72 lines
1.8 KiB
Go
72 lines
1.8 KiB
Go
package alpsviewhtml
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import (
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"io"
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"mime"
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"net/http"
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"net/url"
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"strconv"
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"strings"
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"git.sr.ht/~emersion/alps"
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alpsbase "git.sr.ht/~emersion/alps/plugins/base"
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"github.com/labstack/echo/v4"
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)
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var (
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proxyEnabled = true
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proxyMaxSize = 5 * 1024 * 1024 // 5 MiB
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)
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func init() {
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p := alps.GoPlugin{Name: "viewhtml"}
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p.Inject("message.html", func(ctx *alps.Context, _data alps.RenderData) error {
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data := _data.(*alpsbase.MessageRenderData)
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data.Extra["RemoteResourcesAllowed"] = ctx.QueryParam("allow-remote-resources") == "1"
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hasRemoteResources := false
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if v := ctx.Get("viewhtml.hasRemoteResources"); v != nil {
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hasRemoteResources = v.(bool)
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}
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data.Extra["HasRemoteResources"] = hasRemoteResources
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return nil
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})
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p.GET("/proxy", func(ctx *alps.Context) error {
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if !proxyEnabled {
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return echo.NewHTTPError(http.StatusForbidden, "proxy disabled")
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}
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u, err := url.Parse(ctx.QueryParam("src"))
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if err != nil {
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return echo.NewHTTPError(http.StatusBadRequest, "invalid URL")
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}
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if u.Scheme != "https" {
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return echo.NewHTTPError(http.StatusBadRequest, "invalid scheme")
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}
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resp, err := http.Get(u.String())
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if err != nil {
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return err
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}
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defer resp.Body.Close()
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mediaType, _, err := mime.ParseMediaType(resp.Header.Get("Content-Type"))
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if err != nil || !strings.HasPrefix(mediaType, "image/") {
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return echo.NewHTTPError(http.StatusBadRequest, "invalid resource type")
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}
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size, err := strconv.Atoi(resp.Header.Get("Content-Length"))
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if err != nil || size > proxyMaxSize {
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return echo.NewHTTPError(http.StatusBadRequest, "invalid resource length")
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}
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ctx.Response().Header().Set("Content-Length", strconv.Itoa(size))
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lr := io.LimitedReader{resp.Body, int64(proxyMaxSize)}
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return ctx.Stream(http.StatusOK, mediaType, &lr)
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})
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alps.RegisterPluginLoader(p.Loader())
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}
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