I had been happily using Java live reload while debugging my Vaadin application over the past few months.
Today, after I started my browser and directed it to my locally running Vaadin application I got a popup in the lower right corner stating:
Java live reload unavailable. Live reload for Java changes is currently not set up. Find out how to make use of this functionality to boost your workflow. Read more
Clicking onto the read more link (pointing to 'https://vaadin.com/docs/v14/flow/workflow/workflow-overview') just brings me to a "404 Page Not Found" error page.
So - two or actually three questions:
what could cause my live-reload functionality go missing? I am using MS Edge and the Live-reload plugin is enabled (and it used to work until yesterday).
where has the page gone explaining how to set that up?
and finally: Any idea, what to check or fix to get this working again? I consider that pretty essential functionality for efficient UI development!
For question 2, you can find the documentation here: https://vaadin.com/docs/v14/guide/live-reload
Related
I am building a static app with PouchDB on Google AppEngine.
When I open the site in a browser window, it is showing a version I uploaded several hours ago.
If I open the site in an incognito window, the updated version is displayed (therefore I don't think it is actually an error in the console).
I put a new version number in app.yaml
I have migrated all traffic to the new version.
I have cleared my cache, deleted cookies, checked my application data, everything. I even reinstalled Chrome and Firefox.
I updated my Python version and my Google AppEngine Launcher yesterday; the problem pre-dated that update.
Also: just discovered that if I go to the URL of the updated version
http://4.[app-id].appspot.com, it displays the correct, updated version.
This is happening in Chrome, Firefox, and Edge.
Edit: probably should have mentioned that my site uses Service Workers and IndexedDB. I assume my service workers are caching the previous version, but I would have thought that Ctrl + F5 would clear the cache and show the new version.
I think it must be the Service Workers caching the pages (which is, after all, what they are supposed to do). This is actually really annoying when you are developing though.
A guy called Rich Harris has documented this behaviour and some workarounds on a Github Gist.
Reloading the page doesn't behave as you'd expect
If you make a change to your service worker, then reloading the page
won't kill the old one and activate the new one (it detects the change
by requesting the service worker file each time and comparing the old
and the new byte-for-byte), leaving you somewhat confused as to why
your changes haven't taken effect. This is because the old window is
never actually closed, meaning there's never a time to swap them out –
you need to kill the tab completely then reopen it.
Or you can have the browser do that for you by going to the
Application tab in devtools (in Canary, not stable Chrome yet), going
to the Service Workers section, and checking 'Update on reload'.
UPDATE (13 Nov 2017): This functionality is now available in Chrome, so you don't even need to download Canary.
And here's which bits of the application cache to clear:
I'm having some serious issues with the Server Push support in Vaadin 7, and it's proving difficult to pin down the problem. I've followed all the steps in the Book of Vaadin on enabling server push, including adding the vaadin-push.jar file to WEB-INF/lib, adding the "asyncSupported = true" parameter to the #WebServlet annotation, and adding the #Push annotation to the UI class. (I've also tried specifying the equivalent in the deployment descriptor.) I also added the org.atmosphere.useWebSocketAndServlet3=true property to the catalina.properties file of my Tomcat 7 server, as suggested in https://vaadin.com/wiki/-/wiki/Main/Working%20around%20push%20issues.
I found the Server Push support to be very quirky, making it difficult to identify the problem. For instance, when developing code, the server will often not automatically re-start; only recognizing new code when I close the browser (not just the browser window), stop the server and re-start Eclipse; missing any of these steps will result in the Server Push not working. Note that this issue only occurs when Server Push is enabled. I read something about sessions not expiring when push is enabled (https://vaadin.com/forum#!/thread/3576361), so maybe that's the reason..
I often encounter suspicious log messages:
Mar 02, 2014 9:25:45 PM com.vaadin.server.communication.PushHandler$3 run
WARNING: Could not find push connection to close: 38450652-2a2b-4221-8300-8313e9c4779a with
transport WEBSOCKET
Mar 02, 2014 9:25:45 PM org.apache.catalina.loader.WebappClassLoader loadClass
INFO: Illegal access: this web application instance has been stopped already. Could not load
java.nio.ByteBuffer.
It does seem that the Atmosphere is finding the async support:
INFO: Atmosphere is using async support:
org.atmosphere.container.Tomcat7AsyncSupportWithWebSocket running under container: Apache
Tomcat/7.0.47
I also found this error; don't know whether it indicates a serious problem (haven't tried resolving it, since I don't want to get into the Atmosphere stuff):
WARNING: No BroadcasterCache configured. Broadcasted message between client reconnection will be
LOST. It is recommended to configure the org.atmosphere.cache.UUIDBroadcasterCache
That said, Firefox works quite well with the Server Push, while Chrome has problems and IE spews errors (surprise!). In particular, Chrome often takes quite a while to communicate a UI interaction (e.g., button push) to the server, whereby a spinner (changing color from yellow to orange to red) appears at the right top. IE simply updates the wrong UI components when multiple windows are open. So, as long as every user employs Firefox there's no problem, but I can't possibly assume that.
I came across this post, where developers vented their frustration on the feature: https://vaadin.com/forum#!/thread/4040408. This is quite a recent post, so it doesn't sound too promising.. The only reason I need the Server Push feature is to allow the ChatBox add-on (https://vaadin.com/directory/-/directory/addon/chatbox) to update in real-time.
Any ideas? Has anyone gotten these kinds of errors and managed to get some workaround? Or even better, has anyone gotten the ChatBox add-on to work with the Server Push?
Thanks,
William
Try Again
Web Push is still a young technology, especially the WebSocket variety. Tomcat for example replaced one WebSocket implementation with another. Vaadin’s adoption of the Atmosphere library and all the other work in Vaadin 7 are relatively new. Much has improved in the months following the posting of this Question. I suggest giving Push another try.
Use the latest versions of your web server. For example, both Tomcat 7 & 8 and Jetty have made significant changes in their support of Push and WebSocket.
Use the latest version of Java 8 and Vaadin (7.3.7 now).
No Need For setPollInterval
No need to call UI::setPollInterval as was mentioned in the comments above. That feature uses only one approach to Push.
All you need is the #Push annotation. And a Thread, or better, a ScheduledExecutorService to update the data for display in your app. Using the #Push annotation engages the Atmosphere library. Atmosphere tries multiple techniques of Push, starting with WebSocket, and automatically uses other techniques as a fall-back.
Working Example
I recently (2015-01) posted a working example of Push working in Vaadin 7.3.7 as an answer to another question. My example is purposely minimal, using a single file to replace the MyUI file’s content in a new default Vaadin app project.
Hi I'm sure i am doing something dumb! Fairly new to django and pycharm. I am learning by writing two projects: the tango with django one and another to test ideas and learning (about old girlfriends!).
I am working on the rango project. I've scheme-migrated, syncdb, migrate, debugged and no errors. But when i run server, the admin page shows the other project only. I have not worked on it today.
As far as I can tell I have all the right code including registering the models and admin.autodiscover plus i have cleared the cache.
SO the question is: which projects does it show on the admin page - all? How does it know?
Final odd point the windows circle on the site admin tab is still going round as though its looking for something else.
Many thanks for help. I haven't pasted any code as not sure what would be helpful.
I eventually realized that the admin server was still running. As laptops don't have a ctrl break key (and i couldn't find my Samsung mapping) i killed the server using task manager and all was fine.
I'm getting a weird error while trying to click on a Capybara Element
I'm using find(:xpath,"//a[contains(text(),'Connect')]").click
(find(:xpath,"//a[contains(text(),'Connect')]").present? return true)
the error I get is:
Selenium::WebDriver::Error::MoveTargetOutOfBoundsError Exception: Element cannot be scrolled into view:javascript:void(0);
i did some research and the only solution i found is that setting the selenium version to 2.16 may fix this issue (i'm using 2.25).
anybody got an idea?
It may happen when the page being tested is not fit into the current window size. If you know such pages where usually these error happening, you may explicitly scroll down before doing the operation on such hidden elements(like click, clear etc). Here the code to explicitly scroll down the page.
In java,
JavascriptExecutor js = (JavascriptExecutor) driver;
js.executeScript("javascript:window.scrollBy(250,350)");
From the times I used selenium webdriver to test .NET apps, I would get that error when the issue was exactly what it sounds like: It's looking for an object on the page that it cant scroll to for some reason. In my case it was because some dialogue boxes would appear without scrollbars and the driver had no way to "scroll the object into view"
Can you watch the execution of your test and see if that's the case? I had some luck rolling back to a previous version of firefox because 15+ was (as of about 2 months ago when I had the issue) unsupported by web driver and had this problem periodically. Rolling back selenium versions may help too.
First step though is definitely to watch the execution of the test and see whats happening though. And a good debugging idea may be to try to work through your steps manually yourself to make sure the test works by hand.
Its also worth noting that for the webdriver to be able to execute click the object actually has to be visible. IsPresent doesnt require that, it just searches the page files. Also an issue I ran into. IsPresent will still return true for objects that are not and cannot be made visible on the page (i.e. something at the bottom of the page that you cant see at the time)
Couple of tips here:
Webdriver should ideally be on the most recent update, it's what most use (Unless you're doing Ruby Automation)
Use css selectors, xpath (Whilst rendered), is almost always heavier on both resources and code.
Try defensive coding, first of all ascertain it exists. There are many ways to do that dependent on what package you are using. In ruby you would do page.has_css?('css_string')
Quite not sure why I see this error.
I navigate to my Login View like so http://test.staging.com/mywebsite/Login
My Login view was just redone using MVC but I have seen this same error message going to an aspx page as well...
If I use http I get the error message The specified request cannot be executed from current Application Pool.
If I use https://test.staging.com/mywebsite/Login, I'm good.
If I don't specify a protocol, test.staging.com/mywebsite/Login, I get the error as well
Is there an error happening under the covers and my custom error page can't be shown like discussed here?
What are some other causes of this error?
That usually means your custom errors are configured to run as a different AppPool.
You can read more at MSDN. (See section "Using Custom Errors from Another Application Pool").
There are two ways to correct this behavior. The first is possibly not one that you are interested in because it would require you to change your current architecture and run both sites in the same application pool (such as share the same worker process memory space). To do this, simply move the /errors virtual directory to run in the same application pool as the site for which it serves the custom error.
The second way is to make use of a registry key provided by IIS 6.0. This registry key makes sure IIS 6.0 does not check the metadata during the execution of the custom error and therefore allowing this to work.
See the article for information on the registry key fix.
It may also mean that you are using something along the lines of Server.Transfer to a page that is in a different AppPool.
It could be because you're using different versions of ASP.NET for one or many apps in the pool.
Make sure all apps in the pool use the same version of ASP (e.g. ASP 2.0.50727)
If you just added a new app, try changing the app momentarily to a different version of ASP, then back to same version. I experienced an issue where the displayed version was correct, but under the hood, a different version was used!
Check your event log, under Application, to get more details about the error.
The message would be caused by your page server-side redirecting to a page served by another application pool. Such as for example, in your link, the error page.
I know this is an old thread, but I stumbled upon it and found a different solution. Here's what worked for me: Make sure your application handles .asmx files correctly
From IIS:
Right Click on your project > Properties > Configuration
If necessary, add the .asmx file extension that maps to the aspnet_isapi.dll
Limit to: "GET,HEAD,POST,DEBUG" and restart.
Because I can't comment on vcsjones's answer, I'll add it down here. The DWORD value IgnoreAppPoolForCustomErrors needs to be set under HKLM\SYSTEM\CurrentControlSet\Services\W3SVC\ Parameters vs HKLM\SYSTEM\CurrentControlSet\Services\W3SVC referenced in that technet article. Set it to 1 and do an iisreset and you're good to go.
Source Blog Post
In my particular case, I received this error while trying to serve a content (non ASP.NET) website while it was an Application. Right-Clicking the virtual folder and removing the application fixed it for me.
In my case the application used the application pool that didn't exist. I have no idea how it's happened.