mirror of
https://github.com/caddyserver/caddy.git
synced 2024-12-23 22:27:38 -05:00
146 lines
3.4 KiB
Go
146 lines
3.4 KiB
Go
package templates
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import (
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"bytes"
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"fmt"
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"io"
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"net/http"
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"strconv"
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"strings"
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"github.com/caddyserver/caddy"
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"github.com/caddyserver/caddy/modules/caddyhttp"
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)
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func init() {
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caddy.RegisterModule(caddy.Module{
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Name: "http.middleware.templates",
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New: func() interface{} { return new(Templates) },
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})
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}
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// Templates is a middleware which execute response bodies as templates.
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type Templates struct {
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FileRoot string `json:"file_root,omitempty"`
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MIMETypes []string `json:"mime_types,omitempty"`
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Delimiters []string `json:"delimiters,omitempty"`
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}
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// Provision provisions t.
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func (t *Templates) Provision(ctx caddy.Context) error {
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if t.MIMETypes == nil {
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t.MIMETypes = defaultMIMETypes
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}
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return nil
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}
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// Validate ensures t has a valid configuration.
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func (t *Templates) Validate() error {
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if len(t.Delimiters) != 0 && len(t.Delimiters) != 2 {
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return fmt.Errorf("delimiters must consist of exactly two elements: opening and closing")
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}
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return nil
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}
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func (t *Templates) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
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buf := bufPool.Get().(*bytes.Buffer)
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buf.Reset()
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defer bufPool.Put(buf)
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// shouldBuf determines whether to execute templates on this response,
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// since generally we will not want to execute for images or CSS, etc.
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shouldBuf := func(status int) bool {
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ct := w.Header().Get("Content-Type")
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for _, mt := range t.MIMETypes {
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if strings.Contains(ct, mt) {
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return true
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}
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}
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return false
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}
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rec := caddyhttp.NewResponseRecorder(w, buf, shouldBuf)
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err := next.ServeHTTP(rec, r)
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if err != nil {
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return err
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}
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if !rec.Buffered() {
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return nil
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}
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err = t.executeTemplate(rec, r)
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if err != nil {
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return err
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}
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w.Header().Set("Content-Length", strconv.Itoa(buf.Len()))
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w.Header().Del("Accept-Ranges") // we don't know ranges for dynamically-created content
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w.Header().Del("Last-Modified") // useless for dynamic content since it's always changing
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// we don't know a way to guickly generate etag for dynamic content,
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// but we can convert this to a weak etag to kind of indicate that
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if etag := w.Header().Get("ETag"); etag != "" {
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w.Header().Set("ETag", "W/"+etag)
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}
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w.WriteHeader(rec.Status())
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io.Copy(w, buf)
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return nil
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}
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// executeTemplate executes the template contained in wb.buf and replaces it with the results.
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func (t *Templates) executeTemplate(rr caddyhttp.ResponseRecorder, r *http.Request) error {
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var fs http.FileSystem
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if t.FileRoot != "" {
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fs = http.Dir(t.FileRoot)
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}
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ctx := &templateContext{
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Root: fs,
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Req: r,
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RespHeader: tplWrappedHeader{rr.Header()},
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config: t,
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}
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err := ctx.executeTemplateInBuffer(r.URL.Path, rr.Buffer())
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if err != nil {
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return caddyhttp.Error(http.StatusInternalServerError, err)
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}
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return nil
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}
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// virtualResponseWriter is used in virtualized HTTP requests
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// that templates may execute.
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type virtualResponseWriter struct {
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status int
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header http.Header
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body *bytes.Buffer
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}
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func (vrw *virtualResponseWriter) Header() http.Header {
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return vrw.header
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}
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func (vrw *virtualResponseWriter) WriteHeader(statusCode int) {
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vrw.status = statusCode
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}
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func (vrw *virtualResponseWriter) Write(data []byte) (int, error) {
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return vrw.body.Write(data)
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}
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var defaultMIMETypes = []string{
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"text/html",
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"text/plain",
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"text/markdown",
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}
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// Interface guards
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var (
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_ caddy.Provisioner = (*Templates)(nil)
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_ caddy.Validator = (*Templates)(nil)
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_ caddyhttp.MiddlewareHandler = (*Templates)(nil)
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)
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