Examples

The Slumber CLI can be composed with other CLI tools, making it a powerful tool for scripting and bulk tasks. Here are some examples of how to use it with common tools.

Note: These examples are written for a POSIX shell (bash, zsh, etc.). It assumes some basic familiarity with shell features such as pipes. Unfortunately I have no shell experience with Windows so I can't help you there :(

Filtering responses with jq

Let's say you want to fetch the name of each fish from your fish-tracking service. Here's your collection file:

requests:
  list_fish: !request
    method: GET
    url: "https://myfishes.fish/fishes"

This endpoint returns a response like:

[
  {
    "kind": "barracuda",
    "name": "Jimmy"
  },
  {
    "kind": "striped bass",
    "name": "Balthazar"
  },
  {
    "kind": "rockfish",
    "name": "Maureen"
  }
]

You can fetch this response and filter it down to just the names:

slumber rq list_fish | jq -r '.[].name'

And the output:

Jimmy
Balthazar
Maureen

Running requests in parallel with xargs

Building on the previous example, let's say you want to fetch details on each fish returned from the list response. We'll add a get_fish recipe to the collection. By default, the fish name will come from a prompt:

chains:
  fish_name:
    source: !prompt
      message: "Which fish?"

requests:
  list_fish: !request
    method: GET
    url: "https://myfishes.fish/fishes"

  get_fish: !request
    method: GET
    url: "https://myfishes.fish/fishes/{{chains.fish_name}}"

We can use xargs and the -o flag of slumber request to fetch details for each fish in parallel:

slumber rq list_fish | jq -r '.[].name' > fish.txt
cat fish.txt | xargs -L1 -I'{}' -P3 slumber rq get_fish -o chains.fish_name={} --output {}.json

Let's break this down:

• -L1 means to consume one argument (in this case, one fish name) per invocation of slumber
• -I{} sets the substitution string, i.e. the string that will be replaced with each argument
• -P3 tells xargs the maximum number of processes to run concurrently, which in this case means the maximum number of concurrent requests
• Everything else is the slumber command
  • -o chains.fish_name={} chains.fish_name` with the argument from the file, so it doesn't prompt for a name
  • --output {}.json writes to a JSON file with the fish's name (e.g. Jimmy.json)