JMESPath – A query language for JSON • Hacker News Board

JMESPath – A query language for JSON

#1

Post by selrond » Sat, Feb 17, 2018, 11:59 AM UTC

JMESPath – A query language for JSON
jmespath.org

Re: JMESPath – A query language for JSON

#2

Post by zero_intp » Sat, Feb 17, 2018, 12:48 PM UTC

Thanks for taking the time to write this tool. Can you explain how it is distinguished from jq?

Re: JMESPath – A query language for JSON

#3

Post by maxsavin » Sat, Feb 17, 2018, 12:49 PM UTC

This looks interesting - but doesn't MongoDB basically achieve the same effect? I kind of prefer MongoDB because you query JSON with JSON - but I'm open to changing my mind :)

Re: JMESPath – A query language for JSON

#4

Post by eli » Sat, Feb 17, 2018, 12:58 PM UTC

May also be interested in the `jq` CLI, which on first glance appears to use a similar but not identical query language. https://stedolan.github.io/jq/

Re: JMESPath – A query language for JSON

#5

Post by crooked-v » Sat, Feb 17, 2018, 12:59 PM UTC

The example on the front page seems equivalent to (and only marginally less verbose than):

    locations
      .filter(l => l.state === 'WA')
      .map(l => l.name)
      .sort()
      .join(', ')

Re: JMESPath – A query language for JSON

#6

Post by avoidwork » Sat, Feb 17, 2018, 1:03 PM UTC

why choose this over jsonpath (like xmlpath) or jq?

Re: JMESPath – A query language for JSON

#7

Post by skywhopper » Sat, Feb 17, 2018, 1:07 PM UTC

maxsavin wrote: post #3

This looks interesting - but doesn't MongoDB basically achieve the same effect? I kind of prefer MongoDB because you query JSON with JSON - but I'm open to changing my mind :)

If you're using MongoDB already, then sure use MongoDB's query tools. But if you are just working with raw JSON from a potential variety of sources, or in a streaming context, then you need something more in-place and general-purpose, which this appears to be.

Re: JMESPath – A query language for JSON

#8

Post by skywhopper » Sat, Feb 17, 2018, 1:09 PM UTC

crooked-v wrote: post #5

The example on the front page seems equivalent to (and only marginally less verbose than): locations .filter(l => l.state === 'WA') .map(l => l.name) .sort() .join(', ')

I'm guessing the point is to be a common type of query language that can be used from any number of other languages: http://jmespath.org/libraries.html

In at least some languages if these queries can be used without deserializing into a native data structure and then serialized back into a string, this could be a major win.

Re: JMESPath – A query language for JSON

#9

Post by jeswin » Sat, Feb 17, 2018, 1:10 PM UTC

crooked-v wrote: post #5

The example on the front page seems equivalent to (and only marginally less verbose than): locations .filter(l => l.state === 'WA') .map(l => l.name) .sort() .join(', ')

Your example however will not support dynamic or user-configurable paths without eval(). Alternatively, instead of eval you could run expressions through a JS parser, but it'll be more code than your example. The library we're discussing also defines a grammar for the query language.

Re: JMESPath – A query language for JSON

#10

Post by nimish » Sat, Feb 17, 2018, 1:13 PM UTC

jq exists, is fast, and works well. Is this compatible?