add spawn-form example

examples/spawn-form/jupyterhub_config.py

@@ -0,0 +1,46 @@
+"""
+Example JuptyerHub config allowing users to specify environment variables and notebook-server args
+"""
+import shlex
+
+from jupyterhub.spawner import LocalProcessSpawner
+
+class DemoFormSpawner(LocalProcessSpawner):
+    def _options_form_default(self):
+        default_env = "YOURNAME=%s\n" % self.user.name
+        return """
+        <label for="args">Extra notebook CLI arguments</label>
+        <input name="args" placeholder="e.g. --debug"></input>
+        <label for="env">Environment variables (one per line)</label>
+        <textarea name="env">{env}</textarea>
+        """.format(env=default_env)
+    
+    def options_from_form(self, formdata):
+        options = {}
+        options['env'] = env = {}
+        
+        env_lines = formdata.get('env', [''])
+        for line in env_lines[0].splitlines():
+            if line:
+                key, value = line.split('=', 1)
+                env[key.strip()] = value.strip()
+        
+        arg_s = formdata.get('args', [''])[0].strip()
+        if arg_s:
+            options['argv'] = shlex.split(arg_s)
+        return options
+    
+    def get_args(self):
+        """Return arguments to pass to the notebook server"""
+        argv = super().get_args()
+        if self.user_options.get('argv'):
+            argv.extend(self.user_options['argv'])
+        return argv
+    
+    def get_env(self):
+        env = super().get_env()
+        if self.user_options.get('env'):
+            env.update(self.user_options['env'])
+        return env
+
+c.JupyterHub.spawner_class = DemoFormSpawner