I want to create an internally used web app that can be run with just a copy of the web app and the DB (anything from a text file to MS Access/Excel would work fine). Is this possible? I don't want users to have to setup a SQL server to get the app to work. Having the files necessary to run the web app stored on a shared network drive would be ideal, for example. The problem is that JS can't write to a DB. Is there anything that can use to do this?
Like mentioned, I can assume that Access/Excel are installed, if there's anything that might help there.
It's most certainly possible. W3 has put up the specs for a client side database that can be accessed by JavaScript. The modern browsers have good support for it, and since this is for an internal application, you would have some level of control I believe.
Checkout this slide that shows a live demo of Indexed Database. The full spec can be found here. See this link for browsers that currently support IndexedDB. Here's another set of slides showcasing how to use IndexedDB.
However, with this approach, each user's browser has its own DB locally. If you want a centralized DB, then you will need a server.
You can perform database transactions with JavaScript. This is generally discouraged, because it has terrible security implications. However, in a completely local environment, you are probably not causing any additional security risks. (Because, your database is already on the user's machine.) You can see an example of how to use ADO in JavaScript at How to connect to SQL Server database from JavaScript in the browser? .
Possible, yes, Like Making cars that can float in the sea but could not work on dry roads.
Use winforms or something similar. Use the right tool.
If you insists, Firefox plugins can behave in the way you mentioned, and there is a way to bundle a web application with it's server (check the beginner tutorials for RoR to have an example for something similar with webrick).
If I understand your requirements, you might look into ColdFusion.
For example, you can run a DB query pretty simply, check here, in Adobe
Related
I need to create a web application that perform queries on a remote Oracle DB Server instance.
Unfortunately it is not possible to install any additional software on the machines - and yes, I know that connecting directly from JavaScript to the Oracle DB Server is dangerous - but I need to do this.
In previous versions of the application the ActiveXComponent in the Internet Explorer was used. But this does not work in any other browser and I can't use Internet Explorer any longer.
So, does anyone has an idea that solves this problem only with the help of JavaScript?
Take it easy,
Julian
It's not possible to do this from a browser-based JavaScript environment - you don't even get to the point of it being dangerous, it simply won't work to begin with.
You won't be able to load the database drivers, and browser-based JS won't be able to make that kind of socket connection, it can only make HTTP connections (for security reasons, mainly).
The bottom line is, you need some server-side code as an intermediary - either your own creation, or provided by someone else. This is universal for all database platforms. (Even ones you may find which might expose functionality via a HTTP API are like this, it's just that the vendor wrote the API using some server-side code and then deployed it in front of the database - it's still not a direct connection to the DBMS).
Thank you for your answers.
I've found an other solution (java programm connects to the database and shows the webpage in a JWebBrowser). Working for my use-case.
I used to use mysql databases and a php backend for my web applications. Now that I am diving deeper into the the javascript world I am looking for a more compatible way to store my data. I like the idea of writing everything in one language, and javascript seems to be capable to make that job.
I started reading about couchDB and the JSON/javaScipt approach seems to fit perfectly to my needs. My question is now, which would be a convenient way to connect to the database from my pages.
I found this post, which explains how to connect to a couchDB directly from a client-side javascript using a library called couch.js. The post is quite a few years old and the library I cannot find anywhere in the web. So I am asking myself If this approach is still up to date.
I was thought that one important reason for using a server backend is to provide a security mechanism to protect the database authentification process. So: Is it generally secure to save an (encrypted) db pwd in a client side script?
So what I am looking for is a quite simple way to access and store json-like data from webpages. Are there any suggestions?
The hosting of the production solution should also be not that difficult and in the end not expansive, since it's rather meant for smaller projects at the moment.
If the post does not fit to the forum, let me know a better place for it..
I have been using the CouchDB jQuery Plugin for development. At first I was hesitant as well to use it due to most documentation being at least a few years old. So far it has worked really well and been very easy to use, especially if you are familiar with JavaScript/jQuery.
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You can get the plugin from Github
CouchDB jQuery Plugin
Or you can save it directly from Futon:
http://localhost:5984/_utils/script/jquery.couch.js (where local host is your IP and 5984 is the port CouchDB is on)
Whatever you do, make sure you enable CORS on your database. There are instructions on the Github Readme page, or this script is super useful and easy to use through npm.
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Documentation can be found here.
This reference has also been very useful for me.
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Good luck!
I just released Slouch, a JavaScript client for CouchDB that can be used in both the browser and in node. I hope this helps!
I have a simple offline html5/javascript single-html-file web application that I store in my dropbox. It's a sort of time tracking tool I wrote, and it saves the application data to local storage. Since its for my own use, I like the convenience of an offline app.
But I have several computers, and I've been trying to come up with any sort of hacky way to synchronize this app's data (which is currently using local storage) between my various machines.
It seems that chrome allows synchronization of data, but only for chrome extensions. I also thought I could perhaps have the web page automatically save/load its data from a file in a dropbox folder, but there doesn't appear to be a way to automatically sync with a specific file without user prompting.
I suppose the "obvious" solution is to put the page on a server and store the data in a database. But suppose I don't want a solution which requires me to maintain apps on a server - is there another way, however hacky, to cobble together synchronization?
I even looked for a while to see if there was a vendor offering a web database service - where I could, say, post/get a blob of json on demand, and then somehow have my offline app sync with this service, but the same-origin policy seems to invalidate that plan (and besides I couldn't find such a service).
Is there a tricky/sneaky solution to this problem using chrome, or google drive, or dropbox, or some other tool I'm not aware of? Or am I stuck setting up my own server?
I have been working on a Project that basically gives you versioned localStorage with support for conflict resolution if the same resource ends up being edited by two different clients. At this point there are no drivers for server or client (they are async in-memory at the moment for testing purposes) but there is a lot of code and abstraction to make writing your own drivers really easy... I was even thinking of doing a dropbox/google docs driver myself, except I want DynamoDB/MongoDB and Lawnchair done first.
The code is not dependent on jQuery or any other libraries and there's a pretty full features (though ugly) demo for it as are well.
Anyway the URL is https://github.com/forbesmyester/SyncIt
Apparently, I have exactly the same issue and invetigated it thoroghly. The best choice would be remoteStorage, if you could manage to make it work. It allows to use 3rd party server for data storage or run your own instance.
I am working on a Google Gadget that will collect some data through Google API's. What I am getting stuck on is how to collect the data and then save it somewhere to be processed later. The final idea being that I would run the gadget on my own computer it would collect the data and then save it to somewhere on my own computer. (I guess I want to emphasize that this is, for now, a small personal project and does not necessarily need fancy server scripts, I want to be able to run this all on my PC running XP).
Is there a pure Javascript way to save a file on a computer?
Can I use other languages besides XML, HTML, and Javascript to add functionality to my Google Gadget?
Edit: The goal of this is to be able to log how many of my contacts are signed into gchat over a period of time. I decided on a Gadget because that was the only way I could figure out how to access that information. Any other ways to approach this idea are welcome!
No, Javascript alone cannot save a file automatically. And be careful, javascript is affected by the no cross domain rule. If you're hosting the project on your own computer, why bother writing a complex Google Gadget?
I suggest a simple PHP script, and MySQL, if you like, to store the data. By itself, PHP should be more than enough to run most tasks. If you would like me to add in more info about this, please tell me what type of task.
In increasing order of flexibility:
The options object is almost certainly the easiest approach - not really designed for that kind of usage but I suspect it would be fine for your use case.
On windows you could use system.filesystem to get hold of the WScript FileSystemObject which you can then use to create files and write to them.
Also see the Google desktop API blog for embedding an SQLite database in your gadget (looks pretty easy).
I've written a simple web page that uses Javascript to control a Quicktime plugin for movie playback. There's also some AJAX stuff using jquery to get info on the movies from an MSSQL database. The web page is served to the user from an Apache 2.0 server, this also hosts MSSQL. The end users will view the page in IE6 (unfortunately).
My problem is that the end users now want to use an RS422 jog/shuttle deck control to drive the movie timeline, in place of another jog/shuttle unit that relied on emulating keypresses which was easy for me to detect.
As I'm not a programmer I'm at a loss what to start looking at for a solution to receive the RS422 data and then send that to the Javascript to control the timeline. Is this something that a custom activeX bit of code could do? I've googled ActiveX with Javascript but it's unclear to me (as a novice) how the two work together, or whether this would be suitable at all.
If anyone could give me an overview of what to start researching that'd be much appreciated.
Many thanks.
Jon
JavaScript runs in a sandbox and has no access to the computer at all (for security reasons; you really don't want to make it any more simple for frauds to get at your credit card data).
ActiveX would work but it's a security risk, too. ActiveX is written in C++, no JavaScript there. You'll find information about that on the M$ Website. Note that ActiveX is usually disabled today because of said security risks. Depending how serious your client take security, the virus scanner might not allow to start an A/X control.
Another option would be to write small program which is installed on the client's computer that reads the serial port and send that to the web server where your JavaScript can query it. Okay, that's more than a bit convoluted but probably the least risky.
Or you write a program which transforms the serial codes into key presses (just create the event and post it to Windows). Again, you need C++ or maybe Python with the win32 package.
Your client must understand that this is something which sounds incredibly simple but you'll have to jump through a lot of hoops to make it work. A web browser is not a local application with full reign of the hardware (and it must never be).