88 lines
2.8 KiB
Go
88 lines
2.8 KiB
Go
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"github.com/hashworks/go-chart"
|
|
"log"
|
|
"net/http"
|
|
)
|
|
|
|
const style = "svg .background { fill: white; }" +
|
|
"svg .canvas { fill: white; }" +
|
|
"svg path.blue { fill: blue; stroke: lightblue; }" +
|
|
"svg path.green { fill: green; stroke: lightgreen; }" +
|
|
"svg path.gray { fill: gray; stroke: lightgray; }" +
|
|
"svg text.blue { fill: white; }" +
|
|
"svg text.green { fill: white; }" +
|
|
"svg text.gray { fill: white; }"
|
|
|
|
func svgWithCustomInlineCSS(res http.ResponseWriter, _ *http.Request) {
|
|
res.Header().Set("Content-Type", chart.ContentTypeSVG)
|
|
|
|
// Render the CSS with custom css
|
|
err := pieChart().Render(chart.SVGWithCSS(style, ""), res)
|
|
if err != nil {
|
|
fmt.Printf("Error rendering pie chart: %v\n", err)
|
|
}
|
|
}
|
|
|
|
func svgWithCustomInlineCSSNonce(res http.ResponseWriter, _ *http.Request) {
|
|
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src
|
|
// This should be randomly generated on every request!
|
|
const nonce = "RAND0MBASE64"
|
|
|
|
res.Header().Set("Content-Security-Policy", fmt.Sprintf("style-src 'nonce-%s'", nonce))
|
|
res.Header().Set("Content-Type", chart.ContentTypeSVG)
|
|
|
|
// Render the CSS with custom css and a nonce.
|
|
// Try changing the nonce to a different string - your browser should block the CSS.
|
|
err := pieChart().Render(chart.SVGWithCSS(style, nonce), res)
|
|
if err != nil {
|
|
fmt.Printf("Error rendering pie chart: %v\n", err)
|
|
}
|
|
}
|
|
|
|
func svgWithCustomExternalCSS(res http.ResponseWriter, _ *http.Request) {
|
|
// Add external CSS
|
|
res.Write([]byte(
|
|
`<?xml version="1.0" standalone="no"?>`+
|
|
`<?xml-stylesheet href="/main.css" type="text/css"?>`+
|
|
`<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">`))
|
|
|
|
res.Header().Set("Content-Type", chart.ContentTypeSVG)
|
|
err := pieChart().Render(chart.SVG, res)
|
|
if err != nil {
|
|
fmt.Printf("Error rendering pie chart: %v\n", err)
|
|
}
|
|
}
|
|
|
|
func pieChart() chart.PieChart {
|
|
return chart.PieChart{
|
|
// Note that setting ClassName will cause all other inline styles to be dropped!
|
|
Background: chart.Style{ClassName: "background"},
|
|
Canvas: chart.Style{
|
|
ClassName: "canvas",
|
|
},
|
|
Width: 512,
|
|
Height: 512,
|
|
Values: []chart.Value{
|
|
{Value: 5, Label: "Blue", Style: chart.Style{ClassName: "blue"}},
|
|
{Value: 5, Label: "Green", Style: chart.Style{ClassName: "green"}},
|
|
{Value: 4, Label: "Gray", Style: chart.Style{ClassName: "gray"}},
|
|
},
|
|
}
|
|
}
|
|
|
|
func css(res http.ResponseWriter, req *http.Request) {
|
|
res.Header().Set("Content-Type", "text/css")
|
|
res.Write([]byte(style))
|
|
}
|
|
|
|
func main() {
|
|
http.HandleFunc("/", svgWithCustomInlineCSS)
|
|
http.HandleFunc("/nonce", svgWithCustomInlineCSSNonce)
|
|
http.HandleFunc("/external", svgWithCustomExternalCSS)
|
|
http.HandleFunc("/main.css", css)
|
|
log.Fatal(http.ListenAndServe(":8080", nil))
|
|
}
|