gecko/toolkit/components/search/SearchSuggestionController.jsm

395 lines
14 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
this.EXPORTED_SYMBOLS = ["SearchSuggestionController"];
const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/Promise.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "NS_ASSERT", "resource://gre/modules/debug.js");
const SEARCH_RESPONSE_SUGGESTION_JSON = "application/x-suggestions+json";
const DEFAULT_FORM_HISTORY_PARAM = "searchbar-history";
const HTTP_OK = 200;
const REMOTE_TIMEOUT = 500; // maximum time (ms) to wait before giving up on a remote suggestions
const BROWSER_SUGGEST_PREF = "browser.search.suggest.enabled";
/**
* Remote search suggestions will be shown if gRemoteSuggestionsEnabled
* is true. Global because only one pref observer is needed for all instances.
*/
let gRemoteSuggestionsEnabled = Services.prefs.getBoolPref(BROWSER_SUGGEST_PREF);
Services.prefs.addObserver(BROWSER_SUGGEST_PREF, function(aSubject, aTopic, aData) {
gRemoteSuggestionsEnabled = Services.prefs.getBoolPref(BROWSER_SUGGEST_PREF);
}, false);
/**
* SearchSuggestionController.jsm exists as a helper module to allow multiple consumers to request and display
* search suggestions from a given engine, regardless of the base implementation. Much of this
* code was originally in nsSearchSuggestions.js until it was refactored to separate it from the
* nsIAutoCompleteSearch dependency.
* One instance of SearchSuggestionController should be used per field since form history results are cached.
*/
/**
* @param {function} [callback] - Callback for search suggestion results. You can use the promise
* returned by the search method instead if you prefer.
* @constructor
*/
this.SearchSuggestionController = function SearchSuggestionController(callback = null) {
this._callback = callback;
};
this.SearchSuggestionController.prototype = {
/**
* The maximum number of local form history results to return. This limit is
* only enforced if remote results are also returned.
*/
maxLocalResults: 5,
/**
* The maximum number of remote search engine results to return.
* We'll actually only display at most
* maxRemoteResults - <displayed local results count> remote results.
*/
maxRemoteResults: 10,
/**
* The maximum time (ms) to wait before giving up on a remote suggestions.
*/
remoteTimeout: REMOTE_TIMEOUT,
/**
* The additional parameter used when searching form history.
*/
formHistoryParam: DEFAULT_FORM_HISTORY_PARAM,
// Private properties
/**
* The last form history result used to improve the performance of subsequent searches.
* This shouldn't be used for any other purpose as it is never cleared and therefore could be stale.
*/
_formHistoryResult: null,
/**
* The remote server timeout timer, if applicable. The timer starts when form history
* search is completed.
*/
_remoteResultTimer: null,
/**
* The deferred for the remote results before its promise is resolved.
*/
_deferredRemoteResult: null,
/**
* The optional result callback registered from the constructor.
*/
_callback: null,
/**
* The XMLHttpRequest object for remote results.
*/
_request: null,
// Public methods
/**
* Fetch search suggestions from all of the providers. Fetches in progress will be stopped and
* results from them will not be provided.
*
* @param {string} searchTerm - the term to provide suggestions for
* @param {bool} privateMode - whether the request is being made in the context of private browsing
* @param {nsISearchEngine} engine - search engine for the suggestions.
*
* @return {Promise} resolving to an object containing results or null.
*/
fetch: function(searchTerm, privateMode, engine) {
// There is no smart filtering from previous results here (as there is when looking through
// history/form data) because the result set returned by the server is different for every typed
// value - e.g. "ocean breathes" does not return a subset of the results returned for "ocean".
this.stop();
if (!Services.search.isInitialized) {
throw new Error("Search not initialized yet (how did you get here?)");
}
if (typeof privateMode === "undefined") {
throw new Error("The privateMode argument is required to avoid unintentional privacy leaks");
}
if (!(engine instanceof Ci.nsISearchEngine)) {
throw new Error("Invalid search engine");
}
if (!this.maxLocalResults && !this.maxRemoteResults) {
throw new Error("Zero results expected, what are you trying to do?");
}
if (this.maxLocalResults < 0 || this.remoteResult < 0) {
throw new Error("Number of requested results must be positive");
}
// Array of promises to resolve before returning results.
let promises = [];
this._searchString = searchTerm;
// Remote results
if (searchTerm && gRemoteSuggestionsEnabled && this.maxRemoteResults &&
engine.supportsResponseType(SEARCH_RESPONSE_SUGGESTION_JSON)) {
this._deferredRemoteResult = this._fetchRemote(searchTerm, engine, privateMode);
promises.push(this._deferredRemoteResult.promise);
}
// Local results from form history
if (this.maxLocalResults) {
let deferredHistoryResult = this._fetchFormHistory(searchTerm);
promises.push(deferredHistoryResult.promise);
}
function handleRejection(reason) {
if (reason == "HTTP request aborted") {
// Do nothing since this is normal.
return null;
}
Cu.reportError("SearchSuggestionController rejection: " + reason);
return null;
}
return Promise.all(promises).then(this._dedupeAndReturnResults.bind(this), handleRejection);
},
/**
* Stop pending fetches so no results are returned from them.
*
* Note: If there was no remote results fetched, the fetching cannot be stopped and local results
* will still be returned because stopping relies on aborting the XMLHTTPRequest to reject the
* promise for Promise.all.
*/
stop: function() {
if (this._request) {
this._request.abort();
} else if (!this.maxRemoteResults) {
Cu.reportError("SearchSuggestionController: Cannot stop fetching if remote results were not "+
"requested");
}
this._reset();
},
// Private methods
_fetchFormHistory: function(searchTerm) {
let deferredFormHistory = Promise.defer();
let acSearchObserver = {
// Implements nsIAutoCompleteSearch
onSearchResult: (search, result) => {
this._formHistoryResult = result;
if (this._request) {
this._remoteResultTimer = Cc["@mozilla.org/timer;1"].
createInstance(Ci.nsITimer);
this._remoteResultTimer.initWithCallback(this._onRemoteTimeout.bind(this),
this.remoteTimeout || REMOTE_TIMEOUT,
Ci.nsITimer.TYPE_ONE_SHOT);
}
switch (result.searchResult) {
case Ci.nsIAutoCompleteResult.RESULT_SUCCESS:
case Ci.nsIAutoCompleteResult.RESULT_NOMATCH:
if (result.searchString !== this._searchString) {
deferredFormHistory.resolve("Unexpected response, this._searchString does not match form history response");
return;
}
let fhEntries = [];
for (let i = 0; i < result.matchCount; ++i) {
fhEntries.push(result.getValueAt(i));
}
deferredFormHistory.resolve({
result: fhEntries,
formHistoryResult: result,
});
break;
case Ci.nsIAutoCompleteResult.RESULT_FAILURE:
case Ci.nsIAutoCompleteResult.RESULT_IGNORED:
deferredFormHistory.resolve("Form History returned RESULT_FAILURE or RESULT_IGNORED");
break;
}
},
};
let formHistory = Cc["@mozilla.org/autocomplete/search;1?name=form-history"].
createInstance(Ci.nsIAutoCompleteSearch);
formHistory.startSearch(searchTerm, this.formHistoryParam || DEFAULT_FORM_HISTORY_PARAM,
this._formHistoryResult,
acSearchObserver);
return deferredFormHistory;
},
/**
* Fetch suggestions from the search engine over the network.
*/
_fetchRemote: function(searchTerm, engine, privateMode) {
let deferredResponse = Promise.defer();
this._request = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"].
createInstance(Ci.nsIXMLHttpRequest);
let submission = engine.getSubmission(searchTerm,
SEARCH_RESPONSE_SUGGESTION_JSON);
let method = (submission.postData ? "POST" : "GET");
this._request.open(method, submission.uri.spec, true);
if (this._request.channel instanceof Ci.nsIPrivateBrowsingChannel) {
this._request.channel.setPrivate(privateMode);
}
this._request.mozBackgroundRequest = true; // suppress dialogs and fail silently
this._request.addEventListener("load", this._onRemoteLoaded.bind(this, deferredResponse));
this._request.addEventListener("error", (evt) => deferredResponse.resolve("HTTP error"));
// Reject for an abort assuming it's always from .stop() in which case we shouldn't return local
// or remote results for existing searches.
this._request.addEventListener("abort", (evt) => deferredResponse.reject("HTTP request aborted"));
this._request.send(submission.postData);
return deferredResponse;
},
/**
* Called when the request completed successfully (thought the HTTP status could be anything)
* so we can handle the response data.
* @private
*/
_onRemoteLoaded: function(deferredResponse) {
if (!this._request) {
deferredResponse.resolve("Got HTTP response after the request was cancelled");
return;
}
let status, serverResults;
try {
status = this._request.status;
} catch (e) {
// The XMLHttpRequest can throw NS_ERROR_NOT_AVAILABLE.
deferredResponse.resolve("Unknown HTTP status: " + e);
return;
}
if (status != HTTP_OK || this._request.responseText == "") {
deferredResponse.resolve("Non-200 status or empty HTTP response: " + status);
return;
}
try {
serverResults = JSON.parse(this._request.responseText);
} catch(ex) {
deferredResponse.resolve("Failed to parse suggestion JSON: " + ex);
return;
}
if (this._searchString !== serverResults[0]) {
// something is wrong here so drop remote results
deferredResponse.resolve("Unexpected response, this._searchString does not match remote response");
return;
}
let results = serverResults[1] || [];
deferredResponse.resolve({ result: results });
},
/**
* Called when this._remoteResultTimer fires indicating the remote request took too long.
*/
_onRemoteTimeout: function () {
this._request = null;
// FIXME: bug 387341
// Need to break the cycle between us and the timer.
this._remoteResultTimer = null;
// The XMLHTTPRequest for suggest results is taking too long
// so send out the form history results and cancel the request.
if (this._deferredRemoteResult) {
this._deferredRemoteResult.resolve("HTTP Timeout");
this._deferredRemoteResult = null;
}
},
/**
* @param {Array} suggestResults - an array of result objects from different sources (local or remote)
* @return {Object}
*/
_dedupeAndReturnResults: function(suggestResults) {
if (this._searchString === null) {
// _searchString can be null if stop() was called and remote suggestions
// were disabled (stopping if we are fetching remote suggestions will
// cause a promise rejection before we reach _dedupeAndReturnResults).
return null;
}
let results = {
term: this._searchString,
remote: [],
local: [],
formHistoryResult: null,
};
for (let result of suggestResults) {
if (typeof result === "string") { // Failure message
Cu.reportError("SearchSuggestionController: " + result);
} else if (result.formHistoryResult) { // Local results have a formHistoryResult property.
results.formHistoryResult = result.formHistoryResult;
results.local = result.result || [];
} else { // Remote result
results.remote = result.result || [];
}
}
// If we have remote results, cap the number of local results
if (results.remote.length) {
results.local = results.local.slice(0, this.maxLocalResults);
}
// We don't want things to appear in both history and suggestions so remove entries from
// remote results that are already in local.
if (results.remote.length && results.local.length) {
for (let i = 0; i < results.local.length; ++i) {
let term = results.local[i];
let dupIndex = results.remote.indexOf(term);
if (dupIndex != -1) {
results.remote.splice(dupIndex, 1);
}
}
}
// Trim the number of results to the maximum requested (now that we've pruned dupes).
results.remote =
results.remote.slice(0, this.maxRemoteResults - results.local.length);
if (this._callback) {
this._callback(results);
}
this._reset();
return results;
},
_reset: function() {
this._request = null;
if (this._remoteResultTimer) {
this._remoteResultTimer.cancel();
this._remoteResultTimer = null;
}
this._deferredRemoteResult = null;
this._searchString = null;
},
};
/**
* Determines whether the given engine offers search suggestions.
*
* @param {nsISearchEngine} engine - The search engine
* @return {boolean} True if the engine offers suggestions and false otherwise.
*/
this.SearchSuggestionController.engineOffersSuggestions = function(engine) {
return engine.supportsResponseType(SEARCH_RESPONSE_SUGGESTION_JSON);
};