以下代码的作用如下:
转到数据库中的表并检索我将发送给Google API的一些搜索条件(PHP文件为getSearchSon.php)
获得结果后,我想绕过它,调用Google API(searchCriteriasFuc)并将结果存储在数组中
代码的最后一部分是使用Google API(updateSearchDb.php)返回的结果对两个不同的表进行更新
在我的代码中,我在一些我不喜欢的场合使用setTimeout。而不是使用setTimeout,我想以更有效的方式正确使用回调函数(这可能是我的问题的原因)我这样做的最佳方式是什么?
$(document).ready(function() {
$.ajax({
url: 'getSearchSon.php',
type: 'POST',
async: true,
dataType: 'Text',
/*data: { }, */
error: function(a, b, c) { alert(a+b+c); }
}).done(function(data) {
if(data != "connection")
{
var dataSent = data.split("|");
var search_criterias = JSON.parse(dataSent[0]);
var date_length = dataSent[1];
var divison_factor = dataSent[2];
var length = search_criterias.length;
var arrXhr = [];
var totalResultsArr = [];
var helperFunc = function(arrayIndex)
{
return function()
{
var totalResults = 0;
if (arrXhr[arrayIndex].readyState === 4 && arrXhr[arrayIndex].status == 200)
{
totalResults = JSON.parse(arrXhr[arrayIndex].responseText).queries.nextPage[0].totalResults;
totalResultsArr.push(totalResults);
}
}
}
var searchCriteriasFuc = function getTotalResults(searchParam, callback)
{
var searchParamLength = searchParam.length;
var url = "";
for(var i=0;i<searchParamLength;i++)
{
url = "https://www.googleapis.com/customsearch/v1?q=" + searchParam[i] + "&cx=005894674626506192190:j1zrf-as6vg&key=AIzaSyCanPMUPsyt3mXQd2GOhMZgD4l472jcDNM&dateRestrict=" + date_length;
arrXhr[i] = new XMLHttpRequest();
arrXhr[i].open("GET", url, true);
arrXhr[i].send();
arrXhr[i].onreadystatechange = helperFunc(i);
}
setTimeout(function()
{
if (typeof callback == "function") callback.apply(totalResultsArr);
}, 4000);
return searchParam;
}
function callbackFunction()
{
var results_arr = this.sort();
var countResultsArr = JSON.stringify(results_arr);
$.ajax({
url: 'updateSearchDb.php',
type: 'POST',
async: true,
dataType: 'Text',
data: { 'countResultsArr': countResultsArr },
error: function(a, b, c) { alert(a+b+c); }
}).done(function(data) {
var resultsDiv = document.getElementById("search");
if(data == "NORECORD") resultsDiv.innerHTML = 'Updated failed. There was a problem with the database';
else resultsDiv.innerHTML = 'Update was successful';
}); //end second ajax call
}
//llamando funcion principal
var arrSearchCriterias = searchCriteriasFuc(search_criterias, callbackFunction);
}
else
{
alert("Problem with MySQL connection.");
}
}); // end ajax
});
答案 0 :(得分:2)
回调是过去的事情。现在,您使用Promise
来表示异步任务的结果值。这是一些未经测试的代码:
$(document).ready(function() {
$.ajax({
url: 'getSearchSon.php',
type: 'POST',
async: true,
dataType: 'text'
/*data: { }, */
}).then(function(data) {
if (data == 'connection') {
alert("Problem with MySQL connection.");
} else {
var dataSent = data.split("|");
var search_criterias = JSON.parse(dataSent[0]);
var date_length = dataSent[1];
var divison_factor = dataSent[2];
return Promise.all(search_criterias.map(function(criteria) {
return $.ajax({
url: "https://www.googleapis.com/customsearch/v1"
+ "?q=" + criteria
+ "&cx=005894674626506192190:j1zrf-as6vg"
+ "&key=AIzaSyCanPMUPsyt3mXQd2GOhMZgD4l472jcDNM"
+ "&dateRestrict=" + date_length,
type: 'GET'
});
})).then(function(totalResultsArr) {
totalResultsArr.sort();
var countResultsArr = JSON.stringify(totalResultsArr);
return $.ajax({
url: 'updateSearchDb.php',
type: 'POST',
async: true,
dataType: 'text',
data: { 'countResultsArr': countResultsArr },
error: function(a, b, c) { alert(a+b+c); }
});
}).then(function(data) {
var resultsDiv = document.getElementById("search");
if(data == "NORECORD") {
resultsDiv.innerHTML = 'Updated failed. There was a problem with the database';
} else {
resultsDiv.innerHTML = 'Update was successful';
}
});
}
}).then(null, function() {
alert('Some unexpected error occured: ' + e);
});
});
您可以使用async / await。
$(document).ready(async() => {
try {
var data = await $.ajax({
url: 'getSearchSon.php',
type: 'POST',
async: true,
dataType: 'text'
/*data: { }, */
});
if (data == 'connection') {
alert("Problem with MySQL connection.");
} else {
var dataSent = data.split("|");
var search_criterias = JSON.parse(dataSent[0]);
var date_length = dataSent[1];
var divison_factor = dataSent[2];
var totalResultsArr = await Promise.all(
search_criterias.map(criteria => $.ajax({
url: "https://www.googleapis.com/customsearch/v1"
+ "?q=" + criteria
+ "&cx=005894674626506192190:j1zrf-as6vg"
+ "&key=AIzaSyCanPMUPsyt3mXQd2GOhMZgD4l472jcDNM"
+ "&dateRestrict=" + date_length,
type: 'GET'
}))
);
totalResultsArr.sort();
var countResultsArr = JSON.stringify(totalResultsArr);
var data2 = await $.ajax({
url: 'updateSearchDb.php',
type: 'POST',
async: true,
dataType: 'text',
data: { 'countResultsArr': countResultsArr },
error: function(a, b, c) { alert(a+b+c); }
});
if(data2 == "NORECORD") {
resultsDiv.innerHTML = 'Updated failed. There was a problem with the database';
} else {
resultsDiv.innerHTML = 'Update was successful';
}
}
} catch(e) {
alert('Some unexpected error occured: ' + e);
}
});
2016年更新
不幸的是async/await
提案最终没有达到ES7规范,所以它仍然是非标准的。
答案 1 :(得分:0)
要在Google调用完成后执行回调,您可以更改:
var requestCounter = 0;
var helperFunc = function(arrayIndex)
{
return function()
{
if (arrXhr[arrayIndex].readyState === 4 && arrXhr[arrayIndex].status == 200)
{
requestCounter++;
totalResults = JSON.parse(arrXhr[arrayIndex].responseText).queries.nextPage[0].totalResults;
totalResultsArr.push(totalResults);
if (requestCounter === search_criterias.length) {
callbackFunction.apply(totalResultsArr);
}
}
}
}
然后删除searchCreteriaFuc上的setTimeout。
考虑使用promises和Promise.all来更清洁:D
答案 2 :(得分:0)
你可以在下面的事情中重新格式化你的getTotalResults函数,然后它会搜索相当顺序,但它也应该通过额外的回调来返回结果。
'use strict';
function getTotalResults(searchParam, callback) {
var url = "https://www.googleapis.com/customsearch/v1?q={param}&cx=005894674626506192190:j1zrf-as6vg&key=AIzaSyCanPMUPsyt3mXQd2GOhMZgD4l472jcDNM&dateRestrict=" + (new Date()).getTime(),
i = 0,
len = searchParam.length,
results = [],
req, nextRequest = function() {
console.log('received results for "' + searchParam[i] + '"');
if (++i < len) {
completeRequest(url.replace('{param}', searchParam[i]), results, nextRequest);
} else {
callback(results);
}
};
completeRequest(url.replace('{param}', searchParam[0]), results, nextRequest);
}
function completeRequest(url, resultArr, completedCallback) {
var req = new XMLHttpRequest();
req.open("GET", url, true);
req.onreadystatechange = function() {
if (this.readyState === 4 && this.status == 200) {
var totalResults = JSON.parse(this.responseText).queries.nextPage[0].totalResults;
resultArr.push(totalResults);
completedCallback();
}
};
req.send();
}
getTotalResults(['ford', 'volkswagen', 'citroen', 'renault', 'chrysler', 'dacia'], function(searchResults) {
console.log(searchResults.length + ' results found!', searchResults);
});
但是,由于您已经在代码中使用了JQuery,因此您还可以构造所有请求,然后使用JQuery.when功能,如本问题中所述