templates: Add `humanize` function (#4767)

Co-authored-by: Francis Lavoie <lavofr@gmail.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/modules/caddyhttp/templates/templates.go b/modules/caddyhttp/templates/templates.go
index b2fe184..85612ba 100644
--- a/modules/caddyhttp/templates/templates.go
+++ b/modules/caddyhttp/templates/templates.go
@@ -238,6 +238,29 @@ func init() {
 // {{stripHTML "Shows <b>only</b> text content"}}
 // ```
 //
+// ##### `humanize`
+//
+// Transforms size and time inputs to a human readable format.
+// This uses the [go-humanize](https://github.com/dustin/go-humanize) library.
+//
+// The first argument must be a format type, and the last argument
+// is the input, or the input can be piped in. The supported format
+// types are:
+// - **size** which turns an integer amount of bytes into a string like `2.3 MB`
+// - **time** which turns a time string into a relative time string like `2 weeks ago`
+//
+// For the `time` format, the layout for parsing the input can be configured
+// by appending a colon `:` followed by the desired time layout. You can
+// find the documentation on time layouts [in Go's docs](https://pkg.go.dev/time#pkg-constants).
+// The default time layout is `RFC1123Z`, i.e. `Mon, 02 Jan 2006 15:04:05 -0700`.
+//
+// ```
+// {{humanize "size" "2048000"}}
+// {{placeholder "http.response.header.Content-Length" | humanize "size"}}
+// {{humanize "time" "Fri, 05 May 2022 15:04:05 +0200"}}
+// {{humanize "time:2006-Jan-02" "2022-May-05"}}
+// ```
+
 type Templates struct {
 	// The root path from which to load files. Required if template functions
 	// accessing the file system are used (such as include). Default is