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.
Related
I have a little question here. Is there any way to build a server side JS without any use of external software. The reason for this is I am not able to install any software on the webspace but I wanted to experiment with realtime communication with the server and another user for a game or something like this.
If someone knows a way to establish something like this I would be quite happy to hear about it.
EDIT: Guys NOT NodeJS I AM NOT ALLOWED TO INSTALL ANY OTHER SOFTWARE!
https://cloud.google.com/nodejs/
or
https://devcenter.heroku.com/articles/getting-started-with-nodejs#introduction
Those $15 a year webhosts typically don't allow you advanced customization. You need a better web hosting service that allows you CLI access to the server back end.
Running JavaScript on backend requires NodeJS runtime environment. Download it here https://nodejs.org/en/
Alternatively you can can configure an instance on Heroku and run your application there. But I would suggest to try the first one.
No. Javascript is a scripting language that was designed to work within the browser. There's no out of the box solution for you, as Javascript doesn't do server-side out of the box
However, Node.Js (and others) use Chrome's V8 engine to create an event-driven runtime environment which can allow writing server-side code with Javascript. That's your best option
I work with a team whose only way to get a user in their company's database, is to navigate through and fill out ~5 or so pages of web forms in their browser. Truly brutal stuff. I've developed web automation scripts in VBScript, Java (w/ Selenium WebDriver) and iMacro, but all of these solutions are slow. They also depend on the browser, which I'm trying to move away from.
I'm looking for a new platform, possibly some scripting technique/language that will allow me to issue HTTP requests and read HTTP responses, then build my script around there. The script would perform calculations on the HTTP responses, use File I/O and use this data to issue further HTTP requests. Again, I'm just spitballing here. If anyone else has a better solution, I'm all ears!
My question for you is: Accepting the team's limitations (read-only DB access), how would you approach a solution and what tools/languages/platforms would you use to do so?
Broad and ambiguous answers are welcome. Thank you for your time.
I agree with #Grisk on using NodeJS/ioJS as a platform. It is a powerful tool designed from the ground up for I/O, making it perfect for solving your problem. Additionally, the node community is extraordinarily vibrant, with npm, the nodejs package manager, hosting thousands of easily accessible modules. To avoid any future confusion: don't mistake NodeJS for a language or a backend framework; it is a native javascript interpreter built atop Google's V8 engine as well as a set of built in modules to build powerful I/O applications. Read up about node online.
As for your specific problem, I'd say you have two options:
To feign being a browser using phantom cookies
By programmatically navigating through the website as you have been doing.
As for the former option, you'd need to manually determine which cookies are sent to the server when forms are submitted on each page and then in your script generate these cookies and include them in the http request. Check out the nodejs http documentation for more information on customizing the headers of requests.
You're header will need to look something like this:
var headers = {
'host': < website host address here > ,
'origin' : <website origin here>
'referer' : <website origin here>
'User-Agent': 'Opera/9.52 (X11; Linux i686; U; en)',
'Cookie': <cookie sent over by server here>
}
I recently came across the node-icloud library, which uses the first method I describe above to provide programmatic access to one's icloud account. I strongly suggest reading through its code to see how it works here.
Additionally, I'd suggest reading up about http headers here
For the second option, check out phantomjs and zombiejs. Phantom is nice because it works without a browser. I'm not sure how the speed of these two libraries compare to what you have already been doing, but they are worth testing out.
One last thing: I would recommend building a custom (JSON)DSL for automating interaction with webpages so you can very easily redesign your browser interaction workflows.
Additionally, if you choose to use nodejs, an understanding of node streams and the details behind its event loop would be beneficial.
Best of luck!
I would start looking into NodeJS as a platform. The HTTP library is an incredibly powerful method for writing applications that need to make multiple http requests with unusual structure and it can communicate easily with a browser or basically anything else you could possibly need. Look at using the FileSystem class if you need to do file I/O.
If you wanted to get really fancy and use websockets to build a dynamic webapp that you can use as a front-end for your tool, you could even do that, so there's a lot of flexibility.
How can I connect to mysql DB from JS function?
I found this question:
How to connect to SQL server database from javascript?
but it doesn't work on Chrome, because they're using ActiveXObject.
Thank you.
There is no good solution on web browser side which will allow you to work with all browsers. There are many disadvantages to work with database on browser site.
First of all, you show your database structure and it is very dangerous. Imagine, how easier is to make SQL-injection while you know tables and fields?
You have to establish connection in some way using password which will be shown to third party users. Or you have to set password-less connection, which is also dangerous.
When you establish connection with database, somebody can easly execute own query what is trivial, because you are showing your structure.
I strongly recommended you to not do it on browser side.
but I have cross-domain problem, so I just need to do simple select from db
Direct browser-to-database communication is definitely not a proper solution.
If you want to get a list of values out of the db, just write a method in whatever server-side language you prefer (or need) to use, make the client-side JavaScript code call that method through its public URI and parse the response body into some data structure.
A more general solution to this kind of problems is XMLRPC (for the record, I've used it under Code Igniter / Flash ActionScript 3.0), though it's not all that simple to use.
If you need to get data from two different domains, then implement the above on both of them and make the JavaScript code call the two different URIs and combine the data (if needed).
You must use AJAX, because JavaScript itself can't connect to server. You can call some PHP script with AJAX and in JavaScript handle response from it. See jQuery.ajax().
make Ajax call from your javascript to php which connects you to database
Without some sort of plugin, or sending requests to a server side application that will access the database for you, you can't. So focus on those instead, specially server side apps.
A comment under this question
How to make a database connection
suggests that's only possible with a particular mix of Microsoft technologies specifically designed to deploy desktop-like software using a web browser. The bits mentioned there are:
HTA - HTML Applications
JScript - a Microsoft flavor of JavaScript
ActiveX objects
A link is also provided: Introduction to HTML Applications (HTAs)
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 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