BARB

Barb is a file-based API query tool that works nicely with version control and fits into UNIX terminal usage.

Table of Contents

• BARB
  • Installation
  • Example usage
    • CLI options
  • Barb format
    • Verb line
    • Headers
    • Filter
      • JSONPath
      • JQ
    • Dependencies
    • Body
    • Variable substitution
      • Placeholder format
      • Default value
  • Credits

Installation

Barb is only available through Cargo at this time. To install the default version with JSONPath only, install rust with rustup.do like so:

cargo install barb

If you'd like to have JQ filtering; ensure the libjq is installed on your machine, then run:

cargo install barb --features jq

Example usage

barb [options] <file 1> <file 2> ... <file n>

CLI options

• -a, --all-headers: Print all headers, request and response
• -b, --body: Only print the response body
• -h, --headers: Only print the response headers
• -r, --raw: Don't format the response body
• -V, --version: Print the software version
• -n, --no-color: Don't use color output
• -f, --filter: A JSON path to override any filters defined in the barb file
• -F, --no-filter: Disable all filters (except for dependencies)
• --hdr <HDR>: Set/override a header with format NAME=VALUE, can appear multiple times (does not affect dependencies)
• --help: Displays the help page

Barb format

Barb uses a custom file format to perform requests. Each file contains one request and is started by a request preamble. Example:

#POST^http://my-blog.com/posts
#Authorization: TOKEN {API_TOKEN}
#$$.filter

{
    "title": "A post",
    "content": "My pretty blog post"
}

The preamble contains the directives relevant to performing the request, such as the method, URL and headers. The preamble must end with an empty line.

Verb line

The verb line indicates to barb what sort of request to perform and where to. It follows this rigid format:

#<METHOD>^<URL>

The URL supports variable substitution, but METHOD does not.

Supported methods are:

• GET
• POST
• PUT
• DELETE
• PATCH

Headers

Headers are formatted as follows:

#<HEADER NAME>: <HEADER VALUE>

The HEADER VALUE supports variable substitution, HEADER NAME does not.

There can be none or many headers.

Filter

Barb supports JSONPath filtering by default, and optionally JQ.

JSONPath

Barb supports filtering of the response body with JSONPath. This has the following format:

#$<JSON path>

The PATH supports variable substitution. Refer to the JSONPath for more information on the filters and their syntax.

Filters can be named to populate execution variables by extracting values. Consider the following that will set the value of variable FOOBAR:

#FOOBAR$<JSON path>

JQ

Barb supports JQ filtering of the response body. This has the following format:

#|<JQ FILTER>

The JQ FILTER supports variable substitution. Refer to the JQ manual for more information on the filters and their syntax.

Filters can be named to populate execution variables by extracting values. Consider the following that will set the value of variable FOOBAR:

#FOOBAR|<JQ FILTER>

Dependencies

A barb file can declare only one dependency which will be executed before the main file is executed. If multiple dependencies are declared, only the last one will be executed.

Syntax:

#>relative/path/to/file.barb

The path to the dependency can either be relative to the current file or absolute. When running multiple barb files which have the same dependency, that dependency will only be executed once.

A barb dependency cannot have dependencies of its own. Any dependency declared within a dependency will simply be ignored.

Body

Anything after the preamble is considered as a body and will be send in the request for the following methods:

• PUT
• POST
• PATCH

Body does not support variable substitution.

Variable substitution

Barb can include environment variable values and variables defined in .env into the requests with the following placeholder format:

Placeholder format

{VARIABLE NAME}

This allows to do the following:

$ export BASE_URL="http://127.0.0.1:8000"
$ cat api-status.barb
#GET^{BASE_URL}/api/v1/status

$ barb api-status.barb
GET http://127.0.0.1:8000/api/v1/status

200 OK

{"status": "OK"}

Default value

A placholder can be given a default value that will be used if the environment variable is not available. The format is as follows:

{VARIABLE NAME:-DEFAULT}

Example:

$ cat api-ping.barb
#GET^http://{HOST:-foobar.com}/api/ping

$ barb api-ping.barb
GET http://foobar.com/api/ping

200 OK

{"response": "pong"}

$ HOST=bar.com barb api-ping.barb
GET http://bar.com/api/ping

200 OK

{"response": "pong"}

Credits

• Code: Guillaume Pasquet
• Logo: Harpoon Chain Icon by Lorc under CC By 3.0