feat: Human Input Node (#32060)

The frontend and backend implementation for the human input node.

Co-authored-by: twwu <twwu@dify.ai>
Co-authored-by: JzoNg <jzongcode@gmail.com>
Co-authored-by: yyh <92089059+lyzno1@users.noreply.github.com>
Co-authored-by: zhsama <torvalds@linux.do>

api/libs/email_template_renderer.py

@@ -0,0 +1,49 @@
+"""
+Email template rendering helpers with configurable safety modes.
+"""
+
+import time
+from collections.abc import Mapping
+from typing import Any
+
+from flask import render_template_string
+from jinja2.runtime import Context
+from jinja2.sandbox import ImmutableSandboxedEnvironment
+
+from configs import dify_config
+from configs.feature import TemplateMode
+
+
+class SandboxedEnvironment(ImmutableSandboxedEnvironment):
+    """Sandboxed environment with execution timeout."""
+
+    def __init__(self, timeout: int, *args: Any, **kwargs: Any):
+        self._deadline = time.time() + timeout if timeout else None
+        super().__init__(*args, **kwargs)
+
+    def call(self, context: Context, obj: Any, *args: Any, **kwargs: Any) -> Any:
+        if self._deadline is not None and time.time() > self._deadline:
+            raise TimeoutError("Template rendering timeout")
+        return super().call(context, obj, *args, **kwargs)
+
+
+def render_email_template(template: str, substitutions: Mapping[str, str]) -> str:
+    """
+    Render email template content according to the configured template mode.
+
+    In unsafe mode, Jinja expressions are evaluated directly.
+    In sandbox mode, a sandboxed environment with timeout is used.
+    In disabled mode, the template is returned without rendering.
+    """
+    mode = dify_config.MAIL_TEMPLATING_MODE
+    timeout = dify_config.MAIL_TEMPLATING_TIMEOUT
+
+    if mode == TemplateMode.UNSAFE:
+        return render_template_string(template, **substitutions)
+    if mode == TemplateMode.SANDBOX:
+        env = SandboxedEnvironment(timeout=timeout)
+        tmpl = env.from_string(template)
+        return tmpl.render(substitutions)
+    if mode == TemplateMode.DISABLED:
+        return template
+    raise ValueError(f"Unsupported mail templating mode: {mode}")