pressly/minify

Name: minify

Owner: Pressly Inc.

Description: Go minifiers for web formats

Forked from: tdewolff/minify

Created: 2017-06-26 23:13:40.0

Updated: 2017-06-26 23:13:41.0

Pushed: 2017-06-05 20:11:18.0

Homepage:

Size: 962

Language: Go

GitHub Committers

UserMost Recent Commit# Commits

Other Committers

UserEmailMost Recent Commit# Commits

README

Minify Build Status GoDoc Coverage Status Join the chat at https://gitter.im/tdewolff/minify

The preferred stable release is v2. Master has some new changes for SVG that haven't yet endured the test of time, bug reports are appreciated.

Online demo if you need to minify files now.

Command line tool that minifies concurrently and supports watching file changes.

All releases on Equinox for various platforms.

If this software is useful to you, consider making a donation! When a significant amount has been deposited, I will write a much improved JS minifier.

Minify is a minifier package written in Go. It provides HTML5, CSS3, JS, JSON, SVG and XML minifiers and an interface to implement any other minifier. Minification is the process of removing bytes from a file (such as whitespace) without changing its output and therefore shrinking its size and speeding up transmission over the internet and possibly parsing. The implemented minifiers are high performance and streaming, which implies O(n).

The core functionality associates mimetypes with minification functions, allowing embedded resources (like CSS or JS within HTML files) to be minified as well. Users can add new implementations that are triggered based on a mimetype (or pattern), or redirect to an external command (like ClosureCompiler, UglifyCSS, …).

Table of Contents Status
Prologue

Minifiers or bindings to minifiers exist in almost all programming languages. Some implementations are merely using several regular-expressions to trim whitespace and comments (even though regex for parsing HTML/XML is ill-advised, for a good read see Regular Expressions: Now You Have Two Problems). Some implementations are much more profound, such as the YUI Compressor and Google Closure Compiler for JS. As most existing implementations either use Java or JavaScript and don't focus on performance, they are pretty slow. And loading the whole file into memory is bad for really large files (or impossible for infinite streams).

This minifier proves to be that fast and extensive minifier that can handle HTML and any other filetype it may contain (CSS, JS, …). It streams the input and output and can minify files concurrently.

Installation

Run the following command

go get github.com/tdewolff/minify

or add the following imports and run the project with go get

rt (
"github.com/tdewolff/minify"
"github.com/tdewolff/minify/css"
"github.com/tdewolff/minify/html"
"github.com/tdewolff/minify/js"
"github.com/tdewolff/minify/json"
"github.com/tdewolff/minify/svg"
"github.com/tdewolff/minify/xml"
API stability

There is no guarantee for absolute stability, but I take issues and bugs seriously and don't take API changes lightly. The library will be maintained in a compatible way unless vital bugs prevent me from doing so. There has been one API change after v1 which added options support and I took the opportunity to push through some more API clean up as well. There are no plans whatsoever for future API changes.

The API differences between v1 and v2 are listed below. If m := minify.New() and w and r are your writer and reader respectfully, then v1 → v2:

Testing

For all subpackages and the imported parse and buffer packages, test coverage of 100% is pursued. Besides full coverage, the minifiers are fuzz tested using github.com/dvyukov/go-fuzz, see the wiki for the most important bugs found by fuzz testing. Furthermore am I working on adding visual testing to ensure that minification doesn't change anything visually. By using the WebKit browser to render the original and minified pages we can check whether any pixel is different.

These tests ensure that everything works as intended, the code does not crash (whatever the input) and that it doesn't change the final result visually. If you still encounter a bug, please report here!

HTML

HTML (with JS and CSS) minification typically runs at about 40MB/s ~= 140GB/h, depending on the composition of the file.

Website | Original | Minified | Ratio | Time* ——- | ——– | ——– | —– | ———————– Amazon | 463kB | 414kB | 90% | 10ms BBC | 113kB | 96kB | 85% | 3ms StackOverflow | 201kB | 182kB | 91% | 5ms Wikipedia | 435kB | 410kB | 94%** | 11ms

*These times are measured on my home computer which is an average development computer. The duration varies a lot but it's important to see it's in the 10ms range! The benchmark uses all the minifiers and excludes reading from and writing to the file from the measurement.

**Is already somewhat minified, so this doesn't reflect the full potential of this minifier.

The HTML5 minifier uses these minifications:

Options:

After recent benchmarking and profiling it became really fast and minifies pages in the 10ms range, making it viable for on-the-fly minification.

However, be careful when doing on-the-fly minification. Minification typically trims off 10% and does this at worst around about 20MB/s. This means users have to download slower than 2MB/s to make on-the-fly minification worthwhile. This may or may not apply in your situation. Rather use caching!

Whitespace removal

The whitespace removal mechanism collapses all sequences of whitespace (spaces, newlines, tabs) to a single space. If the sequence contained a newline or carriage return it will collapse into a newline character instead. It trims all text parts (in between tags) depending on whether it was preceded by a space from a previous piece of text and whether it is followed up by a block element or an inline element. In the former case we can omit spaces while for inline elements whitespace has significance.

Make sure your HTML doesn't depend on whitespace between block elements that have been changed to inline or inline-block elements using CSS. Your layout should not depend on those whitespaces as the minifier will remove them. An example is a menu consisting of multiple <li> that have display:inline-block applied and have whitespace in between them. It is bad practise to rely on whitespace for element positioning anyways!

CSS

Minification typically runs at about 25MB/s ~= 90GB/h.

Library | Original | Minified | Ratio | Time* ——- | ——– | ——– | —– | ———————– Bootstrap | 134kB | 111kB | 83% | 4ms Gumby | 182kB | 167kB | 90% | 7ms

*The benchmark excludes the time reading from and writing to a file from the measurement.

The CSS minifier will only use safe minifications:

It does purposely not use the following techniques:

It's great that so many other tools make comparison tables: CSS Minifier Comparison, CSS minifiers comparison and CleanCSS tests. From the last link, this CSS minifier is almost without doubt the fastest and has near-perfect minification rates. It falls short with the purposely not implemented and often unsafe techniques, so that's fine.

Options:

JS

The JS minifier is pretty basic. It removes comments, whitespace and line breaks whenever it can. It employs all the rules that JSMin does too, but has additional improvements. For example the prefix-postfix bug is fixed.

Minification typically runs at about 50MB/s ~= 180GB/h. Common speeds of PHP and JS implementations are about 100-300kB/s (see Uglify2, Adventures in PHP web asset minimization).

Library | Original | Minified | Ratio | Time* ——- | ——– | ——– | —– | ———————– ACE | 630kB | 442kB | 70% | 12ms jQuery | 242kB | 130kB | 54% | 5ms jQuery UI | 459kB | 300kB | 65% | 10ms Moment | 97kB | 51kB | 52% | 2ms

*The benchmark excludes the time reading from and writing to a file from the measurement.

TODO:

JSON

Minification typically runs at about 95MB/s ~= 340GB/h. It shaves off about 15% of filesize for common indented JSON such as generated by JSON Generator.

The JSON minifier only removes whitespace, which is the only thing that can be left out.

SVG

Minification typically runs at about 15MB/s ~= 55GB/h. Performance improvement are due.

The SVG minifier uses these minifications:

TODO:

Options:

XML

Minification typically runs at about 70MB/s ~= 250GB/h.

The XML minifier uses these minifications:

Options:

Usage

Any input stream is being buffered by the minification functions. This is how the underlying buffer package inherently works to ensure high performance. The output stream however is not buffered. It is wise to preallocate a buffer as big as the input to which the output is written, or otherwise use bufio to buffer to a streaming writer.

New

Retrieve a minifier struct which holds a map of mediatype → minifier functions.

 minify.New()

The following loads all provided minifiers.

 minify.New()
dFunc("text/css", css.Minify)
dFunc("text/html", html.Minify)
dFunc("text/javascript", js.Minify)
dFunc("image/svg+xml", svg.Minify)
dFuncRegexp(regexp.MustCompile("[/+]json$"), json.Minify)
dFuncRegexp(regexp.MustCompile("[/+]xml$"), xml.Minify)

You can set options to several minifiers.

d("text/html", &html.Minifier{
KeepDefaultAttrVals: true,
KeepWhitespace: true,
From reader

Minify from an io.Reader to an io.Writer for a specific mediatype.

rr := m.Minify(mediatype, w, r); err != nil {
panic(err)
From bytes

Minify from and to a []byte for a specific mediatype.

rr = m.Bytes(mediatype, b)
rr != nil {
panic(err)
From string

Minify from and to a string for a specific mediatype.

rr = m.String(mediatype, s)
rr != nil {
panic(err)
From reader

Get a minifying reader for a specific mediatype.

= m.Reader(mediatype, r)
, err := mr.Read(b); err != nil {
panic(err)
From writer

Get a minifying writer for a specific mediatype. Must be explicitly closed because it uses an io.Pipe underneath.

= m.Writer(mediatype, w)
w.Write([]byte("input")); err != nil {
panic(err)

rr := mw.Close(); err != nil {
panic(err)
Custom minifier

Add a minifier for a specific mimetype.

 CustomMinifier struct {
KeepLineBreaks bool


 (c *CustomMinifier) Minify(m *minify.M, w io.Writer, r io.Reader, params map[string]string) error {
// ...
return nil


d(mimetype, &CustomMinifier{KeepLineBreaks: true})
r
dRegexp(regexp.MustCompile("/x-custom$"), &CustomMinifier{KeepLineBreaks: true})

Add a minify function for a specific mimetype.

dFunc(mimetype, func(m *minify.M, w io.Writer, r io.Reader, params map[string]string) error {
// ...
return nil

dFuncRegexp(regexp.MustCompile("/x-custom$"), func(m *minify.M, w io.Writer, r io.Reader, params map[string]string) error {
// ...
return nil

Add a command cmd with arguments args for a specific mimetype.

dCmd(mimetype, exec.Command(cmd, args...))
dCmdRegexp(regexp.MustCompile("/x-custom$"), exec.Command(cmd, args...))
Mediatypes

Using the params map[string]string argument one can pass parameters to the minifier such as seen in mediatypes (type/subtype; key1=val2; key2=val2). Examples are the encoding or charset of the data. Calling Minify will split the mimetype and parameters for the minifiers for you, but MinifyMimetype can be used if you already have them split up.

Minifiers can also be added using a regular expression. For example a minifier with image/.* will match any image mime.

Examples
Common minifiers

Basic example that minifies from stdin to stdout and loads the default HTML, CSS and JS minifiers. Optionally, one can enable java -jar build/compiler.jar to run for JS (for example the ClosureCompiler). Note that reading the file into a buffer first and writing to a pre-allocated buffer would be faster (but would disable streaming).

age main

rt (
"log"
"os"
"os/exec"

"github.com/tdewolff/minify"
"github.com/tdewolff/minify/css"
"github.com/tdewolff/minify/html"
"github.com/tdewolff/minify/js"
"github.com/tdewolff/minify/json"
"github.com/tdewolff/minify/svg"
"github.com/tdewolff/minify/xml"


 main() {
m := minify.New()
m.AddFunc("text/css", css.Minify)
m.AddFunc("text/html", html.Minify)
m.AddFunc("text/javascript", js.Minify)
m.AddFunc("image/svg+xml", svg.Minify)
m.AddFuncRegexp(regexp.MustCompile("[/+]json$"), json.Minify)
m.AddFuncRegexp(regexp.MustCompile("[/+]xml$"), xml.Minify)

// Or use the following for better minification of JS but lower speed:
// m.AddCmd("text/javascript", exec.Command("java", "-jar", "build/compiler.jar"))

if err := m.Minify("text/html", os.Stdout, os.Stdin); err != nil {
    panic(err)
}
Custom minifier

Custom minifier showing an example that implements the minifier function interface. Within a custom minifier, it is possible to call any minifier function (through m minify.Minifier) recursively when dealing with embedded resources.

age main

rt (
"bufio"
"fmt"
"io"
"log"
"strings"

"github.com/tdewolff/minify"


 main() {
m := minify.New()
m.AddFunc("text/plain", func(m *minify.M, w io.Writer, r io.Reader, _ map[string]string) error {
    // remove newlines and spaces
    rb := bufio.NewReader(r)
    for {
        line, err := rb.ReadString('\n')
        if err != nil && err != io.EOF {
            return err
        }
        if _, errws := io.WriteString(w, strings.Replace(line, " ", "", -1)); errws != nil {
            return errws
        }
        if err == io.EOF {
            break
        }
    }
    return nil
})

in := "Because my coffee was too cold, I heated it in the microwave."
out, err := m.String("text/plain", in)
if err != nil {
    panic(err)
}
fmt.Println(out)
// Output: Becausemycoffeewastoocold,Iheateditinthemicrowave.
ResponseWriter
Middleware 
 main() {
m := minify.New()
m.AddFunc("text/css", css.Minify)
m.AddFunc("text/html", html.Minify)
m.AddFunc("text/javascript", js.Minify)
m.AddFunc("image/svg+xml", svg.Minify)
m.AddFuncRegexp(regexp.MustCompile("[/+]json$"), json.Minify)
m.AddFuncRegexp(regexp.MustCompile("[/+]xml$"), xml.Minify)

http.Handle("/", m.Middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    http.ServeFile(w, r, path.Join("www", r.URL.Path))
})))
ResponseWriter 
 Serve(w http.ResponseWriter, r *http.Request) {
mw := m.ResponseWriter(w, r)
defer mw.Close()
w = mw

http.ServeFile(w, r, path.Join("www", r.URL.Path))
Custom response writer

ResponseWriter example which returns a ResponseWriter that minifies the content and then writes to the original ResponseWriter. Any write after applying this filter will be minified.

 MinifyResponseWriter struct {
http.ResponseWriter
io.WriteCloser


 (m MinifyResponseWriter) Write(b []byte) (int, error) {
return m.WriteCloser.Write(b)


inifyResponseWriter must be closed explicitly by calling site.
 MinifyFilter(mediatype string, res http.ResponseWriter) MinifyResponseWriter {
m := minify.New()
// add minfiers

mw := m.Writer(mediatype, res)
return MinifyResponseWriter{res, mw}


go
sage
(w http.ResponseWriter, req *http.Request) {
w = MinifyFilter("text/html", w)
if _, err := io.WriteString(w, "<p class="message"> This HTTP response will be minified. </p>"); err != nil {
    panic(err)
}
if err := w.Close(); err != nil {
    panic(err)
}
// Output: <p class=message>This HTTP response will be minified.
Templates

Here's an example of a replacement for template.ParseFiles from template/html, which automatically minifies each template before parsing it.

Be aware that minifying templates will work in most cases but not all. Because the HTML minifier only works for valid HTML5, your template must be valid HTML5 of itself. Template tags are parsed as regular text by the minifier.

 compileTemplates(filenames ...string) (*template.Template, error) {
m := minify.New()
m.AddFunc("text/html", html.Minify)

var tmpl *template.Template
for _, filename := range filenames {
    name := filepath.Base(filename)
    if tmpl == nil {
        tmpl = template.New(name)
    } else {
        tmpl = tmpl.New(name)
    }

    b, err := ioutil.ReadFile(filename)
    if err != nil {
        return nil, err
    }

    mb, err := m.Bytes("text/html", b)
    if err != nil {
        return nil, err
    }
    tmpl.Parse(string(mb))
}
return tmpl, nil

Example usage:

lates := template.MustCompile(compileTemplates("view.html", "home.html"))
License

Released under the MIT license.

This work is supported by the National Institutes of Health's National Center for Advancing Translational Sciences, Grant Number U24TR002306. This work is solely the responsibility of the creators and does not necessarily represent the official views of the National Institutes of Health.