feat(config): custom_wiki2html external converter + base_url for RSS (P2)

Add three per-wiki HtmlConfig keys mirroring vimwiki globals:

- custom_wiki2html / custom_wiki2html_args: when set, export shells out
  to the external converter via `sh -c` with vimwiki's exact arg order
  (<cmd> <force> <syntax> <ext> <out_dir> <in_file> <css> <tpl_path>
  <tpl_default> <tpl_ext> <root_path> <args>, `-` for empty optionals)
  instead of the built-in renderer.
- base_url: when set, diary RSS item + channel links become
  <base_url><diary_rel_path>/<date>.html instead of file:// URIs.

write_page() gains a `force` flag threaded through export_current (false),
export_all (its own flag) and the did_save auto-export path (false).

Tests: write_page_invokes_custom_wiki2html_converter,
write_rss_uses_base_url_for_public_links (html_export.rs), config
round-trip + defaults (index_and_config.rs). Docs: README, doc/nuwiki.txt,
lua config comment, vimwiki-gap.md item ticked.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/nuwiki-lsp/src/commands.rs

@@ -1143,7 +1143,7 @@ fn export_current(
         })));
     }
     let name = crate::index::page_name_from_uri(&p.uri, Some(&cfg.root));
-    let outcome = match crate::commands::export_ops::write_page(&doc.ast, &name, cfg) {
+    let outcome = match crate::commands::export_ops::write_page(&doc.ast, &name, cfg, false) {
         Ok(o) => o,
         Err(e) => return Err(format!("nuwiki.export.currentToHtml: {e}")),
     };
@@ -1222,7 +1222,7 @@ fn export_all(backend: &Backend, args: Vec<Value>, force: bool) -> Result<Option
                 }
             }
         }
-        match crate::commands::export_ops::write_page(&ast, &name, &cfg) {
+        match crate::commands::export_ops::write_page(&ast, &name, &cfg, force) {
             Ok(outcome) => exported.push(outcome.to_json()),
             Err(e) => skipped.push(serde_json::json!({"uri": uri, "reason": e.to_string()})),
         }
@@ -3342,6 +3342,7 @@ pub mod export_ops {
         doc: &DocumentNode,
         name: &str,
         cfg: &WikiConfig,
+        force: bool,
     ) -> std::io::Result<PageExport> {
         if is_excluded(&cfg.html.exclude_files, name) {
             return Err(std::io::Error::new(
@@ -3349,6 +3350,11 @@ pub mod export_ops {
                 format!("excluded by exclude_files: {name}"),
             ));
         }
+        // When a `custom_wiki2html` converter is configured, hand the page off
+        // to it instead of the built-in renderer (vimwiki parity).
+        if !cfg.html.custom_wiki2html.trim().is_empty() {
+            return run_custom_wiki2html(name, cfg, force);
+        }
         let template_source = template_for(&cfg.html, doc);
         let template = load_template(&template_source)
             .unwrap_or_else(|| fallback_template(&cfg.html.css_name));
@@ -3378,6 +3384,86 @@ pub mod export_ops {
         })
     }
 
+    /// `sh`-quote a path/string for the `custom_wiki2html` command line.
+    fn sh_quote(s: &str) -> String {
+        format!("'{}'", s.replace('\'', "'\\''"))
+    }
+
+    /// Run an external `custom_wiki2html` converter for `name`, mirroring
+    /// vimwiki's argument order:
+    ///   script force syntax ext output_dir input_file css_file
+    ///          template_path template_default template_ext root_path args
+    /// Empty optional args are passed as `-` (vimwiki convention). The script
+    /// is responsible for writing the output file; we return the path it is
+    /// expected to produce (`output_path_for`).
+    fn run_custom_wiki2html(
+        name: &str,
+        cfg: &WikiConfig,
+        force: bool,
+    ) -> std::io::Result<PageExport> {
+        let h = &cfg.html;
+        let input = cfg.root.join(format!("{name}{}", cfg.file_extension));
+        std::fs::create_dir_all(&h.html_path)?;
+        let css = crate::export::css_path(h);
+        let ext = cfg.file_extension.trim_start_matches('.');
+        let dash = |s: &str| {
+            if s.is_empty() {
+                "-".to_string()
+            } else {
+                s.to_string()
+            }
+        };
+        let tpl_path = if h.template_path.as_os_str().is_empty() {
+            "-".to_string()
+        } else {
+            sh_quote(&h.template_path.display().to_string())
+        };
+        let root_path = {
+            let rp = crate::export::compute_root_path(name);
+            if rp.is_empty() {
+                "-".to_string()
+            } else {
+                sh_quote(&rp)
+            }
+        };
+        let cmd = format!(
+            "{} {} {} {} {} {} {} {} {} {} {} {}",
+            h.custom_wiki2html,
+            if force { 1 } else { 0 },
+            cfg.syntax,
+            ext,
+            sh_quote(&h.html_path.display().to_string()),
+            sh_quote(&input.display().to_string()),
+            sh_quote(&css.display().to_string()),
+            tpl_path,
+            dash(&h.template_default),
+            dash(&h.template_ext),
+            root_path,
+            dash(h.custom_wiki2html_args.trim()),
+        );
+        let status = std::process::Command::new("sh")
+            .arg("-c")
+            .arg(&cmd)
+            .status()
+            .map_err(|e| {
+                std::io::Error::new(
+                    std::io::ErrorKind::Other,
+                    format!("custom_wiki2html spawn failed: {e}"),
+                )
+            })?;
+        if !status.success() {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::Other,
+                format!("custom_wiki2html exited with {status}"),
+            ));
+        }
+        Ok(PageExport {
+            page: name.to_string(),
+            output_path: output_path_for(&cfg.html, name),
+            source_uri: tower_lsp::lsp_types::Url::from_file_path(&input).ok(),
+        })
+    }
+
     /// Two-tier template load. Returns the resolved template body, or
     /// `None` if neither file exists — caller falls back to the built-in
     /// template.
@@ -3423,12 +3509,29 @@ pub mod export_ops {
 "#,
         );
         xml.push_str(&format!("<title>{}</title>\n", xml_escape(&cfg.name)));
+        // `base_url` (per-wiki) prefixes the feed + item links so a hosted
+        // feed points at public URLs rather than local `file://` paths.
+        let base_url = cfg.html.base_url.trim();
+        if !base_url.is_empty() {
+            xml.push_str(&format!("<link>{}</link>\n", xml_escape(base_url)));
+        }
         xml.push_str("<description>nuwiki diary</description>\n");
         for e in sorted {
+            // With base_url set, build a public URL from the diary path + date;
+            // otherwise fall back to the entry's `file://` URI.
+            let link = if base_url.is_empty() {
+                e.uri.as_str().to_string()
+            } else {
+                format!(
+                    "{base_url}{}/{}.html",
+                    cfg.diary_rel_path.trim_matches('/'),
+                    e.date.format()
+                )
+            };
             xml.push_str("<item>");
             xml.push_str(&format!("<title>{}</title>", e.date.format()));
-            xml.push_str(&format!("<link>{}</link>", e.uri.as_str()));
-            xml.push_str(&format!("<guid>{}</guid>", e.uri.as_str()));
+            xml.push_str(&format!("<link>{}</link>", xml_escape(&link)));
+            xml.push_str(&format!("<guid>{}</guid>", xml_escape(&link)));
             xml.push_str("</item>\n");
         }
         xml.push_str("</channel></rss>\n");

crates/nuwiki-lsp/src/config.rs

@@ -130,6 +130,13 @@ pub struct HtmlConfig {
     /// renderer falls back to `class="color-<name>"` when a name
     /// isn't in the dict.
     pub color_dic: std::collections::HashMap<String, String>,
+    /// External wiki→HTML converter (vimwiki's `custom_wiki2html`). When
+    /// non-empty, export shells out to it instead of the built-in renderer.
+    pub custom_wiki2html: String,
+    /// Extra args appended to the `custom_wiki2html` invocation.
+    pub custom_wiki2html_args: String,
+    /// URL prefix prepended to RSS feed / diary item links (`base_url`).
+    pub base_url: String,
 }
 
 impl Default for HtmlConfig {
@@ -145,6 +152,9 @@ impl Default for HtmlConfig {
             html_filename_parameterization: false,
             exclude_files: Vec::new(),
             color_dic: std::collections::HashMap::new(),
+            custom_wiki2html: String::new(),
+            custom_wiki2html_args: String::new(),
+            base_url: String::new(),
         }
     }
 }
@@ -634,6 +644,12 @@ struct RawWiki {
     exclude_files: Option<Vec<String>>,
     #[serde(default)]
     color_dic: Option<std::collections::HashMap<String, String>>,
+    #[serde(default)]
+    custom_wiki2html: Option<String>,
+    #[serde(default)]
+    custom_wiki2html_args: Option<String>,
+    #[serde(default)]
+    base_url: Option<String>,
     // per-wiki keys mirroring vimwiki globals. All optional so
     // existing single-wiki configs migrate without touching anything.
     #[serde(default)]
@@ -720,6 +736,15 @@ impl From<RawWiki> for WikiConfig {
         if let Some(v) = r.color_dic {
             html.color_dic = v;
         }
+        if let Some(s) = r.custom_wiki2html {
+            html.custom_wiki2html = s;
+        }
+        if let Some(s) = r.custom_wiki2html_args {
+            html.custom_wiki2html_args = s;
+        }
+        if let Some(s) = r.base_url {
+            html.base_url = s;
+        }
         let d = wiki_defaults();
         WikiConfig {
             name: r.name.unwrap_or(derived_name),

crates/nuwiki-lsp/src/lib.rs

@@ -728,7 +728,7 @@ impl LanguageServer for Backend {
             return;
         }
         let name = index::page_name_from_uri(&uri, Some(&wiki.config.root));
-        let outcome = commands::export_ops::write_page(&doc.ast, &name, &wiki.config);
+        let outcome = commands::export_ops::write_page(&doc.ast, &name, &wiki.config, false);
         drop(doc);
         match outcome {
             Ok(out) => {