Add "raw" flag equivalent for JQ

[LorisFriedel]

Hello! Thank you for the amazing work :)

I would like to suggest the possibility to output a string using JQ but with the equivalent of "-r" or "--raw" we can find on the official jq command: this allows to get a clean output for a single field for example, instead of having to sanitize it by doing some triming.

What do you think?

Thanks!

[bitfield]

Nice suggestion, @LorisFriedel! Can you give a brief example of a program like this, showing how you'd like this behaviour to work?

[LorisFriedel]

For example, I would ideally do this to find a single element in a json object and use it directly:

nodeName, err := script.
		Exec("kubectl get pod myPod -o json").
		JQRaw(".spec.nodeName").
		String()

// output would be: xxx-ffkch-something-e32as-someregion-gsbn4

Today, that's what I need to do:

nodeName, err := script.
		Exec("kubectl get pod myPod -o json").
		JQ(".spec.nodeName").
		String()

// output is: "xxx-ffkch-something-e32as-someregion-gsbn4"\n

nodeName = strings.Trim(strings.TrimSpace(nodeName), "\"") // extra step to sanitze the output
// output is then: xxx-ffkch-something-e32as-someregion-gsbn4

In fact the trailing "\n" is almost always a bit of a pain to handle, not really related to JQ :/

[bitfield]

Maybe this could be done with a more general-purpose trim method—something like Trim?

nodeName, err := script.
		Exec("kubectl get pod myPod -o json").
		JQ(".spec.nodeName").
		Trim().
		String()
// output would be: xxx-ffkch-something-e32as-someregion-gsbn4

[LorisFriedel]

This could be, but the trim would need to strip spaces AND quotes, and that would make it a weird "Trim" method I guess, WDYT?

[bitfield]

Maybe there's a better name for this...

[LorisFriedel]

Maybe just a Trim(cutset string) and TrimSpace() functions could be perfectly suited here, easy to implement and easy to understand as they match their strings.Trim and strings.TrimSpace equivalent! WDYT?

[bitfield]

I'd like to gather a bit more data on exactly how people are using JQ within script programs, so that we can come up with an API which fits well in that context. So if you're reading this issue and you have a program that uses jq queries, please post it in a comment!

[kwilczynski]

Hi @bitfield,

I'd like to gather a bit more data on exactly how people are using JQ within script programs, so that we can come up with an API which fits well in that context. So if you're reading this issue and you have a program that uses jq queries, please post it in a comment!

I cannot speak for every jq user out there however, using jq with the -r command-line switch is definitely a thing, as otherwise, you often have to resort to some sed, grep or awk invocation to remove the unwanted quoting and/or newlines.

Update:

That said, given your proposal in the comments #125 (comment) and #125 (comment), perhaps we could add Trim(), we could also add good 'ol Tr() (man 1 tr) to keep it close to the shell scripting as much as possible.

[bitfield]

using jq with the -r command-line switch is definitely a thing

I believe you, but we need a realistic example to use as the input to the design process.

[kwilczynski]

Hi @bitfield,

using jq with the -r command-line switch is definitely a thing

I believe you, but we need a realistic example to use as the input to the design process.

Thinking about it some more... I wouldn't do it.

Adding some convenience functions like Trim() or Strip(), and also Tr() might be a better alternative - new API could be easily reused somewhere else, other than removing bloat from jq's output.

[LorisFriedel]

Anything like Trim(), Strip() and such would save a lot a painful code handling those polluted outputs indeed!

[bitfield]

Is there any example you can think of where a 'trim spaces and quotes' method would be used with anything other than JQ?

[LorisFriedel]

For the "trim quote" part, not really, but for the "trim space" part I guess everywhere where Fprintln() function is used in the library could be a good candidate, as when getting the output of something you generally don't want additional whitespace that serves no purposes!

[kwilczynski]

Hi @bitfield,

Is there any example you can think of where a 'trim spaces and quotes' method would be used with anything other than JQ?

I think, if anything, we would want the following:

• Trim() (or Strip(); whichever naming works best)
• Tr(set1, set2)

The Trim() can be used as part of the pipeline and such to sanitise whitespaces - both leading and trailing at once. Perhaps a specialised variety could be added too if it at all makes sense, so that would be TripLeading() and TrimTrailing(), but I am not sure if we need this (an open question here).

An example use case (aside from using it for JQ): working with a result of a process spawned with Exec() to clean up output from the external process.

The Tr(), that could be used to strip anything... anything you see fit from the pipeline.

For example:

script.Exec(`echo 'a"  b`).Tr(`" `, "").Stdout()

Would produce:

ab

This would be akin to running tr -d where leaving the second argument empty would mean we want to remove the set that matches rather than replace it with something as far as an API idea goes.

[bitfield]

An example use case (aside from using it for JQ): working with a result of a process spawned with Exec() to clean up output from the external process.

The problem I see is that a Trim method specialised for trimming jq output most likely wouldn't be much use for anything else.

Conversely, a Trim method that's configurable enough to trim both jq data and a variety of other cases would probably require an inconvenient amount of paperwork.

It's possible that we could get the best of both worlds, by providing a Trim method that performs general-purpose substitution, like tr, and also a "raw mode" for JQ that could use Trim under the hood.