deye

Pass permissions to deno run more easily.

Generates and runs a long-form command via shorthands, with a preview option and self-test.

Why?

The permissions flags are reasonably long and several might be needed to run a project. This can be a relatively large overhead when prototyping or running occasional scripts.

How?

The deye command takes as its first argument a shorthand string. This is a set of characters identifying the permissions or other options required, e.g. rwx represents --allow-read, --allow-write and --allow-run.

Additional arguments usually passed directly to deno run, e.g. the file path and any arguments to the file, are passed to deye immediately after the shorthand string.

deye <shorthand_string> [<additional_arg>[ ...]]

The shorthand string either:

• has one character per permission or other option, e.g. as above r to allow read, or
• is three characters long - all - to apply every permission at once

For the full set of shorthands available, see Mapping below.

Examples

For the --allow-read, --allow-write and --allow-run flags the corresponding characters are r, w and x:

deye rwx script.js

Flags taking values are simply passed after the string:

deye rw --allow-run="util" script.js

For --allow-all use all:

deye all script.js

Other options

The --no-prompt, --compat, --unstable, --config, --import-map, --check and --watch options are also available:

deye tcuCITW script.js

The default path for --config is 'deno.json', and for --import-map 'import_map.json', per the Deno docs.

Preview

To see the full command generated, without running it, the --preview or -p flag can be used (see Options below).

Mapping

Permissions - individual

• e --allow-env
• f --allow-ffi
• h --allow-hrtime
• n --allow-net
• s --allow-sys
• r --allow-read
• w --allow-write
• x --allow-run

Permissions - combined

• all --allow-all

Other options

• t --no-prompt ('throw')
• c --compat
• u --unstable
• C --config deno.json
• I --import-map=import_map.json
• T --check ('types')
• W --watch

NB Permission flag --allow-sys introduced in Deno v1.26.0. Retained for backward compatibility: --compat (mode removed in Deno v1.25.2).

Source

The script can be run with the command ./deye while in the same directory, and from elsewhere using the pattern path/to/deye, by first making it executable, if not already, with chmod +x deye. Once executable, it can be run from any directory with the simpler deye by placing it in a directory listed on the $PATH environment variable, e.g. '/bin' or '/usr/bin'.

The hashbang at the top of the file assumes the presence of Bash in '/bin', the source code that several utils and Deno itself are installed and can be invoked directly, e.g. Deno with deno. A list can be found close to the top of the file.

Defaults

The mapping is defined close to the top of the source file.

Making changes

Running the self-test after making changes plus extending or adding test cases to cover new behaviour is recommended. The self-test is run with the --test or -T flag (see Options below). The test cases are set in the perform_self_test function, which is the first primary function defined.

Options

The following can be passed to deye before the shorthand string:

• --preview / -p, to show but not run the full command generated then exit

The following can be passed to deye in place of the shorthand string:

• --show / -s, to grep the deno run help text for the flag mapped to the next argument, e.g. for '--allow-read' with -s r, then exit
• --version / -v, to show name and version number then exit
• --help / -h, to show help text, incl. the shorthands available, then exit
• --test / -T, to perform the self-test then exit

Streams

Sets of arguments can be piped to deye from another process, with each complete argument set occupying a single line and each line being handled individually.

If a batch of lines consists only of the additional arguments passed to deno run, the same shorthand string is used for all:

ls | grep .js | deye rwx

Alternatively, each line in a batch can include its own shorthand string:

echo -e "r read.js\nw write.js\nx run.js" > cmds.txt
cat cmds.txt | deye

Development plan

The following are the expected next steps in the development of the code base. The general medium-term aim is a more portable and robust implementation. Pull requests are welcome for these and other potential improvements.

• add automatic dependency checking with notification
• modify the show option for contextual awareness
• revise for full POSIX compatibility