the JSON document (anything
+currently open), you can replace parts of the YAML document (anything
-except object keys) with [Jinja2 templates][jinja], from which you can
+except object keys) with custom plugin invocations.  These plugins
-invoke custom plugins, which look up and return your dynamic content.
+look up and return your dynamic content.
 
 <table>
 <thead>
@@ -39,15 +39,19 @@ invoke custom plugins, which look up and return your dynamic content.
 <tr>
 <td>
 
-```json
+```yaml
-{
+---
-  "api": "0.13",
+api: "0.13"
-  "space": "My Hackerspace",
+space: My Hackerspace
-  "state": "{{ space_state() }}",
+# This is a plugin invocation
-  "sensors": {
+# with no arguments
-    "network_connections": "{{ network_connections() }}"
+state: !space_state {}
-  }
+sensors:
-}
+  # This is a plugin invocation with
+  # arguments.  They are passed to the
+  # plugin function as kwargs.
+  network_connections: !network_connections
+    networks: [ "2.4 GHz", "5 GHz" ]
 ```
 
 </td>
@@ -100,10 +104,10 @@ server as an OS distribution package.
 The configuration of this server consists of three parts:
 
 - The **main configuration** file, usually located at
-  `/etc/spaceapi-server/config.json`.  This file controls all the
+  `/etc/spaceapi-server/config.yaml`.  This file controls all the
   internal settings of the server.
 - The **response template** file, located at
-  `/etc/spaceapi-server/template.json`.  This file defines the content
+  `/etc/spaceapi-server/template.yaml`.  This file defines the content
   served by your sever.
 - The **plugins** directory, located at
   `/etc/spaceapi-server/plugins/`.  Here you can put your plugins for
@@ -111,36 +115,38 @@ The configuration of this server consists of three parts:
 
 ### 2. Configure the Server
 
-Open the file `/etc/spaceapi-server/config.json`.
+Open the file `/etc/spaceapi-server/config.yaml`.
 
 The following options are currently available:
 
-```json
+```yaml
-{
+---
-    "address": "::1",     # The address to listen on.
+# The address to listen on.
-    "port": 8000,         # The TCP port to listen on.
+address: "::1"
-    "server": "wsgiref",  # The Bottle backend server to use.
+# The TCP port to listen on.
-    "template": "template.json",  # Path to the SpaceAPI response template file.
+port: 8000
-    "plugins_dir": "plugins",     # Path to the directory containing your plugins.
+# The Bottle backend server to use.
-
+server: wsgiref
-    "plugins": {
+# Path to the SpaceAPI response template file.
-        # Plugin-specific configuration should go in here, separated by plugin
+template: template.yaml
-        "my_plugin": {
+# Path to the directory containing your plugins.
-            "my_option": "Hello, World!",
+plugins_dir: plugins
-            "my_other_option": [ 42, 1337 ]
+plugins:
-        }
+  # Plugin-specific configuration should go in here, separated by plugin
-    }
+  my_plugin:
-}
+    my_option: "Hello, World!"
+    my_other_option: [ 42, 1337 ]
 ```
 
 ### 3. Configure a Static SpaceAPI Endpoint
 
-Open the file `/etc/spaceapi-server/template.json`.  By default it
+Open the file `/etc/spaceapi-server/template.yaml`.  By default it
 contains a minimal example response.  If you only want to serve static
 content, your `template.json` should simply contain the SpaceAPI JSON
 response you want to serve.
 
-The content is served "almost-as-is" (once parsed and re-serialized).
+The content is served "almost-as-is" (apart from the conversion from
+YAML to JSON).
 
 To learn about how a SpaceAPI response should look like, have a look
 at [SpaceAPI: Getting Started][spaceapi-getting-started].
@@ -160,6 +166,7 @@ the space as open depending on its existence.
     from spaceapi_server import config, plugins
 
     @plugins.template_function
+    # The plugin can be invoked by using the !space_state YAML tag
     def space_state():
         # Get the plugin config dict
         conf = config.get_plugin_config('filestate')
@@ -180,39 +187,27 @@ the space as open depending on its existence.
         }
     ```
 
-    The `@template_function` decorator registers the function as a
+    The `@template_function` decorator registers a constructor in
-    callable in Jinja's globals.  There's also `@template_filter`,
+    PyYAML's parser with the function's name as tag
-    which registers a Jinja2 filter.  For more information on the
+    (e.g. `!space_state).
-    Jinja2 templating engine, see [Jinja2][jinja].
 
 2. Call the template function in your template:
 
-    ```json
+    ```yaml
-    {
+    # ...
-        # ...
+    state: !space_state
-        "state": "{{ space_state() }}"
+    # ...
-        # ...
-    }
     ```
 
-    Although the value for the `state` key is a string containing the
-    Jinja2 template, the return value of your template function is a
-    complex data type, which will be inserted into the result as such.
-    Please be aware that only the first token of a templated string is
-    used in the result.  This limitation is caused by the way Jinja2
-    is (ab-) used.
-
 3. Configure the server:
 
-    ```json
+    ```yaml
     # ...
-    "template": "template.json",
+    template: template.yaml
-    "plugins_dir": "plugins",
+    plugins_dir: plugins
-    "plugins": {
+    plugins:
-        "filestate": {
+      filestate:
-            "filename": "/var/space_state"
+        filename: /var/space_state
-        }
-    }
     # ...
     ```
 
@@ -230,7 +225,7 @@ e.g. through `systemctl reload`.
 If you need to run the server ad-hoc, you can start it with:
 
 ```bash
-python3 -m spaceapi_server /path/to/config.json
+python3 -m spaceapi_server /path/to/config.yaml
 ```
 ### 6. Test the Server
 
@@ -267,8 +262,8 @@ print(plugins.get_plugin_config('my_plugin'))
 
 ### Templating
 
-The following decorators register a function in the Jinja2
+The following decorators register a function for use as a PyYAML
-environment, so they become usable from within templates.  They are
+constructor, so they become usable from within templates.  They are
 invoked when the template is rendered, which happens for each HTTP
 request.
 
@@ -277,11 +272,11 @@ plugins, or by using a caching HTTP reverse proxy.
 
 #### `spaceapi_server.plugins.template_function`
 
-This decorator registers a function as a **global function** in the
+This decorator registers the function's name as a YAML tag in the parser.
-Jinja2 environment.
 
-The decorated function may take any arguments that can be represented
+The decorated function may take arguments (always passed as
-in a Jinja2 template.
+`**kwargs`, so `*args`, or arguments before `*` won't work) that can
+be represented in a YAML file.
 
 The decorated function may return any value that can be serialized
 into JSON.  This includes objects and arrays.
@@ -300,45 +295,11 @@ def lookup_sensor(query, default=None):
         return default or []
 ```
 
-```json
+```yaml
-{
+# ...
-  # ...
+state: !lookup_sensor
-  "state": "{{ lookup_sensor('SELECT timestamp, value FROM people_now_present LIMIT 1') }}"
+  query: SELECT timestamp, value FROM people_now_present LIMIT 1
-  # ...
+# ...
-}
-```
-
-#### `spaceapi_server.plugins.template_filter`
-
-This decorator registers a function as a **filter** in the Jinja2
-environment.  The decorated function must take at least one argument.
-
-The decorated function may take any arguments that can be represented
-in a Jinja2 template.
-
-The decorated function may return any value that can be serialized
-into JSON.  This includes objects and arrays.
-
-Usage:
-
-```python
-from spaceapi_server import plugins
-
-@plugins.template_filter
-def lookup_sensor(query, default=None):
-    # Do something with the query
-    result = ...
-    # If the loo
-    if not result:
-        return default or []
-```
-
-```json
-{
-  # ...
-  "state": "{{ 'SELECT timestamp, value FROM people_now_present LIMIT 1' | lookup_sensor }}"
-  # ...
-}
 ```
 
 
@@ -346,7 +307,7 @@ def lookup_sensor(query, default=None):
 [releases]: https://gitlab.com/s3lph/spaceapi-server/-/releases
 [spaceapi]: https://spaceapi.io/
 [pypi-bottle]: https://pypi.org/project/bottle/
-[pypi-jinja2]: https://pypi.org/project/Jinja2/
+[pypi-yaml]: https://pypi.org/project/PyYAML/
 [mit]: https://gitlab.com/s3lph/spaceapi-server/blob/master/LICENSE
 [spaceapi-getting-started]: https://spaceapi.io/getting-started/
 [jinja]: https://jinja.palletsprojects.com/

package/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.8-buster as python
+FROM python:3.9-buster as python
 
 RUN apt update \
     && apt install -y --no-install-recommends lintian rsync sudo docker.io \

package/archlinux/PKGBUILD

@@ -8,7 +8,7 @@ url="https://gitlab.com/s3lph/spaceapi-server"
 license=('MIT')
 groups=()
 depends=('python'
-         'python-jinja'
+         'python-yaml'
          'python-bottle')
 makedepends=('python-setuptools')
 checkdepends=()
@@ -16,8 +16,8 @@ optdepends=()
 provides=()
 conflicts=()
 replaces=()
-backup=('etc/spaceapi-server/config.json'
+backup=('etc/spaceapi-server/config.yaml'
-        'etc/spaceapi-server/template.json'
+        'etc/spaceapi-server/template.yaml'
         'etc/spaceapi-server/plugins')
 install=$pkgname.install
 changelog=$pkgname.changelog

package/archlinux/spaceapi-server/etc/spaceapi-server/config.json

@@ -1,7 +0,0 @@
-{
-  "address": "::",
-  "port": 8080,
-  "template": "/etc/spaceapi-server/template.json",
-  "plugins_dir": "/etc/spaceapi-server/plugins",
-  "plugins": {}
-}

package/archlinux/spaceapi-server/etc/spaceapi-server/config.yaml

@@ -0,0 +1,6 @@
+---
+address: "::"
+port: 8080
+template: /etc/spaceapi-server/template.json
+plugins_dir: /etc/spaceapi-server/plugins
+plugins: {}

package/archlinux/spaceapi-server/etc/spaceapi-server/template.json

@@ -1,19 +0,0 @@
-{
-  "api": "0.13",
-  "space": "Example Space",
-  "logo": "https://example.org/logo.png",
-  "url": "https://example.org",
-  "location": {
-    "lat": 0.0,
-    "lon": 0.0
-  },
-  "state": {
-    "open": null
-  },
-  "contact": {
-    "email": "example@example.org"
-  },
-  "issue_report_channels": [
-    "email"
-  ]
-}

package/archlinux/spaceapi-server/etc/spaceapi-server/template.yaml

@@ -0,0 +1,14 @@
+---
+api: "0.13"
+space: Example 
+logo: https://example.org/logo.png
+url: https://example.org
+location:
+  lat: 0.0
+  lon: 0.0
+state:
+  open: null
+contact:
+  email: example@example.org
+issue_report_channels:
+  - email

package/archlinux/spaceapi-server/usr/lib/systemd/system/spaceapi-server.service

@@ -2,7 +2,7 @@
 Description=Lightweight SpaceAPI Endpoint Server
 
 [Service]
-ExecStart=/usr/bin/python -m spaceapi_server /etc/spaceapi-server/config.json
+ExecStart=/usr/bin/python -m spaceapi_server /etc/spaceapi-server/config.yaml
 ExecReload=/usr/bin/kill -HUP $MAINPID
 User=spaceapi-server
 

package/debian/spaceapi-server/DEBIAN/conffiles

@@ -1,3 +1,3 @@
-/etc/spaceapi-server/config.json
+/etc/spaceapi-server/config.yaml
-/etc/spaceapi-server/template.json
+/etc/spaceapi-server/template.yaml
 /etc/spaceapi-server/plugins/example.py

package/debian/spaceapi-server/etc/spaceapi-server/config.json

@@ -1,7 +0,0 @@
-{
-  "address": "::",
-  "port": 8080,
-  "template": "/etc/spaceapi-server/template.json",
-  "plugins_dir": "/etc/spaceapi-server/plugins",
-  "plugins": {}
-}

package/debian/spaceapi-server/etc/spaceapi-server/config.yaml

@@ -0,0 +1,6 @@
+---
+address: "::"
+port: 8080
+template: /etc/spaceapi-server/template.json
+plugins_dir: /etc/spaceapi-server/plugins
+plugins: {}

package/debian/spaceapi-server/etc/spaceapi-server/template.json

@@ -1,19 +0,0 @@
-{
-  "api": "0.13",
-  "space": "Example Space",
-  "logo": "https://example.org/logo.png",
-  "url": "https://example.org",
-  "location": {
-    "lat": 0.0,
-    "lon": 0.0
-  },
-  "state": {
-    "open": null
-  },
-  "contact": {
-    "email": "example@example.org"
-  },
-  "issue_report_channels": [
-    "email"
-  ]
-}

package/debian/spaceapi-server/etc/spaceapi-server/template.yaml

@@ -0,0 +1,14 @@
+---
+api: "0.13"
+space: Example 
+logo: https://example.org/logo.png
+url: https://example.org
+location:
+  lat: 0.0
+  lon: 0.0
+state:
+  open: null
+contact:
+  email: example@example.org
+issue_report_channels:
+  - email

package/debian/spaceapi-server/lib/systemd/system/spaceapi-server.service

@@ -2,7 +2,7 @@
 Description=Lightweight SpaceAPI Endpoint Server
 
 [Service]
-ExecStart=/usr/bin/python3 -m spaceapi_server /etc/spaceapi-server/config.json
+ExecStart=/usr/bin/python3 -m spaceapi_server /etc/spaceapi-server/config.yaml
 ExecReload=/usr/bin/kill -HUP $MAINPID
 User=spaceapi-server
 

package/docker/Dockerfile

@@ -1,13 +1,13 @@
-FROM python:3.8-alpine
+FROM python:3.9-alpine
 
 ADD spaceapi_server/ /spaceapi_server/
 ADD setup.py /setup.py
 RUN python setup.py install && mkdir -p /config/plugins && chmod 0755 -R /config
-ADD package/docker/config.json /config/config.json
+ADD package/docker/config.yaml /config/config.yaml
-ADD package/docker/template.json /config/template.json
+ADD package/docker/template.yaml /config/template.yaml
 
 VOLUME /config
 EXPOSE 8000/tcp
 USER 1000
 
-ENTRYPOINT [ "/usr/local/bin/python3.8", "-m", "spaceapi_server", "/config/config.json" ]
+ENTRYPOINT [ "/usr/local/bin/python3.9", "-m", "spaceapi_server", "/config/config.yaml" ]

package/docker/config.json

@@ -1,8 +0,0 @@
-{
-    "address": "0.0.0.0",
-    "port": 8000,
-    "server": "wsgiref",
-    "template": "/config/template.json",
-    "plugins_dir": "/config/plugins",
-    "plugins": {}
-}

package/docker/config.yaml

@@ -0,0 +1,6 @@
+---
+address: "::"
+port: 8080
+template: /etc/spaceapi-server/template.json
+plugins_dir: /etc/spaceapi-server/plugins
+plugins: {}

package/docker/template.json

@@ -1,23 +0,0 @@
-{
-  "api": "0.13",
-  "space": "example.space",
-  "logo": "http://example.space/logo.png",
-  "url": "http://example.space",
-  "location": {
-    "address": "example.space, 42 Example Street, 1337 Example Town",
-    "lon": 42.42,
-    "lat": 13.37
-  },
-  "contact": {
-    "email": "example@example.space"
-  },
-  "issue_report_channels": [
-    "email"
-  ],
-  "state": {
-    "open": null
-  },
-  "projects": [
-    "http://example.space/projects"
-  ]
-}

package/docker/template.yaml

@@ -0,0 +1,14 @@
+---
+api: "0.13"
+space: Example 
+logo: https://example.org/logo.png
+url: https://example.org
+location:
+  lat: 0.0
+  lon: 0.0
+state:
+  open: null
+contact:
+  email: example@example.org
+issue_report_channels:
+  - email

setup.py

@@ -19,7 +19,7 @@ setup(
     python_requires='>=3.6',
     install_requires=[
         'bottle',
-        'jinja2==2.10'
+        'PyYAML',
     ],
     entry_points={
         'console_scripts': [
@@ -31,7 +31,7 @@ setup(
         'Environment :: Web Environment',
         'Intended Audience :: System Administrators',
         'License :: OSI Approved :: MIT License',
-        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.9',
         'Topic :: Internet :: WWW/HTTP :: WSGI :: Application'
     ]
 )

spaceapi_server/__init__.py

@@ -1,2 +1,2 @@
 
-__version__ = '0.3.1'
+__version__ = '0.4'

spaceapi_server/config/__init__.py

@@ -1,5 +1,5 @@
 
-import json
+import yaml
 
 
 # The parsed config object
@@ -8,13 +8,13 @@ __CONFIG = {}
 
 def load(filename: str) -> None:
     """
-    Load a JSON-formatted configuration file.
+    Load a YAML-formatted configuration file.
     :param filename: The config file to load.
     """
     global __CONFIG
-    # Open and parse the JSON config file
+    # Open and parse the YAML config file
     with open(filename, 'r') as conf:
-        __CONFIG = json.load(conf)
+        __CONFIG = yaml.safe_load(conf)
 
 
 def get() -> dict:

spaceapi_server/config/test/test_config.py

@@ -1,38 +0,0 @@
-
-import unittest
-import tempfile
-
-from spaceapi_server.config import load, get
-from spaceapi_server.plugins import get_plugin_config
-
-
-class ConfigTest(unittest.TestCase):
-
-    CONFIG = '''
-    {
-        "foo": "bar",
-        "baz": 42,
-        "plugins": {
-            "myplugin": {
-                "foo": "baz"
-            }
-        }
-    }
-    '''
-
-    def setUp(self) -> None:
-        _, self.temp = tempfile.mkstemp('.json', 'spaceapi_server_config_', text=True)
-        with open(self.temp, 'w') as f:
-            f.write(self.CONFIG)
-
-    def test_load(self):
-        pre = get()
-        pre_plugin = get_plugin_config('myplugin')
-        self.assertEqual({}, pre)
-        self.assertEqual({}, pre_plugin)
-        load(self.temp)
-        post = get()
-        post_plugin = get_plugin_config('myplugin')
-        self.assertEqual('bar', post['foo'])
-        self.assertEqual(42, post['baz'])
-        self.assertEqual('baz', post_plugin['foo'])

spaceapi_server/plugins/__init__.py

@@ -1,4 +1,6 @@
 
+import yaml
+
 from spaceapi_server import config, template
 
 
@@ -7,22 +9,8 @@ def template_function(fn):
     Register the decorated function as a callable template function.
     :param fn: The function to register.
     """
-    # Make sure the Jinja2 environment is initialized
+    yaml.SafeLoader.add_constructor(f'!{fn.__name__}', template.plugin_constructor)
-    env = template._env_init()
+    template.PluginInvocation.register_plugin(fn.__name__, fn)
-    # Add the function to the environment's globals
-    env.globals[fn.__name__] = fn
-    return fn
-
-
-def template_filter(fn):
-    """
-    Register the decorated function as a template filter.
-    :param fn: The function to register.
-    """
-    # Make sure the Jinja2 environment is initialized
-    env = template._env_init()
-    # Add the function to the environment's filters
-    env.filters[fn.__name__] = fn
     return fn
 
 

spaceapi_server/server/__init__.py

@@ -1,6 +1,7 @@
 import os
 import sys
 import json
+import yaml
 import signal
 import importlib
 
@@ -51,10 +52,10 @@ def load(*args, **kwargs):
             m_spec.loader.exec_module(module)
 
     # Get the template path
-    template_path = conf.get('template', 'template.json')
+    template_path = conf.get('template', 'template.yaml')
     # Load and parse the JSON template
     with open(template_path, 'r') as f:
-        __TEMPLATE = json.load(f)
+        __TEMPLATE = yaml.safe_load(f)
 
 
 def init():

spaceapi_server/template/__init__.py

@@ -1,44 +1,31 @@
-import json
 
-import jinja2
+class PluginInvocation():
+    _plugins = {}
+
+    def __init__(self, name, data):
+        super().__init__()
+        if name not in self._plugins:
+            raise KeyError(f'No such plugin function: {name}')
+        self._name = name
+        self._data = data
+
+    def __call__(self):
+        return self._plugins[self._name](**self._data)
+
+    @classmethod
+    def register_plugin(cls, name, fn):
+        cls._plugins[name] = fn
 
 
-# The Jinja2 environment
+def plugin_constructor(loader, node):
-__ENV = None
+    data = loader.construct_mapping(node)
-
+    return PluginInvocation(node.tag[1:], data)
-
-def _env_init(force: bool = False):
-    """
-    Initialize the Jinja2 environment.
-    :param force: If true, force reload the environment.
-    """
-    global __ENV
-    if __ENV is None or force:
-        # Use json.dumps as finalizer in order to preserve complex data structures
-        __ENV = jinja2.Environment(finalize=json.dumps)
-    return __ENV
-
-
-def render(template: str):
-    """
-    Render the given string as a Jinja2 template.
-    :param template: The template string to render.
-    """
-    # Make sure the Jinja2 environment is initialized
-    env = _env_init()
-    # Create a Jinja2 template from the input string
-    t = env.from_string(template)
-    decoder = json.JSONDecoder()
-    # Render the template and turn the JSON dump back into complex data structures
-    # Only parse the first JSON object in the string, ignore the rest
-    obj, i = decoder.raw_decode(t.render())
-    return obj
 
 
 def render_traverse(obj):
     """
-    Walk through a complex, JSON-serializable data structure, and pass
+    Walk through a complex, JSON-serializable data structure, and
-    string objects through the Jinja2 templating engine.
+    invoke plugins if for custom tags.
     :param obj: The object to traverse.
     """
     if isinstance(obj, list):
@@ -47,9 +34,9 @@ def render_traverse(obj):
     elif isinstance(obj, dict):
         # dict -> recurse into the value of each (key, value)
         return {k: render_traverse(v) for k, v in obj.items()}
-    elif isinstance(obj, str):
+    elif isinstance(obj, PluginInvocation):
-        # str -> template
+        # PluginTag -> invoke the plugin with the stored arguments
-        return render(obj)
+        return obj()
     else:
         # anything else -> return as-is
         return obj

spaceapi_server/template/test/test_template.py

@@ -1,69 +0,0 @@
-
-import unittest
-
-from spaceapi_server.template import _env_init, render, render_traverse
-from spaceapi_server.plugins import template_function, template_filter
-
-
-class TemplateTest(unittest.TestCase):
-
-    @staticmethod
-    @template_function
-    def template_test_function(value):
-        return f'test_{value}'
-
-    @staticmethod
-    @template_filter
-    def template_test_filter(value, other):
-        return f'test_{other}_{value}'
-
-    @staticmethod
-    @template_function
-    def template_test_function_nocache():
-        TemplateTest.counter1 += 1
-        return TemplateTest.counter1
-
-    def setUp(self) -> None:
-        TemplateTest.counter1 = 0
-
-    def test_template(self):
-        env = _env_init()
-        self.assertEqual('"not a template"', env.from_string('not a template').render())
-        self.assertEqual('"a template"', env.from_string('{{ "a template" }}').render())
-        self.assertEqual('42', env.from_string('{{ 42 }}').render())
-        self.assertEqual('["foo"]', env.from_string('{{ [ "foo" ] }}').render())
-        self.assertEqual('{"foo": ["bar"]}', env.from_string('{{ { "foo": [ "bar" ] } }}').render())
-
-    def test_render(self):
-        self.assertEqual('not a template', render('not a template'))
-        self.assertEqual('a template', render('{{ "a template" }}'))
-        self.assertEqual(42, render('{{ 42 }}'))
-        self.assertEqual(['foo'], render('{{ [ "foo" ] }}'))
-        self.assertEqual({'foo': ['bar']}, render('{{ { "foo": [ "bar" ] } }}'))
-        self.assertEqual('foo', render('foo{{ "bar" }}'))
-
-    def test_render_traverse(self):
-        template = {
-            'foo': 42,
-            'bar': [1, 2, 3],
-            'notemplate': 'foo',
-            'builtin': '{{ [ 1337, 42 ] | first }}',
-            'test_functions': {
-                'test_function': '{{ template_test_function("foo") }}',
-                'test_filter': '{{ "bar" | template_test_filter("other") }}'
-            }
-        }
-        rendered = render_traverse(template)
-        self.assertEqual(42, rendered['foo'])
-        self.assertEqual([1, 2, 3], rendered['bar'])
-        self.assertEqual('foo', rendered['notemplate'])
-        self.assertEqual(1337, rendered['builtin'])
-        self.assertEqual('test_foo', rendered['test_functions']['test_function'])
-        self.assertEqual('test_other_bar', rendered['test_functions']['test_filter'])
-
-    def test_no_cache(self):
-        template = ['{{ template_test_function_nocache() }}']
-        r1 = render_traverse(template)
-        r2 = render_traverse(template)
-        self.assertEqual(1, r1[0])
-        self.assertEqual(2, r2[0])