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[英]How do I redirect to error page after receiving status 404 from API call in React?
[英]Node http server, receiving a 404 after first api call
您好,我正在嘗試創建一個使用API獲取公交車發車時間的網站。 它第一次成功調用api,並接收正確的信息。 但是,當我嘗試實現刷新功能時,我首先收到以下錯誤消息。
跨源請求僅支持以下協議方案:http,數據,chrome,chrome擴展名,https。
解決此問題的方法應該是啟動本地服務器,因此我通過使用node和“ http-server -c-1”命令來完成此操作。 可以通過localhost訪問該網站,但不會刷新。 我收到以下錯誤。
“ GET http:// localhost:8080 / undefined 404(未找到)”(Dev工具說該錯誤發生在第12行)
的HTML
HTML`<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8"/>
<title>Tider</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
<h1 id="Resa">Resa</h1>
<p id="UpdatedP"></p>
<div id="OriginDiv">
<ul id= "OriginList">
<li>Från</li>
</ul>
</div>
<div id="DestinationDiv">
<ul id="DestinationList">
<li>Mot</li>`enter code here`
</ul>
</div>
<div id="TimeDiv">
<ul id="timeList"><li>Avgång</li></ul>
</div>
<div id="FrammeDiv">
<ul id="FrammeList">
<li>Framme</li>
</ul>
</div>
<button type="button" onclick="httpGetAsync()">Uppdatera</button>
<script src="ApiScript.js"></script>
</body>
</html>`
JS
var url = "https://api.resrobot.se/v2/trip?key=XXXXX&originId=XXXXX&destId=XXXXXX&format=json";
httpGetAsync(url, displayResponse);
function httpGetAsync(theUrl, callback) {
console.log("httpGetAsync running...");
var xmlHttp = new XMLHttpRequest();
xmlHttp.onreadystatechange = function() {
if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
callback(xmlHttp.responseText);
};
xmlHttp.open("GET", theUrl, true); // true for asynchronous
xmlHttp.send(null);
setTimeout(httpGetAsync, 3000);
}
function checkIfArray(x) {
console.log("CheckIfArray running...");
var returnval = Object.prototype.toString.call(x) == '[object Array]'
return returnval;
}
function CreateElement(input, ElType) {
var liElement;
var textNode;
var HTMLElement;
if (ElType == "origin") {
HTMLElement = document.getElementById("OriginList");
} else if (ElType == "destination") {
HTMLElement = document.getElementById("DestinationList");
} else if (ElType == "time") {
HTMLElement = document.getElementById("timeList");
} else if (ElType == "framme") {
HTMLElement = document.getElementById("FrammeList");
}
liElement = document.createElement("li");
textNode = document.createTextNode(input);
liElement.appendChild(textNode);
HTMLElement.append(liElement);
}
function updated(){
console.log("updated running...");
var date = new Date();
var returnTime = 0;
returnTime = "Uppdaterad: " +date.getHours() +":"+ date.getMinutes();
var HTMLElement = document.getElementById("UpdatedP");
var timeElement = document.createElement("p");
var UpdateNode = document.createTextNode(returnTime);
timeElement.appendChild(UpdateNode);
HTMLElement.append(timeElement);
}
function displayResponse(data) {
console.log("displayResponse running...");
var ResultObj = JSON.parse(data);
//console.log("DATA: " + data);
//console.log("TestObj: " + ResultObj.Trip[0].LegList.Leg[0].Origin.name);
//console.log("More TIme: " + ResultObj.Trip[1].LegList.Leg[0].Origin.time);
if (checkIfArray(ResultObj.Trip)) {
for (var i = 0; i < ResultObj.Trip.length; i++) {
//console.log("Origin " + i + ": " + ResultObj.Trip[i].LegList.Leg[0].Origin.name);
CreateElement(ResultObj.Trip[i].LegList.Leg[0].Origin.name, "origin");
}
for (var i = 0; i < ResultObj.Trip.length; i++) {
CreateElement(ResultObj.Trip[i].LegList.Leg[0].Destination.name, "destination");
}
for (var i = 0; i < ResultObj.Trip.length; i++) {
CreateElement(ResultObj.Trip[i].LegList.Leg[0].Origin.time.substring(0,5), "time");
}
for ( var i =0; i<ResultObj.Trip.length; i++){
CreateElement(ResultObj.Trip[i].LegList.Leg[ResultObj.Trip[i].LegList.Leg.length-1].Destination.time.substring(0,5), "framme");
}
}
}
function checkArray(x) {
var returnval = Object.prototype.toString.call(x) === '[object Array]';
return returnval;
}
創建“刷新”計時器時,您正在調用不帶任何參數的httpGetAsync
。
這行:
setTimeout(httpGetAsync, 3000);
將每3秒調用httpGetAsync()
。 因此,您將每三秒鍾向http://localhost:8080/undefined
發送一個XMLHttpRequest
。
設置超時時,請在閉包中包含正確的參數。
setTimeout(function(){
httpGetAsync(theUrl,displayResponse);
},3000);
或在setTimeout()
調用中包含參數(此處有更多詳細信息: MDN Web文檔:setTimeout ):
setTimeout(httpGetAsync,3000,theUrl,displayResponse);
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