Awesome
jql is a JSON Query Language tool built with Rust 🦀.
Pronounce it as jackal 🐺.
📜 Philosophy
- ⚡Be fast
- 🪶 Stay lightweight
- 🎮 Keep its features as simple as possible
- 🧠 Avoid redundancy
- 💡 Provide meaningful error messages
- 🍰 Eat JSON as input, process, output JSON back
🚀 Installation
Alpine Linux
The package is maintained by @jirutka.
apk add jql
Archlinux
The AUR package is maintained by @barklan.
yay -S jql
Cargo
cargo install jql
Cargo Binstall
cargo binstall jql
Fedora
dnf install jql
FreeBSD
pkg install jql
Homebrew
brew install jql
Nix
nix-env -i jql
openSUSE
zypper install jql
Manual installation from GitHub
Compiled binary versions are automatically uploaded to GitHub when a new release is made. You can install jql manually by downloading a release.
🛠️ Usage
To make a selection from a JSON input, jql expects a query as a sequence of tokens.
To be fully compliant with the JSON format, jql always expect key selectors to be double-quoted, see The JavaScript Object Notation (JSON) Data Interchange Format.
{
".valid": 1337,
"": "yeah!",
"\"": "yup, valid too!"
}
Consequently, to be shell compliant, a query must be either enclosed by single quotation marks or every inner double quotation mark must be escaped.
Separators
Group separator
Group separators build up an array from sub-queries.
JSON input
{ "a": 1, "b": 2, "c": 3 }
Query
'"a","b","c"'
JSON output
[1, 2, 3]
Selectors
Arrays
Array index selector
Indexes can be used in arbitrary order.
JSON input
[1, 2, 3]
Query
'[2,1]'
JSON output
[3, 2]
Array range selector
Range can be in natural order [0:2], reversed [2:0], without lower [:2] or upper bound [0:].
JSON input
[1, 2, 3]
Query
'[2:1]'
JSON output
[3, 2]
Lens selector
Lens can be a combination of one or more selectors with or an optional value, a value being any of boolean | null | number | string.
JSON input
[
{ "a": 1, "b": { "d": 2 } },
{ "a": 2, "b": "some" },
{ "a": 2, "b": { "d": null } },
{ "a": 2, "b": true },
{ "c": 3, "b": 4 }
]
Query
'|={"b""d"=2, "c"}'
JSON output
[
{ "a": 1, "b": { "d": 2 } },
{ "c": 3, "b": 4 }
]
Objects
Key selector
Any valid JSON key can be used.
JSON input
{ "a": 1, "b": 2, "c": 3 }
Query
'"c"'
JSON output
3
Multi key selector
Keys can be used in arbitrary order.
JSON input
{ "a": 1, "b": 2, "c": 3 }
Query
'{"c","a"}'
JSON output
{ "c": 3, "a": 1 }
Object index selector
Indexes can be used in arbitrary order.
JSON input
{ "a": 1, "b": 2, "c": 3 }
Query
'{2,0}'
JSON output
{ "c": 3, "a": 1 }
Object range selector
Range can be in natural order {0:2}, reversed {2:0}, without lower {:2} or upper bound {0:}.
JSON input
{ "a": 1, "b": 2, "c": 3 }
Query
'{2:1}'
JSON output
{ "c": 3, "b": 2 }
Operators
Flatten operator
Flattens arrays and objects.
JSON input
[[[[[[[[[[[[[[{ "a": 1 }]]]]]]]]]]]]], [[[[[{ "b": 2 }]]]], { "c": 3 }], null]
Query
'..'
JSON output
[{ "a": 1 }, { "b": 2 }, { "c": 3 }, null]
JSON input
{ "a": { "c": false }, "b": { "d": { "e": { "f": 1, "g": { "h": 2 } } } } }
Query
'..'
JSON output
{
"a.c": false,
"b.d.e.f": 1,
"b.d.e.g.h": 2
}
Keys operator
Returns the keys of an object or the indices of an array. Other primitives are returned as is.
JSON input
{ "a": 1, "b": 2, "c": 3 }
Query
'@'
JSON output
["a", "b", "c"]
Pipe in operator
Applies the next tokens in parallel on each element of an array.
JSON input
{ "a": [{ "b": { "c": 1 } }, { "b": { "c": 2 } }] }
Query
'"a"|>"b""c"'
JSON output
[1, 2]
Pipe out operator
Stops the parallelization initiated by the pipe in operator.
JSON input
{ "a": [{ "b": { "c": 1 } }, { "b": { "c": 2 } }] }
Query
'"a"|>"b""c"<|[1]'
JSON output
2
Truncate operator
Maps the output into simple JSON primitives boolean | null | number | string | [] | {}.
JSON input
{ "a": [1, 2, 3] }
Query
'"a"!'
JSON output
[]
💻 Shell integration
How to save the output
jql '"a"' input.json > output.json
How to read from stdin
cat test.json | jql '"a"'
Available flags
Inline the JSON output
By default, the output is pretty printed in a more human-readable way, this can be disabled.
-i, --inline
Read the query from file
The command will read the provided query from a file instead of the stdin.
-q, --query <FILE>
Write to stdout without JSON double-quotes
This can be useful to drop the double-quotes surrounding a string primitive.
-r, --raw-string
Read a stream of JSON data line by line
This flag is only about reading processing any JSON output streamed line by line (e.g. Docker logs with the --follow flag). This is not an option to read an incomplete streamed content (e.g. a very large input).
-s, --stream
Validate the JSON data
The command will return a matching exit code based on the validity of the JSON content or file provided.
-v, --validate
Print help
-h, --help
Print version
-V, --version
Help
jql -h
jql --help
🦀 Workspace
This project is composed of following crates:
- jql (binary)
- jql-parser (library)
- jql-runner (library)
Development
Some commands are available as a justfile at the root of the workspace (testing / fuzzing).
Prerequisites
Commands
just --list
⚠️ Non-goal
There's no plan to align jql with jq or any other similar tool.
⚡ Performance
Some benchmarks comparing a set of similar functionalities provided by this tool and jq are available here.