我在标题中所说的仅在 chrome 中发生,因为在 firefox 中“(导航器中的'serviceWorker')”总是错误的,并且“console.warn('此浏览器不支持服务工作者。');” 而是触发。
如果您清除浏览器或运行隐身模式,那么它最初可以工作,但是当您第一次注销然后重新登录时,问题就开始了。
这是我在其中注册 SW 的代码:
function activateSW(){
if('serviceWorker' in navigator){
if(window.location.pathname != '/'){
//register with API
if(!navigator.serviceWorker.controller) navigator.serviceWorker.register('/service-worker', { scope: '/' });
//once registration is complete
navigator.serviceWorker.ready.then(function(serviceWorkerRegistration){
//get subscription
serviceWorkerRegistration.pushManager.getSubscription().then(function(subscription){
//enable the user to alter the subscription
$('.js-enable-sub-test').removeAttr("disabled");
//set it to allready subscribed if it is so
if(subscription){
$('.js-enable-sub-test').prop("checked", true);
$('.js-enable-sub-test').parent().addClass('checked');
}
});
});
}
}else{
console.warn('Service workers aren\'t supported in this browser.');
}
}
'/service-worker' 是一个发送到 index.php 的请求(通过 .htaccess)。它最终以这个函数结束:
function serviceworkerJS($params){
$hash = API::request('settings', 'getSWHash', '');
if($hash != false){
setcookie('SW_Hash', $hash, time() + (86400 * 365 * 10), "/");
header('Content-type: text/javascript');
echo "'use strict';
var hash = '".$hash."';";
include(ROOT_PATH.'public/js/service-worker.js');
}elseif(isset($_COOKIE['SW_Hash'])){
header('Content-type: text/javascript');
echo "'use strict';
var hash = '".$_COOKIE['SW_Hash']."';";
include(ROOT_PATH.'public/js/service-worker.js');
}else{
header('HTTP/1.1 404 Not Found');
}
}
在 chrome://serviceworker-internals/ 中看到的 Service-worker.js 看起来像这样:(对地址的几个引用已被星号替换)
'use strict';
var hash = 'bd8e78963deebf350f851fbf8cdc5080';
var *****_API_ENDPOINT = 'https://*********.***/';
//For displaying notifications
function showNotification(title, body, icon, data, id) {
var notificationOptions = {
body: body,
icon: icon,
tag: id,
data: data
};
//possibly unnecessary
if(self.registration.showNotification){
return self.registration.showNotification(title, notificationOptions);
}else{
return new Notification(title, notificationOptions);
}
}
//asks the server for messages and sends them for displaying.
function getMessages(event){
//showNotification('debug', 'initial', '', '', 'debug1');
//build question
var FD = new FormData();
FD.append('hash', hash);
//ask start20 for the notifications
event.waitUntil(
fetch(*****_API_ENDPOINT + 'ajax-get-SW-notification/', {method: 'post', body: FD}).then(function(response){
//something went wrong
if (response.status !== 200){
console.log('Error communicating with ******, code: ' + response.status);
showNotification('debug', 'picnic', '', '', 'debug2');
throw new Error();
}
//decode the response
return response.json().then(function(data){
var len = data.notifications.length;
//showNotification('debug', len, '', '', 'propertyName');
//Display
for(var i = 0; i < len -1; i++){
showNotification(data.notifications[i].title,
data.notifications[i].body,
data.notifications[i].imageurl,
data.notifications[i].linkurl,
data.notifications[i].hash);
}
//the last one needs to be returned to complete the promise
return showNotification(data.notifications[len -1].title,
data.notifications[len -1].body,
data.notifications[len -1].imageurl,
data.notifications[len -1].linkurl,
data.notifications[len -1].hash);
});
})
);
}
//when the user installs a new SW
/*self.addEventListener('activate', function(event){
//getMessages(event);
//event.preventDefault();
event.waitUntil(return self.registration.showNotification('bicnic', { body: '*p' }));
});*/
//when the serviceworker gets a puch from the server
self.addEventListener('push', function(event){
getMessages(event);
event.preventDefault();
});
//get the link associated witht he message when a user clicks on it
self.addEventListener('notificationclick', function(event){
//ask if the notification has any link associated with it
var FD = new FormData();
FD.append('hash', event.notification.tag);
//get the link
event.waitUntil(
fetch(******_API_ENDPOINT + 'ajax-notification-has-link/', {method: 'post', body: FD}).then(function(response){
//something went wrong
if (response.status !== 200){
console.log('Error communicating with ********, code: ' + response.status);
return;
}
//decode the response
return response.json().then(function(data){
//if there's a link associated with the message hash
if(data.link){
console.log(******_API_ENDPOINT + 'notification-link/' + event.notification.tag);
return clients.openWindow(*****_API_ENDPOINT + 'notification-link/' + event.notification.tag);
}
});
})
);
});
//unnecessary?
/*self.addEventListener('install', function(event){
//event.preventDefault();
});
self.addEventListener("fetch", function(event) {
});//*/
现在,如果您注释掉“if(!navigator.serviceWorker.controller) navigator.serviceWorker.register('/service-worker', { scope: '/' });” 然后问题消失了,但是订阅和取消订阅的服务人员停止工作。(if 语句似乎没有多大作用,只是为了解决这个问题而添加的)
我已经尝试了许多具有不同条件的 activateSW() 版本来运行不同的表达式,并且没有设法制作一个在不破坏 serviceworker 的情况下工作的版本。我还尝试在各个点(注册、帖子)上捕获错误,但这没有成功,因为它们都没有抛出任何错误。
我怀疑可能是问题在于,当您注册服务人员时,会触发激活事件。现在,如果您抓住了这一点并完成了事件承诺,那么您将无法订阅。但是,我怀疑服务人员在您注销时仍然处于活动状态,这会导致问题。
如果您有疑问或想查看更多代码,请询问。
编辑; 这是解决方案:
self.addEventListener("fetch", function(event) {
event.respondWith(
fetch(event.request)
);
});