I have a Google Apps Script bound to a Google Sheet, and have published that as a Web App. It is restricted to a certain Google Workspace. That Google Sheet is kind of an improvised database for that web app and changes over time. I would like to send the updated data to all clients once the Google sheet gets changed. Is that possible? I don't need a trigger for the edit, since I know in the script when I add new data, so this is the time to send the new data.
Basically the same question can be formulated as follows: We know that we can execute a server-side function from the client with google.script.run, but is it also possible to execute a client-side function from the server i.e. the apps script?
My current workaround is a client-side setInterval which checks for server-side updates (and fetches them using successHandler) every 30 seconds or so. It works, but is not optimal.
Just to mark this one as answered. Cooper writes in the comments:
"It's not possible to execute a client side function from the server unless it has been first initiated by the client and it's responding with a callback. Polling is your only option I think."
Related
Theres a ton of videos and websites trying to explain backend vs frontend, but unfortunately none of them explains it in a way that you know how to develop a backend - driven website (at least I haven't found anything good).
So, I wanted to ensure that I understood it and kindly ask you to confirm or correct me on this topic.
Example:
I wanted to build Mini - Google. I have a Database containing 1000 stored websites.
Assumption #1:
Everytime I type something into the search bar, the autofill suggestions change. This means, everytime i type, another website / API gets called returning the current autofill suggestions. On a developer site, this means the website e.g. is a Python script which gets called with the current word typed in as a Parameter and is returning all suggestions as e.g. JSON:
// Client Side Script
function ontype(input):
suggestions = get("https://api.googlemini.com/suggestions?q=" + str(input))
show(suggestions)
Assumption #2:
This also means I could manually call the website containing the Python script, providing a random word and it would always return a JSON containing the autofill suggestions for that word.
Question #1:
If A#1 turns out true but A#2 turns out false, how could I prevent a user from randomly accessing the "API" while still returning results when called by a script?
Assumption #3:
After pressing enter, my website googlemini.com/search?... would be called. As google.com/search reloads everytime searching for a new query (or going to page 2 etc.), I assume, instead of calling an API, when the server gets the client request, it first searches through its database, sorts the results and then returns a whole html as a static webpage:
// Server Side Script
#app.route("/search")
function oncall():
query = getparam("q")
results = searchdatabase(query)
html = buildhtml(results)
return html
Question #2:
Often, I hear (or at least understand it this way) that database and webserver are 2 seperate servers. How would that work? Wouldn't that mean the database server needs to be accessible to the web too (of course it would have security layers etc., but technically it would)? How could I access the database server from the webserver?
Question #3:
Are there, on a technical basis, any other ways to build backend services?
That's it. I would also appreciate any recommendations like videos, websites or others to learn how to technically setup and / or secure backend servers.
Thanks in advance.
For your first question you can yes there is a way to prevent miss use.
What you can do is add identifier to api like Auth token to identify a user and every time a user access the api you can save the count on the server n whenever the count has exceeded a limit within a time span you can reject the call. And the limit can be set in such a way that it doesn't trouble the honest user and punishes the wrong one. There are even more complex and effective methods but this is the basic idea.
For question number to let me explain you a simple concept a database is a very efficient, resourcefull and expensive data storage solution we never want it to be used in a general sense as varible store or something. We always want to access the database in call get the data process the data update the data. So we do it data way and its not necessary you make sepreate server for data base. The thing is we mostly make databse to be accessible to various platforms android, ios, windows. So its better to add some abstraction and keep data base as a separte entity.
For the last, I am not well aware about what you meant by other but I am listing some backend teechnologies, some of these might be used in isolation some of these not some other tools as well.
Django
FLask
Djnago rest
GraphQL
SQL
PHP
Node
Deno
We integrated Office Online Server in our web application and in the WOPI web integration we are setting File URL properties such as FileUrl. This URL points to /wopi/files/{file_id}/contents link and internally, it will call the API once we start editing the document.
From this API, we are updating the file version but the issue is that after editing the WOPI document, the triggering of the API /wopi/files/{file_id}/contents is taking a long time and we are unable to find how it is getting triggered? Is there a way we can trigger this method directly?
So if I get it right it takes a long time BEFORE the /wopi/files/{file_id}/contents endpoint is hit.
In such a case, I'd recommend four things:
Run the WOPI host in a debug mode and trigger the endpoint from the OOS machine manually and see if there are any delays related to the network infrastructure.
Checking whether you set the WOPI host capabilities right in the CheckFileInfo. If you set the WOPI Client's expectations incorrectly, it may take time for it to figure out what's going on and potentially fall back to a different method.
Using the WOPI validator app
Checking the event viewer for any errors related to a specific Session ID and Correlation ID
We have a GWT based thick client like web application. The application is considerably large and has some initial load time.
We would like to send the users of our application e-mail messages with href links that would open up a specific asset in our application. Well this of course has the effect that clicking the link opens up the application again, reloads it which we would like to avoid. Ideally we would like the href link to just signal our application/web page somehow so that we could pick up the event in our application and react to it.
Any ideas how we should approach this or is this even possible ?
Thanks!
You need to use a GWT Hyperlink which is a widget that serves as an "internal" hyperlink. That is, it is a link to another state of the running application. When clicked, it will create a new history frame using History.newItem(java.lang.String), but without reloading the page.
If you are not already using it, information is here on GWT's History mechanism
There seems not to be any elegant solution to send an event from a link to an existing browser window. Few solutions I have encountered this far:
a) Implement a cookie polling solution for the application to poll if a cookie exists or changes. The link points to our server which just sets the cookie and this way informs the running app about the event. Some tricky handling should be implemented with some kind of 2-way protocol between the returned temporary page from server to handle the situation where the application is not (yet) running.
b) The same approach as in solution a) but use html5 local storage for communication. This way the poller is not needed as the local storage fires an event when content changes. This would be a possible solution but is not for me as we have to support older browsers without local storage support.
c) A long polling ajax or a web socket for delivering events from the server to the client. A solution but seems overkill and might require a modern browser for atleast web sockets.
I am very new to backbone.js (and MVC with javascript), and while reading several resources about backbone.js to adopt it in my project, I now have a question: how can I detect when multiple users(browsers) attempt to update? (and prevent it?)
My project is a tool for editing surveys/polls for users who want to create and distribute their own surveys. So far, my web app maintains a list of edit-commands fired by browser, sends it to the server, and the server does batch update.
What I did was, each survey maintains a version number and browser must request update with that version number, and if the request's version number does not match with the one in the server, the request fails and the user must reload his page (you know, implementing concurrent editing is not easy for everyone). Of course, when the browser's update was successful, it gets new version number from the server as ajax response, and one browser can request update to server only when its past update request is done.
Now, I am interested in RESTful APIs and MV* patterns, but having a hard time to solve this issue. What is the best / common approach for this?
There is a common trick instead of using versions, use TIMESTAMPS in your DB and then try to UPDATE WHERE timestamp = model.timestamp. If it returns zero result count - use appropriate HTTP 409 (conflict) response and ask the user to update the page in save() error callback. You can even use the local storage to merge changes, and compare the non-equivalent side by side.
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I'm going to build realtime push notification feature for my web application ( a small social network) and I don't know where to start.
This is what I want to build: there are like buttons, comment forms, ... Users click like, write their comments and (relatively) immediately, on the owner's browser shows the number of new likes and comments, ... Something like that.
I've read about socketIo on nodeJs, MeteorJS but unfortunately, they need WebSocket supported by mordern browsers. I've just read about Comet technic and find it pretty easy to apply. But i'm not sure it will performs well because Comet relies on long-polling connection (correct me if I'm wrong).
In addition, I think facebook is using Comet for its push notification feature. Through console tab on firebug plugin I can see there's alway a holding connection to facebook.
So can anybody show me a technic, a model to develop a feature like that?
A promising idea is to work with the HTML5 notification API; it's perfect if you want notifications to pop on the user screen as long as his browser is running (even if you're surfing another website or if all windows are closed).
http://www.paulund.co.uk/html5-notifications
However, if what you want is to update different parts of your page asynchronously (without refreshing or pushing a button), you should use together :
Ajax calls;
Listeners and observers.
When you Ajax calls retrieve particular types of json data (for example), it can trigger appearance of a badge (listener) with a number of new notifications, or so...
With JQuery installed, you should be fine...
Even though it's often not the case, sometimes, for simple tweaks, it's easier to code the job done...
You can start here :
How implement a "observer" in Jquery without plugins? (it's old, but interesting)
Or see this page :
browser instant updates with ajax/jquery
(incredible how often google queries return stacko' pages)
You should check out MQTT. It basically works on the Publish-Subscribe model and is very easy to use. This protocol has a small footprint and consumes less bandwidth. Facebook's Messenger uses MQTT too.
you can use an ajax call coming into (for example) a php script on the server, which keeps the connection open and only replies if and when something needs to be displayed to the user. should nothing happen within a certain time, the connection gets closed and the client fires a new ajax call.
note that this only addresses the client/server communication, you would still need a notification method inside the server to wake up the php script if you want to avoid having a script constantly polling the database, but there are quite a lot of soultuions to this and they depend on what language you use on the server.
I have got an idea, it is simple but it may work. Why don't you hide notification bar as Div tag and design it with css to make it look like notification bar. Then whenever some user likes or comments about the page, write php or js function and connect it to like or comment submit button that will reveal page owners invisible div to visible. And I believe , depending on what you use, I would probably prefer php session() to Identify if page owner is online and can get notifications. moreover, if you need to track statistics of the page, you may create a small database that holds, page id and user comments. You can use this database to push multiple notifications on that hidden Div. you can use Jquery to make it move like Facebook if you want to. I m not %100 percent sure if this is the most optimized way to do that but it is possible. By the way, I surfed some to see what people use to do that. surprisingly I couldn't find something as well.