I am making a chrome extension that fetched JSON data from CoinMarketCap.com API and currently I have it running in the background script. I'm not 100% sure what the purpose of the page is really. I was wondering if I could simply fetch the data from the popup script after I click a button within my popup?
Each button represents a different coin. I basically want to get the price of a chosen coin and display it on whatever page the user is on when they double click the coin in a text article. Eventually I want to make it so you can double click any coin and have it show a live price conversion while you're on the web-page.
The point of a background page is to be always available (running if persistent: true, woken up / recreated for registered events if persistent: false).
A popup's lifetime is determined by its visibility. The moment the user clicks away and closes it, the page is closed (as if the tab with it was closed), so it can no longer process any events and its state is lost.
As long as:
The data you need fetched is to be received/processed while the popup is open
Any state you need to persist between popups being shown can be stored in chrome.storage
Then you don't need the background page to do the fetching. Popup page has the same level of access to Chrome APIs.
However, consider this scenario: suppose you want the data to be ready as soon as popup is opened (at least, you want it to be fresher than "since last time"). You may want to do periodic updates even while the popup is closed to refresh the data. You can only do that reliably with a background page (and, say, chrome.alarms API). Then you can cache the latest available data in chrome.storage and use that in the popup.
Background pages have their uses as some code that can run periodically regardless of user actions, and to be able to always react to events.
According to Changes to Cross-Origin Requests in Chrome Extension Content Scripts now you have to do your fetches in Background Script. Not in Content Script.
Related
Sorry for cumbersome title, couldn't come up with more descriptive one.
The problem is when opened tab is left without user activity, for example user switched to another screen, Chrome stops rendering changes on that tab. Looks like any background activity is put on hold which is great from perspective of saving power and resources. But if user still needs to see all live updates what is the way to prevent tab to go to 'idle' state despite of having no user activity?
I was looking into chrome.idle API but it doesn't say how to prevent, only how to check.
My web application is mimicing the UI of my desktop application, flow is as follows
Select Task in browser window
Change any Options and then start
Show Progress in same browser window, the progress bar goess back to server every 5 seconds checking progress.
When task has completed we show report in new tab
and go back to Select task Window,
this is done by running following Javascript in progress page
window.open('/start','_self'); window.open('/reporturl','_blank');
This works fine on my PC but when trying on Safari on OSX and on Android phone and iPad one of two things happen
The progress page becomes the start page but the report page is not opened in tab
The Progress page becomes the report page
My question is does opening window in new tab with _blank have all the problems of using popup windows. If so should I modify my prcoess so that at stage 3 it just displays report page, and then add a back button or navigable footer to the report to allow user to get back to start page ?
I can think of some options you could use instead of new tab.
Modal with Ajax
-- With jQuery it is posible to open modal
dialogs they can be populated with html (or other data) fetched with ajax (async). I am a big fan of these and use them all over my projects. Users will not be annoyed with pop-up warning messages, etc. Once the content is read (or whatever) the user can simply close the dialog. (If I had to make your app I would certainly implement this).
Besides the jQuery dialogs, other modal/dialog scripts are out there. Check out Bootstrap Modal if you like it modern.
Serve report as download
-- Depending on what the user can/will do with the report, it might be interesting to write the report page in a way that it sends back a .pdf file, or another type of file, as download. Loading the URL in a new tab will now always start a download. Triggering this from JS without user interaction might be a problem though (same as with pop-up / new tab). Adding a button to trigger the download on complete will solve this.
I know the question was about the use of tabs.. But try to avoid it. Browsers handle it all in their own way. And many users get confused when suddenly stuff is opening in tabs when they did not ask for it. In case of pop-ups, it is possible for users to turn them of or convert into opening a new tab from within the browser settings. If they have been fiddling with browser defaults, you'll have troubles of keeping the 'flow' of the app the same for all users (and cross browser).
I'm building a Google Chrome extension at the moment and I have a question about when to use an event page.
A quick look at the Chrome extension docs shows that Google really want its developers to use event pages, if possible.
My extension currently uses a background page, but I was wondering if I should switch to an event page?
This is what my extension does:
When matched with a particular website, it injects a script that adds buttons for the user to access extra functionality.
Most of this extra functionality consists of doing fairly computationally expensive operations on user-entered data - this is all done in the background page (it is all it does).
When a user wants to run these operations on their data they press a button and this passes a message, from the injected script to the background page, which then passes a message back containing the results of its operations.
Essentially, all the background page is doing is waiting for message passing from an injected script in one particular website and then running some operations. Since it doesn't need to be active all the time, this suggests that I should be using an event page.
Can anyone confirm if this would be a good idea for me? Or are there reasons why I should stick to a background page?
Allowing the background page to suspend (chrome.runtime.onSusend) is great, because it will free up system resources. The page will automatically be launched when a matching event happens (chrome.tab.onUpdated etc). I can't think of any compelling reason to use a persistent background page. You can always store any long term state in chrome.storage.local or indexedDb, etc.
Is there any way to completely duplicate the state of a current tab in Google Chrome? I want an exact copy of the current state of the page without having to reload the page in another tab.
An example use case:
While browsing a "slideshow" on a news website, I want to preserve the current slide that I'm on, but create a duplicate so that I can continue viewing the next slide. If I simply Right-Click and "Duplicate" the tab, the new page will completely Reload, reprocessing all of the Javascript and running the pre-slideshow advertisement again.
In short "NO" you can't.
I am not expert on this
but a similar behavior can be achieved in some ways i know :
Dump the whole DOM
Never tried this though. You can convert the DOM to a string, pass it to the new window and then parse it as a document. This will let you lose your DOM events and State manipulation javascript. (But that's good for your case)
var dtab = window.open('about:blank', 'duplicate_a_tab');
dtab.document.open();
dtab.document.write("... yout html string ..");
dtab.document.close();
Develop an extension
Let the users continue on the current tab with the current state, your extension should be able to capture the screenshot of that area and open that screenshot in new tab. There are plenty of screenshot taking extensions are available in the market.
If that website is your own
You can develop your services that uses state locally like progressive web apps. Give a link separately to 'duplicate' which will eventually open the same URL in different tab with the same local state and with the flag do-not-sync.
This will not work when the user uses browser inbuilt duplicate
feature.
So I am running into an issue. I have certain fields that I store within the request from page to page, because each page requires different fields to be populated within a collector that I used cross-page. The problem is the back button.
If I click the link to take my to my login page, the server populates the collector from the request with the appropriate pagename and event name, etc., to allow me to navigate to the login page. (Certain things have to load, so it has to go through a servlet). However, on that page, there are static modules for ads and whatnot, so clicking on one of the ads will take you to a separate, static page that does not require these attributes to access. In Chrome, Safari and FF, if I click the back button after accessing this static page, the browser asks me to reload the request to be able to view the page. In IE8, however, there is no page reload. It just kicks me back to the page, and does not populate the request, and it crashes with my sorry page.
I need to know if there is a way to populate the request on the back button click, and how to do so. Otherwise, my servlet is throwing a null pointer when trying to access the fields because they are all null in the request. Any help would be greatly appreciated. I am not even sure if this is at all possible.
I guess you are using POST requests to navigate to each page. POST should be used only to send some user action different from page view - login, buying something, changing settings, etc. The browsers require the user to confirm that they want to revisit a page using POST, before that implies state change. See What is the difference between POST and GET?
For simple content pages, where the user does not take action, it's better to use GET requests. Also, it is much more common to use request.getSession() to get and store the user fields on the server side. That is, you only send them once, and then look them up for each request. Look up for tutorials on session tracking in java.