Http proxy

[EditKoselak]

Description

Explain how to set HTTP proxy for the "dita" command

Motivation and Context

Fixes #189

How Has This Been Tested?

The documentation was compiled locally using the gradlew -PditaHome=/path/to/dita-ot command

Type of Changes

Documentation

Documentation and Compatibility

No additional documentation needed.

Checklist

• My code follows the code style of this project.
  • https://github.com/dita-ot/dita-ot/wiki/Java-Coding-Conventions - N/A
  • https://github.com/dita-ot/dita-ot/wiki/XSLT-Coding-Conventions - N/A
  • https://github.com/dita-ot/docs/wiki/coding-guidelines - checked
• I have updated the unit tests to reflect the changes in my code. - N/A

[infotexture]

The long line in this code block will require horizontal scrolling in HTML output, and be truncated in PDF output.

We may want to consider inserting \ line continuation characters in the code block to ensure the example remains readable, but I'm not sure if those can be encoded within the ANT_OPTS value in a way that works on all platforms. (Perhaps @raducoravu knows?) 🤔

[infotexture]

I'm also thinking we might want to move this information to a dedicated topic, perhaps in the Troubleshooting section, where other ANT_OPTS workarounds are described, but I can do that in a separate step.

[EditKoselak]

The long line in this code block will require horizontal scrolling in HTML output, and be truncated in PDF output.

We may want to consider inserting \ line continuation characters in the code block to ensure the example remains readable, but I'm not sure if those can be encoded within the ANT_OPTS value in a way that works on all platforms. (Perhaps @raducoravu knows?) 🤔

Thank you for the suggestions! We tested the \ solution in bask and sh and it worked. We hope that this is OK on other platforms. Let us know if any further correction is needed.

[raducoravu]

Maybe instead of "for installing and downloading content" I would say "for installing plugins from the configured registry or processing remote referenced resources"

This part "provide the proxy configuration via the ANT_OPTS environment variable", on various operating systems there are various ways to set env variables, on Windows I would use in a Command Prompt window "set envName=envValue" and then I would call "dita..." on a separate line. On Mac OS I would use in the Terminal "export envName=envValue". I think this would be the same for Linux.
Also the "dita install " part should probably be on a separate line in the codeblock.

[EditKoselak]

Hello @infotexture, @raducoravu,
thanks for the suggestions. Since adding extra info would make the note pretty complex, I think it would be better to move it to a separate section under Troubleshooting/Other error messages (Connection timed out), and create something similar to what we have in Increasing Java memory allocation.
We could keep a reference as a Tip in the original chapter (Arguments and options for the dita command).
What do you think?

[infotexture]

@EditKoselak Yes, I think that's the right approach.

[infotexture]

🙇 Thanks for your input here, looks pretty good now.

I implemented the feedback from @raducoravu in #501 (review) and prepared a few tweaks, but I'm not able to push additional commits to your fork as part of this PR, so I'll merge this as is now, and submit those separately.