Bug 890690 - Support POST searches in about:home. r=gavin

--HG--
extra : transplant_source : %A5%23%F7%EC%87%DC%ED%D3V%00%C1%D7K%90%D4%009Pp%24

browser/base/content/abouthome/aboutHome.js

@@ -294,13 +294,6 @@ function onSearchSubmit(aEvent)
   let searchURL = document.documentElement.getAttribute("searchEngineURL");
 
   if (searchURL && searchTerms.length > 0) {
-    const SEARCH_TOKENS = {
-      "_searchTerms_": encodeURIComponent(searchTerms)
-    }
-    for (let key in SEARCH_TOKENS) {
-      searchURL = searchURL.replace(key, SEARCH_TOKENS[key]);
-    }
-
     // Send an event that a search was performed. This was originally
     // added so Firefox Health Report could record that a search from
     // about:home had occurred.
@@ -308,7 +301,42 @@ function onSearchSubmit(aEvent)
     let event = new CustomEvent("AboutHomeSearchEvent", {detail: engineName});
     document.dispatchEvent(event);
 
-    window.location.href = searchURL;
+    const SEARCH_TOKEN = "_searchTerms_";
+    let searchPostData = document.documentElement.getAttribute("searchEnginePostData");
+    if (searchPostData) {
+      // Check if a post form already exists. If so, remove it.
+      const POST_FORM_NAME = "searchFormPost";
+      let form = document.forms[POST_FORM_NAME];
+      if (form) {
+        form.parentNode.removeChild(form);
+      }
+
+      // Create a new post form.
+      form = document.body.appendChild(document.createElement("form"));
+      form.setAttribute("name", POST_FORM_NAME);
+      // Set the URL to submit the form to.
+      form.setAttribute("action", searchURL.replace(SEARCH_TOKEN, searchTerms));
+      form.setAttribute("method", "post");
+
+      // Create new <input type=hidden> elements for search param.
+      searchPostData = searchPostData.split("&");
+      for (let postVar of searchPostData) {
+        let [name, value] = postVar.split("=");
+        if (value == SEARCH_TOKEN) {
+          value = searchTerms;
+        }
+        let input = document.createElement("input");
+        input.setAttribute("type", "hidden");
+        input.setAttribute("name", name);
+        input.setAttribute("value", value);
+        form.appendChild(input);
+      }
+      // Submit the form.
+      form.submit();
+   } else {
+      searchURL = searchURL.replace(SEARCH_TOKEN, encodeURIComponent(searchTerms));
+      window.location.href = searchURL;
+    }
   }
 
   aEvent.preventDefault();

browser/base/content/browser.js

@@ -2314,6 +2314,9 @@ function BrowserOnAboutPageLoad(doc) {
     let updateSearchEngine = function() {
       let engine = AboutHomeUtils.defaultSearchEngine;
       docElt.setAttribute("searchEngineName", engine.name);
+      docElt.setAttribute("searchEnginePostData", engine.postDataString || "");
+      // Again, keep the searchEngineURL as the last attribute, because the
+      // mutation observer in aboutHome.js is counting on that.
       docElt.setAttribute("searchEngineURL", engine.searchURL);
     };
     updateSearchEngine();

browser/modules/AboutHomeUtils.jsm

@@ -25,13 +25,11 @@ this.AboutHomeUtils = {
   get defaultSearchEngine() {
     let defaultEngine = Services.search.defaultEngine;
     let submission = defaultEngine.getSubmission("_searchTerms_", null, "homepage");
-    if (submission.postData) {
-      throw new Error("Home page does not support POST search engines.");
-    }
   
     return Object.freeze({
       name: defaultEngine.name,
-      searchURL: submission.uri.spec
+      searchURL: submission.uri.spec,
+      postDataString: submission.postDataString
     });
   },