Encode is a middleware which can encode responses.

Field name	Field type	Comment
EncodingsRaw	caddy.ModuleMap	Selection of compression algorithms to choose from. The best one will be chosen based on the client's Accept-Encoding header.
Prefer	[]string	If the client has no strong preference, choose these encodings in order.
MinLength	int	Only encode responses that are at least this many bytes long.
Matcher	*caddyhttp.ResponseMatcher	Only encode responses that match against this ResponseMmatcher. The default is a collection of text-based Content-Type headers.
writerPools	map[string]*sync.Pool	No comment on field.

Encoder is a type which can encode a stream of data.

Field name	Field type	Comment
type	any	No comment on field.

Encoding is a type which can create encoders of its kind and return the name used in the Accept-Encoding header.

Field name	Field type	Comment
type	any	No comment on field.

Precompressed is a type which returns filename suffix of precompressed file and Accept-Encoding header to use when serving this file.

Field name	Field type	Comment
type	any	No comment on field.

encodingPreference pairs an encoding with its q-factor.

Field name	Field type	Comment
encoding	string	No comment on field.
q	float64	No comment on field.
preferOrder	int	No comment on field.

responseWriter writes to an underlying response writer using the encoding represented by encodingName and configured by config.

Field name	Field type	Comment
	http.ResponseWriter	No comment on field.
encodingName	string	No comment on field.
w	Encoder	No comment on field.
config	*Encode	No comment on field.
statusCode	int	No comment on field.
wroteHeader	bool	No comment on field.
isConnect	bool	No comment on field.

used to mask ReadFrom method

Field name	Field type	Comment
	io.Writer	No comment on field.

AcceptedEncodings returns the list of encodings that the client supports, in descending order of preference. The client preference via q-factor and the server preference via Prefer setting are taken into account. If the Sec-WebSocket-Key header is present then non-identity encodings are not considered. See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html.

Uses: math.Abs, slices.Index, sort.Slice, strconv.ParseFloat, strings.HasPrefix, strings.Split, strings.ToLower, strings.TrimSpace.

Match determines, if encoding should be done based on the ResponseMatcher.

Provision provisions enc.

Uses: caddyhttp.ResponseMatcher, fmt.Errorf, http.Header.

Uses: http.MethodConnect, strings.HasPrefix, strings.HasSuffix, strings.TrimSuffix.

UnmarshalCaddyfile sets up the handler from Caddyfile tokens. Syntax:

encode [<matcher>] <formats...> {
    gzip           [<level>]
    zstd
    minimum_length <length>
    # response matcher block
    match {
        status <code...>
        header <field> [<value>]
    }
    # or response matcher single line syntax
    match [header <field> [<value>]] | [status <code...>]
}

Specifying the formats on the first line will use those formats' defaults.

Uses: caddyconfig.JSON, caddyfile.UnmarshalModule, caddyhttp.ParseNamedResponseMatcher, caddyhttp.ResponseMatcher, strconv.Atoi.

Validate ensures that enc's configuration is valid.

Uses: fmt.Errorf.

Close writes any remaining buffered response and deallocates any active resources.

Uses: strconv.Atoi.

FlushError is an alternative Flush returning an error. It delays the actual Flush of the underlying ResponseWriterWrapper until headers were written.

Uses: http.NewResponseController, http.StatusOK.

ReadFrom will try to use sendfile to copy from the reader to the response writer. It's only used if the response writer implements io.ReaderFrom and the data can't be compressed. It's based on stdlin http1.1 response writer implementation. https://github.com/golang/go/blob/f4e3ec3dbe3b8e04a058d266adf8e048bab563f2/src/net/http/server.go#L586

Uses: io.Copy, io.CopyBuffer, io.LimitReader, io.ReaderFrom.

Unwrap returns the underlying ResponseWriter.

Write writes to the response. If the response qualifies, it is encoded using the encoder, which is initialized if not done so already.

Uses: http.DetectContentType, http.StatusOK, strconv.Atoi.

WriteHeader stores the status to write when the time comes to actually write the header.

Uses: http.StatusNotModified.

CaddyModule returns the Caddy module information.