Printing HTML on specific printer with Golang - html

I am developing a desktop app and I want to print HTML on a physical printer of my choosing on Windows and Linux.
It shouldn't ask the user to choose a printer as I want it to be automated without user input.
Is it possible with pure go and without executing external binaries?
If not which binaries do I need for windows and which for linux?
I found a way that works by using chrome command line flags. Namely --kiosk-printing and --headless and --user-data-dir so a new instance is spawned.
The Javascript necessary is:
window.print();
setTimeout(function() {
var ww = window.open(window.location, '_self');
ww.close();
}, 1250);
The timeout is necessary because chrome's print() doesn't block so we need to wait until it was actually printed.
This way I can print silently without asking the user and this works with Windows and Linux.
However I can't find a way to choose the printer that's used.

Related

How to use brave to automate printing html to pdf?

I currently manually open HTML files using Brave Browser and print the files to pdf files. I want to automate this process in the command line. Is there a way to do it? Since Brave is based on chromium, solutions based on chromium and google-chrome are also welcome.
This is a common use for calling the executable in headless or kiosk modes.
Your milage may vary compared to running heads up with a robotic puppet to press buttons for you, but more often than not is so much simpler for every day basic use in a batch file for multiple uses it is a second or so for each pdf generation.
Edge is not different to Brave or Chromium's so find the executable and append here using windows user folder
--headless --enable-logging --print-to-pdf="%UserProfile%\Documents\Demofile.pdf" --disable-extensions --print-to-pdf-no-header --disable-popup-blocking --run-all-compositor-stages-before-draw --disable-checker-imaging "HTTPs://url"
So darn quick I did not know it had run until opening the result, however note it needs the target to not pop-up blockers like google does, hence next step up is a button pusher to replace you by eating cookies.

pywinauto: accessing chrome gui

I am trying to select a printer and print on chrome browser, using pywinauto, but I am not able to access the gui components. I can see the components in Microsoft Inspect.exe in UIAutomation mode. (See screenshot).
I have started chrome with --force-renderer-accessibility flag.
I tried several things but I am not able to access anything in the chrome window. Is it possible to access the chrome gui components using pywinauto?
screenshot: ]1
Probably you use default backend="win32" which is used when you call Application(). To use MS UI Automation you have to set backend="uia" when instantiating Application object:
app = Application(backend='uia').start('chrome.exe <other params>')
My student wrote example script dragging file from explorer.exe to Google Drive in Chrome. Is it working for you?
P.S. If you already use backend='uia', please provide more detailed description with some code and output.

What is the difference between manually opened Chrome browser and opened using chrome driver

I am using Selenium for automating the chrome browser. When I download the files using automated Chrome browser it gives me a warning,
'This type of file can harm your computer' with keep or discard options.
But when I manually open chrome and download the files from same site, I won’t get any warnings.
I know I can disable the warnings using, options.AddUserProfilePreference("safebrowsing.enabled", true);
But my question is why I am getting this warning only in automated window?
What is the difference between browser opened using Chrome driver and manually opened browser?
Please help me.
If during your manual download, in your chrome
Settings > Advance Settings
Privacy -> Protect you and your device from dangerous sites (is_checked)
The download warning wouldn't be displayed on your browser.
On the other hand, not all chrome options are set to the same value during automatic download from your code. Hence you need to specify :
options.AddUserProfilePreference("safebrowsing.enabled", true);
List of all command line arguments for chrome driver goes here.
Note : Though not all of them are certainly of use while using automation and not all of them correspond to a chrome manual setting either.

Automate Chrome console from Desktop app?

I'd like to be able to send info to the Chrome developer console from my application.
For example, my app has some json. I'd like this json to show up in either an existing, or newly created instance of the chrome dev tools console.
Is this possible? If so, any pointers to examples? Note that the platform should be any language, not just javascript. And definitely not a site already running in Chrome. I'm interested in implementing this in another process.
Do you thought of running your app in an environment which is pretty much like a browser?
Node.js
or (this is a whole webkit browser)
phantom.js
Otherwise you could call Chrome directly via commandline and try to simulate the dev tools key stroke like explained here:
Is there a command line argument in Chrome to start the developer tools on startup?
The command of displaying something in the Chrome console is e.g. console.log and it is at the end Javascript. All Console commands are described here:
https://developers.google.com/chrome-developer-tools/docs/console-api
The closest I've seen so far is this library:
https://github.com/ccampbell/chromelogger
which seems to allow logging to the Chrome Console from lots of other server side apis, but no desktop APIs.
This can be done on Mac using osascript. Save the following as a script and run it:
#!/usr/bin/osascript -l JavaScript
var chrome = Application('Google Chrome');
//chrome.activate();
chrome.includeStandardAdditions = true;
var currentTab = chrome.windows[0].activeTab()
currentTab.execute({javascript: 'console.log("Hello")'})

Can Google Chrome be made to auto reload after network outage in kiosk scenario?

I have an unattended touch screen kiosk application which needs to be able to automatically reload the browser home page after a network outage has occurred. At the moment the browser will display an "Unable to connect to the internet" error and will wait for a manual reload to be carried out before proceeding. Can this be automated?
I've searched for plugins and have found some plugins which deal with auto-reload but they don't seem to work in this context. I am guessing that the plugin is only active when a page is loaded so in this case with an error condition, perhaps the plugin is not active.
One alternative might be to override the error page which is displayed by Chrome but I don't know if this is possible. I could then instantiate a Javascript timer to try a reload every n seconds for example. Is this possible?
I saw a suggestion to use frames to allow the outer frame (which is never refreshed) to keep trying the loading of an inner frame but I'm not keen to use frames unless there is no alternative. I also saw a suggestion to use AJAX calls to check if the network was working before attempting a page load but this seems overkill if there is a way to correct the error only when it has occurred rather than pre-empt an error for every page load.
Host system is Windows 7 by the way. I'm keen to keep the browser running if possible rather than kill and create a new browser process.
If you don't want to tackle chrome extension development, you could wrap your site in an iframe, and then periodically refresh the iframe from the parent frame. That way you don't need to worry about OS issues.
if the content were loaded from ajax from the start then the it could simply output a custom message on the page as it does a check via AJAX. Probably prevention over remedy is always recommended
Assuming linux, you could create an ifup script to simply relaunch the browser with something like
#!/bin/sh
killall google-chrome
DISPLAY=:0 google-chrome
On debian/ubuntu, edit /etc/network/interfaces to include a post-up line; Google ifupdown for other distros.
On windows, you'd do roughly the same with a PowerShell script.
If you really want the precise behaviour you describe (without restarting the whole browser), I suggest you develop a plugin/extension: http://code.google.com/chrome/extensions/getstarted.html
I know you are using Chrome, but in Firefox this is trivial by overriding the netError.xhtml page to do a setTimeout(location.reload, 10000);.