/
engine.go
162 lines (149 loc) · 4.01 KB
/
engine.go
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package charts
import (
"bytes"
"html/template"
"io"
"math/rand"
"reflect"
"regexp"
"strconv"
"time"
tpls "github.com/go-echarts/go-echarts/templates"
)
const (
letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
letterIdxBits = 6 // 6 bits to represent a letter index
letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
chartIDSize = 12
)
// 渲染图表
func renderChart(chart interface{}, w io.Writer, name string) error {
contents := []string{tpls.HeaderTpl, tpls.RoutersTpl, tpls.BaseTpl}
switch name {
case "chart":
contents = append(contents, tpls.ChartTpl)
case "page":
contents = append(contents, tpls.PageTpl)
}
tpl := template.Must(template.New("").Parse(contents[0]))
mustTpl(tpl, contents[1:]...)
return tpl.ExecuteTemplate(w, name, chart)
}
func mustTpl(tpl *template.Template, html ...string) {
for i := 0; i < len(html); i++ {
tpl = template.Must(tpl.Parse(html[i]))
}
}
func renderToWriter(chart interface{}, renderName string, removeStr []string, w ...io.Writer) error {
var b bytes.Buffer
if err := renderChart(chart, &b, renderName); err != nil {
return err
}
res := replaceRender(b, removeStr...)
for i := 0; i < len(w); i++ {
_, err := w[i].Write(res)
if err != nil {
return err
}
}
return nil
}
var seed = rand.NewSource(time.Now().UnixNano())
// 生成唯一且随机的图表 ID
func genChartID() string {
b := make([]byte, chartIDSize)
for i, cache, remain := chartIDSize-1, seed.Int63(), letterIdxMax; i >= 0; {
if remain == 0 {
cache, remain = seed.Int63(), letterIdxMax
}
if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
b[i] = letterBytes[idx]
i--
}
cache >>= letterIdxBits
remain--
}
return string(b)
}
// 过滤替换渲染结果
func replaceRender(b bytes.Buffer, notReplace ...string) []byte {
// __x__ 与模板占位符相匹配
idPat, _ := regexp.Compile(`(__x__")|("__x__)`)
// 替换并转为 []byte 类型
content := idPat.ReplaceAllString(b.String(), "")
unusedObj := []string{
`geo: {},?`,
`"normal":{},?`,
`"textStyle":{},?`,
`"subtextStyle":{},?`,
`"inRange":{},?`,
`"label":{},?`,
`"markLine":{},?`,
`"markPoint":{},?`,
`"itemStyle":{},?`,
`"areaStyle":{},?`,
`"lineStyle":{},?`,
`"rippleEffect":{},?`,
`"splitArea":{},?`,
`"outline":{"show":false},?`,
`"waveAnimation":false,?`,
`"viewControl":{},?`,
`"force":{},?`,
}
unusedObj = removeNotReplace(unusedObj, notReplace...)
// 移除无用的 JSON object
// 另一种解决方案是使用 *struct
var unusedPat string
for i := 0; i < len(unusedObj); i++ {
unusedPat += unusedObj[i] + "|"
}
p, _ := regexp.Compile(unusedPat)
res := p.ReplaceAllString(content, "")
return []byte(res)
}
// 针对某些图表移除
func removeNotReplace(unusedObj []string, removeStr ...string) []string {
res := make([]string, 0)
for i := 0; i < len(unusedObj); i++ {
isRemove := false
for j := 0; j < len(removeStr); j++ {
if unusedObj[i] == removeStr[j] {
isRemove = true
break
}
}
if !isRemove {
res = append(res, unusedObj[i])
}
}
return res
}
// 为结构体设置默认值
// 部分代码参考 https://github.com/mcuadros/go-defaults
func setDefaultValue(ptr interface{}) {
elem := reflect.ValueOf(ptr).Elem()
t := elem.Type()
for i := 0; i < t.NumField(); i++ {
//如果没有 `default` tag 则不作处理
if defaultVal := t.Field(i).Tag.Get("default"); defaultVal != "" {
setField(elem.Field(i), defaultVal)
}
}
}
// 为具体字段设置默认值
func setField(field reflect.Value, defaultVal string) {
// 目前只判断 string, bool 两种变量类型
switch field.Kind() {
// string 类型
case reflect.String:
if field.String() == "" {
field.Set(reflect.ValueOf(defaultVal).Convert(field.Type()))
}
// bool 类型
case reflect.Bool:
if val, err := strconv.ParseBool(defaultVal); err == nil {
field.Set(reflect.ValueOf(val).Convert(field.Type()))
}
}
}