Move template rendering and themes onto PluginHost (#559)

crates/yaak-commands/src/templates.rs

@@ -0,0 +1,67 @@
+//! Templates, the functions plugins put in them, and themes.
+//!
+//! Everything here needs the plugin runtime, but only for the one thing it
+//! uniquely provides: running a template function. Resolving the environment
+//! chain and deciding what a render should do about errors are ordinary work
+//! and stay here, where every host gets them the same.
+
+use crate::error::Result;
+use crate::host::PluginHost;
+use crate::render::render_template;
+use yaak_plugins::events::{
+    GetTemplateFunctionConfigResponse, GetTemplateFunctionSummaryResponse, GetThemesResponse,
+    RenderPurpose,
+};
+use yaak_rpc_schema::*;
+use yaak_templates::{RenderErrorBehavior, RenderOptions, transform_args};
+
+pub async fn cmd_render_template<H: PluginHost>(
+    host: H,
+    req: CmdRenderTemplateReq,
+) -> Result<String> {
+    let environment_chain =
+        host.db().resolve_environments(&req.workspace_id, None, req.environment_id.as_deref())?;
+    let cb = host.template_callback(req.purpose.unwrap_or(RenderPurpose::Preview));
+    let options = RenderOptions {
+        // A preview that throws would show the user an error where they expect
+        // to see the value so far, so callers rendering *into the UI* ask for
+        // empties instead.
+        error_behavior: match req.ignore_error {
+            Some(true) => RenderErrorBehavior::ReturnEmpty,
+            _ => RenderErrorBehavior::Throw,
+        },
+    };
+    Ok(render_template(&req.template, environment_chain, &cb, &options).await?)
+}
+
+/// Render only the *arguments* of a template's function calls, leaving the
+/// calls themselves intact. This is what turns a parsed template back into
+/// something displayable without evaluating it.
+pub async fn cmd_template_tokens_to_string<H: PluginHost>(
+    host: H,
+    req: CmdTemplateTokensToStringReq,
+) -> Result<String> {
+    let cb = host.template_callback(RenderPurpose::Preview);
+    Ok(transform_args(req.tokens, &cb)?.to_string())
+}
+
+pub async fn cmd_template_function_summaries<H: PluginHost>(
+    host: H,
+    _req: CmdTemplateFunctionSummariesReq,
+) -> Result<Vec<GetTemplateFunctionSummaryResponse>> {
+    host.template_function_summaries().await
+}
+
+pub async fn cmd_template_function_config<H: PluginHost>(
+    host: H,
+    req: CmdTemplateFunctionConfigReq,
+) -> Result<GetTemplateFunctionConfigResponse> {
+    host.template_function_config(&req.function_name, req.values, &req.model.id()).await
+}
+
+pub async fn cmd_get_themes<H: PluginHost>(
+    host: H,
+    _req: CmdGetThemesReq,
+) -> Result<Vec<GetThemesResponse>> {
+    host.themes().await
+}