Tweak the Update Gravity output

[rdwebdesign]

What does this PR aim to accomplish?

This PR is intended to show the progress of the new parseList function introduced by pi-hole/FTL#1559 and pi-hole/pi-hole#5275.

The new pihole-FTL gravity parseList command starts every message (including error messages) with \r, to allow overwriting lines on the command line output.

The problem is: this brakes the web interface output and no output is shown for this command.

Replacing the initial \r allows the correct output.

How does this PR accomplish the above?

Kepping the original str_replace and adding a second one, to replace any remaining \r with '<------'.

Note:

Use all 3 branches when testing: FTL, core and web.

Link documentation PRs if any are needed to support this PR:

none

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[yubiuser]

I tried it and with this PR I can see the progress counting. However I fail to see a single occurrence of <------

Is this expected?

[rdwebdesign]

Yes.

The <------ string is used only internally and it is replaced.

[yubiuser]

Ah I see... it's the code right below. You search for the position in the line string and remove everything you don't want.

[rdwebdesign]

The logic is:

gravity.sh output is used both on the console and the web interface.

On the console, it uses a carriage return followed by an escape code (ESC+[K) to "go back to the start of the line and clear from the cursor to the end of the line". This is used to allow "overprinting" lines, on the same place (similar to PADD).

This escape sequence is sent to PHP/javascript. PHP replace it with <------. If the string appears on the middle of the line, PHP strips the text before the <------.

The text is sent to javascript with <------. The java script code removes it and removes the last printed line, causing the same "overprint" effect.

[yubiuser]

Thanks. Maybe you could adjust the code comments a bit, because the part replacing ${OVER} was removed but is used as explanation in the code.

[rdwebdesign]

I didn't remove the ${OVER} part. I expanded, but I think I could improve the comments.

The $OVER sequence can be written in different forms:

• FTL uses \r\x1b[K;
• PHP uses \r\e[K;
• Shell is using the character, but github is not able to show it. The same happened with the previous PHP code (the character was not shown on github or some text editors). My second commit fixed this.

I will try to rewrite this comment to allow a better understanding.

[yubiuser]

Thanks for the explanation. My main issue was that I did not know that \r\e[K and \r�[K are the same thing.

[rdwebdesign]

Yeah,

\e = \x1b = ESC (ASCII code = 27)