I have written a program that uses ncurses for the UI and the function mvwgetnstr to read in a string from a window. I want to allow users to make edits to the text they enter, so if they enter foo they can later go back and append bar. I cannot figure out how to do this with the curses API, the getnstr function only takes in a char buffer and length variable. Any ideas? I started making my own string input function, but it's difficult to keep everything constrained within the window.
It depends on what you want. There are many possible ways to organize a program:
getnstr reads the buffer from the standard screen (a window)
The wgetnstr function accepts a buffer from a given window. Using a separate window (or subwindow) reduces the problem of updates for the edited buffer interfering with other things on the screen.
getnstr editing is crude. If you use the form library (which in turn uses ncurses), that allows you to do more than just append/remove characters from the end of the input buffer.
write your own input-function, which can get complicated. The dialog program does this.
The ncurses-examples might be helpful for reading and seeing how to build up a suitable input function.
Related
Could someone share how can i create tui like this one with input boxex and search ?
What do i need?
Normally programmers use a ready to use library like ncurses.
You can also do it by hand if you really have to much time. To get for example the border lines of a dialog window you have to take a look at the current code page your terminal is emulating, for example: Code Page 850. As you can see, you will find single and double line boarders and also crossings and so on. Now you have to move your cursor to a given position, print that char from the code page and ... lots of work. Moving cursors itself can also be done by simple chars from your emulated terminal by using escape codes.
As said: Instead of doing it all by hand, simply use a lib like ncurses.
You can use some python libraries like pyTermTk or textual, there is wide selection of
libraries to choose from.
NOTE: Although I give a lot of info on Inquirer, I'm pretty sure that most of it won't apply (just being safe). For my actual question about curses, its at the bottom.
I'm using the Inquirer module in Python 3 to allow the user to select a value from a list. I run this:
import inquirer
choice = inquirer.prompt([inquirer.List("size",message="Which size do you need?",choices=["Large", "Medium", "Small"])
And I'm given this:
[?] What size do you need?: Medium
Large
> Medium
Small
And using the up and down keys, I can change my selection, and hit enter to choose, after which the "choice" variable contains the value I selected. The issue is: Once the selection is done, the choices still show. I want to delete them when done. I'm currently using ANSI Escape Codes to delete the choices from onscreen when done, where x is the number of choices:
import sys
for i in range (x+1):
sys.stdout.write('\x1b[1A')
sys.stdout.write('\x1b[2K')
Which leaves the printed text as:
[?] What size do you need?: Medium
The issue is, ANSI escape codes aren't universal. I want to use a solution that works on all terminals, preferably curses, but curses isn't very friendly to new users, so I was wondering if anyone knew how to use curses to "delete x lines above current position". Thanks!
curses, as such, would erase the whole display (which is probably not what you want). A low-level terminfo/termcap approach might seem promising, but while ECMA-48 does define a sequence (ED, with parameter 1) which erases above the current position, there is no predefined terminfo/termcap capability which corresponds to this. All that you will find there is the capability for erasing to the end of the screen, or erasing the whole screen.
"ANSI sequences" is an obsolete term. Referring to ECMA-48, you could do
sys.stdout.write('\x1b[1J')
after moving the cursor to the last location you would like to erase.
I am trying to find a way to paste a predefined string upon entering a specific keyboard sequence, on any app.
For example if I have to paste an url or a password into a field, I can have said password in a hidden script and when I press, say, [ctrl] + [5], it would write "example123" on the text field where my cursor is.
Ideally without copying to the clipboard (I'd prefer keeping what I have on my clipboard and also avoiding to paste a password or such by mistake elsewhere).
I have tried every solution I've found so far that include xclip, xdotool and xvkdb. All of them either do not work or are really inconsistent: They only paste the string sometimes, and when they do, it's usually only part of the string ("ample123" instead of "example123").
I thought of using compose key, which I heavily use anyway to write in french on an us keyboard, but it seems it only supports 1 character sequences, as nothing is printed when I modify my .XCompose to include custom output sequences of len > 1.
I am using Ubuntu 18.04 with Gnome as a DE. Ideally something that also works when logging back (like compose keys).
You need to walk the Document Object Model for either Gnome or your web-page. My concern is that with a desktop script you wont be able to access the web page because you will need to be able to establish a target to send string to. I see in your question that you tried using using "x{tool-name}" to grab the text field element. Delivering the sting really isn't the problem. The problem is getting the GUI element of text box pragmatically. The easiest way to get access to this in a user loaded web-page is with WebExtensions API which is how to make extensions for most modern browsers. Otherwise, if you can get away with only having access to Gnome's GUI I would try LDTP, it's a library used for testing, but it looks like it can be used for automation too.
For keyboard shortcuts:
It really shouldn't matter what the script is doing to how you want to activate it. I would just go to Gnome/Settings/Keyboard and set the path to where I saved the script to be the Command. If you go the WebExtension route, you will want to build the shortcut into your extension.
I have an interesting problem interfacing to an IBM mainframe based CICS application. I can login and write to input fields successfully using s3270 and x3270if. However, the CICS system I am working with expects certain commands to simply be written to the "screen", not a proper input field. I am using the String() function to write to input fields, but I cannot seem to find a function that will simply write a string to a given screen position.
Has anyone dealt with a similar scenario and can provide me with some pointers?
With 3270, there is no such thing as "write to the screen," as opposed to writing to a field. A formatted 3270 buffer is a set of fields, each with a certain set of attributes. You cannot write to an arbitrary screen position unless there is an unprotected field that includes that position. That's 3270 specs, that's how 3270 hardware worked, that's how 3270 emulators work, and any API you may be using for working with 3270 emulators will just expose that.
(You may have an unformatted buffer with 3270, but I gather that's not the situation you are facing, since then you would be able to write to any screen position - the buffer is essentially one big field.)
So you need to figure out how the screen you are trying to write to is formatted, and where its fields are, and where the application expects its input. If you can just run the emulation and type the input according to whatever instructions you have then it should be straightforward - wherever your input goes, that's where you should put it programmatically.
I want to know if anyone does know a way to dump or copy the whole lot of viewable messages in a xterm window on linux. The very important thing is I don't want to know how to send a command out and kapture its output for stream 1 and 2 as well as the input, as this is well known to me.
I may explain for what this is needed. You do something and expect not any complications but than you got pages of msg's als err msg or normal output. To be able to see later after it you should be able to get them in a file and as long as you are able to scroll that all back and forther with your mouse it is sure the data is there some where. But the time may be not to scroll and screenshot and scroll ....
I would be glad to help me out in such cases and it would be fine to have the full view including all your own typing and all the msg's in same order as you watch it when you scroll it back.
I don't really know where this is stored and how you could get that saved. I know that I could dump the whole lot of Memory and search it for a part of the xterm window, but that is a bit over the top I think.
There is a control sequence, which I had forgotten. This question reminded me. In XTerm Control Sequences, it is noted "print all pages":
CSI ? Pm i
Media Copy (MC, DEC-specific).
Ps = 1 -> Print line containing cursor.
Ps = 4 -> Turn off autoprint mode.
Ps = 5 -> Turn on autoprint mode.
Ps = 1 0 -> Print composed display, ignores DECPEX.
Ps = 1 1 -> Print all pages.
That dates from 1999 (patch #119), so you likely have it in your xterm. You could do this in a shell command like this:
printf '\033[?11i'
A comment mentions the page Hidden gems of xterm, which uses the corresponding action print-everything (something that can be executed via the translations resource). It is in the manual page, of course. The same comment points to Extra characters in XTerm printerCommand output, which mentions the resource printAttributes. By default, the control sequences for the printer tell xterm to send extra control characters (to reconstruct video attributes). The resource can be modified (set to 0) to suppress that. That is even older (patch #74).
Without that — Conceivably one could construct an application which used the X SendEvent protocol to construct a series of events which would be interpreted as xterm actions to scroll back, select text and copy it chunk-by-chunk via the clipboard. You could even write it in Perl (there is a module for X protocol). But seriously, no.
If you want to capture text which was written to xterm, you can do this by preparing before the text is needed by different methods (see manual):
turn on the xterm logging feature (not that user-friendly because it generates the filename). This can be enabled using the "Log to File (logging)" menu entry.
use the printer control sequences to write lines as they are written (again, not that friendly, though there is a menu entry to turn it on and off, "Redirect to Printer (print-redir)")
use script to capture all output to the terminal. I use this, because it works with any terminal on any POSIX-like system (even Cygwin).
Each of these methods produces a file containing escape/control sequences, which requires filtering out. The hypothetical program using SendEvent could in principle eliminate that.