feat(download): Allow downloading without installing

CHANGELOG.md

@@ -1,6 +1,10 @@
 <a name="unreleased"></a>
 ## [Unreleased]
 
+### Features
+
+- **scoop-download:** Add `scoop download` command ([#4621](https://github.com/ScoopInstaller/Scoop/issues/4621))
+
 ### Bug Fixes
 
 - **autoupdate:** Allow checksum file that contains whitespaces ([#4619](https://github.com/ScoopInstaller/Scoop/issues/4619))

libexec/scoop-download.ps1

@@ -0,0 +1,127 @@
+# Usage: scoop download <app> [options]
+# Summary: Download apps in the cache folder
+# Help: e.g. The usual way to download an app, without installing it (uses your local 'buckets'):
+#      scoop download git
+#
+# To download an app from a manifest at a URL:
+#      scoop download https://raw.githubusercontent.com/ScoopInstaller/Main/master/bucket/runat.json
+#
+# To download an app from a manifest on your computer
+#      scoop download path\to\app.json
+#
+# Options:
+#   -f, --force               Force download (overwrite cache)
+#   -s, --skip                Skip hash validation (use with caution!)
+#   -a, --arch <32bit|64bit>  Use the specified architecture, if the app supports it
+
+. "$psscriptroot\..\lib\manifest.ps1"
+. "$psscriptroot\..\lib\install.ps1"
+. "$psscriptroot\..\lib\help.ps1"
+. "$psscriptroot\..\lib\getopt.ps1"
+
+reset_aliases
+
+$opt, $apps, $err = getopt $args 'fsa:' 'force', 'skip', 'arch='
+if ($err) { error "scoop download: $err"; exit 1 }
+
+$check_hash = !($opt.s -or $opt.skip)
+$use_cache = !($opt.f -or $opt.force)
+$architecture = default_architecture
+try {
+    $architecture = ensure_architecture ($opt.a + $opt.arch)
+} catch {
+    abort "ERROR: $_"
+}
+
+if (!$apps) { error '<app> missing'; my_usage; exit 1 }
+
+if (is_scoop_outdated) {
+    scoop update
+}
+
+# we only want to show this warning once
+if(!$use_cache) { warn "Cache is being ignored." }
+
+foreach ($curr_app in $apps) {
+    # Prevent leaking variables from previous iteration
+    $bucket = $version = $app = $manifest = $url = $null
+
+    $app, $bucket, $version = parse_app $curr_app
+    $app, $manifest, $bucket, $url = Find-Manifest $app $bucket
+
+    info "Starting download for $app"
+
+    # Generate manifest if there is different version in manifest
+    if (($null -ne $version) -and ($manifest.version -ne $version)) {
+        $generated = generate_user_manifest $app $bucket $version
+        if ($null -eq $generated) {
+            error 'Manifest cannot be generated with provided version'
+            continue
+        }
+        $manifest = parse_json($generated)
+    }
+
+    if(!$manifest) {
+        error "Couldn't find manifest for '$app'$(if($url) { " at the URL $url" })."
+        continue
+    }
+    $version = $manifest.version
+    if(!$version) { 
+        error "Manifest doesn't specify a version."
+        continue
+    }
+    if($version -match '[^\w\.\-\+_]') {
+        error "Manifest version has unsupported character '$($matches[0])'."
+        continue
+    }
+
+    $curr_check_hash = $check_hash
+    if ($version -eq 'nightly') {
+        $version = nightly_version $(get-date)
+        $curr_check_hash = $false
+    }
+
+    if(!(supports_architecture $manifest $architecture)) {
+        error "'$app' doesn't support $architecture architecture!"
+        continue
+    }
+
+    if(Test-Aria2Enabled) {
+        dl_with_cache_aria2 $app $version $manifest $architecture $cachedir $manifest.cookie $use_cache $curr_check_hash
+    } else {
+        foreach($url in script:url $manifest $architecture) {
+            try {
+                dl_with_cache $app $version $url $null $manifest.cookie $use_cache
+            } catch {
+                write-host -f darkred $_
+                error "URL $url is not valid"
+                continue
+            }
+
+            if($curr_check_hash) {
+                $manifest_hash = hash_for_url $manifest $url $architecture
+                $cached = cache_path $app $version $url
+                $ok, $err = check_hash $cached $manifest_hash (show_app $app $bucket)
+
+                if(!$ok) {
+                    error $err
+                    if(test-path $cached) {
+                        # rm cached file
+                        Remove-Item -force $cached
+                    }
+                    if ($url -like '*sourceforge.net*') {
+                        warn 'SourceForge.net is known for causing hash validation fails. Please try again before opening a ticket.'
+                    }
+                    error (new_issue_msg $app $bucket "hash check failed")
+                    continue
+                }
+            } else {
+                info "Skipping hash verification."
+            }
+        }
+    }
+
+    success "'$app' ($version) was downloaded successfully!"
+}
+
+exit 0