Fix search CORS in file URIs

Author: mattico

src/renderer/html_handlebars/search.rs

@@ -22,11 +22,11 @@ pub fn create_files(search_config: &Search, destination: &Path, book: &Book) ->
         render_item(&mut index, &search_config, item)?;
     }
 
-    let json = write_to_json(index, &search_config)?;
+    let index = write_to_js(index, &search_config)?;
     debug!("Writing search index ✓");
 
     if search_config.copy_js {
-        utils::fs::write_file(destination, "searchindex.json", json.as_bytes())?;
+        utils::fs::write_file(destination, "searchindex.js", 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)?;
@@ -144,8 +144,10 @@ fn render_item(index: &mut Index, search_config: &Search, item: &BookItem) -> Re
     Ok(())
 }
 
-/// Converts the index and search options to a JSON string
-fn write_to_json(index: Index, search_config: &Search) -> Result<String> {
+/// 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> {
     // These structs mirror the configuration javascript object accepted by
     // http://elasticlunr.com/docs/configuration.js.html
 
@@ -204,6 +206,7 @@ fn write_to_json(index: Index, search_config: &Search) -> Result<String> {
         searchoptions: searchoptions,
         index: index,
     };
+    let json_contents = serde_json::to_string(&json_contents)?;
 
-    Ok(serde_json::to_string(&json_contents)?)
+    Ok(format!("window.search = {};", json_contents))
 }

src/theme/index.hbs

@@ -246,6 +246,9 @@
         <script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
         {{/if}}
 
+        {{#if search_enabled}}
+        <script src="searchindex.js" type="text/javascript" charset="utf-8"></script>
+        {{/if}}
         {{#if search_js}}
         <script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
         <script src="mark.min.js" type="text/javascript" charset="utf-8"></script>

src/theme/searcher/searcher.js

@@ -1,4 +1,4 @@
-window.search = {};
+window.search = window.search || {};
 (function search(search) {
     // Search functionality
     //
@@ -236,28 +236,18 @@ window.search = {};
     }
 
     function init() {
-        var request = new XMLHttpRequest();
-        request.open('GET', 'searchindex.json', true);
-        
-        request.onload = function() {
-            if (this.status >= 200 && this.status < 400) {
-                var json = JSON.parse(this.response);
-
-                searchoptions = json.searchoptions;
-                searchindex = elasticlunr.Index.load(json.index);
-
-                // Set up events
-                searchicon.addEventListener('click', function(e) { searchIconClickHandler(); }, false);
-                searchbar.addEventListener('keyup', function(e) { searchbarKeyUpHandler(); }, false);
-                document.addEventListener('keydown', function (e) { globalKeyHandler(e); }, false);
-                // If the user uses the browser buttons, do the same as if a reload happened
-                window.onpopstate = function(e) { doSearchOrMarkFromUrl(); };
-
-                // If reloaded, do the search or mark again, depending on the current url parameters
-                doSearchOrMarkFromUrl();
-            }
-        };        
-        request.send();
+        searchoptions = window.search.searchoptions;
+        searchindex = elasticlunr.Index.load(window.search.index);
+
+        // Set up events
+        searchicon.addEventListener('click', function(e) { searchIconClickHandler(); }, false);
+        searchbar.addEventListener('keyup', function(e) { searchbarKeyUpHandler(); }, false);
+        document.addEventListener('keydown', function (e) { globalKeyHandler(e); }, false);
+        // If the user uses the browser buttons, do the same as if a reload happened
+        window.onpopstate = function(e) { doSearchOrMarkFromUrl(); };
+
+        // If reloaded, do the search or mark again, depending on the current url parameters
+        doSearchOrMarkFromUrl();
     }
 
     function unfocusSearchbar() {

tests/rendered_output.rs

@@ -349,15 +349,21 @@ mod search {
     use mdbook::MDBook;
     use dummy_book::DummyBook;
 
+    fn read_book_index(root: &Path) -> serde_json::Value {
+        let index = root.join("book/searchindex.js");
+        let index = file_to_string(index).unwrap();
+        let index = index.trim_left_matches("window.search = ");
+        let index = index.trim_right_matches(";");
+        serde_json::from_str(&index).unwrap()
+    }
+
     #[test]
     fn book_creates_reasonable_search_index() {
         let temp = DummyBook::new().build().unwrap();
         let md = MDBook::load(temp.path()).unwrap();
         md.build().unwrap();
 
-        let index = temp.path().join("book/searchindex.json");
-        let index = file_to_string(index).unwrap();
-        let index: serde_json::Value = serde_json::from_str(&index).unwrap();
+        let index = read_book_index(temp.path());
 
         let bodyidx = &index["index"]["index"]["body"]["root"];
         let textidx = &bodyidx["t"]["e"]["x"]["t"];
@@ -393,13 +399,11 @@ mod search {
             let md = MDBook::load(temp.path()).unwrap();
             md.build().unwrap();
 
-            let src = temp.path().join("book/searchindex.json");
-            let src = File::open(src).unwrap();
-            let src: serde_json::Value = serde_json::from_reader(src).unwrap();
+            let src = read_book_index(temp.path());
 
             let dest = Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/searchindex_fixture.json");
-            let mut dest = File::create(&dest).unwrap();
-            serde_json::to_writer_pretty(&mut dest, &src).unwrap();
+            let dest = File::create(&dest).unwrap();
+            serde_json::to_writer_pretty(dest, &src).unwrap();
 
             src
         } else {
@@ -423,9 +427,7 @@ mod search {
         let md = MDBook::load(temp.path()).unwrap();
         md.build().unwrap();
 
-        let book_index = temp.path().join("book/searchindex.json");
-        let book_index = File::open(book_index).unwrap();
-        let book_index: serde_json::Value = serde_json::from_reader(book_index).unwrap();
+        let book_index = read_book_index(temp.path());
 
         let fixture_index = get_fixture();