Optimize search index

book-example/src/format/config.md

@@ -113,6 +113,7 @@ Available configuration options for the `[output.html.playpen]` table:
 
 Available configuration options for the `[output.html.search]` table:
 
+- **enable:** Enables the search feature. Defaults to `true`.
 - **limit-results:** The maximum number of search results. Defaults to `30`.
 - **teaser-word-count:** The number of words used for a search result teaser. 
   Defaults to `30`.
@@ -168,6 +169,7 @@ boost-hierarchy = 1
 boost-paragraph = 1
 expand = true
 heading-split-level = 3
+copy-js = true
 ```
 
 

src/config.rs

@@ -463,9 +463,11 @@ impl Default for Playpen {
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(default, rename_all = "kebab-case")]
 pub struct Search {
+    /// Enable the search feature. Default: `true`.
+    pub enable: bool,
     /// Maximum number of visible results. Default: `30`.
     pub limit_results: u32,
-    /// The number of words used for a search result teaser. Default: `30`,
+    /// The number of words used for a search result teaser. Default: `30`.
     pub teaser_word_count: u32,
     /// Define the logical link between multiple search words.
     /// If true, all search words must appear in each result. Default: `true`.
@@ -494,6 +496,7 @@ impl Default for Search {
     fn default() -> Search {
         // Please update the documentation of `Search` when changing values!
         Search {
+            enable: true,
             limit_results: 30,
             teaser_word_count: 30,
             use_boolean_and: false,

src/renderer/html_handlebars/hbs_renderer.rs

@@ -367,8 +367,10 @@ impl Renderer for HtmlHandlebars {
             .chain_err(|| "Unable to copy across additional CSS and JS")?;
 
         // Render search index
-        #[cfg(feature = "search")]
-        super::search::create_files(&html_config.search.unwrap_or_default(), &destination, &book)?;
+        let search = html_config.search.unwrap_or_default();
+        if cfg!(feature = "search") && search.enable {
+            super::search::create_files(&search, &destination, &book)?;
+        }
 
         // Copy all remaining files
         utils::fs::copy_files_except_ext(&src_dir, &destination, true, &["md"])?;
@@ -446,10 +448,9 @@ fn make_data(
 
     let search = html_config.search.clone();
     if cfg!(feature = "search") {
-        data.insert("search_enabled".to_owned(), json!(true));
-        if search.unwrap_or_default().copy_js {
-            data.insert("search_js".to_owned(), json!(true));
-        }
+        let search = search.unwrap_or_default();
+        data.insert("search_enabled".to_owned(), json!(search.enable));
+        data.insert("search_js".to_owned(), json!(search.enable && search.copy_js));
     } else if search.is_some() {
         warn!("mdBook compiled without search support, ignoring `output.html.search` table");
         warn!(

src/renderer/html_handlebars/search.rs

@@ -18,16 +18,21 @@ use theme::searcher;
 /// Creates all files required for search.
 pub fn create_files(search_config: &Search, destination: &Path, book: &Book) -> Result<()> {
     let mut index = Index::new(&["title", "body", "breadcrumbs"]);
+    let mut doc_urls = Vec::with_capacity(book.sections.len());
 
     for item in book.iter() {
-        render_item(&mut index, &search_config, item)?;
+        render_item(&mut index, &search_config, &mut doc_urls, item)?;
     }
 
-    let index = write_to_js(index, &search_config)?;
+    let index = write_to_json(index, &search_config, doc_urls)?;
     debug!("Writing search index ✓");
+    if index.len() > 10_000_000 {
+        warn!("searchindex.json is very large ({} bytes)", index.len());
+    }
 
     if search_config.copy_js {
-        utils::fs::write_file(destination, "searchindex.js", index.as_bytes())?;
+        utils::fs::write_file(destination, "searchindex.json", index.as_bytes())?;
+        utils::fs::write_file(destination, "searchindex.js", format!("window.search = {};", index).as_bytes())?;
         utils::fs::write_file(destination, "searcher.js", searcher::JS)?;
         utils::fs::write_file(destination, "mark.min.js", searcher::MARK_JS)?;
         utils::fs::write_file(destination, "elasticlunr.min.js", searcher::ELASTICLUNR_JS)?;
@@ -38,18 +43,22 @@ pub fn create_files(search_config: &Search, destination: &Path, book: &Book) ->
 }
 
 /// Uses the given arguments to construct a search document, then inserts it to the given index.
-fn add_doc<'a>(
+fn add_doc(
     index: &mut Index,
-    anchor_base: &'a str,
+    doc_urls: &mut Vec<String>, 
+    anchor_base: &str, 
     section_id: &Option<String>,
     items: &[&str],
 ) {
-    let doc_ref: Cow<'a, str> = if let &Some(ref id) = section_id {
-        format!("{}#{}", anchor_base, id).into()
+    let url = if let &Some(ref id) = section_id {
+        Cow::Owned(format!("{}#{}", anchor_base, id))
     } else {
-        anchor_base.into()
+        Cow::Borrowed(anchor_base)
     };
-    let doc_ref = utils::collapse_whitespace(doc_ref.trim());
+    let url = utils::collapse_whitespace(url.trim());
+    let doc_ref = doc_urls.len().to_string();
+    doc_urls.push(url.into());
+
     let items = items.iter().map(|&x| utils::collapse_whitespace(x.trim()));
     index.add_doc(&doc_ref, items);
 }
@@ -58,6 +67,7 @@ fn add_doc<'a>(
 fn render_item(
     index: &mut Index,
     search_config: &Search,
+    doc_urls: &mut Vec<String>,
     item: &BookItem,
 ) -> Result<()> {
     let chapter = match item {
@@ -92,6 +102,7 @@ fn render_item(
                     // Write the data to the index, and clear it for the next section
                     add_doc(
                         index,
+                        doc_urls,
                         &anchor_base,
                         &section_id,
                         &[&heading, &body, &breadcrumbs.join(" » ")],
@@ -144,6 +155,7 @@ fn render_item(
         // Make sure the last section is added to the index
         add_doc(
             index,
+            doc_urls,
             &anchor_base,
             &section_id,
             &[&heading, &body, &breadcrumbs.join(" » ")],
@@ -153,10 +165,7 @@ fn render_item(
     Ok(())
 }
 
-/// Exports the index and search options to a JS script which stores the index in `window.search`.
-/// Using a JS script is a workaround for CORS in `file://` URIs. It also removes the need for
-/// downloading/parsing JSON in JS.
-fn write_to_js(index: Index, search_config: &Search) -> Result<String> {
+fn write_to_json(index: Index, search_config: &Search, doc_urls: Vec<String>) -> Result<String> {
     use std::collections::BTreeMap;
     use self::elasticlunr::config::{SearchBool, SearchOptions, SearchOptionsField};
 
@@ -169,9 +178,11 @@ fn write_to_js(index: Index, search_config: &Search) -> Result<String> {
     #[derive(Serialize)]
     struct SearchindexJson {
         /// The options used for displaying search results
-        resultsoptions: ResultsOptions,
+        results_options: ResultsOptions,
         /// The searchoptions for elasticlunr.js
-        searchoptions: SearchOptions,
+        search_options: SearchOptions,
+        /// Used to lookup a document's URL from an integer document ref.
+        doc_urls: Vec<String>,
         /// The index for elasticlunr.js
         index: elasticlunr::Index,
     }
@@ -185,7 +196,7 @@ fn write_to_js(index: Index, search_config: &Search) -> Result<String> {
     opt.boost = Some(search_config.boost_hierarchy);
     fields.insert("breadcrumbs".into(), opt);
 
-    let searchoptions = SearchOptions {
+    let search_options = SearchOptions {
         bool: if search_config.use_boolean_and {
             SearchBool::And
         } else {
@@ -195,14 +206,15 @@ fn write_to_js(index: Index, search_config: &Search) -> Result<String> {
         fields,
     };
 
-    let resultsoptions = ResultsOptions {
+    let results_options = ResultsOptions {
         limit_results: search_config.limit_results,
         teaser_word_count: search_config.teaser_word_count,
     };
 
     let json_contents = SearchindexJson {
-        resultsoptions,
-        searchoptions,
+        results_options,
+        search_options,
+        doc_urls,
         index,
     };
 
@@ -211,7 +223,7 @@ fn write_to_js(index: Index, search_config: &Search) -> Result<String> {
     let json_contents = serde_json::to_value(&json_contents)?;
     let json_contents = serde_json::to_string(&json_contents)?;
 
-    Ok(format!("window.search = {};", json_contents))
+    Ok(json_contents)
 }
 
 fn clean_html(html: &str) -> String {

src/theme/searcher/searcher.js

@@ -27,11 +27,12 @@ window.search = window.search || {};
         content = document.getElementById('content'),
 
         searchindex = null,
-        resultsoptions = {
+        doc_urls = [],
+        results_options = {
             teaser_word_count: 30,
             limit_results: 30,
         },
-        searchoptions = {
+        search_options = {
             bool: "AND",
             expand: true,
             fields: {
@@ -139,7 +140,7 @@ window.search = window.search || {};
         teaser_count++;
 
         // The ?URL_MARK_PARAM= parameter belongs inbetween the page and the #heading-anchor
-        var url = result.ref.split("#");
+        var url = doc_urls[result.ref].split("#");
         if (url.length == 1) { // no anchor found
             url.push("");
         }
@@ -196,7 +197,7 @@ window.search = window.search || {};
         }
 
         var window_weight = [];
-        var window_size = Math.min(weighted.length, resultsoptions.teaser_word_count);
+        var window_size = Math.min(weighted.length, results_options.teaser_word_count);
 
         var cur_sum = 0;
         for (var wordindex = 0; wordindex < window_size; wordindex++) {
@@ -246,11 +247,12 @@ window.search = window.search || {};
         return teaser_split.join('');
     }
 
-    function init() {
-        resultsoptions = window.search.resultsoptions;
-        searchoptions = window.search.searchoptions;
-        searchbar_outer = window.search.searchbar_outer;
-        searchindex = elasticlunr.Index.load(window.search.index);
+    function init(config) {
+        results_options = config.results_options;
+        search_options = config.search_options;
+        searchbar_outer = config.searchbar_outer;
+        doc_urls = config.doc_urls;
+        searchindex = elasticlunr.Index.load(config.index);
 
         // Set up events
         searchicon.addEventListener('click', function(e) { searchIconClickHandler(); }, false);
@@ -441,8 +443,8 @@ window.search = window.search || {};
         if (searchindex == null) { return; }
 
         // Do the actual search
-        var results = searchindex.search(searchterm, searchoptions);
-        var resultcount = Math.min(results.length, resultsoptions.limit_results);
+        var results = searchindex.search(searchterm, search_options);
+        var resultcount = Math.min(results.length, results_options.limit_results);
 
         // Display search metrics
         searchresults_header.innerText = formatSearchMetric(resultcount, searchterm);
@@ -460,7 +462,16 @@ window.search = window.search || {};
         showResults(true);
     }
 
-    init();
+    fetch(path_to_root + 'searchindex.json')
+        .then(response => response.json())
+        .then(json => init(json))        
+        .catch(error => { // Try to load searchindex.js if fetch failed
+            var script = document.createElement('script');
+            script.src = path_to_root + 'searchindex.js';
+            script.onload = () => init(window.search);
+            document.head.appendChild(script);
+        });
+
     // Exported functions
     search.hasFocus = hasFocus;
 })(window.search);

tests/rendered_output.rs

@@ -426,33 +426,47 @@ mod search {
 
         let index = read_book_index(temp.path());
 
+        let doc_urls = index["doc_urls"].as_array().unwrap();
+        let get_doc_ref = |url: &str| -> String {
+            doc_urls.iter()
+                .position(|s| s == url)
+                .unwrap()
+                .to_string()
+        };
+
+        let first_chapter = get_doc_ref("first/index.html#first-chapter");
+        let introduction = get_doc_ref("intro.html#introduction");
+        let some_section = get_doc_ref("first/index.html#some-section");
+        let summary = get_doc_ref("first/includes.html#summary");
+        let conclusion = get_doc_ref("conclusion.html#conclusion");
+
         let bodyidx = &index["index"]["index"]["body"]["root"];
         let textidx = &bodyidx["t"]["e"]["x"]["t"];
         assert_eq!(textidx["df"], 2);
-        assert_eq!(textidx["docs"]["first/index.html#first-chapter"]["tf"], 1.0);
-        assert_eq!(textidx["docs"]["intro.html#introduction"]["tf"], 1.0);
+        assert_eq!(textidx["docs"][&first_chapter]["tf"], 1.0);
+        assert_eq!(textidx["docs"][&introduction]["tf"], 1.0);
 
         let docs = &index["index"]["documentStore"]["docs"];
-        assert_eq!(docs["first/index.html#first-chapter"]["body"], "more text.");
-        assert_eq!(docs["first/index.html#some-section"]["body"], "");
+        assert_eq!(docs[&first_chapter]["body"], "more text.");
+        assert_eq!(docs[&some_section]["body"], "");
         assert_eq!(
-            docs["first/includes.html#summary"]["body"],
+            docs[&summary]["body"],
             "Introduction First Chapter Nested Chapter Includes Recursive Second Chapter Conclusion"
         );
         assert_eq!(
-            docs["first/includes.html#summary"]["breadcrumbs"],
+            docs[&summary]["breadcrumbs"],
             "First Chapter » Summary"
         );
         assert_eq!(
-            docs["conclusion.html#conclusion"]["body"],
+            docs[&conclusion]["body"],
             "I put <HTML> in here!"
         );
     }
 
     // Setting this to `true` may cause issues with `cargo watch`,
     // since it may not finish writing the fixture before the tests
     // are run again.
-    const GENERATE_FIXTURE: bool = true;
+    const GENERATE_FIXTURE: bool = false;
 
     fn get_fixture() -> serde_json::Value {
         if GENERATE_FIXTURE {
@@ -481,7 +495,7 @@ mod search {
     //
     // If you're pretty sure you haven't broken anything, change `GENERATE_FIXTURE`
     // above to `true`, and run `cargo test` to generate a new fixture. Then
-    // change it back to `false`. Include the changed `searchindex_fixture.json` in your commit.
+    // **change it back to `false`**. Include the changed `searchindex_fixture.json` in your commit.
     #[test]
     fn search_index_hasnt_changed_accidentally() {
         let temp = DummyBook::new().build().unwrap();