vweb.assets: adds AssetManager for combining/minifying/caching css & js assets (#1452)

* start

* more work

* more

* more work

* update comments

* add back mut

* make minify faster

* add mut

* revert option size

* ret bool from public methods not ?bool for now

* update comments etc

* update comment

* dont return option for now

* clean up
pull/1454/head
joe-conigliaro 2019-08-03 20:09:09 +10:00 committed by GitHub
parent e446f988f7
commit 45e76609b0
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@ -0,0 +1,212 @@
module assets
// this module provides an AssetManager for combining
// and caching javascript & css.
import (
os
time
crypto.md5
)
const (
UnknownAssetTypeError = 'vweb.assets: unknown asset type'
)
struct AssetManager {
mut:
css []Asset
js []Asset
pub:
// when true assets will be minified
minify bool
// the directory to store the cached/combined files
cache_dir string
}
struct Asset {
file_path string
last_modified time.Time
}
// new_manager returns a new AssetManager
pub fn new_manager() *AssetManager {
return &AssetManager{}
}
// add_js adds a css asset
pub fn (am mut AssetManager) add_css(file string) bool {
return am.add('css', file)
}
// add_js adds a js asset
pub fn (am mut AssetManager) add_js(file string) bool {
return am.add('js', file)
}
// combine_css returns the combined css as a string when to_file is false
// when to_file is true it combines the css to disk and returns the path of the file
pub fn (am mut AssetManager) combine_css(to_file bool) string {
return am.combine('css', to_file)
}
// combine_js returns the combined js as a string when to_file is false
// when to_file is true it combines the css to disk and returns the path of the file
pub fn (am mut AssetManager) combine_js(to_file bool) string {
return am.combine('js', to_file)
}
// include_css returns the html <link> tag(s) for including the css files in a page.
// when combine is true the files are combined.
pub fn (am mut AssetManager) include_css(combine bool) string {
return am.include('css', combine)
}
// include_js returns the html <script> tag(s) for including the js files in a page.
// when combine is true the files are combined.
pub fn (am mut AssetManager) include_js(combine bool) string {
return am.include('js', combine)
}
fn (am mut AssetManager) combine(asset_type string, to_file bool) string {
if am.cache_dir == '' {
panic('vweb.assets: you must set a cache dir.')
}
cache_key := am.get_cache_key(asset_type)
out_file := '$am.cache_dir/${cache_key}.$asset_type'
mut out := ''
// use cache
if os.file_exists(out_file) {
cached := os.read_file(out_file) or {
return ''
}
out = cached
if !to_file {
return out
}
}
// rebuild
for asset in am.get_assets(asset_type) {
mut data := os.read_file(asset.file_path) or {
return ''
}
out += data
}
if am.minify {
if asset_type == 'css' {
out = minify_css(out)
} else {
out = minify_js(out)
}
}
if !to_file {
return out
}
if !os.dir_exists(am.cache_dir) {
os.mkdir(am.cache_dir)
}
file := os.create(out_file) or {
panic(err)
}
file.write(out)
file.close()
return out_file
}
fn (am mut AssetManager) get_cache_key(asset_type string) string {
mut files_salt := ''
mut latest_modified := 0
for asset in am.get_assets(asset_type) {
files_salt += asset.file_path
if asset.last_modified.uni > latest_modified {
latest_modified = asset.last_modified.uni
}
}
hash := md5.sum(files_salt.bytes()).hex()
return '$hash-$latest_modified'
}
fn (am mut AssetManager) include(asset_type string, combine bool) string {
assets := am.get_assets(asset_type)
mut out := ''
if asset_type == 'css' {
if combine {
file := am.combine(asset_type, true)
return '<link rel="stylesheet" href="$file">\n'
}
for asset in assets {
out += '<link rel="stylesheet" href="$asset.file_path">\n'
}
}
if asset_type == 'js' {
if combine {
file := am.combine(asset_type, true)
return '<script type="text/javascript" src="$file"></script>\n'
}
for asset in assets {
out += '<script type="text/javascript" src="$asset.file_path"></script>\n'
}
}
return out
}
// dont return option until size limit is removed
// fn (am mut AssetManager) add(asset_type, file string) ?bool {
fn (am mut AssetManager) add(asset_type, file string) bool {
if !os.file_exists(file) {
// return error('vweb.assets: cannot add asset $file, it does not exist.')
return false
}
asset := Asset{
file_path: file
last_modified: time.Time{uni: os.file_last_mod_unix(file)}
}
if asset_type == 'css' {
am.css << asset
} else if asset_type == 'js' {
am.js << asset
} else {
panic('$UnknownAssetTypeError ($asset_type).')
}
return true
}
fn (am mut AssetManager) exists(asset_type, file string) bool {
assets := am.get_assets(asset_type)
for asset in assets {
if asset.file_path == file {
return true
}
}
return false
}
fn (am mut AssetManager) get_assets(asset_type string) []Asset {
if asset_type != 'css' && asset_type != 'js' {
panic('$UnknownAssetTypeError ($asset_type).')
}
assets := if asset_type == 'css' {
am.css
} else {
am.js
}
return assets
}
// todo: implement proper minification
pub fn minify_css(css string) string {
mut lines := css.split('\n')
for i, _ in lines {
lines[i] = lines[i].trim_space()
}
return lines.join(' ')
}
// todo: implement proper minification
pub fn minify_js(js string) string {
mut lines := js.split('\n')
for i, _ in lines {
lines[i] = lines[i].trim_space()
}
return lines.join(' ')
}