readurl

Summary

readurl extends Zinit snippets to automatically discover and download the latest version of a file whose download URL is hosted on a webpage, using the dlink and dlink0 ices plus a special as'readurl|…' value.

Details

• Problem it solves: Download URLs for versioned releases (e.g., fzf-0.42.0-linux_amd64.tgz) change with every release. readurl scrapes the release page, extracts the current version, and constructs the correct download URL automatically.

• Works only with snippets, not with plugins.

• New ices:

  • dlink'{URL-pattern-with-%VERSION%}' — the download URL pattern; %VERSION% is replaced with the version found on the page
  • dlink0'{URL-pattern}' — for a two-level download page (e.g., HashiCorp-style): points to an intermediate page listing the actual download links; supports ! prefix to sort matched URLs/versions, and ~%filter-regex% suffix to exclude unwanted matches
  • as'readurl' / as'readurl|command' / as'readurl|completion' / as'readurl|null' — activates readurl processing; the part after | has the same meaning as a normal as'' value

• Shorthand without dlink: Append ++rest-of-download-url to the snippet URL to skip the dlink ice when the download URL differs from the page URL by only a few path segments; use extra + characters to strip conflicting sections.

• Install:

  zinit light zdharma-continuum/z-a-readurl

Examples

# Auto-download latest fzf for Linux from GitHub releases page
zinit for \
    as'readurl|command' \
    dlink'/junegunn/fzf-bin/releases/download/%VERSION%/fzf-%VERSION%-linux_amd64.tgz' \
    extract \
    id-as'fzf' \
  https://github.com/junegunn/fzf-bin/releases/

# Two-level page (HashiCorp terraform)
zinit for \
    as'readurl|command' \
    dlink0'/terraform/%VERSION%/' \
    dlink'/terraform/%VERSION%/terraform_%VERSION%_linux_386.zip' \
    extract \
    id-as'terraform' \
  http://releases.hashicorp.com/terraform/

# Sort + filter unwanted URLs (OpenShift client)
zinit for \
    as'readurl|command' \
    dlink'openshift-client-windows-%VERSION%.zip' \
    dlink0'!%VERSION%~%(stable|latest|fast|candidate).*%' \
    id-as'ocp' \
  https://mirror.openshift.com/pub/openshift-v4/clients/ocp/

# Pulumi — readurl|null with sbin for the binary
zi for \
    as'readurl|null' \
    dlink'https://get.pulumi.com/releases/sdk/pulumi-%VERSION%-linux-x64.tar.gz' \
    extract'!' \
    id-as'pulumi' \
    sbin'pulumi*' \
  https://www.pulumi.com/docs/get-started/install/versions/

Caveats / Common Mistakes

• readurl only works with snippet invocations (or the for syntax pointing at an HTTP URL), not with plugin loads.
• The dlink0 ice is only needed when the release download link is listed on a secondary page, not directly on the URL you pass to Zinit.
• Prepend ! to dlink or dlink0 to sort matched URLs when the page does not list versions newest-first.