I have a web page made with HtmlServices.
This page has a form I want to submit to a GAS web app made to behave as a web service.
When I use google app script UrlFetch to call my web service from my first GAS app, I very often get a timeout. Unfortunately we cannot set the GAS UrlFetch timeout value which I think is around 10s. 10s is not enough for a GAS app to copy a file, open/edit a spreadsheet and send an email!
So I decided to use Jquery and do an ajax post (because I can set the timeout value) within my web page built with HtmlServices. (so my page is sanitized by Google Caja). Jquery is said to be supported by Caja.
But I noticed that the Ajax URL is always rewritten to be the first web app URL (the url I want to post to is changed by Caja I assume). Seems to me that Google's Caja is preventing that Ajax call.
I could not find anything on Caja / Ajax post limitations within a GAS HtmlService.
Would you have suggestions on how to call a web service from a GAS Web App, without having the limitation of the GAS timeout?
The best suggestion I can give for right now is to use JSONP instead of Ajax to make the call. You should not see timeouts in that case, and it should work fine.
Couple of things
AJAX calls (with jQuery or vanilla JS) from a web app deployed on script.google.com to a content service deployed on script.google.com does not work. I've confirmed this and I believe this is a security restriction. I tried a few different workarounds and this looks like there is no short term options.
Regarding the server side option with UrlFetchApp. I believe the timeout is actually 30 seconds. However, that might still not be enough and it looks you are running into frequently enough.
So basically the 3rd (less optimal) option that I would recommend is a "queue" based approach. In this approach - have your HTML web app call a ScriptDb queue. Then you can have a timed trigger (every minute or every hour) that runs as you to perform the requisite operations. Just share the same script library between both scripts so you can share the script DB reference for the queue.
According to this answer from Eric Koleda, Caja was removed from Google Apps Script, but still the client-side code passed to the HtmlService is satinized some way and still there are restrictions. From https://developers.google.com/apps-script/guides/html/restrictions
HTTPS required for active content
"Active" content like scripts, external stylesheets, and XmlHttpRequests must be loaded over HTTPS, not HTTP.
Related
I am currently developing an instant messaging feature for my apps (ideally cross platform mobile app/web app), and I am out of ideas to fix my issue.
So far, I have been able to make everything work locally, using a Node.js server with socket.io, django, and redis, following what most tutorials online suggest.
The step I am now at consists in putting all that in the cloud using amazon AWS. My Django server is up and running, I created a new separate Node.js server, and I am using Elasticache to handle the Redis part. I launch the different parts, and no error shows up.
However, whenever I try using my messaging feature on the web, I keep getting an error 500:
handshake error
I then used the console to check the request header, and I observed that the cookies are not in there, contrary to when I am on localhost. I know it is necessary to authorize the handshake, so I guess that's where my error is coming from..
Furthermore, I have also checked that the cookies do exist, they are just not set in the request header.
My question is then: How can I make sure Django or socket client (not sure who's responsible here..) puts the cookies in the header??
One of my ideas was that maybe I am supposed to put everything on the same server, with different ports, instead of 2 separate servers? Documentation on that specific architecture problem is surprisingly scarce, compared to the number of tutorials describing how to make it work on local.
I hope I described the problem accurately enough! :)
Important note: I am using socket.io v0.9.1-1, only one compatible with a titanium mobile app.
Thank you for any help!
All right, so I've made some progress.
The cookie problem came from the fact I was making cross-domain request, adding a few lines enabled CORS, which didn't solve the cookie issue, but allowed me to communicate between servers (basically I set the headers of the response using express. I then passed necessary data in the query, even if not the most secure way to do it, I'm just building an MVP, and it's enough for now.
I haven't been able to make the chat work from my Titanium mobile app, but since I can use a webview to handle it, I will be fine.
Hopefully that will help someone.. If anyone needs me to post some code snippets I will gladly do so upon request!
Cheers
I've designed a desktop app using PyQt GUI toolkit and now I need to embed this app on my Django website. Do I need to clone it using django's own logic or is there a way to get it up on website using some interface. Coz I need this to work on my website same way it works as desktop. Do I need to find out packages in django to remake it over the web or is there way to simplify the task?
Please help.
I'm not aware of any libraries to port a PyQT desktop app to a django webapp. Django certainly does nothing to enable this one way or another. I think, you'll find that you have to rewrite it for the web. Django is a great framework and depending on the complexity of your app, it might not be too difficult. If you haven't done much with web development, there is a lot to learn!
If it seemed like common sense to you that you should be able to run a desktop app as a webapp, consider this:
Almost all web communication that you likely encounter is done via HTTP. HTTP is a protocol for passing data between servers and clients (often, browsers). What this means is that any communication that takes place must be resolved into discrete chunks. Consider an example flow:
You go to google in your browser.
Your browser then hits a DNS server (or cache) that resolves the name google.com to some IP address.
Cool, now your browser makes a request to that IP address and says "get me some stuff".
Google decides to send you back a minimal amount of HTML and lots of minified JavaScript in the page.
Your browser realizes that there are some image links in the HTML and so it makes additional requests to google to get each of the images so that it can display them.
Now all the content is loaded on your browser so it starts to execute the JavaScript code, and that code needs some more data from google so it starts sending requests to google too.
This is just a small example of how fundamentally different a web application operates than how a desktop application does. On a desktop app you have the added convenience that any operation doesn't need to be "packaged up" and sent, then have an action taken, etc (unless you're using a messaging architecture, but that's relatively uncommon outside of enterprise apps).
I've a huge django project and have to use Instagram API and its subscriptions model to work. For the subscriptions, my server has to be very responsive and be ready to work asynchronously to set up a hook so as to receive notifications once the user posts. Or that's what the documentation suggests. Now will it be a good thing to use Tornado there? Just for that small part or can I do it using Django in an effective way? if so, how?
You can use the WSGI container on top of Tornado to host any WSGI application, including Django, however, when you do that the WSGI application is still running as a blocking application and will not magically be running as an asynchronous application. So, when Django is handling a request there is no ability to handle another request at the same time within Django. The solution at that point is not much different to running a single threaded WSGI server and you would need to have multiple Tornado instances to handle concurrent requests.
So all really depends on what you mean by asynchronous. You certainly can't make use of Tornado's direct asynchronous programming API in Django. Thus there isn't really any great benefit from using Tornado with Django via the WSGI interface.
As I understand you are talking about this paragraph in Instagram docs
You should build your system to accept multiple update objects per payload - though often there will be only one included. Also, you should acknowledge the POST within a 2 second timeout--if you need to do more processing of the received information, you can do so in an asynchronous task.
That's another type of "asynchronous" that Tornado provides.
I think Django + Celery will suite better for this.
Your application will work in this way:
You receive JSON-data from Instagram
Create a celery-task, e.g. instagram_process.delay(request.raw_post_data) or instagram_process.delay(request.body) according to your Django version
Response to Instagram with 200 status code
In instagram_process task you do all your procession - parse JSON, store it do database and anything else you need.
If you want to check X-Hub-Signature you can either do it between steps 1 and 2, or pass this header to the task and verify the signature at step 4.
You can use tornado.wsgi to integrate Tornado with other WSGI compliant frameworks. Check out this demo project for details:
https://github.com/bdarnell/django-tornado-demo
I have built a website in django framework. It has a lot of features such as blog, discussion forum, basically there are lots of ways users can interact. I have built a basic notification framework where a user gets notified when somebody comments on their blog, or answers their question in the forum.
Since the notifications are stored in db, new notifications are displayed only when a page refresh is done. I would like to make it real time using some push server using something like long polling technique.
I have come across NowJS which seems to be pretty handy for this, but in all the examples that are given I could not see any example where there was any interaction with the database. In all the cases there was some information sent by one client and it was displayed to one or more clients.
What I actually want to do is to call a function using NowJS, and make it go to sleep until a new notification is added in the database. When a new notifications comes in the server responds back with the notification and a new request is done immediately.
I can figure out all other parts except how to access the database from Node server that is used by NowJS. Any help or guidance is appreciated.
Either:
Have your node.js server make an http call to the Django server via something like a REST api to get info back
Google for a database connector for node.js - I found enough evidence for a MySQL one, and rumours of a PostgreSQL one. Note this won't get you access to the Django DB API, so you'll have to work out all your related queries and craft your SQL by hand (make sure Bobby Tables doesn't bother you: http://www.xkcd.com/327)
Re-implement the NowJS protocol so that you can write a django server for it, keeping the same JS client code on the clients... but then you may as wel.....
...use django-socketio http://blog.jupo.org/2011/08/13/real-time-web-apps-with-django-and-websockets/
I am looking for a web app framework which can automatically generate an HTML5 offline storage based app, so while the users become disconnected they still can view the data which normally is stored on a server
Also currently I am using Django and it would be great if there was a framework which could pull data from Django and present that as an offline app.
From the related questions suggested by stackoverflow, while writing this question, I found one interesting link mentioning that GWT has such functionality, I would like to know more about that if possible and if it can generate an HTML5 offline app
Thanks in Advance
Rather than server-side frameworks, you should be taking a look at JavaScript frameworks.
Dojo Storage will transparently select between providers such as Google Gears, Adobe AIR or plain old HTML 5 local storage. Dojo 1.5 - dojox.storage: http://dojotoolkit.org/api/1.5/dojox/storage
There's also jQuery local storage: http://plugins.jquery.com/project/saveit
... or jStorage, which can act as a storage plugin for jQuery, Prototype or MooTools: http://www.jstorage.info/
With any of these, you should be able to use a quick little AJAX call to pull (JSON perhaps) data from your server and use one of these tools to help minimise your storage code.
You're talking about a standalone app, not a django app.
This can be done with javascript (jQuery, Sproutcore, JavascriptMVC, Pyjamas ...) or Adobe AIR, or...
Pulling data from Django is just a matter of setting up a syncing method, most probably using JSON, to fill up the browser local storage. So this is not django-specific at all.
If you want a standalone django app, this can be done if you bundle in a python desktop app django with a built-in server, that's another question
You could suggest the users to create web apps or use google gears instead... I don't know if this will fill the question, but, i'm in the same way. However, I'm developing an governamental solution who will run only for some kind of people, so, I can have a few control about the user's environment... All you need to do is to use jquery to detect if user has a live connection, or offer to the users a 'preferences' page where you define the behavior of the page itself...
Some info about offline cache: http://diveintohtml5.ep.io/offline.html
PS.: In another post in stackoverflow, I 've found another question: html5 offline caching with php driven sites... The last Post said:
HTML5 offline caching does not work to make your pages interact; it works only to make a
particular page available offline. Basically, it works on a URL-by-URL basis. If you
absolutely need offline functionality, you will be forced to make it work in JS.
Also, make sure your manifest includes all resources used by all pages.
Hope this helps!
Hope it helps!!