I have a USB line display, similar to the ones that are used in store point of sale systems.
To print ABC to this line display, I run the following command:
echo ABC > \\.\LCLD9\
This prints ABC to the line display.
I'm trying to figure out how to control this output from a website, if possible, although I am not sure if it would be possible, as I can see security issues with being able to run arbitrary commands form web pages.
I'm trying to figure out how to control this output from a website, if possible, although I am not sure if it would be possible, as I can see security issues with being able to run arbitrary commands form web pages.
This is indeed not possible on an unmodified system. There is no way for a web page to run an arbitrary command on the user's machine -- that is the definition of a security vulnerability.
If you can get the user to install software ahead of time, you could use a Chrome extension with the serial, usb
or nativeMessaging APIs to expose this functionality to web pages.
Check out function shell_exec. http://php.net/manual/en/function.shell-exec.php
There are several ways to do this. One way is to simply have your website store the current text somewhere and then build a script on the local PC that asks your website for the current text and updates the display. You can schedule that script to run periodically using the Task Scheduler.
This script can be as simple as this (assuming PHP is installed on your local PC):
<?php
$text = file_get_contents('https://example.com/current_text.php');
shell_exec('echo "' . $text . '" > \\.\LCLD9\');
If you don't have PHP installed and don't want to install it, you can probably do something similar in a Powershell script or in a plain old batch file.
Note that you probably want to add some extra checks to this, you don't want to accidentally clutter your display with a 404 error page, a 500 internal server error or a network error.
Related
Inside Jenkins Jobs & Builds folder, I am creating a text file and writing some content through Java program. As I am part of corporate network, I am inside firewall with many security rules where I have been restricted to write/update the program files directory under C: drive. Although I am administrator in my local machine, however the company policies are still applied which is denying me access to write/delete any files from the Jenkins directory. I see Jenkins is nicely reading/modifying/writing any files/folders without any issues which is believed to the typical behavior of Jenkins's USER.
Question 1: Is there any way I can use this Jenkins's user through my code so I can avail access on to these directories?
Question 2: Are there ways to solve this issue through Java code? (Note: I have tried writing a file with Run as Administration java code as well)
Kindly let me know if I am missing any details,.any help is highly appreciated.
It's about the user who launched the jenkins server, who might have the permissions to access the directories.
You can use the same user for your operations if available.
Question 1: Is there any way I can use this Jenkins's user through my code so I can avail access on to these directories?
Jenkins users - Jenkins server can have its own users and privileges can be set for each users differently. You cannot use these users outside of Jenkins server.
You can use the user who launched the Jenkins server, must be a user at OS level.
Question 2: Are there ways to solve this issue through Java code? (Note: I have tried writing a file with Run as Administration java code as well)
Again, only OS level users can be used and not the Jenkins users(users created inside Jenkins server)
If you want your application to run with same credentials as Jenkins user, then hold Shift+Right Click your application, select "Run as different user", provide Jenkins's user credentials and press OK.
If you are launching your Java application from command line, do the Shift+Right Click on the cmd.exe first, and once again select "Run as different user"
If you want to impersonate a Windows user from within code, then you should really reword your question body and title (and remove Jenkins references as it has nothing to do with this). But even in this case, you need to know the credentials of the user you are trying to impersonate
I have a program that I've created that is meant to poll an html internal page with different IPs that update and then will run a telnet session to those IPs to see if the device still has a connection... I'm attempting to challenge myself in creating something further with a dynamic webpage instead of my program spitting out console output...
My Issue:
I dont know what technologies / libraries Java has to execute such things
I want:
A Local Server, to upload a page LOCALLY only (no security is needed as this will be strictly intranet)
My program to implement: A database of sorts to save "logs" essentially that a certain IP / device has had successful connections
in the past....maybe stored to an external file is fine i presume (my
program currently has to re-poll everytime i run it.. i want some kind
of "remembering"..
Is it possible this can all be done in one file? so if i want my computer to run this as soon as it starts up... it will run... grab
its current state of the database of IPs... poll them (periodically)
and then persist and save and update the HTML page dynamically....
I hope i'm being as descriptive as possible... Its a bit of an abstract.. I really just want some introduction to different libraries ... a friend recommended stuff like MongoDB or something but I want to stay strictly to Java programming
Is there any way I can check my browser history via java program or command line?
My requirement is I need to check how many times a person has accessed a particular site in a day from the browser.
Is there any way I can achieve this ?
You can view cached DNS entries from CMD.
Every time you browse to a web page, your PC has to request the IP Address for that web site from your default DNS server, and then caches them locally on your machine for a while to speed up future access to that web site — even in a private browsing session.
You can see these for yourself by opening up a command prompt and typing in ipconfig /displaydns to see the full list of cached DNS entries.
Now, the first thing you’ll notice is that a whole lot of information will appear, to the point that all of it can’t fit in the command prompt. What you can do is take the output of the command and send it to a text file somewhere on your machine.
ipconfig /displaydns > c:\desired location
Now, when you open that file you’ll see information about the websites you've visited directly or indirectly.
I'm in the process of developing a web application; where in the admin backend I need to have the functionality to do automatic print jobs for different processes that run and generate a pdf (labels, packing slips) in admin that will be sent to pre-selected LAN network printers in my warehouse.
I've been doing some research on this and I know due to security issues automatic printing like this is hard to configure. However, I have some posts where people write that they were able to pull this off with active x, java, print server, client software, etc...but there isn't a clear outline on how exactly to do this.
Can someone help me figure out a workaround that I can use to be able to automatically print to different LAN network printers in my warehouse when a certain process runs and generates a pdf file?
Thank you!
I also manage a warehouse system that does these tasks. I will not claim that the following solutions are the best way to go, but they have been working for us. Our system is built using PHP 5.3 on a Windows server using Apache. With this setup, the user does not need to print anything from the browser, it's all handle server-side.
Requirements: Apache needs to be running with Administrator privileges. Probably not recommended for web-facing servers.
To print a PDF on Windows via PHP:
$file = "c:\\path\\to\\file.pdf";
$exec = '"C:\\Program Files\\bioPDF\\Acrobat Wrapper\\acrowrap.exe" /t ';
session_write_close(); // prevents hanging
pclose(popen($exec. $file . " \\networked\\printer",'r'));
This just launches reader, prints the file, and closes reader.
On a Linux/Mac you should be able to use (without Admin privliages):
$file = "/path/to/file.pdf";
$command = "lpr -P /printer/path " . $file;
exec($command);
I have a java application that will take the image as an input and output another image. I have a website with a popular host (PHP+MYSQL Hosting). I want to create a page on the website with PHP with a form where a user can upload an image which will then pass the image onto the Java application.
What I am planning on doing is when then user uploads the image, it gets stored in a folder on the web server. I will then call the java app on the server passing the url of the image as an argument and then the java app will output another image, let’s say, to a result folder. The PHP page after the execution will then display the result image on the browser.
Now my questions are:
Is it possible to execute java apps on popular webhosts (for example mine is WebHostingBuzz.com)?
The java app is fairly heavy as it does a lot of image processing. Should I offload the java app to another web server? If yes, are there any services that will run my java app?
(Optional) It’s a demo of my java app and I don’t want to store the images people upload. Is there a way where I can directly pass the uploaded image to the java app and output the image generated directly instead of storing it on the web server? I would prefer this because, if the image is big, I can make PHP stop the execution after a timeout.
How do I communicate with the java app from PHP for info on its execution, for example When PHP calls the java app, the page has to wait till the app finishes processing? I want the java app to send a response to the PHP page saying that the processing is completed and the page is redirected or refreshed accordingly.
I hope you get the idea, please suggest the technologies that I can use to implement this and also if you have a better idea, post it!
Thanks!
Now my questions are: Is it possible to execute java apps on popular webhosts (for example mine is WebHostingBuzz.com)?
It's technically possible. But the hosting has to install JRE at the host and give the PHP user sufficient OS-level and filesystem-level permissions. So you're really dependent on the hosting whether they provide this opportunity. Best is to just contact their support team and ask it.
If it is supported, you could just use shell_exec().
$result = shell_exec("java -jar /path/to/imageprocessor.jar " + $imagepath);
if ($result) {
// Shell execution succeed.
} else {
// Shell execution failed.
}
For asynchronous communication / background processing, the client has to fire an ajaxical request.
If it is not supported, consider porting Java to PHP. The GD image library has pretty a lot of functions which may be of use.
Google App Engine allows to host Java (and Python) web applications. The SDK and the basic account is free of charges. With the SDK, you could develop and test the application locally and then simply deploy to App Engine (NetBeans and Eclipse plugins are available).
Then the PHP app could send the data in a HTTP POST to the Google App Engine application and get the result in the response data.
Or the data is stored first in a database blob and a processing job is put in a task queue (a 'message queue'). This has the advantage that the PHP client request will return immediately after the data has been POSTed. Then, the PHP application could poll for the result data while Google App Engine processes the image. The PHP side would be more responsive this way.
Wouldn't it be easier to make your java app a web app, that PHP could call via an url in wich he would put the url of the image so java can download it?
like http://yourjavaserver/imageprocessing?imgurl=IMAGE_URL
and the java servlet would reply with the image file itlsef.
You can look for "java hosting" on google, to find a host for this, but it's more expensive than PHP hosting. Maybe the best choice would be to get a dedicated server which could host both PHP and java applications...
I think your best bet here is with your java app running as cron(or a deamon) that can load the file details from the database. This will require a (one or more) page-refresh on the users part after the generation is complete, at which point your script can recall the image from the database/filesystem.
I do not think you will be able to do this in real-time due to timeout restrictions on the PHP webpage. However, you could write a java applet that can take the file and process it before sending it to the server (or depending on how you intend to use it, perhaps you do not need to upload it after the transformation?).